Abstract:

Anthocyanin extracts prepared from 9 varieties of litchi pericarp were compared for differences in particle size distribution in different concentrations of aqueous ethanol solutions and various color parameters such as L*, a*, b*, C* and h°. In the case of the extracts having different anthocyanin contents, the correlations among anthocyanin content, particle size distribution parameters and color parameters in 35% aqueous ethanol solution and maximum hydroxyl free radical scavenging rate or median effective concentration (EC50) were analyzed. Results indicated that Nuomici litchi pericarp anthocyanins dissolved in 35% aqueous ethanol solution showed the best particle size distribution (in the range of 2.48－6.51 μm) and the D50 and the specific surface area were 4.56 μm and 498.23 m2/kg, respectively. In addition, anthocyanin extracts prepared from different varieties of litchi pericarp revealed a significant difference in particle size distribution. Meanwhile, Nuomici litchi pericarp anthocyanins had the highest c* (110.27) and a* (87.12) values and Feizixiao litchi pericarp anthocyanins had the highest L*(94.86) and b* (98.79) values. The color of anthocyanin extracts prepared from different varieties of litchi pericarp changed from red to yellow. Correlations were observed among anthocyanin content, maximum hydroxyl free radical scavenging rate or IC50 and particle size distribution parameters and color parameters in 35% aqueous ethanol solution. Moreover, particle size distribution parameters exhibited a dominant effect on color parameters in 35% aqueous ethanol solution.

Key words: litchi pericarp anthocyanins, particle size, antioxidant activity, Lab color system, correlation analysis