Principal component analysis and biochemical characterization of protein and starch reveal primary targets for improving sorghum grain

▶ Multiple in vitro digestibility techniques, principal component analysis of data, and subsequent characterization of the digestibility of protein/starch matrix components has identified putative targets for improving digestibility of sorghum grain. ▶ Percent protein digestion is influenced by the protein matrix and by protein body packaging. Starch content also affects digestion patterns of the protein matrix and protein body, but to a greater extent in non-waxy than waxy lines. ▶ Up-regulation of genes associated with starch accumulation and down-regulation of expression of a g-kafirin of Mr 20 kDa, the major component undigested by pepsin, are likely targets to improve sorghum grain digestibility.