R&D Center, Pulmuone Co., Seoul 120-600, Korea.
J Sci Food Agric. 2010 Apr 15;90(5):843-9. doi: 10.1002/jsfa.3894.
Isoflavones are the most common group of phytoestrogens which are present in significantly large amounts in soybean and soy products such as tofu. Isoflavones occur naturally in glycoside forms having lower bioavailability than their aglycone forms. beta-Glycosidase acts as a bio-catalyst for the conversion of isoflavone glycosides to isoflavone aglycones, raising the bioavailability of isoflavones; therefore, it can be used to improve the quality of tofu. We need to establish process conditions for the optimal outcome of the enzyme reaction in tofu.
By using the beta-glycosidase (0.02% w/v) reaction at 55 degrees C for 30 min, a maximum 84.5% conversion of isoflavone glycoside to isoflavone aglycone was obtained. The enzyme reaction caused no significant effects on the sensory acceptability of soft tofu. The hardness of enzyme-treated hard tofu increased with the coagulant amount whereas prolonged heating resulted in decrease of hardness. Incorporation of enzyme reaction before the coagulation process during soft tofu processing provided a sufficient bio-conversion of isoflavones at optimal conditions.
beta-Glycosidase can be effectively used for the bioconversion of isoflavones in soft tofu manufacturing process at optimal reaction conditions before the onset of coagulation process.
异黄酮是植物雌激素中最常见的一类，在大豆及其制品（如豆腐）中含量非常丰富。异黄酮以糖苷形式存在，其生物利用度低于苷元形式。β-葡萄糖苷酶作为一种生物催化剂，可将异黄酮糖苷转化为异黄酮苷元，从而提高异黄酮的生物利用度；因此，它可以用于改善豆腐的品质。我们需要确定在豆腐中进行酶反应的最佳条件。
通过使用β-葡萄糖苷酶（0.02%w/v）在 55°C 下反应 30 分钟，可获得最大 84.5%的异黄酮糖苷向异黄酮苷元的转化率。该酶反应对软豆腐的感官可接受性没有显著影响。酶处理的硬豆腐的硬度随凝固剂用量的增加而增加，而延长加热时间会导致硬度降低。在软豆腐加工过程中，在凝固过程开始之前进行酶反应，可以在最佳条件下提供足够的异黄酮生物转化。
β-葡萄糖苷酶可在凝固过程开始之前的最佳反应条件下，有效地用于软豆腐生产过程中的异黄酮生物转化。
