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Process optimization for economic recovery of anthocyanins from colored corns
P. SOMAVAT (1), Q. Li (1), E. de Mejia (1), W. Liu (1), V. Singh (1) (1) University of Illinois at Urbana-Champaign, Urbana, IL, U.S.A..

Anthocyanins (ANCs) can be used as natural alternate to synthetic dyes in foods, beverages and cosmetics. Colored corns can be used for their economic recovery. Purple, blue and yellow corns were fractioned using 1 kg lab-scale wet-milling, dry-milling and dry-grind processes to compare coproduct yields. Total ANCs in colored corn coproduct stream were quantified using 2% aqueous formic acid for extraction and pH differential method for quantification. For purple corn, ANCs quantified in wet-milling were 4.91 g/kg with steeping water, gluten slurry, starch, fiber and germ containing 79, 17, 2, 1 and 1%, respectively. In dry-milling, total ANCs were 4.55 g/kg with pericarp, small grits, large grits, fines and germ containing 48, 21, 18, 9 and 4%, respectively. In dry-grind, minimum ANCs were quantified (1.36 g/kg). For blue corn, total ANCs quantified in wet-milling were 0.36 g/kg with gluten slurry, steeping water, starch, germ and fiber containing 70, 15, 8, 4 and 3%, respectively. In dry-milling, 0.29 g/kg ANCs were quantified with small grits, pericarp, large grits, fines and germ containing 37, 21, 20, 16 and 6%, respectively. Total ANCs quantified in dry-grind were 0.08 g/kg. Purple corn processing will involve pericarp recovery at the front end while remaining endosperm and germ fractions can be utilized either in dry-grind or dry-milling. For blue corn, recovery of ANCs from gluten slurry after wet-milling will be the optimal. We propose optimized processes for recovering ANCs from colored corns with a potential to significantly reduce their recovery costs on account of lesser processing volumes for ANCs extraction and complete utilization of feedstock resulting in significantly improved process economics.

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