醇析分级和酶法去蛋白对甜菜膳食纤维性质的影响

为揭示提取纯化方法对甜菜膳食纤维性质的影响,促进废粕高值化,探讨了废粕原料及预处理方法对果胶品质的影响,以HPLC和哈克流变仪分析了酸溶醇析法分级果胶的理化性质,并用扫描电镜研究了酶法去蛋白对不溶性膳食纤维(IDF)形貌结构的影响.结果表明:3种废粕提取果胶不需稀酸或温水预处理;最佳条件下颗粒粕提取的果胶的得率和纯度之积最大;酸溶醇析法分级果胶含悬浮层和沉淀层,悬浮层果胶密度小、色泽浅、黏度高、大分子果胶比例大;提取果胶后压粕孔状骨架结构更光洁,孔内填充颗粒物消失,再经去蛋白处理后孔隙变大,IDF出现层状骨架结构.

Effects of Fractionation by Alcohol Precipitation and Deproteinization by Enzyme on Properties of Beet Dietary Fibre

In order to reveal the influences of extraction and purification on the properties of beet dietary fibre and promote the value increment of beet pulp,the effects of beet pulp materials and pretreatment method on the quality of beet pectin were discussed.Then,the physiochemical properties of the beet pectin graded by acid extraction and alcohol precipitation were analyzed by using a HPLC and a Haake rheometer,and the morphological and structural changes of the insoluble dietary fibre(IDF) after the deproteinization by enzymes were investigated by means of SEM.The results indicate that the pretreatment with dilute acid or warm water is unnecessary for the extraction of pectin from 3 kinds of beet pulp,that the product of yield and purity reaches the maximum in the extraction of pectin from grain pulp under optimal conditions,and that the beet pectin graded by acid extraction and alcohol precipitation includes a suspended layer and a deposited layer,and that the suspended pectin layer is of lower density,lighter color,higher viscosity and greater percentage of large molecules.Moreover,it is found that,after the pectin extraction,the cavernous skeleton structure of the pressed beet pulp becomes smoother and the filler particles in cavity disappear,and that further deproteinzation treatment enlarges the cavity and results in the lamellar skeleton structure.