The Impact of Blanching and Vacuum Packaging to The Shelf Life of Fresh Seasoned Tempe

THE IMPACT OF BLANCHING AND VACUUM PACKAGING
TO THE SHELF LIFE OF FRESH SEASONED TEMPE

GIDEON SATRIA PUTRA SUGIYANTO

DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY
FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015

STATEMENT LETTER OF MANUSCRIPT AND SOURCE OF
INFORMATION*
Hereby I genuinely state that the manuscript entitled The Impact of
Blanching and Vacuum Packaging to The Shelf life of Fresh-Seasoned Tempe
is an authentic work of mine under supervision of academic advisor and never
being presented in any forms and universities. All the information taken and
quoted from published or unpublished works of other writers have been
mentioned in the texts and attached in the references at the end of the manuscript.

Bogor,

The Undersigned,

Gideon Satria Putra S
NIM F24100064

ABSTRACT
GIDEON SATRIA PUTRA SUGIYANTO. The Impact of Blanching and
Vacuum Packaging to the Shelf Life of Fresh Seasoned Tempe. Supervised by
JOKO HERMANIANTO, MADE ASTAWAN, SULIANTARI.
Tempe is an indigenous fermented food from Indonesia, prepared by the
action of molds, Rhizopus sp., on cooked soybeans. In 2012, up to 60% of
soybean production went to tempe industry with consumption of tempe reaching
8.5 kg per person per year in Indonesia. However, the export of tempe seems still
impossible due to its perishable characteristic whose shelf life is very short. Preblanching and vacuum packaging were expected to extend the shelf life of tempe.
This research was aimed to study the application of blanching and vacuum
packaging on the shelf life of fresh-seasoned tempe. Steam blanching of 80 oC for
three minutes was selected from pre-investigation for pre-treatment of the tempe
without inducing cooked-tempe characteristic. The result of main research
revealed that steam blanching and vacuum packaging were able to extend the
shelf life of fresh-seasoned tempe for two days in room temperature (23-24 oC),

32 days in refrigeration temperature (4-6 oC), and 49 days in chilling temperature
(0-4 oC). The pH of tempe was found increasing during storage with texture
getting overstuffed or tender during storage.
Keywords: Fresh-seasoned tempe, shelf life, storage temperature, vacuum
packaging

THE IMPACT OF BLANCHING AND VACUUM PACKAGING
TO THE SHELF LIFE OF FRESH SEASONED TEMPE

GIDEON SATRIA PUTRA SUGIYANTO

Manuscript
Submitted as a partial fulfilment of the requirement for
degree of
Bachelor of Agricultural Technology (STP)
At the Department of Food Science and Technology

DEPARTEMENT OF FOOD SCIENCE AND TECHNOLOGY
FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY (IPB)

BOGOR
2015

PREFACE
Thank God, Thank God, Thank God for Your abundant grace and blessing so that
finally I could finish this final year project and my bachelor degree in Food
Science and Technology - IPB regardless hesitations and uncertainties I had
before. In this occasion, I would like to embrace my appreciation and gratitude to
people and organization whose contribution cannot be disregarded.
1. Mama, Ayah, my two little angels, Maria and Yosua, and my whole
family in Kediri for genuine and never ending love, prayers, and support
given
2. Dr. Joko Hermanianto, Prof. Made Astawan, and Dr. Suliantari for being
my final year project supervisors. Thanks for the constant
encouragements, advice, input, constructive criticism, and moral value
shared
3. The Directorate of Research and Community Service, the Directorate
General of Higher Education, Ministry of Education and Culture, for
funding this research through the “Hibah Kompetensi” scheme under the
name of Made Astawan

4. Karya Salemba Empat (KSE) for providing me scholarship.
5. Gerardus Yosua, Mustika Aminta, Ayu Pramesti for sharing laugh-tears,
happy-sad and bearing with my vicissitudes. Fahlul Bariqi, Raditya
Prabowo, Stella Alinneshia, and Mutiara Pratiwi for always inspiring.
Not to mention all of my friends in ITP 47 „Doa Ibu‟ such as but not
limited to Nurul Falah, Tessa, Diki, Tasya thanks for three years
irreversible FST life, also to my „extended family‟, USM-AIMS
exchange students and ITP 48 for a short colorful semester.
6. Indonesia Tempe House (Rumah Tempe Indonesia) for allowing me to
come over and make the tempe there.
7. Technicians of laboratories of Food Science and Technology and UPT
ITP for being wonderfully helpful.
8. IPB Debating Community family for nurturing me to be high achiever,
especially Mam Alfa for being great, inspiring, humble Ibu in IDC and
giving me exceptional motivation.
9. House mates in „The Dharma House‟, Alam, Habib, Luqman, Hijran,
Sodik, and Dias for being my true family in Bogor.
10. Everyone who has given contribution toward this manuscript and help or
support during my university life in IPB.

