45G-16 |
Phytochemical composition and pigment stability of açai (Euterpe oleracea) |
D. DEL POZO-INSFRAN1, S. T. Talcott1, and C. H. Brenes2. (1) Dept. of Food Science & Human Nutrition, Univ. of Florida, 359 FSHN Bldg., Newell Dr., PO Box 110370, Gainesville, FL 32611-0370, (2) Dept. of Food Technology, ITESM-Campus Monterrey, E. Garza Sada 2501 Sur, Monterrey, 64849, Mexico Consumer trends have shown desirability towards processed food without synthetic color additives. Anthocyanins from novel sources have potential as a natural colorant; however, instability during processing and storage may limit their use in the food industry. Polyphenolics, anthocyanins, and antioxidant capacity (AOX) in açai puree were determined. Açai color stability was compared to other anthocyanin sources (hibiscus, black carrot, red cabbage, red grape, and purple sweet potato) using kinetic parameters. Polyphenolics were purified using reverse phase C18 columns, then characterized and quantified by HPLC/PDA techniques. AOX was determined using the oxygen radical absorbance capacity assay. Color stability was assessed spectrophotometrically in the presence of hydrogen peroxide (30mmol/L) over a temperature range of 10 to 30°C. Stability against ascorbic acid (AA; 450mg/L) was also assessed using a soft drink-model system (100g/L sucrose, pH=3.5) at 37°C in the presence or absence of their naturally occurring polyphenolics. Epicatechin (129 mg/kg fresh weight) and p-OH-benzoic (80.5 mg/kg) were the major phenolics found. Gallic acid, (+)-catechin, protocatechuic and ellagic acid were found with average values of 60 mg/kg. p-coumaric, ferulic and vanillic acid were found in a less extent (22 mg/kg). Cyanidin (1,040 mg/kg) and pelargonidin 3-glucoside (74 mg/kg) were the major pigments present in the pulp. AOX (233 mmolTE/g) was highly correlated to anthocyanin content (r=0.99). Comparison of color half-life revealed that pigments rich in acylated anthocyanins displayed reduced stability against H2O2(80 min) with respect to those non acylated (100 min). Temperature increments (10°C) increased color degradation over 1.5-fold, regardless of pigment composition. Natural polyphenolics present in each extract influenced color stability in both the presence and absence of AA by 3 and 6-fold, respectively. AA degradation was reduced up to 3-fold for acylated anthocyanins and were similar to açai. Açai offers a new source of anthocyanins with high AOX and pigment stability.
Session 45G, Fruit & Vegetable Products: Vegetables (Fresh)
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