啤酒中阿拉伯木聚糖的溶解、降解及堵塞膜机制的研究

Solubilization, Degradation and Membrane Plugging ofArabinoxylan in Brewing

阿拉伯木聚糖是谷物细胞壁中的一种非淀粉质多糖,在啤酒酿造过程中,阿拉伯木聚糖会造成浸出率降低、麦汁黏度升高、影响麦汁和啤酒过滤(尤其是纯生啤酒的膜过滤)、成品啤酒浑浊等.本文系统的研究了谷物中阿拉伯木聚糖的结构、理化性质和对酿造的影响;比较了气相色谱法和比色法测定阿拉伯木聚糖;报道了阿拉伯木聚糖在酿造过程中含量的变化,并以小麦和小麦芽为辅料,系统的研究了糖化温度、谷物粒径和料水比对阿拉木聚糖在糖化过程中溶解的影响;在热力学和动力学方程的基础上,建立了糖化过程中预测内切木聚糖酶和阿拉伯木聚糖的模型;通过电子显微镜手段表征了不同分子量阿拉伯木聚糖对膜过滤的影响;运用响应面分析法,采用木聚糖酶优化了酶解阿拉伯木聚糖的条件.

Arabinoxylan is a kind of non-starch polysaccharides in the cell walls of the starchy endosperm in cereal gains.Historically, reduced beer filtration efficiency has been mainly attributed to β-glucan in brewing process.However,under-modified malts,as arabinoxylan can not be degraded sufficiently,it may cause many problems such as low extract yield,high wort viscosity,decrease of filtration rate (especially micro-membrane filtration),and haze formation in brewery.Recently,more and more researches paid much attention on studying arabinoxy- lan.In this paper,the structural and physicochemical properties of arabinoxylan and their effects on brewing were reported.Gas Chromatography and colorimetric method for determining arabinoxylan were compared.The degradation of arabinoxylan during brewing was studied.The effects of mashing temperature,liquor-grist ratio on the solubilizafion of arabinoxylan were systematically investigated when wheat and wheat malt were used as adjuncts.This paper proposed a model for predicting endo-xylanase activity and arabinoxylan concentration under different mashing profiles and the given initial malting conditions as well.The effect of different molecular weight arabinoxylans on micro-membrane filtration was observed by SEM.Response surface methodology (RSM) was employed to optimize the degradation of arabinoxylan by endo-xylanase.