Properties of Floury Rice Mutant and its Utilization for Rice Flour

Abstract

Rice flour is used to make various traditional foods and also increasingly as a substitute for wheat flour. To explore rice suitable for milling, the properties of grain and flour in floury rice mutants were investigated. Floury rice mutants commonly show loosely packed starch granules in the endosperm, which results in decreased grain hardness. The starch and amylose content of some floury mutant lines declined slightly compared to the wild-type. In wild-type rice, fine flour with low starch damage is obtained when jet-milled under wet condition; while flour which is pin-milled under dry conditions is coarser and more damaged compared to jet-milled flour. Rice flour prepared from floury mutant lines shows low starch damage and fine particle size, in both jet- or pin-milling. The differences in grain components, starch damage and particle size would lead to a characteristic RVA profile. In some mutant lines, the specific loaf volume (SLV) of rice bread made from pin-milled floury mutant rice is reportedly equivalent to that made from the jet-milled wild-type. The dry-milling process needs none of the excess water treatment required in wet-milling. Therefore, using floury mutant lines and the pin-mill, industrial production of rice flour suitable for high-SLV rice bread would be easier.