响应面试验优化桑葚汁复合酶解制备工艺及微滤技术对其品质的影响

以新鲜成熟桑葚果实为原料，桑葚出汁率为指标，通过单因素试验及响应面试验，确定果胶酶和纤维素酶酶解制备桑葚汁的最佳工艺参数，并进一步考察非热力杀菌微滤技术对桑葚汁杀菌、澄清、褐变抑制效果以及理化指标的影响。研究结果表明，适于实际生产的最佳酶解工艺为：果胶酶添加量0.42%、纤维素酶添加量1.84%、酶解时间101.26 min、酶解温度50 ℃、酶解pH 3.5～4.0（桑葚汁自然pH值）。在此条件下，桑葚出汁率为86.37%，与理论值88.10%接近。实验表明微滤技术对桑葚汁不仅有很好的抑菌效果，且对桑葚汁的褐变具有一定的抑制作用。

Optimization of Enzymatic Hydrolysis Conditions for the Production of Mulberry Juice by Response Surface Methodology and Influence of Microfiltration on the Quality of Mulberry Juice

In this study, the enzymatic hydrolysis of ripen fresh mulberries with pectinase and cellulase individually and in
combination was optimized using combination of one-factor-at-a-time method and response surface methodology to obtain
maximum juice yield. Further investigations were carried out to examine the influence of microfiltration as a non-thermal
sterilization technology on microbial load, clarity, browning and physicochemical properties of the mulberry juice. A mixture
of pectinase and cellulase was the most efficient enzyme for actual production of mulberry juice and the optimal hydrolysis
parameters were determined as follows: pectinase concentration, 0.42%; cellulase concentration, 1.84%; hydrolysis time,
101.26 min; hydrolysis temperature, 50 ℃; and pH, 3.5–4 (the natural pH of mulberry juice). Experiments conducted
under the optimized conditions led to a mulberry juice yield of 86.37%, agreeing with the predicted value (88.10%).
Our study also demonstrated that microfiltration could not only reduce the microbial load of mulberry juice but also be
effective against its browning.