Kinetics of Quality Change of Carotenoids-rich Fat Powder Made From Red Palm Oil
KINETICS OF QUALITY CHANGE OF CAROTENOIDSRICH FAT POWDER MADE FROM RED PALM OIL
ARINTIARA RAMADHYASTASARI
DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY
FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015
STATEMENT LETTER OF MANUSCRIPT AND SOURCES OF
INFORMATION*
I hereby genuinely state that the manuscript entitled Kinetics of Quality
Change of Carotenoids-rich Fat Powder Made From Red Palm Oil is an
authentic work of mine under supervision of academic counselor and never
presented in any forms and university. All the information taken and quoted from
published or unpublished works of the writer has been mentioned in the text and
attached in the bibliography at the end of this manuscript.
I hereby release the copyright of my manuscript to the Bogor Agricultural
University.
Bogor, February 2015
Arintiara Ramadhyastasari
NIM F24100105
ABSTRACT
ARINTIARA RAMADHYASTASARI. Kinetics of Quality Change of
Carotenoids-rich Fat Powder Made From Red Palm Oil. Supervised by
PURWIYATNO HARIYADI.
Vitamin A Deficiency (VAD) has been a serious problem in Indonesia and
the underlying cause is a diet which is insufficient in vitamin A. Food fortification
is one of the strategy that can be implemented in Indonesia to reduce the burden of
VAD and to improve vitamin A intake. Red palm oil, Indonesia’s abundant
natural resource rich in carotenoids, is very potential to be used as food fortificant.
Red palm oil can be used by direct addition to food product or by transforming it
into carotenoids-rich fat powder before use. This study was to investigate the
kinetics of quality changes of carotenoids-rich fat powder during storage and to
determine the product shelf life, using Arrhenius accelerated method. Samples of
fat powder were stored at 26C (ambient/room temperature) and at elevated
temperatures of 35C, 40C, and 55C for 30 days, and samples were taken and
analyzed every 5 days. As a reference, samples of fat powder were also stored at
refrigeration of 12C. The results showed that fat powder underwent (i) some
color changes, (ii) increase in free fatty acid and peroxide value, and (iii) decrease
in carotene content and powder flowability. With carotene tolerance 50% of initial
carotene, carotenoids-rich fat powder can be stored for 3 months and 11 days at
ambient/room temperature with light protection.
Keywords : Fat powder, Red Palm Oil, Palm Stearin, Spray chilling, Arrhenius
accelerated method
KINETICS OF QUALITY CHANGE OF CAROTENOIDSRICH FAT POWDER MADE FROM RED PALM OIL
ARINTIARA RAMADHYASTASARI
Manuscript
submitted as a partial fulfillment of the requirement for degree of
Bachelor in Agricultural Technology
at the Department of Food Science and Technology
DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY
FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015
PREFACE
Praise to Allah SWT for the mercy, the guidance, and the graciousness
throughout the research and manuscript completion. By completion of this
research and manuscript, the author would like to express great and sincere thanks
and appreciation to:
1. Beloved Bapak, Ibu, and Dhito for their endless support, love, care, and pray
2. Prof. Purwiyatno Hariyadi, as the academic advisor, for his enormous help
academically throughtout the completion of the manuscript
3. Dr. Ir. Feri Kusnandar, M.Sc and Dr. Edi Puspo Giriwono, M.Agr as
examiners, for their valuable advice and knowledge which has been given
during the manuscript defence
4. SEAFAST Center IPB for full financial support during research
5. Teh Ria N., Mas Arif, Mbak Ria C., Mas Agus, Teh Asih, Mbak Lyra, Pak
Abah, Mbak Ulfa, Bu Antin, and Pak Rojak for their help during research in
laboratory
6. All of the lecturers and staffs in Department of Food Science and Technology
for their time to help
7. Furry, Stephanie, Aby, Maria, As’ad, Anjani, Zeviara, Nurul, Fanny, Farisa,
Andra, Aghit, and all of the ITP 47 family for the togetherness, pray, support,
help, spirit, and laugh during good times and bad times
8. The 21st Tri-University Indonesia Delegation (Gideon, Mutiara, Muhana, Febri,
Raditya, Fadila, Mada, Bang Ihsan, Rumondang, Novi, and Fika) and the
supervisors (Dra. Alfa Chasanah, MA, Ir. Sri Endah Agustina, MS, Dr. Sintho
Wahyuning Ardie, SP, M.Si, and Dr. Rinekso Soekmadi, MSc. F.Trop) for the
inspiration, spirit, advices, support and wonderful memories during the
preparation and during the event in Thailand.
Last but not least, hopefully this manuscript will be useful for the readers
and give a real contribution in food science and technology development in
Indonesia.
Bogor, February 2015
Arintiara Ramadhyastasari
TABLE OF CONTENT
LIST OF TABLES
vi
LIST OF FIGURES
vi
INTRODUCTION
1
Background
1
Objective
1
RESEARCH METHODOLOGY
2
Materials
2
Instruments
2
Method
2
Method of analysis
3
RESULTS AND DISCUSSION
5
Ingredient characterization
5
Carotene content changes
6
Peroxide value changes
9
Free fatty acid changes
11
Angle of repose changes
15
Color changes
17
Shelf life determination of carotenoids-rich fat powder
24
CONCLUSIONS AND SUGGESTIONS
25
Conclusions
25
Suggestions
25
REFERENCES
26
AUTHOR BIOGRAPHY
28
LIST OF TABLES
1 Ingredients characterization
2 Reaction order of carotene degradation in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
3 Activation energy of carotene degradation in carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
4 Reaction order of peroxide value increase in carotenoids-rich fat
powder during storage at temperatures of 26C (ambient/room
temperature), 35C, 40C, and 55C
5 Activation energy of peroxide value increase in carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
6 Reaction order of the increase in free fatty acid percentage of
carotenoids-rich fat powder during storage at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
7 Activation energy of the increase in free fatty acid percentage of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
8 Reaction order of the increase in angle of repose of carotenoids-rich fat
powder during storage at temperatures of 26C (ambient/room
temperature), 35C, 40C, and 55C
9 Activation energy of the increase in angle of repose of carotenoids-rich
fat powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
10 Reaction order of L* value decrease in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
11 Activation energy of the decrease in L* value of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
12 Reaction order of (-a*) value increase in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
13 Activation energy of the increase in (-a*) value of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
14 Reaction order of b* value decrease in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
15 Activation energy of the decrease in b* value of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
5
8
9
10
11
13
14
16
17
19
20
21
22
23
24
16 Activation energy of the five quality parameters of carotenoids-rich fat
powder
24
LIST OF FIGURES
1 Research flow chart
2 Carotene degradation in carotenoids-rich fat powder during storage at
temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
3 Change in carotene degradation rate constant of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
4 The increase in peroxide value of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
5 Change in reaction rate constant of peroxide value increase in
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
6 The increase in free fatty acid percentage of carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
7 Change in reaction rate constant of the increase in free fatty acid
percentage of carotenoids-rich fat powder stored at temperatures of
26C (ambient/room temperature), 35C, 40C, and 55C
8 The increase in angle of repose of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
9 Change in reaction rate constant of the increase in angle of repose of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
10 The decrease in L* value of carotenoids-rich fat powder during storage
at temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
11 Change in reaction rate constant of the decrease in L* value of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
12 The increase in (-a*) value of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
13 Change in reaction rate constant of the increase in (-a*) value of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
14 The decrease in b* value of carotenoids-rich fat powder during storage
at temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
2
7
8
10
11
13
14
16
17
18
19
20
21
22
15 Change in reaction rate constant of the decreases in b* value of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
23
INTRODUCTION
Background
Vitamin A Deficiency (VAD) has been a serious problem in Indonesia. In
2002, West estimated that among 22 million Indonesian preschool-aged children,
there were 12.6 million that affected with low serum retinol concentration and 75
thousand others affected with xerophthalmia. The main underlying cause of
vitamin A deficiency is insufficient vitamin A content in the diet that can lead to
lower body stores and fail to meet the physiologic needs. As the result, it can
leads to disorders such as xerophthalmia, the leading cause of preventable
childhood blindness and anemia. Besides, xerophthalmia can also weaken host
resistance to infection which increase the severity of infectious disease and risk of
death (WHO 2009). To reduce the burden of VAD and to improve vitamin A
intake, there are three overlapping and complementary approaches, according to
Burns and Rice (2010), which are food fortification, supplementation, and dietary
diversification strategies. Food fortification strategy can be implemented in
Indonesia by utilizing red palm oil as Indonesia’s highly available natural resource
rich in carotenoids. Red palm oil can be used by directly added to food product or
by transforming it into carotenoids-rich fat powder before use.
Fat powder is fat or oil specialty product that was developed to facilitate a
wide range of food process, such as mixing, melting, storage, and so on.
Compared with solid fat, fat powder is easier to handle and can increase fat
distribution in the dough thus improving product’s texture, mouth-feel, and
creaminess. It can be made from a variety of raw materials, including red palm oil.
Red palm oil is known for its high content of carotenoids because during
manufacturing process, this product is not subjected to heating at high temperature
and bleaching process. Crude palm oil is reported to contain 642 ppm of
carotenoids (Insani 2011) meanwhile red palm oil and red palm stearin has 533
ppm (Muchtaridi and Justina 2006) and 359 ppm (Anriansyah 2013) of
carotenoids respectively.
Carotenoids serve as a pro-vitamin A in human body which contributes to
prevention of blindness and improvement of body immunity. Among all the
carotenoids, -carotene has the highest vitamin A activity therefore it is
commonly used as the source of vitamin A (Novia 2009). Consequently, red palm
oil may be used as an ingredient to help reduce vitamin A deficiency problem in
Indonesia. Red palm oil is used as palm stearin. The utilization of palm stearin as
the raw material of carotenoids-rich fat powder is considered very profitable
because it can increase the economic and added value of palm stearin. In food
industry, palm stearin is used as ingredients in a wide range of food products,
including shortening, pastry and bakery margarine, and confectionery. The
procedure to produce carotenoids-rich fat powder has been developed. However,
the quality deterioration kinetics during storage of the fat powder is not yet known.
Objective
The objectives of this research are to investigate the kinetics of quality
changes of carotenoids-rich fat powder during storage and to determine products
shelf life, using Arrhenius accelerated method.
2
RESEARCH METHODOLOGY
Materials
The ingredients used in the making of carotenoids-rich fat powder are
neutralized deodorized red palm stearin (NDRPS) and fully hydrogenated palm oil
(FHPO).
Chemical reagent used in this research are sodium thiosulphate 0.1 N,
sodium hydroxide 0.1 N, hexane, aquades, acetic acid, chloroform, distilled water,
ethanol 95%, phenoftalein, starch solution 1%, and crystal potassium iodide.
Instruments
Instruments used in this research are spray chiller Armfield FT80 Tall Form,
heater, thermometer, magnetic stirrer, analytical balance, spectrophotometer
Shimadzu UV2450, Chroma-meter CR300, glassware, polypropylene (PP) plastic
packaging, aluminum foil, incubator 350C, 400C, and 550C, refrigerator,
flowability-meter, ruler, and pipette.
Method
This research, broadly, consisted of four stages, which are ingredients
characterization, carotenoids-rich fat powder production, thermal treatment on
carotenoids-rich fat powder, and data analysis to obtain kinetic model. Flow chart
of the research can be seen in Figure 1.
Ingredients
characterization
Carotenids-rich fat
powder production
Thermal oxidation
treatment on carotenoidsrich fat powder
Kinetic data analysis
Figure 1. Research flow chart
Ingredients characterization
The carotene content, peroxide value, and free fatty acid of neutralized
deodorized red palm stearin and fully hydrogenated palm oil were analyzed to
find out the characteristics of the raw materials used.
3
Carotenoids-rich fat powder production
Carotenoids-rich fat powder was made using spray chiller with the operation
status as follows, spray heater temperature 80C, feed heater temperature 80C,
chiller temperature 14C, inlet temperature 18-19C, exhaust temperature 2930C, feed pump 15.0 Hz, air pressure 0.6 bar, and feed pressure 0.62+0.01 bar.
This settings are based on the research by Anriansyah (2013) with modification.
Both ingredients, NDRPS and FHPO, must be heated at 50-60C until it melts
perfectly before put into the spray chiller. Ingredients ratio used are 80% for
FHPO and 20% for NDRPS.
Thermal oxidation treatment of carotenoids-rich fat powder
Sample of carotenoids-rich fat powder was packed with polypropylene (PP)
plastic packaging, covered with aluminium foil and stored at 26C (ambient/room
temperature) and at elevated temperatures of 35C, 40C, and 55C for 30 days.
As a reference, samples of fat powder were also stored at refrigeration
temperature of 12C. During storaging, free fatty acid, peroxide value, color, and
flowability (angle of repose) analysis of fat powder were done every 5 days, and
carotene content analysis were done every 10 days. Sampling and analysis were
conducted three times.
Kinetic data analysis
Model of changes in quality deterioration parameters, such as carotene
content, peroxide value, free fatty acid content, flowability, and color were
analyzed using Arrhenius equation using Microsoft Excel 2013 software. The data
of changes in fat powder quality deterioration parameters acquired were processed
first to determine the most suitable reaction order, as indicated by the highest
linearity value (R2), and to get the reaction rate constants value at five storage
temperatures of the selected reaction order. The entire rate constants value of five
storage temperatures then processed to obtain an Arrhenius equation that will be
used to generate the activation energy.
Method of Analysis
Carotene content analysis (PORIM 1995)
Zero point one gram of carotenoids-rich fat powder were accurately
weighed in a 25 mL flask. After that, 25 mL of hexane was added to the flask and
then mixed until the entire sample completely dissolved and its absorbance value
was measured using spectrophotometer at the wave length of 446 nm. Carotene
content was calculated using the following formula
4
Determination of peroxide value with titrimetric method (AOCS Ca 8b-90
2012)
Five gram of oil sample were weighed inside the 250 mL Erlenmeyer flask
then it is added with 30 mL of acetic acid-chloroform (3:2), shaken until it
dissolved, later added with 0.5 mL of saturated KI and shaken for 2 minutes. After
that, it was immediately added to 30 mL of distilled water and shortly before the
titration, it is added with 2 mL of starch indicator and titrated with Na2S2O3 0.1 N
until the blue color disappeared.
Free fatty acid analysis (AOCS Ca 5a-40 2012; with modification)
Five grams of fat powder were weighed inside the 250 mL Erlenmeyer flask
and then it heated until perfectly melted. After that, the molten sample was added
with 50 mL neutral ethanol 95% and three drops of phenoftalein indicator. The
sample was shaken until homogenous and then titrated using sodium hydroxide
0.1 N until it became permanently pink for 30 seconds.
Flowability analysis (Geldart et al. 2006)
Flowability of carotenoids-rich fat powder can be detemined based on the
value of angle of repose (AORs) using a funnel. Funnel used has a diameter of 20
mm which makes an angle of 65 with the horizontal plane and the end of the
funnel is at a height of 9 cm above the bottom horizontal plane. Approximately
100 grams of carotenoids-rich fat powder was passed through the funnel and then
the diameter and height of formed pile was measured. After that, the angle of
repose of carotenoids-rich fat powder was calculated using the following formula
Ø = arctg
where h is the height of the pile and D is the diameter of the funnel.
Color analysis with Chromameter (Hutching 1999)
Color measurement was carried out using Chromameter CR300. Number of
samples were placed in a glass container and Chromameter measured the color of
the samples by firing a beam on the sample, then the measurement results came
out in the form of L*a*b* scale. Value of L* indicates the brightness (0 =
black/dark, 100 = white/bright), while value of a* indicates red color (a+ = red, a= green) and value of b* indicates yellow color (b+ = yellow, b- = blue).
Kinetic data analysis
Kinetics of quality changes during storage were analyzed using zero and/or
first order reaction to determine the respective constant rate of change (k).
Activation energy analysis was then done to determine the sensitivity of constant
rate of change (k) in product quality with increasing storage temperature. Quality
parameter with highest activation energy was used as the critical quality parameter
to predict product’s shelf life.
Activation energies of the quality parameters were generated by calcuting
the collected data into Arrhenius equation using Microsoft Excel 2013 software.
5
Generated Arrhenius equation then used to obtain activation energy of the quality
parameter changes.
RESULTS AND DISCUSSION
Ingredients characterization
Carotenoids-rich fat powder was made from a mix of palm stearin and fully
hydrogenated palm oil (FHPO). Palm stearin used here was neutralized
deodorized palm stearin (NDRPS) which was not subjected to bleaching process
so its carotene content remains high. The results of ingredients character step
shows that neutralized deodorized palm stearin contains 346.8 ppm of carotene
meanwhile fully hydrogenated palm oil only contains 2.9 ppm of carotene (Table
1). This data shows that the carotene contained in the carotenoids-rich fat powder
is mainly derived from neutralized deodorized palm stearin.
Table 1. Ingredients characterization
Neutralized deodorized red
Parameters
palm stearin
(NDRPS)
Carotene
346.8
content (ppm)
Peroxide value
2.5
(meq O2/kg)
Free fatty acid
0.1
(%)
Fully hydrogenated
palm oil
(FHPO)
2.9
3.9
1.9
Table 1 shows that red palm stearin has lower peroxide value than FHPO.
Red palm stearin has 2.5 meq O2/kg peroxide value, while FHPO has 3.9 meq
O2/kg peroxide. Both ingredients are classified as low oxidized state because their
peroxide value are between 1 and 5 meq O2/kg, according to Moigradean et al
(2012), and they also comply with the established standard because they have
lower peroxide value than the maximum limit of refined palm stearin peroxide
value, according to Draft East African Standard (2012), which is 10 meq O2/kg.
DEAS also established the maximum limit of free fatty acid as palmitic acid in
refined stearin, which is 0.25% (DEAS 2012). From the data in Table 1, it is
known that red palm stearin used in this research has lower free fatty acid content
than the standard (0.1 %) meanwhile FHPO used has higher free fatty acid content
than the standard (1.9 %).
These two ingredients are mixed until homogenous and sprayed to powder
form using spray chiller. Carotenoids-rich fat powder generated was stored at five
different temperatures, for 30 days, which will show different changes in its
quality. The observed quality parameters were carotene content, peroxide value,
free fatty acid content, flowability, and color.
6
Carotene content changes1
Red palm oil is the richest naturally occuring source of carotenoid and
generally contains 200-800 mg of provitamin A carotenoids per kg oil which is 15
times higher than the carotenoid content of carrots on weight-by-weight basis.
These carotenoids are easily absorbed because they are already dissolved in oil
(Rice and Burns 2010). Therefore, the utilization of red palm stearin, solid
fraction of red palm oil, as food fortificant by converting it into carotenoids-rich
fat powder is one potential way to overcome the vitamin A deficiency problem in
Indonesia. Carotene, especially -carotene, is used as the source of vitamin A in
human body which prevents blindness and improves body immunity. Betacarotene has a hundred percent pro-vitamin A activity in trans-isomer form but it
can be easily degraded by the presence of oxygen, heat, light, metal, and other
oxidative substances (Wulan 2013). The main factor that affects carotenoid
content during the food processing and storage is oxidation by atmospheric
oxygen and structural changes by heat. To see the effect of temperature on the
carotene content in carotenoids-rich fat powder, carotenoids-rich fat powder was
stored at four different storage temperatures.
Carotene content of carotenoids-rich fat powder continues to decrease with
the length of storage time (Appendix 1). The decrease in carotene content of
carotenoids-rich fat powder can be seen in Figure 2. Storage at temperatures of
26C, 35C, 40C, and 55C shows that carotenoids-rich fat powder have 0.24
ppm/day, 0.48 ppm/day, 1.11 ppm/day, and 1.58 ppm/day reaction rate constant,
respectively (Table 2). Based on the reaction rate law, the bigger the value of
reaction rate constant, the faster the reaction takes place, thus storage temperature
of 55C has the greatest carotene degradation rate followed by storage
temperatures of 40C, 35C, and 26C. Wulan (2013) explained that chemical
reation rate is affected by the amount of the reactant concentration used in the
reaction and also by the value of reaction rate constant (k). Reaction rate constant
is the comparation between reaction rate and reactant concentration. It is an
absolute value of the slope of the graph between concentration and time which
used after get the chosen reaction order. The value of k will be greater if the
reaction is rapid though it occurs with a small amount of reactant concentrations.
1
This part of manuscript has been presented in The 21st Tri-University International Joint
Seminar and Symposium (2014 November 2-7), Chiang-Mai, Thailand.
7
70
60
y = -0.2419x
R² = 0.9695
Carotene content
(ppm)
50
40
y = -1.1105x
R² = 0.9548
30
y = -0.4773x
R² = 0.9500
20
y = -1.5780x
R² = 0.9590
10
0
0
5
10
Room
15
20
Storage time (day)
35
40
25
30
35
55
Figure 2. Carotene degradation in carotenoids-rich fat powder during storage at
temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
Carotene has double bonds which make it sensitive to oxidation accelerated
by heat or high temperature. Heating up to 60C resulted in isomeric changes
from trans-isomer to cis-isomer which has a lower pro-vitamin A activity
compared with trans-isomer form (Novia 2009). Carotene oxidation is also
triggered by hydroperoxide generated from lipid oxidation (Insani 2011). This was
also explained by Novia (2009) that lipid oxidation reaction causes the increase of
carotene oxidation so that the -ionone ring at the end of carotene molecule is
open which then cause the decrease of carotene activity.
Carotene degradation in carotenoids-rich fat powder stored at four different
temperatures follows the zero-order reaction which means this reaction does not
depend on the reactant concentration (Muchtaridi and Justina 2006). It is similar
to the study done by Novia (2009) in investigating the stability of thin layer
drying microencapsulated red palm oil during storage. Carotene degradation
reaction order was generated by calculating the greatest linearity (R2) value of
correlation of storage time (in days) and carotene content (in ppm), as shown on
Table 2. Reaction order is required to choose the chart in the determination of
reaction rate constants.
8
Table 2. Reaction order of carotene degradation in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature
(C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
-0.2419
0.9695
-0.4773
0.9500
-1.1105
0.9548
-1.5780
0.9590
-0.0046
0.9657
-0.0095
0.9555
-0.0250
0.9223
-0.0488
0.9980
The rate of carotene degradation rises with the storage temperature.
Temperature is one of the factor that affect the reaction rate and the temperature
increase generally will lead to a faster reaction rate due to the increasing number
of collisions between molecules, as well as the average kinetics energy of
molecules (Wulan 2013). The study done by Novia (2009) on microencapsulated
red palm oil stored at temperature of 35C, 45C, and 55C for 30 days also
shows a decrease in carotene content, from 248 ppm to 133 ppm for the red palm
oil microencapsulate stored at temperature of 55C.
Ln Reaction Rate Constant
(ppm/day)
Carotene degradation rate constant obtained then converted into the natural
numbers of logarithm (ln k) and plotted with the inverse of temperature, in Kelvin,
(Figure 3) to get the Arrhenius equation. Arrhenius equation can be used to study
the relation between temperature, reaction rate constant, and activation energy
(Ea).
1.0
0.5
0.0
-0.5
-1.0
y = -6,466.7419x + 20.3505
R² = 0.8912
-1.5
-2.0
0.0030
0.0031
0.0031
0.0032
0.0032 0.0033
1/T (K)
0.0033
0.0034
0.0034
Figure 3. Change in carotene degradation rate constant of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Activation energy is the minimum amount of energy needed for a chemical
reaction may take place. Its value can be known after the value of slope of graph
9
has been obtained. The Arrhenius equation generated from Figure 2 (Eq.(1))
shows the carotene degradation of carotenoids-rich fat powder has 53,764.49
J/mole activation energy, as also shown by Table 3. This value is 2 times much
higher than the activation energy of carotene degradation of red palm oil
microencapsulate from study conducted by Novia in 2009, which is 19,995.17
J/mole. A higher activation energy indicates that carotene degradation of
carotenoids-rich fat powder is more sensitive to temperature increases during
storage compared with carotene degradation of red palm oil microencapsulate.
Ln KT = 20.3505 – 6466.7419(1/T)
(1)
Table 3. Activation energy of carotene degradation in carotenoids-rich fat powder
stored at temperatures of 26C (ambient/room temperature), 35C, 40C,
and 55C
Temperature (C)
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
Accelerated
storage test
-6466.7419
8.314
53,764.49
Peroxide value changes
Peroxide value is one of the important parameter in determining degree of
fat or oil damage. Peroxide is a chemical substance that can accelerate oxidation,
in other words it is an oxidizing agent. During thermal oxidation, peroxide value
increases due to lipid oxidation triggered by heating which resulting in the
formation of a number of peroxide. According to Ketaren (2005), unsaturated
fatty acid can binds oxygen to its double bond and forms peroxide. Oxidation
takes place if there is contact between a number of oxygen and fat or oil which
usually begins with the formation of peroxide and hydro-peroxide. On the next
stages, fatty acid decomposes and it is followed by the changes in hydro-peroxide
to aldehydes and ketones, as well as free fatty acids (Ketaren 2005). This
oxidation reaction will lead to rancidity in fat or oil which formed due to the
presence of aldehydes. Thus, the increase of peroxide value is only an indicator
and a warning that the fat or oil will soon smell rancid (Novia 2009).
Storage of carotenoids-rich fat powder at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C causes an increase in peroxide
value of the fat powder (Figure 4). This result is similar to study done by Novia
(2009) about stability of microencapsulated red palm oil during storage and study
conducted by Zungur et al (2014) about storage stability of microencapsulated
extra virgin olive oil powder. An increase in peroxide value also happened in the
research done by Moigradean et al (2012) in investigating the oxidative stability
of coconut oil during 18 months of storage. However, this increase occured only
in the first 9 months of storage. In the next 9 months of storage, coconut oil
peroxide value decreases due to the formation of secondary oxidation products.
10
2.60
y = 0.0215x
R² = 0.4604
Ln Peroxide Value (meq O2/kg)
2.50
2.40
y = 0.0119x
R² = 0.9365
2.30
2.20
y = 0.0091x
R² = 0.8469
2.10
y = 0.0072x
R² = 0.9483
2.00
1.90
1.80
1.70
0
5
10
15
20
Storage time (day)
Room
35
40
25
30
35
55
Figure 4. The increase in peroxide value of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
Peroxide value of carotenoids-rich fat powder steadily increase with the
length of storage time (Appendix 2) and the rate of the increase in peroxide value
is increasing as the storage temperature increases. Fat powder stored at
temperatures of 26C and 35C have 0.007/day and 0.009/day reaction rate
constant respectively while fat powder stored at 40C, and 55C have 0.011/day
and 0.021/day reaction rate constant respectively (Table 4).
Table 4. Reaction order of peroxide value increase in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
0.0279
0.5483
0.0502
0.1988
0.0852
0.8059
-0.1127
0.9508
0.0072
0.9483
0.0091
0.8469
0.0119
0.9365
0.0215
0.4604
11
The rate of peroxide value increase in carotenoids-rich fat powder during
storage at four different temperatures follows first-order reaction and it is similar
to the increase in peroxide value of microencapsulated olive oil from study done
by Zungur et al 2014 which also follow first-order reaction. All the obtained
reaction rate constants then converted into natural numbers of logarithm (ln k) and
plotted with the inverse of temperatures in Kelvin degree (Figure 5).
Ln Reaction Rate Constant (/day)
0.00
-1.00
-2.00
-3.00
y = -3,790.2293x + 7.6858
R² = 0.9843
-4.00
-5.00
-6.00
0.003
0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 0.0034
1/T (K)
Figure 5. Change in reaction rate constant of peroxide value increase in
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
Arrhenius equation of peroxide value increase in carotenoids-rich fat
powder generated from Figure 4 (Eq. (2)) is used to determine the activation
energy of the increase in peroxide value during storage. Table 5 shows that this
reaction has 31,511.97 J/mole activation energy. The increase in peoxide value of
carotenoids-rich fat powder has lower activation energy compared with peroxide
value increase in olive oil triacylglycerols, which has 32,100.00 J/mole activation
energy (Gomez-Alonso et al 2004). A lower activation energy indicates that
peroxide value increase in carotenoids-rich fat powder is less sensitive to
temperature increase than peroxide value increase in olive oil triacylglycerols.
Ln KT = 7.6858 – 3790.2293(1/T)
(2)
Table 5. Activation energy of peroxide value increase in carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature
(C)
Accelerated
storage test
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
-3790.2293
8.314
31,511.97
12
Free fatty acid changes
Free fatty acid is the result of the termination of the ester bond between the
fatty acid and glycerol (Wulan 2013). The acid value indicates the amount of free
fatty acids contained in fat or oil which derived from the hydrolysis of fats or due
to unfavorable processing (Novia 2009) and this reaction can be accelerated by
the presence of water, heat, and enzyme catalysts. Ketaren (2005) explained that a
high acid value indicates a high free fatty acid content, the higher the acid value,
the lower the quality of fats or oils. Increase in free fatty acids may occur during
processing and storaging of palm oil due to autocatalytic hydrolysis and also due
to the activity of microorganisms because of the production process which is not
clean. This increase may then facilitate a serial oxidation process and facilitate the
formation of peroxide compounds, aldehydes, and ketones which will then lead to
the formation of rancidity, oil browning, and even could cause poisoning (Ketaren
2008). Measurement of free fatty acid value in carotenoids-rich fat powder made
from red palm oil is calculated in the form of palmitic acid as the predominant
fatty acid in the product. Changes in free fatty acid percentage of carotenoids-rich
fat powder during storage at five different temperatures were observed to see the
properties of the hydrolysis reactions occured in fat powder.
Free fatty acid percentage of carotenoids-rich fat powder stored at
temperatures of 26C (ambient/room temperature), 35C, 40C, and 55C
constantly increase with the length of storage time (Appendix 3) and the increase
occurs more rapidly with the increasing storage temperature. As shown by Figure
6, carotenoids-rich fat powder stored at temperature of 55C has 0.0211/day
reaction rate constant while carotenoids-rich fat powder stored at temperature of
40C, 35C, and 26C only have 0.0174/day, 0.0164/day, and 0.0153/day,
respectively. It shows that carotenoids-rich fat powder stored at temperature of
55C has the fastest increase in free fatty acid percentage. There are other studies
that also discovered that the free fatty acid percentage will increase with
increasing in storage temperature. Ayustaningwarno (2010) found that the
reaction rate of free fatty acid formation in red palm oil has increased as much as
three times from palm oil stored at temperature of 60C to red palm oil stored at
temperature of 90C. A year later, Tadakittisarn et al (2011) also found that the
storage of Jatropha curcas oil at temperature of 50C caused the formation of a
high free fatty acid content compared to those which stored at temperature of
37C.
