| dc.description.abstract | The aim of this research was to investigate the effect of thermal treatments including roasting, microwave, steaming on anti-nutritional factors, physical and antioxidant properties of black gram (Vigna cylindrica (L.) Skeels). For physical properties, thermal treatments increased water-holding capacity and decreased oil-holding capacity of the samples. No significant difference was observed between the roasted and control samples. For chemical properties analysis, anthocyanin, which was determined by spectrophotometric pH differential method, accounted for the vast majority in total phenolic compounds (TPC). The steamed sample was shown for the lowest TPC and anthocyanin values, with the TPC was 272.46 mg/100 g dry basis and the anthocyanin content was 121.20 mg/100 g dry basis. Among three thermal treatments, roasting resulted in the highest TPC content, which was 424.35 mg/100 g dry basis. There was a strong correlation between anthocyanin content and antioxidant capacity (AC), hereby a similar trend was obtained from these two analytical tests. The AC was measured through absorbance of the prepared solution at 515 nm using an ultraviolet-visible (UV-Vis) spectrophotometer. Steaming treatment led to the lowest anthocyanin content and AC among four samples while there were no significant differences in the TPC and AC values between the microwaved sample and roasted samples. The colorimetric method was used to determine phytate content. It was reduced significantly in all heat-treated samples. Tannin content was much higher than phytate content in Vigna cylindrica, and the value of the steamed sample was recorded to be the lowest, which was 164.19 mg/100 g dry basis. Among three treatments, microwave was considered to be the best treatment to decrease anti-nutritional factors and avoid a substantial reduction in antioxidant capacity.
Keywords: black gram, heat treatments, physical properties, tannin content, phytate content, anthocyanin content. | en_US |
