3
2 LITERATURE REVIEW
2.1 Soybean
Soybean Glycine max L. Merrill is a species of legume native to China
which is member of the family Leguminosae, subfamily Papilionoideae, and the genus Glycine, L. Liu 1997. There are two kinds of soybean: yellow soybean
coat usually used in Indonesia as raw material of tempe, tofu, bean sprout, and soymilk, and black soybean as main material of soy sauce production Purwanti
2004. Besides, soy bean is processed into soy protein ingredients including soy flour, concentrates, isolates, and textured soy proteins applied in various types of
bakery, dairy, and meat products, infant formulas, and the so-called new generation soyfoods Liu 1997. Comparation of chemical composition between
soybean and tempe is tabulated in Table 1.
Table 1 Chemical composition of soybean and tempe Kwon et al. 2010. Component
Soybean Tempe
Protein 20-42
23-55 Lipid
18-22 14-23
Carbohydrate 35
10-30 Isoflavone mg100 g
Genistin 36-86
6-19 Daidzin
15-57 2-3
Glycitin 2-6
0.1-0.4 Malonyl genistin
123-186 39-42
Genistein 0.2-5
7-10 Daidzein
0.3-5 7-8
Glycitein 0.1-0.6
0.5-0.7 Asam amino g100 g Aspartate
1.4-1.7 1.5
Glutamate 3.8-4.8
2.3 Serine
1.1-1.4 0.8
Glycine 0.7-0.9
0.6 Arginine
1.5-1.9 0.9
Alanine 0.8-1.0
0.6 Proline
1.1-1.3 0.6
Histidine 0.7-0.9
0.4 Valine
0.8-1.0 0.6
Methionine 0.2-0.3
0.2 Cystein
0.5-0.6 0.2
Isoleucine 1.0-1.3
0.7 Leucine
1.6-2.0 1.1
Phenylalanine 1.1-1.4
0.5 Tyrosine
0.8-1.0 0.5
Lysine 1.4-1.7
0.8 Threonine
0.8-1.0 0.5
Mineral g100 g Na
0.02 0.006
K 2.3
0.4
4
2.2 Tempe
Tempe is a product made from fermented soybean with Rhizopus spp. mould having compact solid form, grey-white color, and specific aroma of tempe
BSN 2009. The main mold used for the preparation of tempe in Indonesia is Rhizopus oligosporus Feng 2006. More strains identified in tempe, including
Rhizopus formosaensis and Rhizopus oryzae Babu et al. 2009. Various microorganisms, including filamentous fungi, yeasts and bacteria, are found in the
traditional tempe. The growth of lactic acid bacteria LAB, coexisting with R. oligosporus, is performed to improve the safety and could inhibit the growth of
pathogenic bacteria Ashenafi and Busse 1991, Feng et al. 2005. Table 2 shows the requirements of tempe quality regulated by National Standardization Agency
of Indonesia BSN.
Table 2 Requirements of tempe quality based on Indonesian national standard SNI 3144:2009.
Parameters Unit
Requirements Conditions
Aroma Color
Taste -
- -
normal, specific normal
normal
Moisture ww max. 65
Ash ww max. 1.5
Lipid ww min. 10
Protein N × 6.25 ww min. 16
Crude fiber ww min. 2.5
Metal poisoning Cd
Pb Sn
Hg As
mgkg mgkg
mgkg mgkg
mgkg max. 0.2
max. 0.25 max. 40.0
max. 0.03 max. 0.25
Microorganisms Coliform
Salmonnella MPNg
- max. 10
negative25 g
Tempe is made by soaking soybeans in water, removal of the seed coat, boiling the cotelydons, cooling, inoculating them with pure or traditional mixture
of starters, and incubating as a solid bed at 25-30
o
C for 24-72 h Nout and Kiers 2005. During fungal fermentation the enzymes degrades some substrates leading
to an increase of free amino acids, water-soluble nitrogen compounds, free fatty acids, and the development of specific flavor
Jeleń et al. 2013. Anti nutritional factors, such as trypsin inhibitors, tannin, and phytic acids, were also leached out
during cooking, dehulling, and fermentation. Besides, tempe processing eliminated almost stachyose, the most flatulent oligosaccharide in soybean
Egounlety and Aworh 2003.
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