Aplikasi Edible Coating Lidah Buaya dan Suhu Penyimpanan untuk Menjaga Mutu Salak Pondoh (Salacca edulis Reinw.) Terolah Minimal.

APPLICATION OF ALOE VERA EDIBLE COATING AND
STORAGE TEMPERATURE TO MAINTAIN MINIMALLY
PROCESSED SALAK PONDOH (Salacca edulis Reinw.)

NUR KHOLIQ

DEPARTMENT OF AGROINDUSTRIAL TECHNOLOGY
FACULTY OF AGRICULTURAL TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015

STATEMENT ON THESIS AND SOURCE OF INFORMATION*
Herewith, I declare that this thesis entitled Application of Aloe Vera Edible
Coating and Storage Temperature to Maintain Minimally Processed Salak
Pondoh (Salacca edulis Reinw.) is my own work with the guidance from advisor and
has not been published in any form and for another degree. Source of information
which is collected or cited from published or unpublished works has acknowledged in
this text and put it in the list of references at the end of thesis.
I hereby assign copyright of my paper to Bogor Agricultural University (IPB).
Bogor, August 2015

Nur Kholiq
NIM F34110105

ABSTRACT
NUR KHOLIQ. Application of Aloe Vera Edible Coating and Storage Temperature to
Maintain Minimally Processed Salak Pondoh (Salacca edulis Reinw.). Supervised by
SUGIARTO.
Application of edible coating and storage temperature are common to
maintain fruit’s quality. A source that can be used as edible coating is aloe vera which
contains antimicrobial substance. Unfortunately extra effort is needed to prepare aloe
vera to be edible coating (peeling, crushing, and filtering) that causes difficulties in
application. Formulation of aloe vera edible coating in powder form could ease the
application. This research aimed to know the effect of spray drying process on aloe
vera edible coating characteristics and its effectiveness to maintain minimally
processed salak pondoh. Furtheremore, this research aimed to get information about
the effect of aloe vera edible coating and storage temperature on minimally processed
salak pondoh (Salacca edulis Reinw.). Fruits quality parameters in this research were
firmness, weight loss, percentage of damage, and visual changes. Statistical analysis
used was Completely Randomized Design with twice replications. The result showed
that spray drying process decreased aloe vera edible coating viscosity, total soluble

solid (TSS), and titratable acidity, while its pH value increased. Aloe vera edible
coating color changed to be yellowish from smooth green. Furtheremore storage
temperature gave significant (α=0.01) effect on all parameters, while aloe vera edible
coating did not give significant effect on all parameters analyzed, but uncoated fruits
were contaminated by molds sooner than coated ones.
Keywords: Edible coating, aloe vera, polysaccharides, minimally processed fruit, spray
dry.

ABSTRAK
NUR KHOLIQ. Aplikasi Edible Coating Lidah Buaya dan Suhu Penyimpanan untuk
Menjaga Mutu Salak Pondoh (Salacca edulis Reinw.) Terolah Minimal. Dibimbing
oleh SUGIARTO.
Cara yang biasa dilakukan untuk menjaga mutu buah adalah perlakuan edible
coating dan suhu penyimpanan. Lidah buaya yang mengandung bahan antimikroba
dapat digunakan sebagai edible coating. Namun dibutuhkan usaha yang cukup rumit
dalam menyiapkan lidah buaya menjadi edible coating (pengupasan, penghancuran,
dan penyaringan) yang menyebabkan kerumitan dalam aplikasi. Pembuatan edible
coating lidah buaya menjadi bentuk serbuk dapat dijadikan alternatif untuk
memudahkan aplikasi. Penelitian ini bertujuan untuk mengetahui pengaruh edible
coating lidah buaya dan suhu penyimpanan dalam menjaga mutu salak pondoh terolah

minimal. Penelitian ini juga bertujuan untuk mengetahui pengaruh spray dryer pada
karakteristik dan efektivitas edible coating lidah buaya dalam menjaga mutu buah.
Parameter buah yang dianalisis antara lain kekerasan, susut bobot, persentase

