Optimized Sorghum Fermentation on Production of Antioxidants and Value-added Products from Distillers Dried Grains with Solubles (DDGS)

Goals / Objectives
The objective is to evaluate how components, such as antioxidants, in sorghum grain impact fermentation efficiency and the quality of co-products produced during fermentation.

Project Methods
Experiments will be conducted to isolate and identify antioxidants and protease inhibitors in sorghum grain including both protein based inhibitors and small molecule based inhibitors (e.g. phenolic compounds, phytic acid). Inhibitors will be screened for impacts on protein digestibility in in-vitro protein digestibility assays. For those inhibitors identified as having substantial impact on protein digestibility, their effect on sorghum fermentation will be evaluated through pre-treatment of sorghum flour to extract the compounds prior to fermentation. The nutritional quality of the dried distillers grains left after fermentation will also be evaluated to determine if pre-treatment impacted the quality of co-products from the ethanol process. In separate experiments, genetically diverse sorghum populations will be screened for levels of inhibitors, protein digestibility, total starch, and fermentable sugars. Lines will be evaluated for fermentation efficiency to determine how variation in antioxidants and inhibitor levels interacts with grain composition and impacts fermentation and co-product quality. Samples grown at multiple locations and/or grown across multiple years will also be evaluated for levels of protease inhibitors to determine how environment influences levels of such compounds. Finally, inhibitor levels in decorticated grain and alkali treated grain will be measured to determine what degree these methods of pre-treatment impact fermentation quality.