Abstract:

Brewer's yeast (Saccharomyces cerevisiae) cells subjected to a 24 h plasmolysis treatment were used to encapsulate chlorogenic acid, a water-soluble antioxidant. The optimal encapsulation for 6 h at 40 ℃ and 3:1 core material/wall material ratio (g/g) in 6 mL of distilled water as encapsulation medium determined using orthogonal array design resulted in a maximum encapsulation efficiency of 18.9%. Infrared spectral analysis indicated the disappearance of characteristic function groups of chlorogenic acid. Fluorescence microscopic studies revealed that the microcapsules were spherical in shape and that the spontaneous fluorescence of chlorogenic acid was observed on the inner side of yeast cell wall. The similar retention time and UV-Vis profiles between unmicroencapsulated and microencapsulated chlorogenic acid were found through HPLC analysis. All these results suggested that chlorogenic acid was successfully encapsulated and no significant chemical changes occurred during the encapsulation process.

Key words: chlorogenic acid, microencapsulation, cell wall, orthogonal array design, HPLC