Abstract
Anthocyanin pigments (shiso AN) were extracted from the purple leaves of Perilla ocimoides L. var. crispa (Japanese name, "shiso") and were examined regarding the anthocyanin composition and their stability to heating, ultraviolet (UV)-light irradiation, and effects under the coexistence of additives such as polysaccharides and glycyrrhizinate (GR). The results obtained were as follows. 1)By means of high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (LC/MS) analyses, the structures of three isolated anthocyanins from shiso AN were presumed to be cyanidin 3, 5-diglucoside, cyanidin 3-(6-p-coumarylglucoside)-5-glucoside; shisonin and cyanidin 3-(6-p-coumarylglucoside)-5-(6-malonylglucoside); malonylshisonin, while the remaining components have not been identified yet. 2)A major pigment estimated to be malonylshisonin in shiso AN was shown to be the most labile under heating and UV-light irradiation. 3)Addition of polysaccharides essentially did not increase the absorbance (ABS) of shiso AN solution as compared with that of non-addition; however GR addition increased the ABS. 4)When shiso AN solution containing added polysaccharides was heated to 100°C for 8h (heating), the sample with alginate addition was stabler than that the non-addition sample. While under UV-light irradiation for 8h (UV), the fading ratio of every polysaccharide containing shiso AN was lower than that of non-addition samples. 5) Shiso AN solution containing added GR decreased in fading ratio compared with the non-addition sample under both heating and UV conditions.