13
0.6
y = 0.0211x
R² = 0.8419
y = 0.0174x
R² = 0.8008
0.4
Ln FFA (%)
0.2
y = 0.0164x
R² = 0.8063
0.0
y = 0.0153x
R² = 0.8298
-0.2
-0.4
-0.6 0
5
10
15
20
Storage periode (day)
Room
35
40
25
30
35
55
Figure 6. The increase in free fatty acid percentage of carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Reaction order is required to select the reaction rate constant determining
chart which obtained by calculating the highest linearity (R2) on a graph of the
relation between time and concentration. Based on the calculation of the reaction
order in Table 6, it is known that the increase in free fatty acid of carotenoids-rich
fat powder follows the first-order reaction meaning that the rate of the increase in
free fatty acid percentage of carotenoids-rich fat powder is affected by the
changes in reactant concentration. This result is different from the increase in free
fatty acid percentage of red palm oil during storage, which has zero-order reaction
(Ayustaningwarno 2010).
Table 6. Reaction order of the increase in free fatty acid percentage of
carotenoids-rich fat powder during storage at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
0.0125
0.7812
0.0137
0.7563
0.0148
0.7511
0.0189
0.7786
0.0153
0.8298
0.0164
0.8063
0.0174
0.8008
0.0211
0.8419
14
Reaction rate constant of free fatty acid formation which obtained after
determining the reaction order is then converted into a natural logarithm and is
plotted with inverse temperature (in Kelvin degree) in order to obtain a graph of ln
reaction rate constant with inverse temperature, as seen in Figure 7. This graph is
then used to obtain the Arrhenius equation that will be used to see the relationship
between temperature (T), reaction rate constant (k), and activation energy (Ea).
Ln Reaction Rate Constant (/day)
-3.8
-3.85
-3.9
-3.95
y = -1,107.3295x - 0.4969
R² = 0.9784
-4
-4.05
-4.1
-4.15
-4.2
-4.25
0.003
0.00305
0.0031
0.00315
0.0032 0.00325
1/T (K)
0.0033
0.00335
0.0034
Figure 7. Change in reaction rate constant of the increase in free fatty acid
percentage of carotenoids-rich fat powder stored at temperatures of
26C (ambient/room temperature), 35C, 40C, and 55C
The Arrhenius equation of the increase in free fatty acid percentage of
carotenoids-rich fat powder stored at five different temperatures generated from
graph above (Eq. (3)) is then calculated to obtain the activation energy of this
reaction. Table 7 shows that the increase in free fatty acid of carotenoids-rich fat
powder has 9,206.34 J/mole activation energy. This value is lower than the
activation energy of free fatty acid increase in red palm oil, which has 39,470
J/mole (Ayustaningwarno 2004). A lower activation energy signifies that increase
in free fatty acid of carotenoids-rich fat powder is less sensitive to temperature
increase.
Ln KT = -0.4969 – 1107.3295 (1/T)
(3)
Table 7. Activation energy of the increase in free fatty acid percentage of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
Temperature (C)
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
Accelerated storage
test
-1107.3295
8.314
9,206.34
15
Angle of repose changes
Bulk powder consists of a collection of individual particles of very different
characteristics, starting from the size, shape, up to consistency which is very
difficult to measure accurately in any existing particles (Schulze 2008). Although
both have flow properties, powder can not be considered the same as liquid
because powder is a solid which can form mound while liquid can not (Marinelli
2005). Physical characteriscs of powder in general depend on each other. Changes
in particle size distribution or moisture content may result in simultaneous
changes in bulk density, flowability, and visual appearance. Bulk density,
compressibility, and flowability of food powder are very dependent on particle
size and its distribution (Barboda-Canovas et al 1987). Small changes in bulk
density can lead to large changes in flowability.
Flowability is the relative movement of bulk particles to other particles in
the surroundings or along the surface of the container wall (Peleg 1977). Powder
flowability was measured to determine the behaviour of the powder in the
production process related to the interaction of the equipment and production
processes (Prescott and Barnum 2000). One of the indicator that can be used to
determine powder flowability is angle of repose (AOR). Geldart et al (2006)
explained that angle of repose 55 indicate sluggish
or very high cohesiveness and very limited flowability.
Knowledge about the characteristics of the powder is very important in the
process of handling and storage of materials. Cohesive powders or powders that
have the attractive force between the particles larger than the attractive force with
its weight can usually fail to flow out the container with the aperture
approximately a thousand times larger than the particle diameter. To ensure the
steady and reliable flow, it is important to characterize the powder flow behavior
accurately. Fitzpatrick (2005) explained that the factor of particle shape or size,
interaction surface, moisture content, caking, and storage condition will affect
powder flowability and one of the storage conditions which can affect powder
flowability is temperature.
Storage at temperatures of 26C (ambient/room temperature), 35C, 40C,
and 55C give a tangible change in angle of repose of carotenoids-rich fat powder
(Appendix 4). As seen on Figure 8, the AOR values of carotenoids-rich fat
powder are constantly increasing, which indicates that there has been a decline in
flowability of the product, and these changes occur more rapidly with increasing
storage temperature. Angle of repose of fat powder stored at temperature of 40C
and 55C only can be measured up to day 20 and day 10 of storage respectively,
because carotenoids-rich fat powder started to agglomerate.
16
50
45
Angle of Repose ()
y = 0.5859x
R² = 0.3676
y = 1.2949x
R² = 1.0000
y = 0.5165x
R² = 0.9191
y = 0.4483x
R² = 0.8649
40
35
30
25
20
0
5
10
15
20
Storage time (day)
Room
35
40
25
30
35
55
Figure 8. The increase in angle of repose of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
It can be seen on Table 8 that reaction rate constants of fat powder
flowability changes are increasing as the storage temperature increases from
0.45/day for storage temperature of 26C to 0.52/day, 0.59/day, and 1.29/day
for storage temperatures of 35C, 40C, and 55C respectively. From Table 8, it is
also known that the increase in angle of repose of carotenoids-rich fat powder
follows zero-order reaction.
Table 8. Reaction order of the increase in angle of repose of carotenoids-rich fat
powder during storage at temperatures of 26C (ambient/room
temperature), 35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
0.4483
0.8649
0.5165
0.9191
0.5859
0.3676
1.2949
1.0000
0.0132
0.8647
0.0149
0.9191
0.0176
0.3615
0.0376
0.9964
Reaction rate constants of the increase in carotenoids-rich fat powder
flowability are then converted into natural logarithm and plotted with the inverse
temperature (in Kelvin) (Figure 9) to get an Arrhenius equation so that the
relationship between temperature, reaction rate constant, and activation energy of
changes in flowability of carotenoids-rich fat powder can be studied.
17
Ln Reaction Rate Constant (/day)
0.4
0.2
0
-0.2
y = -3,679.7007x + 11.3724
R² = 0.9135
-0.4
-0.6
-0.8
-1
0.003
0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 0.0034
1/T (K)
Figure 9. Change in reaction rate constant of the increase in angle of repose of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
From the Arrhenius equation obtained from Figure 9 above (Eq. (4)), it is
known that an increase in angle of repose of carotenoids-rich fat powder has
30,593.03 J/mole activation energy, as also shown by Table 9.
Ln KT = 11.3724 – 3679.7007 (1/T)
(4)
Table 9. Activation energy of the increase in angle of repose of carotenoids-rich
fat powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature (C)
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
Accelerated storage
test
-3679.7007
8.314
30,593.03
Color changes
Color is a sensory attributes which have an important role in determining
the quality of food products because color is the first factor that will attract
consumers before they considering the taste and the nutritional value. If a food
product has a deviated color, consumers will not choose the product althought
other attributes, such as flavour and texture, are normal. Leön et al (2005)
explained that physical appereance, especially color, is the first parameter that will
be used by the consumer in determining the quality of the food product
objectively. Therefore, color determination in food industry is not only for
economic reasons but also for the quality of the brand and for product
standardization. During processing and handling process, food color can rapidly
changes with time, temperature, and light.
18
Natural food color is caused by the presence of organic compund called
pigment. In fruit and vegetables, there are four groups of pigment, i.e. chlorophyll,
carotenoid, anthocyanin, and anthoxanthin. Carotenoid is widely distributed
natural pigments which responsible for yellow, orange, and red colors so that the
yellow color of the carotenids-rich fat powder derived from carotenoids contained
in red palm stearin. Like the other pigments, carotenoid contained in carotenoidsrich fat powder is also sensitive to temperature, light, and time so that the yellow
color of carotenoids-rich fat powder can be changed during processing and
handling. Hence, it is necessary to take an action to maintain the color remains in
accordance with the standard in order the produced food product can be uniform.
However, before taking the preventive action, the pattern of color changes during
storage needs to be studied beforehand by observing changes in the value of L*,
a*, and b* of carotenoids-rich fat powder during the storage at temperatures of
26C (ambient/room temperature), 35C, 40C, and 55C.
Observation result shows that the value of L* of carotenoids-rich fat powder
which indicates the extent of product’s brightness is decreasing with the length of
storage time (Appendix 5) and the greatest reduction occurs at higher storage
temeperature, as shown in Figure 10.
88.00
87.00
86.00
L* value
85.00
84.00
y = -0.1196x
R² = 0.7453
83.00
y = -0.1323x
R² = 0.9764
82.00
y = -0.1676x
R² = 0.8980
81.00
80.00
y = -0.2350x
R² = 0.8452
79.00
78.00
0
5
10
15
20
Storage time (day)
Room
35
40
25
30
35
55
Figure 10. The decrease in L* value of carotenoids-rich fat powder during storage
at temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
Reaction rate constant of decline in the value of L* in Table 10 also shows
that the decrease in brightness of carotenoids-rich fat powder occurs more rapidly
at temperature of 55C with the value of reaction rate constants 0.24 unit/day and
19
it is followed by storage temperatures of 40C, 35C, and 26C with the reaction
rate constants value respectively 0.17 unit/day, 0.13 unit/day, and 0.12 unit/day.
From Table 10, it is also known that the decrease in L* value of carotenoids-rich
fat powder follows the zero-order reaction.
Table 10. Reaction order of L* value decrease in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
-0.1196
0.7453
-0.1676
0.8980
-0.1323
0.9764
-0.2350
0.8450
-0.0014
0.7514
-0.0020
0.9046
-0.0016
0.9762
-0.0028
0.8573
Ln Reaction Rate Constant (unit/day)
Reaction rate constant of L* value decrease is then converted into a natural
logarithm and is plotted with inverse temperature, in Kelvin degree, in order to
obtain a graph of ln reaction rate constant with inverse temperature, as seen in
Figure 11. This graph is used to o
ARINTIARA RAMADHYASTASARI
DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY
FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015
STATEMENT LETTER OF MANUSCRIPT AND SOURCES OF
INFORMATION*
I hereby genuinely state that the manuscript entitled Kinetics of Quality
Change of Carotenoids-rich Fat Powder Made From Red Palm Oil is an
authentic work of mine under supervision of academic counselor and never
presented in any forms and university. All the information taken and quoted from
published or unpublished works of the writer has been mentioned in the text and
attached in the bibliography at the end of this manuscript.
