Thermal processing of wheat bran: Effect on the bioactive compounds and dietary fiber

In the current study bran from six wheat cultivars were subjected to different heat treatments and the effect of heat treatments on the bioactive composition, dietry fibre content and structure of wheat bran was evaluated. The findings indicated that thermally treated wheat bran contains higher soluble dietary fiber, but lower insoluble and total dietary fiber than untreated wheat bran samples. Microwave heat treatment caused highest increase in the soluble dietary fiber content and highest soluble dietary fiber content was observed in bran of WH-1105 wheat variety. The presence of six different phenolic acids evaluated were gallic acid, p-hydroxybenzoic acid, ferulic acid, syringic acid, vanillic acid, and p-coumeric. Heat treatment caused significant increase in all the six phenolic acids. The bran sample obtained from wheat variety WH-1105 showed highest level of all phenolic acid among the all-bran sample obtained from other wheat varieties. Among the all heat treatments, microwave heat treatment caused highest increase in the phenolic acids. Among all phenolic acid evaluated highest increase was observed for syringic acid after microwave heat treatment in the bran of WH-1105 wheat variety. Further it was observed that crystallinity index significantly increased after thermal treatment and microwave heating caused higher increase in crystallinity than other heat treatments.