Bogor,
Gideon Satria PS

TABLE OF CONTENT
ABSTRACT

iv

PREFACE

vii

TABLE OF CONTENT

ix

LIST OF TABLE

x

LIST OF FIGURE

x

LIST OF APPENDICES

x

INTRODUCTION

1

Background

1

Objectives

2

Advantages of Research

2

METHODOLOGY

3

Time and Places

3

Materials

3

Instruments

3

Methods

3

RESULT AND DISCUSSION

6

Preliminary Study

6

Main Research

7

CONCLUSION AND RECOMEDATION

17

Conclusion

17

Recommendation

17

REFERENCES

17

APPENDICES

22

LIST OF TABLE
1.
2.
3.

4.
5.
6.

Blanching Time
Extended Storage Study for Fresh Seasoned Tempe
Extended Storage Study for Fresh Non-Seasoned Tempe
Chemical Composition of Fresh Seasoned Tempe
Result of Microbial Analysis
Heavy Metal Contamination Analysis of Fresh Seasoned Tempe

7
9
9
14
15
16

LIST OF FIGURE
1. Result of Sensory Evaluation on Attributes of Aroma and Taste room

(a), refrigeration (b), and chiller (c) with area below yellow line ( )
is rejected area
2. Change of penetrometer score during storage in room (a),
refrigeration (b), and chilling temperature(c).
3. Change of pH of tempe during storage in room(a), refrigeration(b),
and chilling temperature (c).

8
11
13

LIST OF APPENDICES
1.
2.
3.
4.
5.

Independent Sample Test (T-Test) for Pre-Blanching
Univariate Analysis of Variance One Way ANOVA Water Content
Univariate Analysis of Variance One Way ANOVA Protein Content
Univariate Analysis of Variance One Way ANOVA Lipid Content
Univariate Analysis of Variance One Way ANOVA Carbohydrate
Content
6. Univariate Analysis of Variance One Way ANOVA Ash Content

22
32
33
34
35
36

INTRODUCTION
Background
Tempe is an indigenous fermented food from Indonesia, prepared by the
action of molds, such as but not limited to Rhizopus sp., on cooked soybeans
through controlled fermentation process. Tempe has been being preferred staple
food in Indonesia for years. Tempe is well known for its nutritional value, health
benefits (Astuti et al. 2000; Astawan 2008; Babu et al. 2009; Messina et al. 2009),
and admirable digestibility (Nout and Kiers 2005). Indonesia is acknowledged as
world‟s biggest producer of tempe and centre of soybean market in Asia. In 2012,
up to 60% of soybean stocks went to tempe industry with the average population
consumption of tempe in Indonesia reached 8.5 kg per person per year (BPS
2012). It was also estimated that there were more than 81 thousand small
enterprises of tempe in Indonesia that produced up to 2.4 million ton of tempe per
year. Indonesia was only able to supply 600 thousand ton soybean out of 2.2
million ton soybean‟s needs every year. Normally, Indonesia imports soybean
from the United States of America to satisfy the demand of soybean (BSN 2012).
Tempe becomes one of meat alternative for people living as vegetarian or
veganism due to its high protein content. Sarwono (2002) revealed that in 100 g of
fresh tempe contain around 18.3 g protein while in 100 g of beef contain 12.8 g
protein. Following that fact, potential market of tempe is not only domestic scale
but also international one, countries like India, China, Japan, Australia, European
countries (Vegetarian Victoria 2011), as well the United States are listed as top
countries with high number of vegans (Stahler 2009). In 2013, there were up to
540 million people were vegetarian with the top consumers spread in India up to
500 million people (Vegetarians 2013) and the rest 40 million were European and
American (Raw Food Health 2008). The prediction, which said that up to nine
billion people around the world would follow vegetarian trend in 2050, has even
strengthened the prospect of tempe in the future (Huffpost Living 2014).
The development of tempe has been significantly done all over the world.
Shurtleff W and Aoyagi A (2004) informed that tempe is also popular and has
attracted attention in USA, Canada, Australia, European countries, etc. In
Indonesia, tempe improvement is also rapid in term of raw materials
diversification, processing method improvement, and regulation. Nowadays,
tempe is not only made from soybean but also being varied by utilizing other
beans, such as cowpea (Vigna unguiculata subsp. unguiculata), jack bean
(Canavalia ensiformis), red bean (Vigna angularis), barley kernels (Feng et al.
2007), chickpeas (Reyes-Moreno et al. 2000), etc (BB-Pascapanen 2008),
however, soybean-based tempe is still among favourite due to its organoleptic
acceptance and higher nutrition content. Processing of tempe is no longer
conservative which has no concern on food safety, some tempe producers and
enterprises have applied Good Manufacturing Practices (GMP) and afforded
certification of Hazard Analysis Critical Control Point (HACCP) to ensure
standard quality and safety of tempe. Not to mention, Government of Indonesia
has genuinely established the standard quality of tempe by establishing Indonesia
National Standard of Tempe – SNI 01-3144-1998 that has been updated to SNI
3144-2009. In the 36th Codex Allimentarius Commission (CAC) Assembly in
Rome in 2013, tempe standard was adopted as regional CODEX standard and

