33F-17 |
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K. G. BARRETT1, M. R. Bennink1, and K. D. Dolan2. (1) Dept. of Food Science & Human Nutrition, Michigan State Univ., 109 G. Malcolm Trout FSHN Bldg., East Lansing, MI 48824-1224, (2) Dept. of Food Science & Human Nutrition/Dept. of Agricultural Engineering, Michigan State Univ., 208 G. Malcolm Trout FSHN Bldg., East Lansing, MI 48824-1224 Blueberries contain phenolic compounds that are reportedly beneficial to human health. Mechanized harvesting and sorting result in 6 million tons of unmarketable cull blueberries yearly in Michigan. These cull berries are currently discarded, but they could be a valuable source of phytochemicals. Our objective was to quantify the total phenolic content and antioxidant level of cull blueberries as influenced by processing/extracting for phytochemicals. Cull blueberries were heated and processed through a screen finisher, resulting in a pulp (Product 1, P1). The pulp was oven dried to produce Product 2 (P2). For products 3 and 4, blueberries were mixed with ethanol/water, heated and filtered. The collected liquid extract was condensed and spray dried (P3) or extracted with Optipore resin, condensed and freeze dried (P4). Total phenolic content and antioxidant capacity (ORAC) were determined. Total phenolic contents were: P1=3 ± 0.1; P2=16 ± 0.2; P3=9 ± 0.5; P4=201 ± 0.8 g of (+)-catechin equivalents/kg of product. The total phenolic content on a fresh blueberry basis was approximately 2 g of (+)-catechin equivalents/kg of fresh cull blueberries for all products. The ORAC values were: P1=9 ± 0.4; P2=53 ± 1.0; P3=34 ± 4.5; P4=246 ± 15.3 mmol of Trolox equivalents/kg blueberry product. On a fresh blueberry basis the ORAC values were: P1=8 ± 0.3; P2=7 ± 0.2; P3=8 ± 1.0; P4=2 ± 0.1 mmol of Trolox equivalents/kg of fresh cull blueberries. Aqueous-alcohol and Optipore resin extraction resulted in a highly concentrated product, however, this was at the expense of antioxidant activity. P4 was 12 times more concentrated in phenolics than P2, whereas, P4 had only 5 times more antioxidant activity than P2. All approaches can be utilized to recover valuable phytochemicals. The final choice would depend upon processing costs and market demand.
Session 33F, Nutraceuticals & Functional Foods: Antioxidants and phytochemical analysis
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