Pham T Thuy, Shah Nagendra P
School of Biomedical and Health Science, Victoria Univ., PO Box 14428, Melbourne, Victoria 8001, Australia.
J Food Sci. 2009 May-Jul;74(4):M190-5. doi: 10.1111/j.1750-3841.2009.01141.x.
In this study, soy protein isolate (SPI) (4%, v/w) was supplemented to the yogurt mix to increase the amount of biologically active isoflavone in yogurt (SY). The control yogurt was without any SPI supplementation (USY). The supplementation significantly (P < 0.05) increased the lactose metabolism by the yogurt starter including Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842 (Lb 11842) and Streptococcus thermophilus ST 1342 (ST 1342) during the fermentation process by 4.7%. The starter produced more acetic acid and less lactic acid in SY than that in USY and altered the ratio of lactic and acetic acid during the entire storage period. The viability of both Lb 11842 and ST 1342 in SY was significantly (P < 0.05) lower than that in USY from 14 d of the storage period, however, their concentration still remained high (8.11 to 8.84 log CFU/g). The starter transformed 72.8% of total inactive isoflavone glycosides (IG) to active isoflavone aglycones (IA), increasing the IA content from 1.35 to 15.01 mg/100 g sample. During the storage period, IA concentration slowly rose from 15.02 to 15.51 mg/100 g sample.
在本研究中，向酸奶混合物中添加了4%（体积/重量）的大豆分离蛋白（SPI），以增加酸奶（SY）中生物活性异黄酮的含量。对照酸奶未添加任何SPI（USY）。添加SPI显著（P<0.05）提高了包括德氏乳杆菌保加利亚亚种ATCC 11842（Lb 11842）和嗜热链球菌ST 1342（ST 1342）在内的酸奶发酵剂在发酵过程中的乳糖代谢率，提高了4.7%。与USY相比，发酵剂在SY中产生了更多的乙酸和更少的乳酸，并在整个储存期内改变了乳酸和乙酸的比例。从储存期第14天起，SY中Lb 11842和ST 1342的活力均显著（P<0.05）低于USY，然而，它们的浓度仍然很高（8.11至8.84 log CFU/g）。发酵剂将72.8%的总非活性异黄酮糖苷（IG）转化为活性异黄酮苷元（IA），使IA含量从1.35 mg/100 g样品增加到15.01 mg/100 g样品。在储存期内，IA浓度从15.02 mg/100 g样品缓慢上升至15.51 mg/100 g样品。
