小麦胚乳 A、B 型淀粉粒发育特征及黏度特性

利用扫描电镜对4个小麦品种不同发育时期籽粒自然断面和分离提纯的A、B型淀粉粒进行观察,并采用黏度糊化仪对小麦面粉和成熟小麦胚乳A、B型淀粉粒分别进行黏度测定.电镜扫描结果显示,小麦授粉3d有凝胶状物质产生于造粉体内壁,6d可明显看到部分造粉体被淀粉粒充满,此时淀粉粒雏形已现,9d淀粉粒体积增大,基本充满所有造粉体,12d前观察到的均为A型淀粉粒,15d有B型淀粉粒出现,18d以后造粉体被完全破坏降解,只留存有A、B型淀粉粒和各自表面的结合蛋白.这说明12d前是A型淀粉粒形成时期,后逐渐形成B型淀粉粒.黏度糊化测定结果表明,A、B型淀粉粒糊化后呈天蓝色,而面粉糊化后呈白色.其次,所测小麦样品糊化焓变和峰值黏度大小表现为B型淀粉粒＞A型淀粉粒＞小麦面粉.

Development and Viscosity Characteristics of A,B-type Starch Granule in Wheat Endosperm

Four different wheat cultivars were selected to test some physico-chemical characteristics.The transverse section in different growth periods of grain and A-type,B-type starch granule isolated and purified from grain were observed using Scanning Electron Microscope(SEM).The viscosity characteristics of the flour and A-type,B-type starch granule were tested by the Viscosity Amylograph(Brabender,Germany).The observation of SEM showed that some gelatinous substance grow out of the internal wall of the amyloplasts on 3 day after pollination(DAP).Some of amyloplasts were filled with starch granule on 6 day and nearly each amyloplast was filled with bigger starch granule in 9 day.A-type starch granules were observed on 12 day uniquely,and B-type starch granules were observed on 15 day.The amyloplasts were degraded completely after 18 day,when A-type and B-type starch granule only left their surfactant protein.The results showed that A-type starch granule generate on 12 day,and after 12 day B-type starch gradually generate.Starch paste trial showed that the color both A-type and B-type starch paste were blue while the flour paste was white.Moreover,the value of enthalpy change and starch peak viscosity showed that B-type starch granule >A-type starch granule> the flour.