14E-16 |
Effect of filtration and nitrogen flushing on antioxidant capacity and anthocyanins concentration of blueberry juice |
S. Sellappan1, C. C. AKOH1, and G. W. Krewer2. (1) Dept. of Food Science & Technology, Univ. of Georgia, Food Science Bldg., Athens, GA 30602-7610, (2) Dept. of Horticulture, Univ. of Georgia, Rural Development Center, PO Box 1209, Tifton, GA 31793-7548 Processing and storage of fruits can affect the anthocyanins and antioxidant capacity in final products. Blueberry is rich in anthocyanins and has high antioxidant capacity. The retention of antioxidant capacity and anthocyanins in processed fruit juices are important quality parameters in producing high quality products. The effect of processing, such as filtration and nitrogen flushing and storage were studied on the stability of these parameters. Blueberry juice (from Rabbiteye, premier variety) was used as model juice. A10% blueberry juice was prepared with 0.1% sodium benzoate and evaluated for stability of anthocyanins and antioxidant capacity. The effect of micro-filtration (molecular weight cutoff of 30,000), nitrogen flushing and storage were studied at various pH. Initial anthocyanins concentration of nonfiltered-nonflushed juice was 92.28 mg/L (100%). Flushing the nonfiltered juice with nitrogen slightly increased the anthocyanins concentration to 101.05 mg/L (109.50%). Membrane filtration further increased the anthocyanins concentration to 121.29 mg/L (131.43%). Nitrogen flushing of filtered juice increased the concentration to the highest level of 138.70 mg/L (150.30%). During storage, the stability of anthocyanins was better at acidic pH for both processed and unprocessed juices. Filtration combined with nitrogen flushing increased the concentration as well as the stability of anthocyanins. Similarly, processing dramatically increased the stability of antioxidant capacity (half-life, 914 days) in comparison with other juices (half-life of less than 350 days). In conclusion, processing of blueberry juice increased the anthocyanins concentration and stabilized antioxidant capacity. Among all the processes, the combination of filtration and nitrogen flushing was found to be effective.
Session 14E, Nutraceuticals & Functional Foods: General I
|