kerusakan buah, dan perubahan visual. Analisis statistik yang digunakan adalah
Rancangan Acak Lengkap Faktorial (RALF) dengan dua kali ulangan. Hasil
menunjukkan spray drying menurunkan viskositas, total soluble solid (TSS), dan total
asam, sedangkan pH naik. Warna larutan edible coating aloe vera berubah menjadi
kekuningan. Selanjutnya suhu penyimpanan berpengaruh secara signifikan (α=0.01)
pada parameter buah yang diuji, sedangkan perlakuan edible coating lidah buaya tidak
memberikan pengaruh yang signifikan pada kualitas buah, tapi buah tanpa perlakuan
coating terkontaminasi kapang lebih cepat daripada buah dengan coating.
Kata kunci: Edible coating, lidah buaya, polisakarida, buah terolah minimal, spray
dry.

APPLICATION OF ALOE VERA EDIBLE COATING AND
STORAGE TEMPERATURE TO MAINTAIN MINIMALLY
PROCESSED SALAK PONDOH (Salacca edulis Reinw.)

NUR KHOLIQ

Thesis
as a partial fulfillment for Bachelor of Agricultural Technology
in Department of Agroindustrial Technology

DEPARTMENT OF AGROINDUSTRIAL TECHNOLOGY
FACULTY OF AGRICULTURAL TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015

Thesis Title : Application of Aloe Vera Edible Coating and Storage Temperature to
Maintain Minimally Processed Salak Pondoh (Salacca edulis Reinw.)
Name
: Nur Kholiq
NIM
: F34110105

Approved by

Dr Ir Sugiarto MSi
Advisor

Acknowledge by

Prof Dr Ir Nastiti Siswi Indrasti
Head of Department

Graduate date: (…………………….)

PREFACE
Hereby I would like to give my thankfulness to God Almighty, Allah subhanahu
wa ta’ala, who has given me much blessing so I could finish this thesis. The title of
this research is Application of Aloe Vera Edible Coating and Storage Temperature to
Maintain Minimally Processed Salak Pondoh (Salacca edulis Reinw.). This research
was conducted from February to May 2015.
In this moment, I am going to express my thanks and sincere my appreciation to
Dr Ir Sugiarto MSi as my advisor, Dr Ir Muslich, MSi and Dr Farah Fatma, STP, MT
for the guidance to finish this research. Secondly I am very grateful to laboratory
assistants (Bu Ega, Bu Rini, Bu Sri, Pak Nurwanto, Bu Dyah, and Pak Gunawan) who

have given me services and suggestions during this research. Furthermore I said my
thanks to all friends who have helped me to conduct this thesis. Last but not the least,
I said thank you so much to my family for their support and wishes.
I wish this thesis will be useful for any interest.

Bogor, August 2015
Nur Kholiq

CONTENTS
LIST OF TABLES
ix
LIST OF FIGURES
x
LIST OF APPENDIXES
x
INTRODUCTION
1
Background
1
Objective

1
METHODS
2
Materials
2
Edible Coating Preparation
2
Edible Coating Characterization
2
Edible Coating Application
3
Fruit Quality Parameters
4
Statistical Analysis
6
RESULT AND DISCUSSION
6
Preliminary Research
6
Aloe Vera Edible Coating Character

7
Aloe Vera Edible Coating and Storage Temperature Effects on Salak Quality 8
CONCLUSION AND SUGGESTION
14
Conclusion
14
Suggestion
14
REFERENCES
14
APPENDIXES
18
BIOGRAPHY OF AUTHOR
25

LIST OF TABLES
Maltodextrin formulation
6
Edible coating characteristics
8

The effect of edible coating on change rate of salak parameters in different storage
temperature
9
Physical change and damage rate
13

LIST OF FIGURES
Aloe vera solution preparations
Edible coating preparations
Edible coating applications
Weight loss of salak during storage
Firmness of salak during storage
Salak pH value during storage
Percentage of decay during storage

