Abstract

Background: Whole grains may reduce chronic disease risks and these benefits are related to food matrix components, especially phenolic acids. However, food processing may change the total phenol content and antioxidant capacity.

Objective: This study aims to evaluate the effect of processing on the antioxidant capacity and total phenols, tannins and phytate contents in the sorghum grain of seven genotypes.

Methods: Antioxidant capacity (AC), total phenolic content (TPC), tannins and phytate content were evaluated in unheated sorghum grains (USG), heated sorghum grains (HSG) and popped sorghum grains (PSG) of seven genotypes.

Results: AC ranged from 66.5% to 92.9% in USG, decreased after PSG in all genotypes, and maintained after HSG, except for BRS 506. TPC and tannins were higher in BRS 305. PSG decreased tannin content in all genotypes. TPC of HSG was higher than the USG in BRS 310, BRS 305, BR 501 and BR 700 genotypes. PSG affected TPC content mainly in BRS 305 and BR 700. AC and tannins were especially affected by the popping conditions. There was no difference in the phytate content among all genotypes, which were maintained after HSG in BRS 506, BRS 305, BR 700 and CMSXS 136.

Conclusion: AC, TPC, tannins and phytate content were affected by the processing conditions, however, those changes may be related to the compounds type and sorghum genotype.

Keywords: Domestic processing, heat treatment, popped sorghum, Sorghum bicolor (L.) Moench, sorghum flour, tannins.