Effect of processing on the phenolic contents, antioxidant activity and volatile compounds of sorghum grain tea. (January 2019) - Xiong, Yun
Abstract: Sorghum grain is rich in phenolic compounds and may be used to develop functional tea beverages. This work investigated the effect of processing techniques on the phenolic contents, antioxidant activity, and volatile compounds of a white colour sorghum (Liberty) grain tea. Significant ( P ≤ 0.05) increase of total phenolic content, total flavonoid content and condensed tannin content were observed during the processing, whereas the antioxidant activity was not statistically enhanced. A total of 63 volatile compounds were detected including 5 alcohols, 13 alkanes, 2 aldehydes, 2 carboxylic acids, 15 esters, 4 ketones, 3 pyrazines and 1 phenylenediamine, which were affected by the processing techniques. The sorghum tea made from powder form infusion had more abundant volatile compounds compared to whole grain form infusion. The findings of this research have potential to expand human consumption of sorghum grain in the new form of grain tea. Highlights: Sorghum grain was soaked, steamed, and roasted to make grain tea. Processing techniques affected total phenolic content but not antioxidant activity. A total of 63 volatile compounds were detected in sorghum grain tea. Main volatile compounds were alcohols, alkanes, aldehydes, and esters. More volatile compounds were extracted in sorghum powder than whole grain infusion.