3
4
5
10
11

12
13

LIST OF APPENDIXES
Time series sample documentation
Analysis methods
Analysis of salak’s pH during storage
Analysis of salak’s firmness during storage
Analysis of percentage of decay
Analysis of salak’s weight loss

18
19
20
21
22
23

INTRODUCTION
Background

Perishable is the major charracteristic that followed fruits and vegetable
(Ščetar et al. 2010), including minimally processed salak pondoh (Salacca edulis
Reinw.). Thus people are pursuing alternatives to extend the shelf life with high quality.
A very common alternative that is used by most people is storage temperature
manipulation. Storage temperature is well known to maintain fruit’s quality since
temperature affects respiration of fruits during storage (Mahajan et al. 2008). It is
believed that the decreasing of temperature decreases respiration rate, transpiration
rate, and chemical reaction on fruit. In contrary, different fruits have different response
to temperature.
Application of edible coating is also believed to have good impact on fruit
shelf life as it has been being developed in some studies (Dobrucka and Cierpiszewski
2014). Furthermore, Ščetar et al. (2010) said that the development of edible coating
aligns with environmental issues because of high number of conventional plastics
contamination. Briefly, edible coating is a material that can form thin layer of barrier
on food product surface, such as fruits and vegetables (Ciolacu et al. 2014; Winarti et
al. 2012; Krochta and Mulder-Johnson 1997) and meat (Cagri et al. 2004; Krochta and
Mulder-Johnson 1997). Edible coating protects fruits from oxygen and water vapor
(Debeaufort and Voilley 1997), microorganisms (Brody et al. 2002), and mechanical
scratch so fruits perform longer shelf life.
Edible coating application has taken public interest along with the awareness
on food safety. A major requirement that needs to be fulfilled as edible coating are
good barrier to damage factors, does not affect products flavor, has a good mechanical
strength, good biochemical and physicochemical stability, safe, cheap, and applicable
(Diab et al. 2001). Three main sources of edible coating are polysaccharides (starch,
pectin, cellulose, alginate, and carrageenan), proteins (gelatin, casein, gluten, and zein),
and lipids (stearic acid, wax, fatty acid esters) (Sothornvit and Krochta 2001; Vargas
et al. 2008).
Application of aloe vera as edible coating has been studied on grape (Castillo
et al. 2010), minimally processed apple slice (Chauhan et al. 2011), salak (Rahmawati
2012), peach and plum (Guillén et al. 2013), kiwi (Benitez et al. 2013), pomegranate
arils (Martínez-Romero et al. 2013), and raspberry (Hassanpour 2015). Aloe vera is a
polysaccharide source that can form film. Aloe vera does not change fruit’s color since
its film is transparent. It does not change flavor and users-environmentally friendly
(Reynold and Dweck 1999). Furthermore, aloe vera contains bioactive compounds that
give good implication on fruit preservations. Those compounds are acemannan,
glucomannan, pectin, and Aloeride (Ahlawat and Khatkar 2011; Ramachandra and
Rao 2008).
Objective
This research aimed to get information about the effect of aloe vera edible
coating and storage temperature on minimally processed salak pondoh (Salacca edulis

2

Reinw.). Furtheremore, this research aimed to know the effect of spray drying process
on Aloe vera edible coating characteristics and its effectiveness to maintain minimally
processed salak pondoh.

