Antioxidative activities of Ginkgo biloba extract on oil/water emulsion system prepared from an enzymatically modified lipid containing alpha-linolenic acid.

The desired mix of alpha-linolenic acid (ALA)-enriched structured lipid (SL) and physically blended lipid (PB) was prepared from grape seed oil and perilla oil at a weight ratio of 3:1. The major triacylglycerol species (LnLnL) in PB was drastically increased after interesterification (SL), from 0.5% to 16.8%. After the reaction, the total unsaturated fatty acid at the sn-2 position was decreased from 98.83% in PB to 91.36% in SL. The reduction of vitamin E compounds was also observed. Compared with a PB-based emulsion, SL-based emulsions showed oxidative instability, as assessed by lipid hydroperoxide (LOOH) and 2-thiobarbituric acid-reactive substances (TBARS) values, which was mainly due to the SL which contained less LA, ALA, and ΣUSFA at the sn-2 position and less γ-tocopherol than did PB. PB-, and SL-based emulsions with Ginkgo biloba extract (GBE) which showed significantly lower values of LOOH and TBARS compared to a blank control. GBE was effective in retarding the oxidation of the emulsion by quenching the free radicals in the water phase of the emulsion and inhibiting the formation of primary and secondary oxidation products. These results indicate that GBE could be used as an antioxidant additive for stabilizing ALA-enriched emulsions.

CONCLUSIONS

The results suggest the possibility to supplement Ginkgo biloba extract in alpha linolenic acid-enriched structured lipid-based emulsions which would increase the therapeutic value and enhance the antioxidant potential of the emulsions.