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D. DEL POZO-INSFRAN1, S. O. Serna-Saldivar2, C. H. Brenes3, and S. T. Talcott1. (1) Dept. of Food Science & Human Nutrition, Univ. of Florida, 359 FSHN Bldg., Newell Dr., PO Box 110370, Gainesville, FL 32611-0370, (2) Food Technology, ITESM- Campus Monterrey, E. Garza Sada 2501 Sur, Monterrey, N.L., 64849, Mexico, (3) Dept. of Food Technology, ITESM-Campus Monterrey, E. Garza Sada 2501 Sur, Monterrey, 64849, Mexico Interest in anthocyanins and polyphenolics as natural antioxidants has increased due to consumer awareness of their functional and nutraceutical properties. Therefore, it is critical to investigate phytochemical changes during processing, particularly the effect of lime cooking. Commercial dent white corn and two blue corns (Mexican and American) were processed into masa, tortillas and chips. An acidification procedure post-nixtamalization was proposed to improve anthocyanin stability. Polyphenolics were characterized and quantified by HPLC-PDAD. Antioxidant capacity was determined using the ORAC assay and quantified as Trolox equivalents (TE). Spectral analysis before and after acid hydrolysis (2N HCl, 60 min at 90°ÆC) confirmed the presence of four cyanidin monoglucosides in both blue corn cultivars. Both pigmented cultivars contained similar polyphenolic composition, which consisted mainly of ferulic acid along with other 3 compounds that shared spectral characteristics with this polyphenolic. (+)-catechin and two p-coumaric acid derivatives were also found in lower amounts. Seven ferulic acid derivatives along with its free form were identified as the major polyphenolics in the dent white corn cultivar. Gallic acid, and two derivatives of protocatechuic and p-coumaric acid were also found in the later cultivar. Although similar anthocyanin and polyphenolic composition were observed for both blue corn cultivars, the Mexican contained higher anthocyanin concentration (13.9mg/kg) and antioxidant capacity (3.4µMTE/g) than the American; yet the later had higher polyphenolic content (2-fold). Both blue corn cultivars contained higher antioxidant capacity (>8.3µMTE/g) and lower polyphenolic content (22mg/kg) than the white corn. Anthocyanin losses increased at each step in the process from masa (39%), tortilla (54%), and chips (78%). Anthocyanin degradation was highly correlated to polyphenolic (r=0.91) and antioxidant capacity losses (r=0.94). Acidification reduced losses of anthocyanins (23%), polyphenolics (15%), and antioxidant capacity (9%) when compared to control treatments. Phytochemical degradation during processing was successfully assessed, and significantly reduced following the proposed acidification strategy.
Session 29, Food Chemistry: Antioxidants and bioactive agents
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