Coproduct yield comparisons of purple, blue and yellow dent corn for various milling processes

Abstract

Anthocyanins can be used as naturally sourced colors in food and cosmetics. Colored corn cultivars like purple corn and blue corn are rich in anthocyanins. Potential utilization of coproducts in corn processing industry makes colored corns economically attractive for anthocyanin extraction. There is lack of information on various processing characteristics of colored corn cultivars. In this study, wet-milling, dry-milling and dry-grind characteristics of purple and blue corn were compared against yellow dent corn using 1kg lab scale procedures to test whether these can be effectively used in industry. In wet-milling, purple and blue corn starch yields were 63.4 and 61.5% (db) as compared to 70.1% (db) for yellow dent corn. In dry-milling, total endosperm yield was largest for yellow dent corn and minimum for blue corn at 84.9 and 77% (db), respectively. All the corn types had softer endosperm. In dry-grind process, final ethanol concentration was largest for yellow dent corn at 17.2% (v/v) and lowest for blue corn 14.3% (v/v). DDGS yield was highest for purple corn 41.6% (db) and lowest for yellow dent corn 32.9% (db). Purple and blue corn can potentially be used in all the three milling processes with yield differences being offset by health promoting properties of various coproducts recovered. This study will provide a valuable insight about various milling properties of purple and blue corn to the processing industry.