I hereby release the copyright of my manuscript to the Bogor Agricultural
University.
Bogor, February 2015
Arintiara Ramadhyastasari
NIM F24100105
ABSTRACT
ARINTIARA RAMADHYASTASARI. Kinetics of Quality Change of
Carotenoids-rich Fat Powder Made From Red Palm Oil. Supervised by
PURWIYATNO HARIYADI.
Vitamin A Deficiency (VAD) has been a serious problem in Indonesia and
the underlying cause is a diet which is insufficient in vitamin A. Food fortification
is one of the strategy that can be implemented in Indonesia to reduce the burden of
VAD and to improve vitamin A intake. Red palm oil, Indonesia’s abundant
natural resource rich in carotenoids, is very potential to be used as food fortificant.
Red palm oil can be used by direct addition to food product or by transforming it
into carotenoids-rich fat powder before use. This study was to investigate the
kinetics of quality changes of carotenoids-rich fat powder during storage and to
determine the product shelf life, using Arrhenius accelerated method. Samples of
fat powder were stored at 26C (ambient/room temperature) and at elevated
temperatures of 35C, 40C, and 55C for 30 days, and samples were taken and
analyzed every 5 days. As a reference, samples of fat powder were also stored at
refrigeration of 12C. The results showed that fat powder underwent (i) some
color changes, (ii) increase in free fatty acid and peroxide value, and (iii) decrease
in carotene content and powder flowability. With carotene tolerance 50% of initial
carotene, carotenoids-rich fat powder can be stored for 3 months and 11 days at
ambient/room temperature with light protection.
Keywords : Fat powder, Red Palm Oil, Palm Stearin, Spray chilling, Arrhenius
accelerated method
KINETICS OF QUALITY CHANGE OF CAROTENOIDSRICH FAT POWDER MADE FROM RED PALM OIL
ARINTIARA RAMADHYASTASARI
Manuscript
submitted as a partial fulfillment of the requirement for degree of
Bachelor in Agricultural Technology
at the Department of Food Science and Technology
DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY
FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015
PREFACE
Praise to Allah SWT for the mercy, the guidance, and the graciousness
throughout the research and manuscript completion. By completion of this
research and manuscript, the author would like to express great and sincere thanks
and appreciation to:
1. Beloved Bapak, Ibu, and Dhito for their endless support, love, care, and pray
2. Prof. Purwiyatno Hariyadi, as the academic advisor, for his enormous help
academically throughtout the completion of the manuscript
3. Dr. Ir. Feri Kusnandar, M.Sc and Dr. Edi Puspo Giriwono, M.Agr as
examiners, for their valuable advice and knowledge which has been given
during the manuscript defence
4. SEAFAST Center IPB for full financial support during research
5. Teh Ria N., Mas Arif, Mbak Ria C., Mas Agus, Teh Asih, Mbak Lyra, Pak
Abah, Mbak Ulfa, Bu Antin, and Pak Rojak for their help during research in
laboratory
6. All of the lecturers and staffs in Department of Food Science and Technology
for their time to help
7. Furry, Stephanie, Aby, Maria, As’ad, Anjani, Zeviara, Nurul, Fanny, Farisa,
Andra, Aghit, and all of the ITP 47 family for the togetherness, pray, support,
help, spirit, and laugh during good times and bad times
8. The 21st Tri-University Indonesia Delegation (Gideon, Mutiara, Muhana, Febri,
Raditya, Fadila, Mada, Bang Ihsan, Rumondang, Novi, and Fika) and the
supervisors (Dra. Alfa Chasanah, MA, Ir. Sri Endah Agustina, MS, Dr. Sintho
Wahyuning Ardie, SP, M.Si, and Dr. Rinekso Soekmadi, MSc. F.Trop) for the
inspiration, spirit, advices, support and wonderful memories during the
preparation and during the event in Thailand.
Last but not least, hopefully this manuscript will be useful for the readers
and give a real contribution in food science and technology development in
Indonesia.
Bogor, February 2015
Arintiara Ramadhyastasari
TABLE OF CONTENT
LIST OF TABLES
vi
LIST OF FIGURES
vi
INTRODUCTION
1
Background
1
Objective
1
RESEARCH METHODOLOGY
2
Materials
2
Instruments
2
Method
2
Method of analysis
3
RESULTS AND DISCUSSION
5
Ingredient characterization
5
Carotene content changes
6
Peroxide value changes
9
Free fatty acid changes
11
Angle of repose changes
15
Color changes
17
Shelf life determination of carotenoids-rich fat powder
24
CONCLUSIONS AND SUGGESTIONS
25
Conclusions
25
Suggestions
25
REFERENCES
26
AUTHOR BIOGRAPHY
28
LIST OF TABLES
1 Ingredients characterization
2 Reaction order of carotene degradation in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
3 Activation energy of carotene degradation in carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
4 Reaction order of peroxide value increase in carotenoids-rich fat
powder during storage at temperatures of 26C (ambient/room
temperature), 35C, 40C, and 55C
5 Activation energy of peroxide value increase in carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
6 Reaction order of the increase in free fatty acid percentage of
carotenoids-rich fat powder during storage at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
7 Activation energy of the increase in free fatty acid percentage of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
8 Reaction order of the increase in angle of repose of carotenoids-rich fat
powder during storage at temperatures of 26C (ambient/room
temperature), 35C, 40C, and 55C
9 Activation energy of the increase in angle of repose of carotenoids-rich
fat powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
10 Reaction order of L* value decrease in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
11 Activation energy of the decrease in L* value of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
12 Reaction order of (-a*) value increase in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
13 Activation energy of the increase in (-a*) value of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
14 Reaction order of b* value decrease in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
15 Activation energy of the decrease in b* value of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
5
8
9
10
11
13
14
16
17
19
20
21
22
23
24
16 Activation energy of the five quality parameters of carotenoids-rich fat
powder
24
LIST OF FIGURES
1 Research flow chart
2 Carotene degradation in carotenoids-rich fat powder during storage at
temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
3 Change in carotene degradation rate constant of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
4 The increase in peroxide value of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
5 Change in reaction rate constant of peroxide value increase in
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
6 The increase in free fatty acid percentage of carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
7 Change in reaction rate constant of the increase in free fatty acid
percentage of carotenoids-rich fat powder stored at temperatures of
26C (ambient/room temperature), 35C, 40C, and 55C
8 The increase in angle of repose of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
9 Change in reaction rate constant of the increase in angle of repose of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
10 The decrease in L* value of carotenoids-rich fat powder during storage
at temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
11 Change in reaction rate constant of the decrease in L* value of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
12 The increase in (-a*) value of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
13 Change in reaction rate constant of the increase in (-a*) value of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
14 The decrease in b* value of carotenoids-rich fat powder during storage
at temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
2
7
8
10
11
13
14
16
17
18
19
20
21
22
15 Change in reaction rate constant of the decreases in b* value of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
23
INTRODUCTION
Background
Vitamin A Deficiency (VAD) has been a serious problem in Indonesia. In
2002, West estimated that among 22 million Indonesian preschool-aged children,
there were 12.6 million that affected with low serum retinol concentration and 75
thousand others affected with xerophthalmia. The main underlying cause of
vitamin A deficiency is insufficient vitamin A content in the diet that can lead to
lower body stores and fail to meet the physiologic needs. As the result, it can
leads to disorders such as xerophthalmia, the leading cause of preventable
childhood blindness and anemia. Besides, xerophthalmia can also weaken host
resistance to infection which increase the severity of infectious disease and risk of
death (WHO 2009). To reduce the burden of VAD and to improve vitamin A
intake, there are three overlapping and complementary approaches, according to
Burns and Rice (2010), which are food fortification, supplementation, and dietary
diversification strategies. Food fortification strategy can be implemented in
Indonesia by utilizing red palm oil as Indonesia’s highly available natural resource
rich in carotenoids. Red palm oil can be used by directly added to food product or
by transforming it into carotenoids-rich fat powder before use.
Fat powder is fat or oil specialty product that was developed to facilitate a
wide range of food process, such as mixing, melting, storage, and so on.
Compared with solid fat, fat powder is easier to handle and can increase fat
distribution in the dough thus improving product’s texture, mouth-feel, and
creaminess. It can be made from a variety of raw materials, including red palm oil.
Red palm oil is known for its high content of carotenoids because during
manufacturing process, this product is not subjected to heating at high temperature
and bleaching process. Crude palm oil is reported to contain 642 ppm of
carotenoids (Insani 2011) meanwhile red palm oil and red palm stearin has 533
ppm (Muchtaridi and Justina 2006) and 359 ppm (Anriansyah 2013) of
carotenoids respectively.
Carotenoids serve as a pro-vitamin A in human body which contributes to
prevention of blindness and improvement of body immunity. Among all the
carotenoids, -carotene has the highest vitamin A activity therefore it is
commonly used as the source of vitamin A (Novia 2009). Consequently, red palm
oil may be used as an ingredient to help reduce vitamin A deficiency problem in
Indonesia. Red palm oil is used as palm stearin. The utilization of palm stearin as
the raw material of carotenoids-rich fat powder is considered very profitable
because it can increase the economic and added value of palm stearin. In food
industry, palm stearin is used as ingredients in a wide range of food products,
including shortening, pastry and bakery margarine, and confectionery. The
procedure to produce carotenoids-rich fat powder has been developed. However,
the quality deterioration kinetics during storage of the fat powder is not yet known.
Objective
The objectives of this research are to investigate the kinetics of quality
changes of carotenoids-rich fat powder during storage and to determine products
shelf life, using Arrhenius accelerated method.
2
RESEARCH METHODOLOGY
Materials
The ingredients used in the making of carotenoids-rich fat powder are
neutralized deodorized red palm stearin (NDRPS) and fully hydrogenated palm oil
(FHPO).
Chemical reagent used in this research are sodium thiosulphate 0.1 N,
sodium hydroxide 0.1 N, hexane, aquades, acetic acid, chloroform, distilled water,
ethanol 95%, phenoftalein, starch solution 1%, and crystal potassium iodide.
