纤维素酶催化大豆异黄酮的水解

Abstract

为充分发挥大豆异黄酮生物价值，采用纤维素酶催化糖苷型大豆异黄酮水解制备游离苷元型大豆异黄酮。通过考察10种纤维素酶对糖苷型大豆异黄酮总水解率和苷元型大豆异黄酮总转化率的影响，筛选得到一种成本较低且水解效果较好的纤维素酶，用于催化水解糖苷型大豆异黄酮，优化了该纤维素酶在水解工艺中底物质量浓度、酶添加量、反应体系pH、酶解温度、酶解时间等参数。结果表明：选择来源于 Trichoderma viride 的纤维素酶作为大豆异黄酮水解用酶；底物质量浓度0.8~2.0 mg/mL、酶添加量7%~11%、反应体系pH 5.0、酶解温度55 ℃、酶解时间5~6 h是较经济有效的水解工艺参数，实验优化过程中，大豆异黄酮总水解率超过90%，总转化率接近60%。因此，采用纤维素酶催化水解大豆异黄酮可显著增加游离苷元含量，提高大豆异黄酮利用价值。 In order to improve the biological-value of soybean isoflavones, the glycoside-type soybean isoflavones was hydrolyzed to prepare free aglycon-type soybean isoflavones with cellulase as catalyst. A low-cost and effective cellulase was selected by investigating the effects of 10 cellulases on the total hydrolysis rate of glycoside-type soybean isoflavones and the total conversion rate of aglycone-type soybean isoflavones. Meanwhile, the cellulase selected was used to catalyze the hydrolysis of glycoside-type soybean isoflavones, and the parameters such as the substrate mass concentration, enzyme amount, reaction system pH, enzymatic temperature and enzymatic time were optimized. The results showed that the cellulase from Trichoderma viride was selected as the enzyme for the hydrolysis of soybean isoflavones, and the more economical and efficient hydrolysis parameters were obtained as follows: substrate mass concentration 0.8-2.0 mg/mL, enzyme amount 7%-11%, reaction system pH 5.0, hydrolysis temperature 55 ℃, and hydrolysis time 5-6 h. In the optimization, the total hydrolysis rate of glycoside-type soybean isoflavones exceeded 90%, and the total conversion rate of aglycone-type soybean isoflavones was close to 60%. Therefore, the use of cellulase-catalyzed hydrolysis of soybean isoflavones can significantly increase the content of free aglycones and improve the utilization value of soybean isoflavones.

Keywords

• 大豆异黄酮；糖苷水解率；苷元转化率；纤维素酶
• soybean isoflavone; hydrolysis rate of glycosides; conversion rate of aglycones; cellulase