Comparison of fermentation characteristics between colored corn and yellow dent corn using two dry grind process methods

In dry grind ethanol plant, distillers dried grains with solubles (DDGS) is the primary coproduct which is used mainly in ruminant animal diets. Increasing market demand for coproduct in dry grind process is needed. One way is to use corn rich in anthocyanin content as feedstock. Anthocyanin imparts red, blue and purple color to corn kernels. Anthocyanin could also affect yeast during fermentation. The objective of this study was to evaluate the performance of anthocyanin rich corn in dry grind process. Ethanol conversion efficiencies of colored corn sample were comparable to that of yellow dent corn in both conventional dry grind process (78.4±0.5% for blue corn, 74.3±0.4% for red corn and 75.1±0.2% for yellow dent corn) and modified dry grind process using granular starch hydrolyzing enzyme (GSHE) (83.8±0.8% for blue corn, 81.1±0.3% for red corn and 85.6±0.1% for yellow dent corn). In the modified process, GSHE was used to replace the high temperature liquefaction process, which benefited the anthocyanin stability in the processes. The extractable anthocyanin contents in DDGS from modified processes were 1.41, 1.91 and 2.39 times that of DDGS from conventional process for purple, red and blue corn samples, respectively. Corn with rich anthocyanin content did not negatively affect fermentation efficiency in both conventional and modified dry grind processes; therefore, there is potential to use colored corn in dry grind process, especially using granular starch hydrolyzing enzyme