Instruments
Instruments used in this research are spray chiller Armfield FT80 Tall Form,
heater, thermometer, magnetic stirrer, analytical balance, spectrophotometer
Shimadzu UV2450, Chroma-meter CR300, glassware, polypropylene (PP) plastic
packaging, aluminum foil, incubator 350C, 400C, and 550C, refrigerator,
flowability-meter, ruler, and pipette.
Method
This research, broadly, consisted of four stages, which are ingredients
characterization, carotenoids-rich fat powder production, thermal treatment on
carotenoids-rich fat powder, and data analysis to obtain kinetic model. Flow chart
of the research can be seen in Figure 1.
Ingredients
characterization
Carotenids-rich fat
powder production
Thermal oxidation
treatment on carotenoidsrich fat powder
Kinetic data analysis
Figure 1. Research flow chart
Ingredients characterization
The carotene content, peroxide value, and free fatty acid of neutralized
deodorized red palm stearin and fully hydrogenated palm oil were analyzed to
find out the characteristics of the raw materials used.
3
Carotenoids-rich fat powder production
Carotenoids-rich fat powder was made using spray chiller with the operation
status as follows, spray heater temperature 80C, feed heater temperature 80C,
chiller temperature 14C, inlet temperature 18-19C, exhaust temperature 2930C, feed pump 15.0 Hz, air pressure 0.6 bar, and feed pressure 0.62+0.01 bar.
This settings are based on the research by Anriansyah (2013) with modification.
Both ingredients, NDRPS and FHPO, must be heated at 50-60C until it melts
perfectly before put into the spray chiller. Ingredients ratio used are 80% for
FHPO and 20% for NDRPS.
Thermal oxidation treatment of carotenoids-rich fat powder
Sample of carotenoids-rich fat powder was packed with polypropylene (PP)
plastic packaging, covered with aluminium foil and stored at 26C (ambient/room
temperature) and at elevated temperatures of 35C, 40C, and 55C for 30 days.
As a reference, samples of fat powder were also stored at refrigeration
temperature of 12C. During storaging, free fatty acid, peroxide value, color, and
flowability (angle of repose) analysis of fat powder were done every 5 days, and
carotene content analysis were done every 10 days. Sampling and analysis were
conducted three times.
Kinetic data analysis
Model of changes in quality deterioration parameters, such as carotene
content, peroxide value, free fatty acid content, flowability, and color were
analyzed using Arrhenius equation using Microsoft Excel 2013 software. The data
of changes in fat powder quality deterioration parameters acquired were processed
first to determine the most suitable reaction order, as indicated by the highest
linearity value (R2), and to get the reaction rate constants value at five storage
temperatures of the selected reaction order. The entire rate constants value of five
storage temperatures then processed to obtain an Arrhenius equation that will be
used to generate the activation energy.
Method of Analysis
Carotene content analysis (PORIM 1995)
Zero point one gram of carotenoids-rich fat powder were accurately
weighed in a 25 mL flask. After that, 25 mL of hexane was added to the flask and
then mixed until the entire sample completely dissolved and its absorbance value
was measured using spectrophotometer at the wave length of 446 nm. Carotene
content was calculated using the following formula
4
Determination of peroxide value with titrimetric method (AOCS Ca 8b-90
2012)
Five gram of oil sample were weighed inside the 250 mL Erlenmeyer flask
then it is added with 30 mL of acetic acid-chloroform (3:2), shaken until it
dissolved, later added with 0.5 mL of saturated KI and shaken for 2 minutes. After
that, it was immediately added to 30 mL of distilled water and shortly before the
titration, it is added with 2 mL of starch indicator and titrated with Na2S2O3 0.1 N
until the blue color disappeared.
Free fatty acid analysis (AOCS Ca 5a-40 2012; with modification)
Five grams of fat powder were weighed inside the 250 mL Erlenmeyer flask
and then it heated until perfectly melted. After that, the molten sample was added
with 50 mL neutral ethanol 95% and three drops of phenoftalein indicator. The
sample was shaken until homogenous and then titrated using sodium hydroxide
0.1 N until it became permanently pink for 30 seconds.
Flowability analysis (Geldart et al. 2006)
Flowability of carotenoids-rich fat powder can be detemined based on the
value of angle of repose (AORs) using a funnel. Funnel used has a diameter of 20
mm which makes an angle of 65 with the horizontal plane and the end of the
funnel is at a height of 9 cm above the bottom horizontal plane. Approximately
100 grams of carotenoids-rich fat powder was passed through the funnel and then
the diameter and height of formed pile was measured. After that, the angle of
repose of carotenoids-rich fat powder was calculated using the following formula
Ø = arctg
where h is the height of the pile and D is the diameter of the funnel.
Color analysis with Chromameter (Hutching 1999)
Color measurement was carried out using Chromameter CR300. Number of
samples were placed in a glass container and Chromameter measured the color of
the samples by firing a beam on the sample, then the measurement results came
out in the form of L*a*b* scale. Value of L* indicates the brightness (0 =
black/dark, 100 = white/bright), while value of a* indicates red color (a+ = red, a= green) and value of b* indicates yellow color (b+ = yellow, b- = blue).
Kinetic data analysis
Kinetics of quality changes during storage were analyzed using zero and/or
first order reaction to determine the respective constant rate of change (k).
Activation energy analysis was then done to determine the sensitivity of constant
rate of change (k) in product quality with increasing storage temperature. Quality
parameter with highest activation energy was used as the critical quality parameter
to predict product’s shelf life.
Activation energies of the quality parameters were generated by calcuting
the collected data into Arrhenius equation using Microsoft Excel 2013 software.
5
Generated Arrhenius equation then used to obtain activation energy of the quality
parameter changes.
RESULTS AND DISCUSSION
Ingredients characterization
Carotenoids-rich fat powder was made from a mix of palm stearin and fully
hydrogenated palm oil (FHPO). Palm stearin used here was neutralized
deodorized palm stearin (NDRPS) which was not subjected to bleaching process
so its carotene content remains high. The results of ingredients character step
shows that neutralized deodorized palm stearin contains 346.8 ppm of carotene
meanwhile fully hydrogenated palm oil only contains 2.9 ppm of carotene (Table
1). This data shows that the carotene contained in the carotenoids-rich fat powder
is mainly derived from neutralized deodorized palm stearin.
Table 1. Ingredients characterization
Neutralized deodorized red
Parameters
palm stearin
(NDRPS)
Carotene
346.8
content (ppm)
Peroxide value
2.5
(meq O2/kg)
Free fatty acid
0.1
(%)
Fully hydrogenated
palm oil
(FHPO)
2.9
3.9
1.9
Table 1 shows that red palm stearin has lower peroxide value than FHPO.
Red palm stearin has 2.5 meq O2/kg peroxide value, while FHPO has 3.9 meq
O2/kg peroxide. Both ingredients are classified as low oxidized state because their
peroxide value are between 1 and 5 meq O2/kg, according to Moigradean et al
(2012), and they also comply with the established standard because they have
lower peroxide value than the maximum limit of refined palm stearin peroxide
value, according to Draft East African Standard (2012), which is 10 meq O2/kg.
DEAS also established the maximum limit of free fatty acid as palmitic acid in
refined stearin, which is 0.25% (DEAS 2012). From the data in Table 1, it is
known that red palm stearin used in this research has lower free fatty acid content
than the standard (0.1 %) meanwhile FHPO used has higher free fatty acid content
than the standard (1.9 %).
These two ingredients are mixed until homogenous and sprayed to powder
form using spray chiller. Carotenoids-rich fat powder generated was stored at five
different temperatures, for 30 days, which will show different changes in its
quality. The observed quality parameters were carotene content, peroxide value,
free fatty acid content, flowability, and color.
6
Carotene content changes1
Red palm oil is the richest naturally occuring source of carotenoid and
generally contains 200-800 mg of provitamin A carotenoids per kg oil which is 15
times higher than the carotenoid content of carrots on weight-by-weight basis.
These carotenoids are easily absorbed because they are already dissolved in oil
(Rice and Burns 2010). Therefore, the utilization of red palm stearin, solid
fraction of red palm oil, as food fortificant by converting it into carotenoids-rich
fat powder is one potential way to overcome the vitamin A deficiency problem in
Indonesia. Carotene, especially -carotene, is used as the source of vitamin A in
human body which prevents blindness and improves body immunity. Betacarotene has a hundred percent pro-vitamin A activity in trans-isomer form but it
can be easily degraded by the presence of oxygen, heat, light, metal, and other
oxidative substances (Wulan 2013). The main factor that affects carotenoid
content during the food processing and storage is oxidation by atmospheric
oxygen and structural changes by heat. To see the effect of temperature on the
carotene content in carotenoids-rich fat powder, carotenoids-rich fat powder was
stored at four different storage temperatures.
Carotene content of carotenoids-rich fat powder continues to decrease with
the length of storage time (Appendix 1). The decrease in carotene content of
carotenoids-rich fat powder can be seen in Figure 2. Storage at temperatures of
26C, 35C, 40C, and 55C shows that carotenoids-rich fat powder have 0.24
ppm/day, 0.48 ppm/day, 1.11 ppm/day, and 1.58 ppm/day reaction rate constant,
respectively (Table 2). Based on the reaction rate law, the bigger the value of
reaction rate constant, the faster the reaction takes place, thus storage temperature
of 55C has the greatest carotene degradation rate followed by storage
temperatures of 40C, 35C, and 26C. Wulan (2013) explained that chemical
reation rate is affected by the amount of the reactant concentration used in the
reaction and also by the value of reaction rate constant (k). Reaction rate constant
is the comparation between reaction rate and reactant concentration. It is an
absolute value of the slope of the graph between concentration and time which
used after get the chosen reaction order. The value of k will be greater if the
reaction is rapid though it occurs with a small amount of reactant concentrations.
1
This part of manuscript has been presented in The 21st Tri-University International Joint
Seminar and Symposium (2014 November 2-7), Chiang-Mai, Thailand.
7
70
60
y = -0.2419x
R² = 0.9695
Carotene content
(ppm)
50
40
y = -1.1105x
R² = 0.9548
30
y = -0.4773x
R² = 0.9500
20
y = -1.5780x
R² = 0.9590
10
0
0
5
10
Room
15
20
Storage time (day)
35
40
25
30
35
55
Figure 2. Carotene degradation in carotenoids-rich fat powder during storage at
temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
Carotene has double bonds which make it sensitive to oxidation accelerated
by heat or high temperature. Heating up to 60C resulted in isomeric changes
from trans-isomer to cis-isomer which has a lower pro-vitamin A activity
compared with trans-isomer form (Novia 2009). Carotene oxidation is also
triggered by hydroperoxide generated from lipid oxidation (Insani 2011). This was
also explained by Novia (2009) that lipid oxidation reaction causes the increase of
carotene oxidation so that the -ionone ring at the end of carotene molecule is
open which then cause the decrease of carotene activity.
