超声波辅助复合酶法酶解木薯淀粉工艺优化

以木薯淀粉为原料,采用超声波协同复合酶解技术研究其糖化工艺。在单因素实验(超声时间、超声功率、糖化时间、糖化温度、糖化酶添加量、糖化pH、料液比)基础上,选取糖化时间、糖化温度、糖化酶添加量、糖化pH四因素,以糖化率(DE值)为指标,通过4因素3水平的Box-Behnken实验设计,优化了木薯淀粉的糖化工艺参数,结果表明:超声时间15 min,超声功率900 W,糖化时间100 min,糖化温度65 ℃,糖化酶用量5 g/L,糖化pH4.7,料液比9:20 (g/mL)时,DE值达到98.98%。SEM结果显示木薯淀粉超声前后形貌有差异,FT/IR检测显示,木薯淀粉主要组成单糖为葡萄糖,且经GC-MS对木薯淀粉水解后糖化液分析得出其成分只有葡萄糖,这可为木薯淀粉糖化工艺提供一定的理论依据。

Optimization of cassava starch saccharification by ultrasound assisted composite enzymatic hydrolysis

The cassava starch from cassavastarch were saccharified with complex enzymatic methodafter the ultrasonic treatment. Based on the screening of single-factor(ultrasonic time,ultrasonic power,saccharifying time,saccharifying temperature,glucoamylase amount,pH and solid-liquid ratio)experiment design,four experimental factors were selected for the Box-Behnken experimental design using response surface methodology,which gave the optimal extraction conditions:Ultrasonic time of 15 min,ultrasonic power of 900 W,saccharifying time of 100 min,saccharifying temperature of 65 ℃,glucoamylase amount of 5 g/L,pH4.7 and solid-liquid ratio of 9:20 (g/mL).Under these conditions,the saccharification rate(DE value)of cassava starch was 98.98%,which was matched closely to the predicted value. In addition,FT-IR and GC-MS analysis showed that treated samples showed characteristic peaks for cassava starch. SEM analyses indicated that the surface structure of cassava starch before ultrasonic treatment was different from that of cassava starch after ultrasonic treatment. This study provides strong evidence that complex enzymatic saccharification after ultrasound-assisted was an excellent saccharification method for cassava starch from cassavastarch.