METHODS
Materials
Salak pondoh (Salacca edulis Reinw.) fruit was harvested from farm in
Parung, Bogor, while aloe vera (Aloe vera L.) was harvested from IPB’s farm, Bogor.
Sodium hypochlorite 200 ppm was used to sanitize salak fruit before it was coated.
The edible coating was made from polysaccharide, such as aloe vera, Carboxy Methyl
Cellulose (CMC) and maltodextrin, and glycerol as plasticizer.
The analysis materials were iodine solution, starch indicator, NaOH solution
0.1 N, and phenolphthalein (PP) indicator.
Edible Coating Preparation
The aloe vera solution was extracted by peeling and trimming, crushing, and
filtering the aloe vera (Figure 1). Preliminary research was conducted to get percentage
of CMC and maltodextrin on edible coating formula that could be dried by using spray
dryer. The initial percentage of CMC (m/v) were 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, while
maltodextrin (m/v) were 5%, 10%, and 15%. The most suitable percentage of CMC
and maltodextrin that were obtained on the preliminary research was then used in the
main research.
Aloe vera solution, CMC, maltodextrin, and glycerol then homogenized to get
the best substances distribution. Powdered aloe vera based edible coating was obtained
by spray drying method using spray dryer BUCHI 190 in pilot plant laboratory
SEAFAST. Spray drying method is chosen in the drying process since it is the common
method to dehydrate aloe vera solution for cosmetic need. Spray drying is also
common method to make food in powder form. The flow process chart of edible
coating preparation is shown at Figure 2.
Edible Coating Characterization
Water content was observed on fresh edible coating and edible coating powder
to know distilled water that is needed to dissolve powdered edible coating in the
application. Then both edible coating, fresh and diluted powder (so water content was
equal to fresh edible coating), were examined its viscosity, total soluble solid (TSS),
pH, titratable acidity, and vitamin C. Visual color was also observed to know the
implication of high temperature as long as spray drying process on the physical
appearance.

3

Aloe vera

sortation

Water

washing and
cleaning

2.5 % (w/v) Citric
acids solution

15 minutes
submersion

Peeling

Water

Trimmed

Aloe vera rind

Aloe vera muchilage
washing

Crushing

Filtering

Pulp

Aloe vera
solution

Figure 1 Aloe vera solution preparations
Edible Coating Application
Both edible coating were applied to minimally processed salak fruits (Figure
3). Postharvest treatment that was applied to salak before edible coating application
was sortation and trims. Salak was disinfected using 200 ppm sodium hypochlorite
solution, since the fruits were potentially microbes contaminated by touching earth and
dirt during its life. The edible coating was applied to minimally processed salak.

4

Samples were stored at different temperature to know the effect of temperature in
maintaining the sample and effectiveness of edible coating.
Aloe vera
solution

CMC, maltodextrin,
glycerol

mixing

homogenizing

Fresh edible
coating

Spray drying

Powdered edible
coating

Figure 2 Edible coating preparations
Fruit Quality Parameters
Fruits parameter that was observed in this research were weight loss, firmness,
pH, visual appearance, and percentage of decay. Weight loss of fruit was observed
everyday using gravimetric method (AOAC 2005). Salak solution was tested pH value
using pH meter at 22-23 oC (AOAC 2005).
Visual appearance was observed to know fruit’s physical changes during
storage everyday. Camera is used to document each fruits condition. Samples were
placed on dark background (black) to get high contrast to salak and trays. Overall
observations and measurements (fruit’s firmness, pH, and percentage of decay) was
also conducted based on physical change observation. It was conducted when there
was high physical change, such as molds growth on samples and browning. Decay of
fruit was also measured to determined percentage of decay of salak during storage.

5

Salak

sortation

Sodium hypochlorite
200 ppm

5 minutes
submersion

peeling

Sodium hypochlorite
200 ppm

3 minutes
submersion

Air drying

Edible coating

Application (dip
method)

Air drying

Tray and wrap
plastic

Rejects

packaging

Storage (8-10 oC
and 25-28 oC)

observations

Figure 3 Edible coating applications

Salak’s rind

6

Statistical Analysis
This research used Completely Randomized Design as statistical analysis.
Factor for this research was edible coating treatment and storage temperature. There
were 3 degrees of edible coating; these are control, fresh edible coating, and powdered
edible coating, while storage temperature has two degrees; these are cold and ambient
temperatureEach treatment was conducted in two replications. Mathematical model on
the statistical analysis used was:
Yij =  + Ai +Bj + ABij + εij,
Yij was response for each parameter,  was average value, Ai was effect of
storage temperature degree-i (i = 1, 2), Bj was effect of edible coating treatment
degree-j (j = 1, 2, 3), Abij was the interaction between edible coating and storage
temperature, and εij was error.
The data for statistical analysis was the change rate of response variable. The
change rate of the response variable was obtained by slope of time series response
value. The response variables that were statistically analyzed on this research were
firmness, pH, weight loss, and percent of decay.

