Development, structure and in vitro digestibility of type 3 resistant starch from acid-thinned and debranched pea and normal maize starches.

Type 3 resistant starch (RS3) was developed from native pea starch through acid thinning, debranching and recrystallization, and the resultant pea RS3 was then characterized and compared with that generated from native normal maize starch. Starting from the respective native starches, the modification method yielded 68.1% of RS3 from pea and 59.6% from normal maize. The particles of pea and normal maize RS3 showed a coarse surface and irregular shapes and sizes. Both pea and normal maize RS3 displayed the B-type X-ray diffraction pattern, with 41.0% and 37.7% relative crystallinity, respectively. In vitro starch digestibility assay revealed that pea RS3 - in both uncooked and cooked states - was less digestible by amylolytic enzymes than normal maize RS3 because the former possessed double-helical crystallites of a more compact structure. The information presented in the study is valuable for the development of RS ingredient from pea starch for food applications.