Improving dry‐fractionated corn fermentation by supplementation of corn germ meal and pasta mill feed from agro‐food industries

Abstract

Background and objectives Separation of germ from corn using dry fractionation in modified dry‐grind processes results in the sluggish and incomplete fermentation of remaining corn because of nutrient deficiency for yeast. This study investigated the use of two low‐value co‐products, germ meal from corn wet milling and mill feed from pasta manufacturing, as additives to improve the fermentation of corn grits. Findings Addition of 5% germ meal or 2.5% mill feed in corn grits resulted in the complete (no residual glucose) and faster fermentation, compared to 4.3% residual glucose during fermentation of only corn grits. Final ethanol yield (0.51 L/kg) was about 22% higher compared to control (0.42 L/kg). Increase in supplementation (10% of grits) further increased the fermentation rates, however, led to similar final ethanol concentrations and ethanol yields. Conclusions Both germ meal and pasta mill feed can improve fermentation rate and efficiency of dry‐fractionated grits and avoid the need for expensive supplements or enzymes. Significance and novelty This research provides an innovative solution to the challenge of inefficient fermentation of dry‐fractionated corn and also identifies new potential market for two low‐value co‐products from the agro‐food industries.