稻米直链淀粉含量测定方法的探讨

Studies on the Analyzing Method of Amylose Contents in Rice

通过标准碘比色法与改良碘比色法的比较可知 ,“改良碘比色法”既可测定精米粉或糙米粉等粉体材料 ,又可测定精米粒和糙米粒等粒体材料 ,还能将样品的直链淀粉更完全地分离出来且测试误差小。相同品种不同类型样品的直链淀粉含量测定结果为 :精米粒 >精米粉和糙米粒>糙米粉。测试精米粒或精米粉时宜选择强碱KOH ,而测试糙米粒或糙米粉时宜选择强碱NaOH。样品量以 10 0mg为宜 ,但不足 10 0mg时进行品种间的比较仍可考虑采用。

Standard Amylose Procedure and Modified Amylose Procedure were compared in the paper. There are following advantages in Modified Amylose Procedure: not only milled or brown rice powder but also milled or brown rice grains can be analyzed and the testing standard differences are much smaller. The amylose content (AC) of different type samples in a variety is: milled rice grain > milled rice powder and brown rice grain > brown rice powder. KOH should be used while analyzing milled rice grain or powder, and NaOH should be used while analyzing brown rice grain or powder should chose. 100mg sampling weight is better, but less than 100mg also can be used while comparing varietal amylose content.