30G-4 |
Antioxidant activity and phytochemicals of Rabbiteye blueberry (Vaccinium ashei) products and by-products as affected by fermentation |
M. S. SU and J. L. Silva. Department of Food Science and Technology, Mississippi State University, Mississippi State, MS 39762-9805 Blueberries are one of the most anthocyanin-rich and polyphenol-rich fruits. Thus, blueberries have the potential to be processed into functional foods or nutraceuticals for domestic and global markets. Along with enhancing the nutritive value and functional properties of products, there is a trend towards value-added processing and extraction of the most nutritionally valuable components. Antioxidant activity of blueberry products, such as wines and vinegars, might be affected by fermentation. During acetification, anthocyanins and polyphenols are susceptible to degradation. The type of fermentation used is important to facilitate high retention of antioxidant activity. The present study was to evaluate effects of fermentation on retention of total anthocyanins, total phenolics, and antioxidant activity of blueberry products and by-products (pomaces) - juice (BJ), wines without (BW1) or with (BW2) skin contact, vinegars made from BW1 (JV) or BW2 (WV) or blueberries (BV), and their pomaces (JP, WP, and VP). Dried pomaces were extracted individually with 1% HCl in methanol. The content of total polyphenols (Folin-Ciocalteau Method) and total anthocyanins (pH differential method) were analyzed. The antioxidant activities were determined in terms of their Anti-Radical Activity, %AR (DPPH-radical scavenging Method) and their Antioxidant Activity, % AA (Beta-carotene bleaching Method). Results showed that BW2 had the highest content of anthocyanins and polyphenols and the highest %AA and %AR. Total anthocyanin content of vinegars decreased 10 fold. Total polyphenol content, anti-Radical activity, and antioxidant activity also decreased. Among pomaces, WP had higher total anthocyanin content, total polyphenol content, and antioxidant activity. These findings demonstrate that skin contact fermentation is a better method to obtain higher antioxidant activity of blueberry products and by-products. The results also indicate that acetification significantly decreases anthocyanin content, total polyphenols and antioxidant activity.
Session 30G, Fruit & Vegetable Product: Processed Fruits and Vegetables
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