Improvement of in vitro and cellular antioxidant properties of Chinese steamed bread through sorghum addition

Sorghum grain is rich in phenolic compounds with various health benefits. Chinese steamed bread (CSB) is a traditional fermented food, and is widely consumed in China and many other countries. Different concentrations of wholegrain white sorghum flour (WSF) or red sorghum flour (RSF) were incorporated into CSB formulation. Steaming significantly reduced the content of total phenolic compounds in the bread dough. The content of total phenolic compounds of 30% red sorghum flour Chinese steamed bread (RCSB) was higher than that of 30% white sorghum flour Chinese steamed bread (WCSB), followed by the control (100% WSF). Individual flavonoids were only present in RCSB. Chemical-based and cell-based assays indicated the antioxidant activity of CSB was significantly increased after adding sorghum flour, with the 30% RCSB being the highest. Sensory evaluation studies and well-controlled human clinical studies are now required to substantiate the potential health benefits of these new sorghum products to consumers.