18B-24 |
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J.-K. OH and J.-Y. Imm. Food and Nutrition, Kookmin University, 861-1, Chongnung-Dong, Soungbuk-Gu, Seoul, 136-702, South Korea Studies on lipid oxidation in emulsion systems were relatively limited and especially, understanding of lipid oxidation in water in oil emulsion was still fairy poor. Our objective was to examine antioxidative effect of anthocyanins in water in oil microemulsion using reverse micelles. Crude anthocyanins were extracted from grape skin (Cambell early) and the concentration of anthocyanin was estimated using extinction coefficient of cyanidin-3-glucoside. The anthocyanin stock solution (McIlvaine buffer, pH 3.0) was solubilized into organic solvent (hexane, 10 mL) containing a given concentration of surfactant (AOT) and linolenic acid (10%). The desired Wo (the molar ratio of water to surfactant) was obtained by the injection of the buffer. The samples in sealed amber glass vials were held in a 20 oC incubator for 10 days. The extent of lipid oxidation was monitored every other day using peroxide value. The data were analyzed ANOVA and tukey′s multiple comparison test. The lipid oxidation was dramatically decreased as the concentration of anthocyanins increased (5-20 mM) in the micellar phase while reverse micelles containing only the buffer could not retard oxidation of linolenic acids. Virtually no oxidation was occurred when 20 mM of anthocyanin was incorporated into the micellar phase. Lipid oxidation was significantly decreased as micelle size increased (Wo=5-20). The higher concentration of surfactant resulted in increased oxidation. When BHT (7.5 ppm) was present in organic phase synergistic antioxidative effect was found with micellar anthocyanins (10 mM). However, no synergistic effect was observed either with prophyll gallate or with acid synergist, citric acid. The antioxidative effects of anthocyanins solubilized via reverse micelles were demonstrated and structural parameters such as size and number of reverse micelles influencing antioxidative effect were discussed.
Session 18B, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |