36E-12 |
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C. R. BROWNMILLER and L. R. Howard. Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704 Fresh blueberries are a rich source of polyphenolics, which exhibit potent antioxidant properties. Blueberries are commonly preserved by canning in water or syrup, but the effect of canning on changes in polyphenolic composition and antioxidant capacity of the fruit is unknown. Our objective was to determine the retention of polyphenolics and antioxidant capacity in blueberries canned in water and syrup. Blueberries were canned in water (CW) or 40° Brix corn syrup (CS) according to commercial protocols. Polyphenolic extracts were prepared from fresh blueberries and canned samples at 1 d and 1 mo of storage. Anthocyanins, flavonols, and chlorogenic acid were quantified by HPLC. Antioxidant capacity was evaluated using the oxygen radical absorbing capacity (ORACFL) assay. The total flavonol, anthocyanin, chlorogenic acid and ORACFL values for fresh berries were compared to canned samples (brine plus berries) at both storage times. CS samples had greater levels of anthocyanins, flavonols, and ORACFL than fresh berries 1 d after processing, but contained lower levels after 1 mo storage. The brine accounted for 9%, 25%, and 20%of the total flavonols, anthocyanins, and ORACFL, respectively. The CW samples had similar levels of anthocyanins and flavonols as fresh berries throughout storage. The brine accounted for 12%, 20%, and 30% of flavonols, anthocyanins and ORACFL, respectively. CS and CW samples contained higher levels of chlorogenic acid than fresh berries throughout storage, with the brine accounting for 35%. These results demonstrate that canning does not readily destroy the major antioxidant compounds in blueberries though a considerable amount diffuses into the liquid medium.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |