49F-2 |
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P. JING, Nutrition and Food Science, University of Maryland, 3407 Marie Mount Hall, College Park, MD 20742 and M. M. Giusti, Department of Food Science and Technology, Ohio State University, Ohio State Food Science and Technology, 2015 Fyffe Road, Columbus, OH 43210. Anthocyanin pigments have been traditionally used to provide color to acidified food systems. However, anthocyanin-rich waste (ARW) from purple corncobs (Zea mays L), was only soluble at neutral or slightly alkaline environments suggesting it could be used in food systems within such a pH range. Our objective was to study the characteristics of ARW, evaluate its stability as natural colorants for milk, and investigate the potential interactions between anthocyanins and milk constituents that may exert a protective effect on pigment stability. Anthocyanin-rich waste, soluble at neutral or alkaline environment, was used to color whole-fat milk, skimmed milk, and a phosphate buffer solution (pH 6.8). Pigment stability was evaluated using an accelerated stability test, at 70°C for different time periods. Changes in color characteristics (CIELAB, hue and chroma), monomeric anthocyanin content and anthocyanin profiles were monitored during the study. Purple corn anthocyanins provided an attractive purple hue (324 and 347 degrees for skimmed and whole fat milk, respectively) at neutral pH. Heat treatment favored degradation of anthocyanins, but a clear protective effect by milk constituents was evident comparing changes in pigment content and profiles in milk to in buffer solution. After 30min heat treatment, 47.9% of monomeric anthocyanins had degraded in the phosphate buffer, while only 9.7% and 4.5% in skimmed and whole-fat milk, respectively. Anthocyanins were more resistant to heat in the presence of fat and protein, suggesting that anthocyanins and macromolecules formed complexes that protected anthocyanins from hydroxyl ions attack. The results showed the potential of ARW from purple corn (Zea mays L) as colorants. A protective effect of matrix constituents on the stability of anthocyanins at neutral pH was evident. Elucidating these mechanisms may provide light into how anthocyanins may interact in the small intestine in vivo, where the pH values are in the 7.5~8.5 range.
Session 49F, Fruit & Vegetable Products: Fresh vegetables
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