为获得具有更高生理活性的大豆酸奶，作者研究了大豆发芽对豆浆的乳酸菌发酵性能、发酵豆浆的生理活性和豆浆风味的影响。结果表明：在最初72 h内，随发芽时间的延长，大豆的三氯乙酸可溶性氮和游离氨基酸含量显著提高（P＜0.05）；豆浆乳酸菌发酵性能明显改善，达到发酵终点（pH 4.5）的时间由7.2 h缩短至5.0 h，酸度则由42.18 °T提升至66.56 °T；乳酸、柠檬酸等有机酸的含量增加。发芽使乳酸菌发酵豆浆的硬度降低，质构更细腻。在生理活性方面，发芽72 h后，乳酸菌发酵豆浆的γ-氨基丁酸含量增加了19.83 mg/hg，苷元型异黄酮含量增加了115.02%；DPPH、ABTS和羟自由基清除率均显著提高（P＜0.05）。另一方面，发芽导致豆浆中异味成分含量明显增加。在综合考虑发芽对生理活性和风味影响的基础上，以发芽36 h的大豆制备大豆酸奶，考察了4种直投式发酵剂对于大豆酸奶风味及感官品质的影响。结果表明，发酵剂A发酵得到的大豆酸奶异味成分含量最低，感官品质最佳。
To obtain soybean yoghurt with enhanced physiological activity, this study investigated the effect of soybean germination on the fermentation characteristics of soymilk by lactic acid bacteria and the physiological activity and flavor of soymilk. The results showed that within the initial 72 h, the content of trichloroacetic acid-soluble nitrogen and free amino acids in soybean significantly increased (P＜0.05) with the germination time. The fermentation characteristics of lactic acid bacteria-germinated soymilk were significantly improved, resulting in the duration to reach the fermentation endpoint (pH 4.5) shortened from 7.2 h to 5.0 h. Additionally, the titratable acidity increased from 42.18 °T to 66.56 °T, accompanied by an increase in the content of lactic acid and citric acid. Germination also reduced the hardness of lactic acid bacteria-fermented soymilk, resulting in a smoother texture. After 72 h of germination, lactic acid bacteria-fermented soymilk exhibited increased physiological activity with a 19.83 mg/hg increase in γ-aminobutyric acid content, a 115.02% increase in isoflavone glycosides, and significant enhancements in DPPH, ABTS, and hydroxyl radical scavenging rates(P<0.05). On the other hand, germination led to a noticeable increase in off-flavor compounds in soy milk. Considering the combined effect of germination on physiological activity and flavor, soybean yoghurt was prepared using soybeans germinated for 36 h. The influence of 4 direct inoculation fermentation agents on the flavor and sensory quality of soy yogurt was evaluated. The results showed that soy yogurt fermented with Agent A had the lowest content of off-flavor compounds and the best sensory quality.
PENG Lu, KONG Xiangzhen, CHEN Yeming, LI Xingfei, ZHANG Caimeng, HUA Yufei. Study on Preparation of Soybean Yoghurt from Germinated Soybean[J]. Journal of Food Science and Biotechnology,2023,42(10):83-93.