2
soon would become worldwide tempe‟s standard (CODEX Indonesia 2013). It
showed how world has also put highest concern upon tempe as international food
that is indigenous from Indonesia.
Despite the above facts, the export of tempe seems still impossible due to
its perishable characteristic whose shelf life is very short. Tempe can only last for
one to two days in ambient temperature. Consequently, it has been being obstacle
for further development and innovation of tempe product. Consumers are
requested to consume tempe directly or save it in short time prior to consumption.
Whereas, consumers nowadays are demanding food with longer shelf life, simple
in processing or cooking, and delicious. Thus, seasoning with salt and garlic was
chosen as that combination is most favourite and simplest seasoning for tempe in
Indonesia.
Many researches have been done to study methods of extending shelf life
of tempe, such as dried-flavored tempe (Mutiara 1985), drying and sterilization of
tempe (Kemala 2006), and also combination of vacuum packaging and
sterilization (Indriani 2006). Previous studies were mostly applying high
temperature-thermal process that has been proven to extend shelf life of food
product. However, thermal process application changes the natural appearance
and physical properties of fresh tempe which is unable to meet consumers
preference upon fresh tempe. Thus, blanching and vacuum packaging were
expected to extend the shelf life of fresh tempe without changing the natural
appearance and physical properties of fresh tempe. Vacuum technology is also
very applicable for small and medium enterprises. Seasoning is projected as
addition process to increase added value of the tempe and also to fulfil people
nowadays‟ trend upon ready-to-cook food.
Objectives
The objectives of this study were to determine the impact of blanching
process to the shelf life of fresh-seasoned tempe, to determine the impact of
vacuum packaging to shelf life of fresh-seasoned tempe, to predict the shelf life of
fresh-seasoned tempe packed in vacuum packaging in three different storage
temperatures, which were room (23-24 oC), refrigeration (4-6 oC), and chilling
temperature (0-4 oC).
Advantages of Research
The benefits of this research were addressed to the government, society,
farmer and tempe producers, as well as individual who had a major role in the
floating potential of natural resources. For the government, the results of this
study could be used as a basis for the further development of indigenous food,
especially by provisioning fresh-seasoned tempe and extending the shelf life
which increase added value of tempe. For society, tempe product development
could become a new option in the variation of fresh seasoned-tempe. For farmer
and tempe producers, this research was expected to be placed as incentives to
double the cultivation of local soybeans and multiple tempe-based products. For
individuals who were always challenged with creative ideas, this research is
expected to foster the spirit to find other ideas related to the development potential
of local resources, which were worth winning.

