Department of Food Science, Henan Institute of Science and Technology, 453003 Xinxiang, Henan Province, China.
Food Chem. 2013 Dec 1;141(3):2418-25. doi: 10.1016/j.foodchem.2013.05.017. Epub 2013 May 14.
To compare the content of bioaccessible folate, vitamin B12, and isoflavones in tofu and tempe, as influenced by soybean variety and food processing, particularly fermentation.
Raw soybeans contained 2207-2671 μg/kg (dry matter) folate, cooked tempe 1493-4143, and cooked tofu 968-1273 μg/kg, the difference was attributed to the fermentation in tempe. Vitamin B12 was detected only in tempe (0.16-0.72 μg/kg). Isoflavone aglycones were formed during soaking of soybeans, with only minor differences between the contents in cooked tempe (average 1922-2968 μg/kg) or tofu (1667-2782 μg/kg) but strongly depending on bean variety.
Folate and vitamin B12 contents were mainly influenced by microbial activity during fermentation, whereas isoflavone aglycone content was determined by bean variety. Tofu had lower folate and vitamin B12, but equal isoflavone contents as tempe. Bioaccessibility of folate (80-100%) and isoflavone aglycones (100%) were high.
比较不同大豆品种和食品加工（尤其是发酵）对豆腐和豆豉中生物可利用叶酸、维生素 B12 和异黄酮含量的影响。
生大豆中叶酸含量为 2207-2671μg/kg（干重），熟豆豉为 1493-4143μg/kg，熟豆腐为 968-1273μg/kg，这主要归因于豆豉发酵过程。仅在豆豉中检测到维生素 B12（0.16-0.72μg/kg）。大豆浸泡过程中形成了异黄酮苷元，熟豆豉（平均 1922-2968μg/kg）或豆腐（1667-2782μg/kg）中的含量差异不大，但强烈取决于豆种。
叶酸和维生素 B12 含量主要受发酵过程中微生物活性的影响，而异黄酮苷元含量则取决于豆种。豆腐中的叶酸和维生素 B12 含量较低，但异黄酮苷元含量与豆豉相当。叶酸（80-100%）和异黄酮苷元（100%）的生物利用度均较高。
