Characteristics of Gel‐chromatographic Fractions of Starch in Relation to Rice and Expanded Rice‐Product Qualities

Starch from waxy and nonwaxy rices was separated on Sepharose. In nonwaxy rice, the major (void volume) fraction stained a varying shade of blue with iodine depending on the sample. The water‐insoluble amyolose content as estimated in milled rice flour was highly positively correlated with the λ max of the iodine colour as well as with the „amylose”︁ content of the fraction. Debranching with pullulanase showed that the fraction had the dual character of being both amylopectin and amylose. A second fraction was for the most part true amylose. The volume of expanded rice product seemed to increase with average molecular weight of starch. The highest average molecular weight of starch corresponded to analytical values of water‐insoluble amylose as estimated in rice flour and the same corresponded to the greatest expansion volume.