Carotene degradation in carotenoids-rich fat powder stored at four different
temperatures follows the zero-order reaction which means this reaction does not
depend on the reactant concentration (Muchtaridi and Justina 2006). It is similar
to the study done by Novia (2009) in investigating the stability of thin layer
drying microencapsulated red palm oil during storage. Carotene degradation
reaction order was generated by calculating the greatest linearity (R2) value of
correlation of storage time (in days) and carotene content (in ppm), as shown on
Table 2. Reaction order is required to choose the chart in the determination of
reaction rate constants.
8
Table 2. Reaction order of carotene degradation in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature
(C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
-0.2419
0.9695
-0.4773
0.9500
-1.1105
0.9548
-1.5780
0.9590
-0.0046
0.9657
-0.0095
0.9555
-0.0250
0.9223
-0.0488
0.9980
The rate of carotene degradation rises with the storage temperature.
Temperature is one of the factor that affect the reaction rate and the temperature
increase generally will lead to a faster reaction rate due to the increasing number
of collisions between molecules, as well as the average kinetics energy of
molecules (Wulan 2013). The study done by Novia (2009) on microencapsulated
red palm oil stored at temperature of 35C, 45C, and 55C for 30 days also
shows a decrease in carotene content, from 248 ppm to 133 ppm for the red palm
oil microencapsulate stored at temperature of 55C.
Ln Reaction Rate Constant
(ppm/day)
Carotene degradation rate constant obtained then converted into the natural
numbers of logarithm (ln k) and plotted with the inverse of temperature, in Kelvin,
(Figure 3) to get the Arrhenius equation. Arrhenius equation can be used to study
the relation between temperature, reaction rate constant, and activation energy
(Ea).
1.0
0.5
0.0
-0.5
-1.0
y = -6,466.7419x + 20.3505
R² = 0.8912
-1.5
-2.0
0.0030
0.0031
0.0031
0.0032
0.0032 0.0033
1/T (K)
0.0033
0.0034
0.0034
Figure 3. Change in carotene degradation rate constant of carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Activation energy is the minimum amount of energy needed for a chemical
reaction may take place. Its value can be known after the value of slope of graph
9
has been obtained. The Arrhenius equation generated from Figure 2 (Eq.(1))
shows the carotene degradation of carotenoids-rich fat powder has 53,764.49
J/mole activation energy, as also shown by Table 3. This value is 2 times much
higher than the activation energy of carotene degradation of red palm oil
microencapsulate from study conducted by Novia in 2009, which is 19,995.17
J/mole. A higher activation energy indicates that carotene degradation of
carotenoids-rich fat powder is more sensitive to temperature increases during
storage compared with carotene degradation of red palm oil microencapsulate.
Ln KT = 20.3505 – 6466.7419(1/T)
(1)
Table 3. Activation energy of carotene degradation in carotenoids-rich fat powder
stored at temperatures of 26C (ambient/room temperature), 35C, 40C,
and 55C
Temperature (C)
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
Accelerated
storage test
-6466.7419
8.314
53,764.49
Peroxide value changes
Peroxide value is one of the important parameter in determining degree of
fat or oil damage. Peroxide is a chemical substance that can accelerate oxidation,
in other words it is an oxidizing agent. During thermal oxidation, peroxide value
increases due to lipid oxidation triggered by heating which resulting in the
formation of a number of peroxide. According to Ketaren (2005), unsaturated
fatty acid can binds oxygen to its double bond and forms peroxide. Oxidation
takes place if there is contact between a number of oxygen and fat or oil which
usually begins with the formation of peroxide and hydro-peroxide. On the next
stages, fatty acid decomposes and it is followed by the changes in hydro-peroxide
to aldehydes and ketones, as well as free fatty acids (Ketaren 2005). This
oxidation reaction will lead to rancidity in fat or oil which formed due to the
presence of aldehydes. Thus, the increase of peroxide value is only an indicator
and a warning that the fat or oil will soon smell rancid (Novia 2009).
Storage of carotenoids-rich fat powder at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C causes an increase in peroxide
value of the fat powder (Figure 4). This result is similar to study done by Novia
(2009) about stability of microencapsulated red palm oil during storage and study
conducted by Zungur et al (2014) about storage stability of microencapsulated
extra virgin olive oil powder. An increase in peroxide value also happened in the
research done by Moigradean et al (2012) in investigating the oxidative stability
of coconut oil during 18 months of storage. However, this increase occured only
in the first 9 months of storage. In the next 9 months of storage, coconut oil
peroxide value decreases due to the formation of secondary oxidation products.
10
2.60
y = 0.0215x
R² = 0.4604
Ln Peroxide Value (meq O2/kg)
2.50
2.40
y = 0.0119x
R² = 0.9365
2.30
2.20
y = 0.0091x
R² = 0.8469
2.10
y = 0.0072x
R² = 0.9483
2.00
1.90
1.80
1.70
0
5
10
15
20
Storage time (day)
Room
35
40
25
30
35
55
Figure 4. The increase in peroxide value of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
Peroxide value of carotenoids-rich fat powder steadily increase with the
length of storage time (Appendix 2) and the rate of the increase in peroxide value
is increasing as the storage temperature increases. Fat powder stored at
temperatures of 26C and 35C have 0.007/day and 0.009/day reaction rate
constant respectively while fat powder stored at 40C, and 55C have 0.011/day
and 0.021/day reaction rate constant respectively (Table 4).
Table 4. Reaction order of peroxide value increase in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
0.0279
0.5483
0.0502
0.1988
0.0852
0.8059
-0.1127
0.9508
0.0072
0.9483
0.0091
0.8469
0.0119
0.9365
0.0215
0.4604
11
The rate of peroxide value increase in carotenoids-rich fat powder during
storage at four different temperatures follows first-order reaction and it is similar
to the increase in peroxide value of microencapsulated olive oil from study done
by Zungur et al 2014 which also follow first-order reaction. All the obtained
reaction rate constants then converted into natural numbers of logarithm (ln k) and
plotted with the inverse of temperatures in Kelvin degree (Figure 5).
Ln Reaction Rate Constant (/day)
0.00
-1.00
-2.00
-3.00
y = -3,790.2293x + 7.6858
R² = 0.9843
-4.00
-5.00
-6.00
0.003
0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 0.0034
1/T (K)
Figure 5. Change in reaction rate constant of peroxide value increase in
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
Arrhenius equation of peroxide value increase in carotenoids-rich fat
powder generated from Figure 4 (Eq. (2)) is used to determine the activation
energy of the increase in peroxide value during storage. Table 5 shows that this
reaction has 31,511.97 J/mole activation energy. The increase in peoxide value of
carotenoids-rich fat powder has lower activation energy compared with peroxide
value increase in olive oil triacylglycerols, which has 32,100.00 J/mole activation
energy (Gomez-Alonso et al 2004). A lower activation energy indicates that
peroxide value increase in carotenoids-rich fat powder is less sensitive to
temperature increase than peroxide value increase in olive oil triacylglycerols.
Ln KT = 7.6858 – 3790.2293(1/T)
(2)
Table 5. Activation energy of peroxide value increase in carotenoids-rich fat
powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature
(C)
Accelerated
storage test
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
-3790.2293
8.314
31,511.97
12
Free fatty acid changes
Free fatty acid is the result of the termination of the ester bond between the
fatty acid and glycerol (Wulan 2013). The acid value indicates the amount of free
fatty acids contained in fat or oil which derived from the hydrolysis of fats or due
to unfavorable processing (Novia 2009) and this reaction can be accelerated by
the presence of water, heat, and enzyme catalysts. Ketaren (2005) explained that a
high acid value indicates a high free fatty acid content, the higher the acid value,
the lower the quality of fats or oils. Increase in free fatty acids may occur during
processing and storaging of palm oil due to autocatalytic hydrolysis and also due
to the activity of microorganisms because of the production process which is not
clean. This increase may then facilitate a serial oxidation process and facilitate the
formation of peroxide compounds, aldehydes, and ketones which will then lead to
the formation of rancidity, oil browning, and even could cause poisoning (Ketaren
2008). Measurement of free fatty acid value in carotenoids-rich fat powder made
from red palm oil is calculated in the form of palmitic acid as the predominant
fatty acid in the product. Changes in free fatty acid percentage of carotenoids-rich
fat powder during storage at five different temperatures were observed to see the
properties of the hydrolysis reactions occured in fat powder.
Free fatty acid percentage of carotenoids-rich fat powder stored at
temperatures of 26C (ambient/room temperature), 35C, 40C, and 55C
constantly increase with the length of storage time (Appendix 3) and the increase
occurs more rapidly with the increasing storage temperature. As shown by Figure
6, carotenoids-rich fat powder stored at temperature of 55C has 0.0211/day
reaction rate constant while carotenoids-rich fat powder stored at temperature of
40C, 35C, and 26C only have 0.0174/day, 0.0164/day, and 0.0153/day,
respectively. It shows that carotenoids-rich fat powder stored at temperature of
55C has the fastest increase in free fatty acid percentage. There are other studies
that also discovered that the free fatty acid percentage will increase with
increasing in storage temperature. Ayustaningwarno (2010) found that the
reaction rate of free fatty acid formation in red palm oil has increased as much as
three times from palm oil stored at temperature of 60C to red palm oil stored at
temperature of 90C. A year later, Tadakittisarn et al (2011) also found that the
storage of Jatropha curcas oil at temperature of 50C caused the formation of a
high free fatty acid content compared to those which stored at temperature of
37C.
13
0.6
y = 0.0211x
R² = 0.8419
y = 0.0174x
R² = 0.8008
0.4
Ln FFA (%)
0.2
y = 0.0164x
R² = 0.8063
0.0
y = 0.0153x
R² = 0.8298
-0.2
-0.4
-0.6 0
5
10
15
20
Storage periode (day)
Room
35
40
25
30
35
55
Figure 6. The increase in free fatty acid percentage of carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Reaction order is required to select the reaction rate constant determining
chart which obtained by calculating the highest linearity (R2) on a graph of the
relation between time and concentration. Based on the calculation of the reaction
order in Table 6, it is known that the increase in free fatty acid of carotenoids-rich
fat powder follows the first-order reaction meaning that the rate of the increase in
free fatty acid percentage of carotenoids-rich fat powder is affected by the
changes in reactant concentration. This result is different from the increase in free
fatty acid percentage of red palm oil during storage, which has zero-order reaction
(Ayustaningwarno 2010).
