STARCH, ENERGY, AND PROTEIN-UTILIZATION BY RATS IN MILLED RICE OF IR36-BASED AMYLOSE EXTENDER MUTANT

The utilization of starch, energy, and protein in cooked milled rice o f amylose extender (ae) mutant 2064 and its IR36 parent were examined in growing rats. Despite the higher lysine content of the ae mutant (3 .83 vs. 3.32 g per 16 g of N), net protein utilization and protein qua lity of the two rices were comparable because of the lower protein, en ergy, and starch digestibility of the mutant. Starch, energy, and prot ein digestibility of the mutant decreased progressively from raw to co oked to cooked-parboiled, with or without the the addition of the anti biotic Nebacitin (used to suppress hindgut fermentation) in the diet. Unlike the same ae mutants in corn, the rice ae mutant did not have a considerable increase in resistant starch with increased amylose conte nt.