RESULT AND DISCUSSION
Preliminary Research
This research tried to make aloe vera edible coating’s formula that was adopted
from Rahmawati (2012), which contains Aloe vera solution, CMC 0.5% (m/v), and
glycerol 1% (v/v). Unfortunately, spray drying of this edible coating resulted few
yields that was less than 2 grams from 300 ml solution of edible coating. There might
be two main reasons that affected this low yield, it were low soluble solids content and
high viscosity.
Table 1 Maltodextrin formulation
Maltodextrin (%)
0
5
10
15

CMC (%)
0.5
0.5
0.5
0.5

TSS (oBrix)
2
7
13
19

Film characteristic
Flexible and not hard
Flexible and not hard
Crackly and hard
Crackly and hard

This formula has low content of soluble solids since 98% of aloe vera is water
(Nindo et al. 2010; Rahmawati 2012; Hendrawati 2015) and little percentage of CMC
on the edible coating formula. Filler that is commonly used to increase content of
soluble solids on food product is maltodextrin. Furthermore, maltodextrin has been
being used as additional material on aloe vera solution before it is dried (Nindo et al.
2010; Cervantes-Martínez et al. 2014). Basically, more maltodextrin on the solution
increased total soluble solid (TSS). In contrary, the maltodextrin concentration
difference offered different film characteristic. Those 10 and 15 percentage of

7

maltodextrin formed crackly film, while 5% formed better film that did not too hard
and more flexible. So in this step, addition of 5% maltodextrin was determined to be
used in main research.
This edible coating was polysaccharide based, so the high viscosity was
affected by hydrocolloids characteristic of polysaccharide that was used (Skurtys et al.
2010), especially CMC content. High edible coating viscosity caused the difficulties
on spray drying process. Based on spray drying trials, basically all solution 0.1-0.4%
CMC (m/v) and maltodextrin 5% (m/v) could be sprayed. Brown crust was formed on
the drying chamber and some solution piled up in the bottom of drying chamber.
Nozzle on spray dryer tends to spray bigger droplets for more viscous solution (BETE
2005). Water content was also trapped stronger on the droplets so not all droplets were
evaporated. This condition is the reason why some solution was not dried properly on
the spray drying process. So in this step, addition of 0.4% CMC was determined to be
used in main research.
Besides spray drying, there are two drying processes to produce powdered
edible coating. Those methods are dry mixing process and foam-mat drying. Dry
mixing means mix all formulation in dry or powder form. So in dry mixing method,
solution of aloe vera, maltodextrin, and glycerol is sample to be spray dried. Powdered
aloe vera and CMC are mixed to be powdered aloe vera edible coating. While foammat drying does not use spray drying but oven. In this method, tween is added to aloe
vera edible coating solution then is dried by using oven. Those drying method might
be perform better drying process than that was implemented in this research as those
do not have viscosity problem in drying process.
Aloe Vera Edible Coating Character
In general, there was much change from fresh edible coating to powdered
edible coating. Water content of fresh aloe vera edible coating was 93.99%, while
powdered aloe vera edible coating was 4.27%. Little water content on powdered edible
coating surely will delay microbial growth on the powder that is the major factor of
aloe vera edible coating decay. The water content of powdered aloe vera edible coating
is equal to 0.2-0.3 of water activity (aw). This aw could delay edible coating decay that
was caused by microbial activities. At least 0.6 of aw (water content 15-20%) is
required by microbes to grow on food products (Dilbaghi and Sharma 2007).
Based on aloe vera edible coating characterization (Table 2), there was
dramatically change on the powdered aloe vera edible coating that has been diluted on
distilled water. This change was because of shear and high temperature during spray
drying process. Aligned with Nindo et al. (2010) who said that solution viscosity and
bioactive compounds on aloe vera was decreasing because shear force during spraying
on nozzle and high temperature. Those condition breakdown polysaccharide chain on
solution.
Total soluble solid and titratable acidity of aloe vera edible coating decreased
after spray drying. This condition was related to the bioactive compound breakdown
since bioactive was represented as TSS and titratable acidity on its solution. High
temperature during spray drying forced to breakdown bioactive compounds and
volatile compounds loss. Hendrawati (2015) stated that spray drying of aloe vera
solution at 140 oC inlet air temperature decrease soluble bioactive on the solution. The
lost bioactive due to spray drying were Aloe-emodin, Aloeresin A, dan crhysophanol,

