酶法辅助制备核桃蛋白的工艺优化 及超滤回收核桃蛋白Optimization of enzymatic-assisted preparation of walnut protein and ultrafiltration recovery of walnut protein

为提高核桃蛋白得率，分别探索了以碱性蛋白酶、纤维素酶和α-淀粉酶为辅助酶，碱溶酸沉法制备核桃蛋白的工艺，采用超滤工艺回收酸沉废液中核桃蛋白，比较醋酸纤维素（CA）膜、聚醚砜树脂（PES）膜和聚偏氟乙烯（PVDF）膜3种不同超滤膜的回收效率。结果表明，酶法辅助碱溶酸沉法制备核桃蛋白的最佳工艺条件为以纤维素酶为辅助酶、酶解时间60 min、酶解pH 3.6、酶添加量0.5%、酶解温度37 ℃，在最佳工艺条件下核桃蛋白得率为84.11%。CA膜能显著提高核桃蛋白得率，在原料液质量浓度0.363 mg/mL、原料液温度30 ℃的条件下，CA膜的截留率可达9233%，核桃蛋白得率可达87.64%。 In order to improve the yield of walnut protein, alkaline protease, cellulase and α-amylase were used as auxiliary enzyme to extract walnut protein by alkali-solution and acid-precipitation, walnut protein from acid precipitation waste water was recovered by ultrafiltration process, and the recovery efficiency of cellulose acetate (CA) membrane, polyethersulfone resin (PES) membrane and polyvinylidene fluoride （PVDF） membrane on walnut protein was compared. The results showed that the optimal preparation conditions of walnut protein were obtained as follows: with cellulase as auxiliary enzyme, enzymatic hydrolysis time 60 min, enzymatic hydrolysis pH 3.6, dosage of enzyme 05%, and enzymatic hydrolysis temperature 37 ℃.Under the optimal conditions,the yield of walnut protein was 84.11%. CA membrane could significantly improve the yield of walnut protein, under the conditions of mass concentration of feed solution 0.363 mg/mL and temperature of feed solution 30 ℃, the rejection rate of CA membrane could reach 92.33%，and the yield of walnut protein was 87.64%.