Enhancement of isoflavone aglycone, amino acid, and CLA contents in fermented soybean yogurts using different strains: Screening of antioxidant and digestive enzyme inhibition properties.

This study was the first to evaluate changes in isoflavone, amino acid, conjugated linoleic acid (CLA), antioxidant effect, and digestive enzyme inhibition during fermentation of soy-milk to soy-yogurt with L. brevis and L. plantarum. Total average isoflavones were reduced (1318.2 → 971.1 μg/g) with an increase of aglycones (60.2 → 804.9 μg/g, genistein > daidzein > glycitein) in soy powder yogurts (SPYs). Amino acids increased considerably, as did ornithine (average 4.1 → 551.0 mg/g), and CLA showed high variations from not-detected (ND) to 0.5, 0.9 mg/g (cis-9, trans-11) and ND to 0.3, 0.2 mg/g (trans-10, cis-12). Digestive enzyme inhibitions (α-glucosidase, α-amylase, and pancreatic lipase) displayed high activities (average 50.6 → 67.2, 5.2 → 46.4, 10.6 → 51.4%). Moreover, the antioxidant abilities against radicals were elevated as follows: ABTS > DPPH > hydroxyl (average 63.5 → 86.5, 50.2 → 70.3, 39.3 → 55.2%). Specifically, SPY using mixed strains exhibited the greatest enzymatic inhibition and antioxidant capacities.

Hwang CE ，Kim SC ，Kim DH ，Lee HY ，Suh HK ，Cho KM ，Lee JH ... -  《-》

Comparisons of nutritional constituents in soybeans during solid state fermentation times and screening for their glucosidase enzymes and antioxidant properties.

This research was the first to demonstrate the variations of nutritional constituents, glucosidase properties and antioxidant activities in soybeans during different solid state fermentation times (germination → 5 periods for 12 days) with Tricholoma matsutake. Total isoflavones were significantly reduced (2661.54 → 1559.04 μg/g) with the increase of aglycone contents (107.61 → 1285.66 μg/g, 12 times) for fermentation, whereas amino acid and fatty acid slightly increased. Among them, daidzein (43.2 → 43.6 → 421.9 → 721.4 → 634.0 μg/g), genistein (52.7 → 24.4 → 339.5 → 546.6 → 512.8 μg/g) and glutamic acid (0.3 → 1.7 → 3.9 → 6.6 → 16.1 mg/g) markedly increased between germinated and fermented soybeans. Total phenolic contents and antioxidant abilities also considerably increased, especially, ABTS displayed the predominant scavenging capacities (33.1 → 94.8%) at 200 μg/ml, followed by DPPH (11.9 → 87.0%) and hydroxyl (11.2 → 49.2%) radicals. Interestingly, α-glucosidase inhibition (11.8 → 84.9%) and β-glucosidase (3.1 → 40.3 unit/g) exhibited the highest activities after 9 days. Our results implied that fermented soybeans may be contributed to enhance the soybean value in nutrition and biological effect aspects to development of new functional foods.

Lee JH ，Hwang CE ，Son KS ，Cho KM ... -  《-》

A systematic, comparative study on the beneficial health components and antioxidant activities of commercially fermented soy products marketed in China.

The objectives of this study are to systematically assess the bioactive substances and overall antioxidant capacities of commercially fermented soy products and to find the relationships between the presence of beneficial components in different types of soybean fermented products. The results show that phenolic profiles increased significantly after fermentation as compared with raw yellow soybeans. Among all the samples, the douchi and fermented black bean sauce had the highest detected antioxidant profiles. Even though the total isoflavone content was reduced in fermented soybean products (794.84 μg/g on average) as compared with raw yellow soybeans (3477.6 μg/g), there was an obvious trend of conversion of the glucoside form in raw soybeans into the aglycone-form isoflavones in the fermented soybean products. The highest daidzein and genistein values were found in the "Yangfan" black bean douchi, i.e. 860.3 μg/g and 1025.9 μg/g, respectively. The amounts of essential amino acids also were improved in most fermented soybean products. The douchi and black bean fermented products are recommended for consumption due to their abundant bioactive substances.

Xu L ，Du B ，Xu B 《-》

Changes occurring in compositions and antioxidant properties of healthy soybean seeds [Glycine max (L.) Merr.] and soybean seeds diseased by Phomopsis longicolla and Cercospora kikuchii fungal pathogens.

Changes in the compositions (isoflavone, protein, oil, and fatty acid) and antioxidant properties were evaluated in healthy soybeans and soybeans diseased by Phomopsis longicolla and Cercospora kikuchii. The total isoflavone content (1491.3 μg/g) of healthy seeds was observed to be considerably different than that of diseased seeds (P. longicolla: 292.6, C. kikuchii: 727.2 μg/g), with malonlygenistin exhibiting the greatest decrease (726.1 → 57.1, 351.9 μg/g). Significantly, three isoflavones exhibited a slight increase, and their structures were confirmed as daidzein, glycitein, and genistein, based on their molecular ions at m/z 253.1, 283.0, and 269.1 using the negative mode of HPLC-DAD-ESI/MS. The remaining compositions showed slight variations. The effects against 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radicals in healthy seeds were stronger than the diseased soybeans, depending upon the isoflavone level. Our results may be useful in evaluating the relationship between composition and antioxidant activity as a result of changes caused by soybean fungal pathogens.

Lee JH ，Hwang SR ，Lee YH ，Kim K ，Cho KM ，Lee YB ... -  《-》

Multi-response optimisation of the extraction solvent system for phenolics and antioxidant activities from fermented soy flour using a simplex-centroid design.

A simplex-centroid design comprising three solvents (water, ethanol and methanol) was used to optimise the extraction mixture for phenolics and antioxidant activities from defatted soy flour fermented with Monascus purpureus or Aspergillus oryzae. Total phenolics were more efficiently extracted using only water for both samples. The highest antioxidant activities by the DPPH and ABTS methods were obtained using extraction mixtures containing at least 75 wt% water. Specific water:ethanol:methanol ratios promoted the joint optimisation of the total phenolic and isoflavone contents as well as antioxidant activities: 0.5:0.375:0.125 (wt/wt/wt) and 0.5:0.3:0.2 (wt/wt/wt) from defatted soy flour fermented with M. purpureus or A. oryzae, respectively. However, a water:ethanol ratio of 0.5:0.5 (wt/wt) was deemed optimal because it is comprised of green solvents and yielded results that were greater than 90% of the multi-response maximum values. Both the solvents and the sample matrix strongly influenced the extractability of total phenolics and isoflavones.

Handa CL ，de Lima FS ，Guelfi MF ，Georgetti SR ，Ida EI ... -  《-》