Table 6. Reaction order of the increase in free fatty acid percentage of
carotenoids-rich fat powder during storage at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
0.0125
0.7812
0.0137
0.7563
0.0148
0.7511
0.0189
0.7786
0.0153
0.8298
0.0164
0.8063
0.0174
0.8008
0.0211
0.8419
14
Reaction rate constant of free fatty acid formation which obtained after
determining the reaction order is then converted into a natural logarithm and is
plotted with inverse temperature (in Kelvin degree) in order to obtain a graph of ln
reaction rate constant with inverse temperature, as seen in Figure 7. This graph is
then used to obtain the Arrhenius equation that will be used to see the relationship
between temperature (T), reaction rate constant (k), and activation energy (Ea).
Ln Reaction Rate Constant (/day)
-3.8
-3.85
-3.9
-3.95
y = -1,107.3295x - 0.4969
R² = 0.9784
-4
-4.05
-4.1
-4.15
-4.2
-4.25
0.003
0.00305
0.0031
0.00315
0.0032 0.00325
1/T (K)
0.0033
0.00335
0.0034
Figure 7. Change in reaction rate constant of the increase in free fatty acid
percentage of carotenoids-rich fat powder stored at temperatures of
26C (ambient/room temperature), 35C, 40C, and 55C
The Arrhenius equation of the increase in free fatty acid percentage of
carotenoids-rich fat powder stored at five different temperatures generated from
graph above (Eq. (3)) is then calculated to obtain the activation energy of this
reaction. Table 7 shows that the increase in free fatty acid of carotenoids-rich fat
powder has 9,206.34 J/mole activation energy. This value is lower than the
activation energy of free fatty acid increase in red palm oil, which has 39,470
J/mole (Ayustaningwarno 2004). A lower activation energy signifies that increase
in free fatty acid of carotenoids-rich fat powder is less sensitive to temperature
increase.
Ln KT = -0.4969 – 1107.3295 (1/T)
(3)
Table 7. Activation energy of the increase in free fatty acid percentage of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
Temperature (C)
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
Accelerated storage
test
-1107.3295
8.314
9,206.34
15
Angle of repose changes
Bulk powder consists of a collection of individual particles of very different
characteristics, starting from the size, shape, up to consistency which is very
difficult to measure accurately in any existing particles (Schulze 2008). Although
both have flow properties, powder can not be considered the same as liquid
because powder is a solid which can form mound while liquid can not (Marinelli
2005). Physical characteriscs of powder in general depend on each other. Changes
in particle size distribution or moisture content may result in simultaneous
changes in bulk density, flowability, and visual appearance. Bulk density,
compressibility, and flowability of food powder are very dependent on particle
size and its distribution (Barboda-Canovas et al 1987). Small changes in bulk
density can lead to large changes in flowability.
Flowability is the relative movement of bulk particles to other particles in
the surroundings or along the surface of the container wall (Peleg 1977). Powder
flowability was measured to determine the behaviour of the powder in the
production process related to the interaction of the equipment and production
processes (Prescott and Barnum 2000). One of the indicator that can be used to
determine powder flowability is angle of repose (AOR). Geldart et al (2006)
explained that angle of repose 55 indicate sluggish
or very high cohesiveness and very limited flowability.
Knowledge about the characteristics of the powder is very important in the
process of handling and storage of materials. Cohesive powders or powders that
have the attractive force between the particles larger than the attractive force with
its weight can usually fail to flow out the container with the aperture
approximately a thousand times larger than the particle diameter. To ensure the
steady and reliable flow, it is important to characterize the powder flow behavior
accurately. Fitzpatrick (2005) explained that the factor of particle shape or size,
interaction surface, moisture content, caking, and storage condition will affect
powder flowability and one of the storage conditions which can affect powder
flowability is temperature.
Storage at temperatures of 26C (ambient/room temperature), 35C, 40C,
and 55C give a tangible change in angle of repose of carotenoids-rich fat powder
(Appendix 4). As seen on Figure 8, the AOR values of carotenoids-rich fat
powder are constantly increasing, which indicates that there has been a decline in
flowability of the product, and these changes occur more rapidly with increasing
storage temperature. Angle of repose of fat powder stored at temperature of 40C
and 55C only can be measured up to day 20 and day 10 of storage respectively,
because carotenoids-rich fat powder started to agglomerate.
16
50
45
Angle of Repose ()
y = 0.5859x
R² = 0.3676
y = 1.2949x
R² = 1.0000
y = 0.5165x
R² = 0.9191
y = 0.4483x
R² = 0.8649
40
35
30
25
20
0
5
10
15
20
Storage time (day)
Room
35
40
25
30
35
55
Figure 8. The increase in angle of repose of carotenoids-rich fat powder during
storage at temperatures of 26C (ambient/room temperature), 35C,
40C, and 55C
It can be seen on Table 8 that reaction rate constants of fat powder
flowability changes are increasing as the storage temperature increases from
0.45/day for storage temperature of 26C to 0.52/day, 0.59/day, and 1.29/day
for storage temperatures of 35C, 40C, and 55C respectively. From Table 8, it is
also known that the increase in angle of repose of carotenoids-rich fat powder
follows zero-order reaction.
Table 8. Reaction order of the increase in angle of repose of carotenoids-rich fat
powder during storage at temperatures of 26C (ambient/room
temperature), 35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
0.4483
0.8649
0.5165
0.9191
0.5859
0.3676
1.2949
1.0000
0.0132
0.8647
0.0149
0.9191
0.0176
0.3615
0.0376
0.9964
Reaction rate constants of the increase in carotenoids-rich fat powder
flowability are then converted into natural logarithm and plotted with the inverse
temperature (in Kelvin) (Figure 9) to get an Arrhenius equation so that the
relationship between temperature, reaction rate constant, and activation energy of
changes in flowability of carotenoids-rich fat powder can be studied.
17
Ln Reaction Rate Constant (/day)
0.4
0.2
0
-0.2
y = -3,679.7007x + 11.3724
R² = 0.9135
-0.4
-0.6
-0.8
-1
0.003
0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 0.0034
1/T (K)
Figure 9. Change in reaction rate constant of the increase in angle of repose of
carotenoids-rich fat powder stored at temperatures of 26C
(ambient/room temperature), 35C, 40C, and 55C
From the Arrhenius equation obtained from Figure 9 above (Eq. (4)), it is
known that an increase in angle of repose of carotenoids-rich fat powder has
30,593.03 J/mole activation energy, as also shown by Table 9.
Ln KT = 11.3724 – 3679.7007 (1/T)
(4)
Table 9. Activation energy of the increase in angle of repose of carotenoids-rich
fat powder stored at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature (C)
Slope
Gas constant
(/mol K)
Activation energy
(J/mole)
Accelerated storage
test
-3679.7007
8.314
30,593.03
Color changes
Color is a sensory attributes which have an important role in determining
the quality of food products because color is the first factor that will attract
consumers before they considering the taste and the nutritional value. If a food
product has a deviated color, consumers will not choose the product althought
other attributes, such as flavour and texture, are normal. Leön et al (2005)
explained that physical appereance, especially color, is the first parameter that will
be used by the consumer in determining the quality of the food product
objectively. Therefore, color determination in food industry is not only for
economic reasons but also for the quality of the brand and for product
standardization. During processing and handling process, food color can rapidly
changes with time, temperature, and light.
18
Natural food color is caused by the presence of organic compund called
pigment. In fruit and vegetables, there are four groups of pigment, i.e. chlorophyll,
carotenoid, anthocyanin, and anthoxanthin. Carotenoid is widely distributed
natural pigments which responsible for yellow, orange, and red colors so that the
yellow color of the carotenids-rich fat powder derived from carotenoids contained
in red palm stearin. Like the other pigments, carotenoid contained in carotenoidsrich fat powder is also sensitive to temperature, light, and time so that the yellow
color of carotenoids-rich fat powder can be changed during processing and
handling. Hence, it is necessary to take an action to maintain the color remains in
accordance with the standard in order the produced food product can be uniform.
However, before taking the preventive action, the pattern of color changes during
storage needs to be studied beforehand by observing changes in the value of L*,
a*, and b* of carotenoids-rich fat powder during the storage at temperatures of
26C (ambient/room temperature), 35C, 40C, and 55C.
Observation result shows that the value of L* of carotenoids-rich fat powder
which indicates the extent of product’s brightness is decreasing with the length of
storage time (Appendix 5) and the greatest reduction occurs at higher storage
temeperature, as shown in Figure 10.
88.00
87.00
86.00
L* value
85.00
84.00
y = -0.1196x
R² = 0.7453
83.00
y = -0.1323x
R² = 0.9764
82.00
y = -0.1676x
R² = 0.8980
81.00
80.00
y = -0.2350x
R² = 0.8452
79.00
78.00
0
5
10
15
20
Storage time (day)
Room
35
40
25
30
35
55
Figure 10. The decrease in L* value of carotenoids-rich fat powder during storage
at temperatures of 26C (ambient/room temperature), 35C, 40C, and
55C
Reaction rate constant of decline in the value of L* in Table 10 also shows
that the decrease in brightness of carotenoids-rich fat powder occurs more rapidly
at temperature of 55C with the value of reaction rate constants 0.24 unit/day and
19
it is followed by storage temperatures of 40C, 35C, and 26C with the reaction
rate constants value respectively 0.17 unit/day, 0.13 unit/day, and 0.12 unit/day.
From Table 10, it is also known that the decrease in L* value of carotenoids-rich
fat powder follows the zero-order reaction.
Table 10. Reaction order of L* value decrease in carotenoids-rich fat powder
during storage at temperatures of 26C (ambient/room temperature),
35C, 40C, and 55C
Temperature (C)
26
35
40
55
Parameter
Zero-order
First-order
Slope
R2
Slope
R2
Slope
R2
Slope
R2
-0.1196
0.7453
-0.1676
0.8980
-0.1323
0.9764
-0.2350
0.8450
-0.0014
0.7514
-0.0020
0.9046
-0.0016
0.9762
-0.0028
0.8573
Ln Reaction Rate Constant (unit/day)
Reaction rate constant of L* value decrease is then converted into a natural
logarithm and is plotted with inverse temperature, in Kelvin degree, in order to
obtain a graph of ln reaction rate constant with inverse temperature, as seen in
Figure 11. This graph is used to o