超声波预处理对发芽糙米酶解的促进作用  

Enhancing the Enzymatic Hydrolysis of Germinated Brown Rice by Ultrasonic Pretreatment

作　　者：米朕[1] 缪冶炼[1] 陈介余 穆晗[1] 王冀宁[3] 

机构地区：[1]南京工业大学食品与轻工学院材料化学工程国家重点实验室,南京211816 [2]日本秋田县立大学生物资源学部,日本秋田01001953 [3]南京工业大学经济管理学院,南京211816

出　　处：《中国食品学报》2012年第11期77-83,共7页Journal of Chinese Institute Of Food Science and Technology

基　　金：国家重点基础研究发展计划(973项目;2009CB724700);国家自然科学基金项目(71173103/G0310)

摘　　要：大米是啤酒、白酒等产业的原料之一。糙米含有淀粉酶等多种酶。内源淀粉酶的有效利用,可降低酶制剂用量,提高大米糖化效率。本文首先通过发芽激活糙米中的淀粉酶,然后采用超声波对发芽糙米料液进行预处理,并利用内源淀粉酶酶解发芽糙米,研究超声波预处理对还原糖收率、淀粉酶活力的影响,并讨论淀粉酶活力变化的机理。试验结果表明,对发芽糙米料液进行适当的超声波预处理,能够降低料液的最适Ca2+浓度,显著提高酶解的还原糖收率。在超声波强度0.19W/cm2、超声波频率45kHz、处理时间5min的最适条件下预处理,还原糖收率可达37.5%,此值为无超声波预处理时的3.5倍。超声波预处理使淀粉酶从发芽糙米中游离出来,从而提高了料液的淀粉酶活力。这是发芽糙米酶解过程中还原糖收率增加的主要原因。Rice is a raw material in the beer and sake industries. Brown rice contains a variety of enzymes such as amylase. Effective use of the endogenous amylase may lead to reducing requirement for external enzyme preparations and improving of rice saccharification efficiency. In the present study, the amylase in brown rice was activated by a germination process, and then the germinated brown rice was hydrolyzed using the endogenous amylase after ultrasonic pretreatment. The effect of ultrasonic pretreatment on reducing-sugar yield was investigated, and the mechanism for the changes of amylase activity was discussed. The experimental results showed that the optimal Ca 2＋ concentration in the reaction liquid was lowered, and the reducing-sugar yield was remarkably increased by ultrasonic pretreatment under proper conditions. When the reaction liquid was pretreated under the optimal condition of an ultrasonic intensity at 0.19 W/cm 2 , an ultrasonic frequency at 45 kHz and a treatment time at 5 min, a reducing-sugar yield increased to 37.5%, which was 3.5 times as high as that without ultrasonic pretreatment. Endogenous amylases of germinated brown rice transferred to the reaction liquid during the ultrasonic pretreatment, which resulted in the elevation of amylase activity in the reaction liquid. This is the main reason for the improvement of reducing-sugar yield in the enzymatic hydrolysis of germinated brown rice.

关 键 词：大米 糖化 超声波 淀粉酶 还原糖 

分 类 号：TS212[轻工技术与工程—粮食、油脂及植物蛋白工程]