Comparison Of Quality And Antioxidant Capacity Of Different Varieties Of Chinese Bayberry (Myrica Rubra Sieb. & Zucc.) Fruit

Fruit qualities such as contents of soluble sugar, organic acid, and bioactive compounds (total phenolics, flavonoids, anthocyanin, Cy-3-glu) were studied in five Chinese bayberry (Myrica rubra Sieb. & Zucc.) varieties, i.e. 'Biqi', 'Hunan', 'Dongkui', 'Zaodamei' and 'Wuzhong', of three different maturities. In addition, the anthocyanin content and antioxidant capacity as determined by FRPA, DPPH, and ABTS were carried out in four Chinese bayberry varieties of different colors, i.e. 'Baizhong' (white), 'Fenghongzhong' (pink), 'Dongkui'(red) and 'Biqi' (dark red).With the increase of fruit maturities across the five varieties, anthocyanin accumulated rapidly and fruit color increased, content of organic acid decreased while soluble sugar increased. Among the five varieties tested, 'Biqi' had the darkest flesh color, higher content of anthocyanin and soluble sugar, and lower organic acid when fruit become ripe. The content of Cy-3-glu showed significant correlation with the CIRG value and content of soluble sugar in bayberry fruit (both at r=0.93**).With the increase in fruit color among the four varieties, the contents of total phenolics, flavonoids, anthocyanins, Cy-3-glu, and the antioxidant capacity all increased, and 'Biqi' variety contained the highest contents and antioxidant capacity of all these components compared with other three varieties. There is no anthocyanin detected in 'Baizhong' varieties and also lowest antioxidant content and antioxidant capacity in this variety. Based on the result by FRAP assay, Cy-3-glu accounted for 12, 45, and 85% of the total antioxidant capacity in 'Fenhong', 'Dongkui' and 'Biqi'varieties, respectively. Unknown components other than Cy-3-glu comprised the major antioxidant capacity in 'Baizhong' fruit.The antioxidant capacity determined by three methods all significantly correlated with content of total phenolics, flavonoids, anthocyanins, and Cy-3-glu in Chinese bayberry fruit. Among them, results from ABTS assay showed the highest correlation with total phenol content (r=0.93**), and results of FRAP assay showed the highest correlation with contents of anthocyanin (r=0.91**) and Cy-3-glu (r=0.87**).