Effect of fermentation and processing of Sorghum bicolor Grains to produce traditional Sudanese Hulu-Mur on phytochemicals and their biological activities

Sorghum plays an important role in the diet of millions of people in semi-arid regions of sub-saharan Africa, Asia, central America and the middle east. Sorghum grains (feterita) were subjected to processing operations. Ethanolic extraction was done for raw grains, germinated grains, fermented porridge and cooked fermented porridge. All extracts were fractionated to petroleum ether, chloroform and ethyl acetate extracts and also All extracts subjected to phytochemicals profiling, total phenolic contents, antioxidant activity and antimicrobial properties. Thin layer chromatography (TLC) revealed the presence of polyphenols, Flavonoidal acids, coumarin, anthrone, anthraquinones and Terpenoids. Flavonoid mainly accumulated in the ethyl acetate fraction in all extracts before and after fermentation. Flavonoidal acids, coumarin, anthrone and anthraquinones were detected in the chloroform fraction in all extracts before and after fermentation. Terpenoids were accumulated in the petroleum ether fraction. From our finding the fermentation and cooking of the sorghum grains increased the total phenolic contents, the fermented porridge showed the highest phenolic content (305.17 mg GAE/g). The radical scavenging activity of fermented and non-fermented sorghum grain fractions were screened by using 1, 1 diphenyl-2- picrylhydrazyl (DPPH), the ethyl acetate fraction of cooked fermented porridge at a concentration of 1mg/ml had the high inhibition of DPPH radicals (57.33%). Antimicrobial activity of different extracts was recorded against different pathogenic bacteria and fungi, the petroleum ether extract showed antimicrobial activity against Bacillus subtitles and Staphylococcus aureus at concentration of 40mg/ml. These findings proved that fermentation and cooking could increase the bioavailability of phenols, which subsequently may improve the antioxidant and antimicrobial activity so the Sudanese Traditional Hulu-Mur may be a valuable health and nutrition promoting and hence it can consider one of the functional foods.