3

METHODOLOGY
Time and Places
This research was conducted in two places. The first place was Indonesia
Tempe House or Rumah Tempe Indonesia (Bogor) for producing the tempe. The
second place was Faculty of Agricultural Engineering and Technology Laboratory
Bogor Agricultural University (IPB), which were Pilot Plan SEAFAST-Center for
blanching process, Packaging Laboratory of Department of Agricultural Industrial
Technology for packaging process, Laboratory of Department of Food Science
and Technology for analysis. Research was done in March – June 2014.
Materials
Materials of this research were classified into two groups, which were
materials for tempe manufacturing and for analysis purposes. Materials for
producing tempe consisting of local soybean (Glycine max) Grobogan from
Central Java-Indonesia, water, filter cloth, brand Raprima yeast, plastic packaging
polyethylene thickness of 8 mm, seasoning (garlic and salt). The materials needed
for the analysis included H2SO4, HgO, K2SO4, solution of 60% NaOH-5%Na2SO3,
H3BO3, HCl, Boiling stones, methylene blue indicator, the indicator phenoftalein,
hexane, NaOH, Whatman filter paper No. 2, ethanol, and distilled water. Media
required for microbiological analysis were lactose broth, RV medium, TT broth, HEA,
BSA, XLDA, TSIA, LIA, LTB medium, EC Broth, EMBA, Trytone broth, MRVP
Instruments
Instrument of this research were classified into two groups, which were
materials for tempe manufacturing and for analysis purposes. Instruments for
making tempe consisting of buckets, containers stainless boilers, machinery
soybean stainless skinner, rack stainless fermentation, and the fermentation
chamber (incubator), steam blanching, vacuum sealer. The instrument used for the
analysis were analytical balance, oven, desiccator, electric furnace, Kjeldahl
complete, complete distillation apparatus, Soxhlet extraction tools such as
condensers and electric heating, pH meters, penetrometer, chemical analytical and
other standard microbiological analytical tools.
Methods
This research was divided into two parts, which were preliminary
investigation and main research.
Preliminary Investigation
Characterization of soybean
Characterization was done by conducting manual separation of physical
contamination of soybean, such as twig, gravel, sand, and rejected soybean from
selected soybean.

4
Production of Tempe
Production of tempe was done by applying Good Manufacturing Practices
(GMP) and follow standard tempe manufacture in Rumah Tempe Indonesia (RTI),
Bogor-Indonesia. The inoculated soybean was packed in oval-shaped plastic (d=
2cm) which had been perforated.
Determination of Blanching Time
Determination of blanching time was done by exposing hot air using steam
blanching (80 oC) to ten slices of tempe with thickness of two cm. Blanching
times were varied from one minutes to 10 minutes. Texture of blanched tempe
was then observed and being compared with un-blanched tempe (control). Texture
analysis using penetrometer was also done to examine the texture change
objectively. Selected tempe was the tempe that had no significance difference
with control in term of texture (p > 0.05) using T-Test.
Main Research
Production of Fresh Seasoned-Tempe and Packaging Process
Tempe that had been made were sliced uniformly with thickness of two cm.
Tempe was then blanched by exposing 80 oC hot air for three minutes. The tempe
was then marinated in seasoning for one hour to allow optimal absorption.
Seasoning that was chosen in this research was salt and garlic. A 10 gram of salt
was mixed by 30 gram of garlic and 200 ml water. All of those ingredient were
blended homogenously prior to seasoning.
After that, seasoned-tempe was drained before being packed in vacuum
packaging using PE plastic. The processes above were done aseptically to prevent
microbial contamination. Tempe was then stored in three different temperatures,
which were room temperature (23-24 oC), refrigeration temperature (4-6 oC) and
chilling temperature (0-4 oC)
Determination of Shelf life
Determination of shelf life of was done both subjectively and objectively.
Subjective evaluation was done by conducting sensory evaluation test of tempe to
ten trained panellists using hedonic test. Trained panellists were selected after
several selection steps. Starting from their sensitivity upon colours, taste, aroma,
texture and continued by their sensitivity upon tempe‟s attribute changes. Selected
panellists undergone series of training to enhance their assessment‟s sensitivity
upon sensory attributes of tempe. Objective evaluations were conducted through
pH measurement and texture during storage.
Extended Storage Study (Arpah 2001)
Sensory evaluation was conducted as a method of determining shelf life of
fresh-seasoned tempe subjectively. Ten trained panellists were asked to assess its
acceptance based on colour, texture, aroma, and overall acceptability during
storage for fresh-seasoned tempe and added taste parameter for fried tempe.
Hedonic 7-scale test with scale point from 1 represents dislike extremely, 2 dislike,
3 dislike moderately, 4 neither dislike nor like, 5 like moderately, 6 like and 7
which represents like very much or extremely. Previously, panellists were given
adequate information and training to identify good quality of tempe as well as

