小麦籽粒在制麦过程中碳水化合物降解趋势的研究  

Degradation of Carbohydrate During Malting for Wheat Grain

作　　者：李巨秀[1] 魏益民[1,2] 李运发[1] 

机构地区：[1]西北农林科技大学食品科学与工程学院,杨凌712100 [2]中国农业科学院农产品加工研究所,北京100094

出　　处：《中国粮油学报》2008年第5期33-37,共5页Journal of the Chinese Cereals and Oils Association

基　　金：陕西省自然科学基金(2006C24)

摘　　要：以小麦品种扬麦13和皖麦38为研究对象,以啤酒大麦为对照,通过微型制麦工艺(断水浸麦方式、降温式发芽、低温干燥绿麦芽),较为系统的分析了制麦过程中小麦籽粒淀粉降解的趋势,讨论小麦品种的制麦特性以及淀粉降解的机理。结果表明,制麦过程中淀粉含量和直链淀粉含量下降较为缓慢;还原糖的含量变化总体为上升趋势;β-葡聚糖含量下降速度较快,且在发芽结束后小麦样品的β-葡聚糖含量小于啤酒大麦;戊聚糖含量在发芽的前3天内呈下降趋势,但发芽第4天有较大程度的增长,发芽结束后小麦样品中的戊聚糖含量小于啤酒大麦;浸出物在发芽初期以较高速度增加,在发芽后期上升较为缓慢;黏度在制麦中变化幅度较小,呈逐渐下降趋势;通过电子扫描电镜观察淀粉颗粒在制麦过程中的变化发现,小麦麦芽的胚乳结构越来越疏松,在发芽前期只要是蛋白质和大颗粒淀粉的降解,在发芽后期小颗粒淀粉的降解速度较快。由结果可知,小麦和啤酒大麦在制麦过程中碳水化合物的变化有较大差异;小麦发芽结束后除β-葡聚糖含量、戊聚糖含量小于啤酒大麦,其他指标均高于啤酒大麦;β-葡聚糖和戊聚糖含量不是造成小麦麦芽汁具有较高黏度的主要原因。Two wheat cultivars, Yangmai 13 and Wanmai 38, were used to investigate the change in content and composition of carbohydrate during malting with a micro - malting technology, and a beer barley cultivar was used as control. Results show as follows： Malting of wheat grain results in slow decrease in starch and amylose contents and apparent increase in reducing sugar. β - gluean content dramatically decreases, while pentosan content decreases in the beginning 3 d of germination and then increases. Soak - out increases greatly in the beginning 2 d of germination, and then almost keeps constant. The viscosity of malt wort shows little change during malting, just a small declining trend. Scanning electron microscopy reveals that the endosperrn becomes mealy during malting, and that at the start of germination big starch granules and protein appear to be degraded, and at the late phase small starch granules seem to be more susceptible to hydrolysis. It is concluded that there is a big difference between the carbohydrate changes in wheat malting and barley malting; wheat malt exhibits higher level of analysis values except the contents of β - gluean and pentosan, and the contents of β - glucan and pentosan are not the main reason causing the higher viscosity of wheat malt wort.

关 键 词：小麦 籽粒 小麦麦芽 淀粉降解 

分 类 号：TS262.5[轻工技术与工程—发酵工程] TS275.5[轻工技术与工程—食品科学与工程]