8

while Aloenin (B) dan Aloenoside A dan B remained in a very small amount. The rest
remained bioactive compound on the powdered aloe vera was Aloesin. The pH value
(Table 2) of both edible coating also clarified the bioactive compounds loss. Bioactive
compound loss affected the decrease of titratable acidity, and then pH value increased.
Table 2 Edible coating characteristics
Characters
Viscosity (cP)
TSS (oBrix)
pH
Vitamin C (mg/100 grams
sample)
Titratable acidity (ml NaOH
0.1N/100 grams sample)
Color

Fresh edible
coating
77.92
6.30
5.10
0.2567

Edible coating from
powdered form
20.03
4.40
6.25
0.2569

129.45

39.74

smooth green

yellowish

Aloe vera edible coating solution changed to be yellow from fresh smooth
green. This condition indicated that there was browning reaction on the aloe vera
edible coating solution. Browning reaction can be affected by enzymatic and nonenzymatic reaction. Enzymatic browning mostly happens in agricultural produce, i.e.
fruits and vegetables. Enzyme polyphenol oxidase catalyzes polyphenol compound on
fruits and vegetables to quinones, which then polymerize to dark melanin pigments
(Friedman 1996). Non-enzymatic browning reactions on food product are maillard
reaction and charamelization. Maillard reaction happens when there is a chemical
reaction between amino acids and reducing sugars. Charamelization happens during
the heating of sugars (Latifah and Apriliawan 2009). Remembering the spray drying
condition and protein content on aloe vera solution, charamelization is the browning
factor which likely happened on the powdered aloe vera edible coating.
In the application, both aloe vera edible coating’s difference did not affect
salak’s visual appearance and flavor. The aloe vera edible coating solution formed
transparent and thin layer on the product surface so both edible coating difference did
not give any implication on sample’s appearance and flavor.
Aloe Vera Edible Coating and Storage Temperature Effects on Salak Quality
After analysing the effect of spray drying process on aloe vera edible coating
charracteristic, the effect of aloe vera edible coating and storage temperature to fruit’s
quality parameters was also analyzed. The parameters of fruits in this research were
chosen as those are the most parameters which consumers concerns about. Those
paratemers were weight loss rate, pH change rate, firmness change rate, and percentage
of decay rate. The rate of change of salak’s quality parameters was calculated and the
data is shown in Table 3.

9

Table 3 The effect of edible coating on change rate of salak parameters in different
storage temperature
Parameters
Weight loss
(grams per
day)
Firmness
(mm/5
seconds per
day)
pH (per
day)

Ambient storage temperature
Fresh Powdered
Control
EC*
EC

Cold storage temperature
Fresh Powdered
Control
EC
EC

0.55

0.48

0.52

0.04

0.04

0.04

-0.3000

-0.2875

-0.3063

0.1575

0.7350

0.4600

0.12

0.09

0.11

0.06

0.02

0.03

*EC referred to Edible coating

Weight loss
Weight loss of fruits was the result of transpiration (Rahman 2007; Valero and
Serrano 2010; Robertson 2012), since transpiration still happens on fruits besides
respiration. Rahman (2007) said that transpiration is a process of mass transfer in
which the water vapors from the surface of the produce to the surrounding atmosphere.
This water loss makes fruits wilt and decrease its weight.
Figure 4 shows that samples which were stored in ambient temperature had
higher weight loss than cold storage did. The rate of weight loss (Table 3) supported
that temperature storage affected fruit weight loss. Statistical analysis also showed that
storage temperature significantly affected fruit weight loss and both temperatures
significantly different (p