Antioxidative Activity of Douchi (A Chinese Traditional Salt-Fermented Soybean Food) Extracts During Its Processing

Figures & data

Figure 1 A Aspergillus-type Douchi product made by a Douchi manufacturing company.

Figure 2 Flow diagram for processing soybeans to make Douchi.[15]

Table 1 Changes in the antioxidative properties for pretreatment of Douchi processing

Step	TEAC (mg trolox/g dry matter) ^a		The reducing power (absorbance at 700 nm) ^a
	DPPH radical	ABTS radical
Row soybean	1.54 ± 0.03A	13.72 ± 6.74A	0.177 ± 0.004C
Soaked soybean	1.26 ± 0.17A	16.65 ± 1.35A	0.243 ± 0.003B
Cooked soybean	1.36 ± 0.32A	16.84 ± 5.59A	0.271 ± 0.002A
^aMean of three determinations ± S. D. (standard deviation). Means with the same column with different letters were significantly (p < 0.05).

Figure 3 Scavenging activity of Douchi extracts by DPPH method and ABTS method during the prefermentation. Results are the mean ± S. D. of three determinations.

Figure 4 Reducing power of Douchi extracts during the prefermentation. Results are the mean ± S. D. of three determinations.

Figure 5 Scavenging activity of Douchi extracts by DPPH method during the postfermentation. Symbols denoted the experimental data, the mean ± S. D. of three determinations; Lines denoted the predicted data according to the Eq. (1).

Figure 6 Scavenging activity of Douchi extracts by ABTS method during the postfermentation. Results are the mean ± S. D. of three determinations.

Figure 7 Reducing power of Douchi extracts during the postfermentation. Symbols denoted the experimental data, the mean ± S. D. of three determinations; Lines denoted the predicted data according to the Eq. (1).

Figure 8 The rate constants (k) for the DPPH radical scavenging activity and for the reducing power in different salt contents. Results are the mean + S. D. of at 1 week and 2 weeks in postfermentation.

Wang , L.J. , Yin , L.J. , Zou , L. , Saito , M. , Tatsumi , E. and Li , L.T. 2007 . Influences of Processing and NaCl Supplementation on Isoflavone Contents and Composition during Douchi Manufacturing . Food Chemistry , 101 : 1247 – 1253 .

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