Structural and Functional Properties of Fermented Soybean (Tempeh) by Using Rhizopus oligosporus

Figures & data

Table 1 Amount of free amino acids (mg/100 g soybean)in the fermented soybean using R. oligosporus.

	Fermentation time (hr)
Amino Acid	0	24	48	72
Essential Amino Acid
Ile	4.6	5.2	9.5	55.0
Leu	4.2	6.6	10.1	81.7
Lys	5.1	52.6	3.3	194.9
Met	2.1	0.7	1.3	6.3
Phe	1.4	5.6	6.2	63.4
Thr	0.2	0.2	0.4	0.1
Val	3.8	2.8	6.1	59.7
Semi Essential Amino Acid
Arg	26.7	32.4	7.6	21.5
Gly	2.7	5.2	21.4	61.3
His	1.7	26.4	2.0	50.6
Tyr	1.3	13.1	4.6	38.1
Non Essential Amino Acid
Ala	11.2	104.2	229.7	229.8
Asn	1.5	22.5	20.1	54.6
Asp	3.6	5.4	17.1	28.9
Cys	0.9	4.5	6.4	15.0
Glu	42.1	16.7	140.0	147.0
Pro	1.0	6.8	20.7	63.0
Ser	0.1	1.5	3.6	11.2
Orn	1.4	5.1	0.0	8.9
GABA	2.7	21.4	7.1	12.7
Total	118.3	338.9	517.2	1203.7
nd; not determined.

Table 2 Degradation of proteins during fermentation of soybean

	Protein (mg/100 g soybean)
Fermentation time (hr)	Albumin	Globulin	Alkaline soluble	Alcohol soluble
0	1.07 × 10^3a	65.64^a	10.43^a	22.02^a
24	0.37 × 10^3b	17.49^b	7.28^b	27.85^b
48	0.34 × 10^3c	7.47^c	5.85^c	31.74^c
72	0.28 × 10^3d	6.84^c	4.79^d	13.09^d
Values followed by the same letter in the same column are not significantly different (P < 0.05).

Table 3 Color properties of soybean during the growth of R. oligosporus.

	Index value
Fermentation time (hr)	L*	a*	b*
0	83.0^a	+1.1^a	+20.6^a
24	82.1^b	+2.1^b	+15.4^b
48	79.2^c	+2.5^c	+17.2^c
72	72.0^d	+3.8^d	+19.3^d
Values followed by the same letter in the same column are not significantly different (P < 0.05).

Figure 1 Change of pH during fermentation. Values followed by the same letter are not significantly different (P < 0.05).

Table 4 Instrumental texture properties of soybean during fermentationby R. oligosporus.

Fermentation time (hr)	Weakness(N)	Modulus of elasticity10^9 (Pa)	Surrender value10^6 (Pa)
24	2.83^a	0.73^a × 10^9	5.85^a × 10^6
48	7.14^b	1.02^b × 10^9	8.17^b × 10^6
72	2.68^a	0.61^a × 10^9	4.84^a × 10^6
Values followed by the same letter in the same column are not significantly different (P < 0.05).

Figure 2 Scanning electron micrograph of fermented soybean. A: Control; B: 24 hr; C: 48 hr; D: 72 hr; cw: cell wal; c: cytoplasm; v: vacuole