5
spoiled tempe. Sensory evaluations were held every day for tempe that were
stored in room temperature, every three days for tempe that were stored in
refrigeration temperature, and every seven days for tempe that were stored in
chilling temperature. Tempe owning average score below four in particular
attribute would be classified as deteriorated tempe due to rejection from panellist
and the sensory evaluation test would be ended and proceed to simple regression
drawing to determine the predicted shelf life. This conventional method of
determining shelf life is proven accurate for food that has shelf life less than three
months (Arpah 2001).
Measurement of pH
Prior to measurement, pH meter was stabilized for ±10 minutes and
calibrated using pH 4.0 and 7.0 standards. Electrode was rinsed with distillate
water dried thoroughly using dryer paper. Tempe that had been mashed was
mixed homogenously with distillate water with a ratio of 1:1. Electrode was
placed into the sample and allowed to stabilize to measure the pH of sample.
Analysis of Texture using Penetrometer
Selection of appropriate probe was done prior to texture-analysis using
penetrometer. A probe of needle without burden was used in this study. To start
analysing, clutch button was pressed to lock the probe once it was fitted. Probe
was then lowered until almost touching the sample and the run button was pressed
to start analysing for five seconds. This analysis was done ten times for one
sample in different spots to ensure that the result would represent all parts of the
sample. The average of ten scores showed from the display was the result of
texture analyses that expressed in depth (mm/5sec).
Proximate Analysis
Analysis of Moisture Content (AOAC 2005)
Moisture content was determined by drying the sample in the hot air oven at
100-105 oC for four hours. About 10±0.10 g of sample tempe was weighed into
pre-dried and weighed moisture dishes, and place in the oven at 100-105 oC until a
constant weight obtained.
Analysis of Crude Fat Content (AOAC 2005)
Sample of tempe was hydrolysed before undergoing crude fat content
analysis. Crude fat of tempe was determined by solvent extraction using the
Soxhlet system. About three g of tempe sample was weighed into pre-dried
thimble covered with cotton and dried in 105 oC oven for two hours. Hexane was
poured into a pre-dried and weighed vessel in the cup holder. The thimble was
attached onto the magnetic head of extraction unit. The vessel was transferred to
105 oC for 30 minutes to evaporate the excess hexane, cooled in desiccators, and
weighed.
Analysis of Crude Protein Content (AOAC 2005)
Crude protein content was conducted using Kjeldahl method. A total of 250
mg of sample was weighed using an analytical balance. Furthermore, the sample

6
went through three stages of crude protein content analysis using Kjeldahl method,
namely the stage of digestion, distillation, and titration.
Analysis of Ash Content (AOAC 2005)
About ten g of tempe sample was weight into ashing dish that had been
ignited, cooled, and weighed. Sample was burned by Bunsen burner until the
some vanished. The ashing dish was transferred into muffle furnaces at 550 oC
until white or grey-white, cooled in desiccator and weighed.
Analysis of Carbohydrate Content (By Difference)
Carbohydrate content dry basis in the sample was determined by
subtracting the sum of the percentage of crude protein, crude fat, and ash
from 100.
Analysis of Microbiology
Microbial analysis was done to detect the existence of Salmonella sp. and
E. coli in fresh-seasoned tempe. There were several steps to conduct microbial
analyses, which were enrichment, pre-prediction, prediction, identification.
Bacteria were analysed following standard methodologies described in the
Bacteriological Analytical Manual of Escherichia coli (Feng et al. 2002) and
Salmonela sp. (Andrews and Hammack 2007)
Analysis of Heavy Metal Contamination
Heavy metal contamination was conducted to analyse possibility of
contaminations of Cd, Pb, Sn, Hg, Ar. Analysis was conducted using atomic
absorption spectrophotometer (AAS).

RESULT AND DISCUSSION
Preliminary Study
Determination of Blanching Time
Blanching is a unit operation that is commonly done to inactivate enzymes,
modify texture, preserve colour, flavour, and nutritional value, and remove
trapped air in food. Blanching can be done through water blanching, steam
blanching, microwave blanching, or gas blanching (Corcuera 2004). Gokmen
(2005) reported that exposing food with hot air 80 oC through blanching could
inactivate up to 90% of enzyme activities. Compared to hot water blanching,
steam blanching was found to be more effective and beneficial in preventing
excess of nutrients loss (Martinez et al. 2012; Xiao et al. 2014). Steam blanching
80 oC was applied in this research on tempe product as pre-treatment to suppress
metabolic activity of molds (prevent continued fermentation) and also proteolytic
and lipolytic enzyme which were major reasons of fresh tempe deterioration.
In this study, blanching time was pre-determined to ensure that supporting
effect on extending the shelf life could be gained yet blanched-tempe would still
own fresh-like texture. The texture of blanched tempe from every variants of the
blanching was assessed using penetrometer test and compared by non-blanched
tempe. The significance of the texture changing was checked using T-Test SPSS .
Duration of three minutes steam blanching was chosen after assessing the texture

7
changing of blanched tempe compared by un-blanched tempe as a control. The
result of penetrometer test (Table 1) showed that application of steam blanching
80 oC with the duration longer than three minutes had caused tangible undesirable
texture changing (p