36E-72 |
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D. DEL POZO-INSFRAN and S. T. Talcott. Dept. of Food Science and Human Nutrition, Univ. of Florida, 359 FSHN Bldg., Newell Dr., PO Box 110370, Gainesville, FL 32611-0370 The poor stability of anthocyanins during processing and storage is a limiting factor for many food products therefore evaluating strategies and technologies that serve to alleviate these limitations is of importance. Dense Phase-CO2 processing (DP-CO2) is a promising pasteurization technology and may lessen detrimental effects to thermolabile phytochemicals such as anthocyanins. Similarly, formation of intermolecular complexes (copigmentation) by the addition of polyphenolic cofactors will assert a protective effect against anthocyanin and ascorbic acid (AA) degradation. To enhance anthocyanin stability, this study evaluated the addition of polyphenolic cofactors from thyme (Thymus vulgaris) on the phytochemical and sensory attributes of AA-fortified muscadine grape juice following thermal and DP-CO2 processing. Thyme polyphenolics were extracted, partitioned from C18 columns, and quantified spectrophotometrically. Cofactors were added to a fresh grape juice (1:100 anthocyanin-to-cofactor molar ratio), fortified with AA (0, 450mg/L), and pasteurized using DP-CO2 (34.5MPa, 8 or 16%CO2) or heat (75° C, 15 sec) and then stored for 30 days at 4° C. Chemical analyses included anthocyanin 3,5-diglycosides and AA by HPLC, antioxidant capacity (AOX; ORAC assay), and total phenolics (Folin's assay). Sensory attributes of control and copigmented juices were compared using difference-from-control and ranking tests (60 panelists). DP-CO2 processing insignificantly altered juice phytochemical and AOX content, while thermal pasteurization reduced anthocyanins (171mg/L), AA (30mg/L), phenolics (300mg/L) and AOX (3.1µmol Trolox-equivalents/mL). Cofactor addition increased AOX by 27 µM Trolox-equivalents/mL and total phenolic by 150mg/L and served to retain anthocyanin content during thermal processing. AA fortification initially increased AOX, but resulted in a 2-fold decrease in anthocyanin and AOX during storage, an effect that was alleviated with copigmentation. Sensory analysis revealed insignificant changes in aroma and flavor due to cofactor addition, moreover panelists ranked juice color higher than controls. Copigmentation and DP-CO2 processing were effective in preventing phytochemical and quality deterioration in muscadine juice during processing and storage.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |