The Effects Of Ultraviolet Irradiation Treatment On The Major Quality Of Blueberry During Different Stages

Blueberry gains extensive attention because of their flavor indicator such as carbohydrates and polyphenols. It offers high contents of secondary metabolites such as phenolic compounds, flavonoids, anthocyanins, which contribute on its nutrition value resulting from their antioxidant, anti-mutagenic, anti-bacterial effects.This study was conducted by choosing Northland Blueberry (Vaccinium angustifolium× Vaccinium corymbosum) as the experimental material. The prime goal of this study was to monitor and analyze the change of biological and chemistry activities of carbohydrate, phenolic compounds, PAL, and CHI during development The secondary goal was to investigate and compared the effects of conduct after UV-A, UV-B and UV-C three different ultraviolet irradiation treatment time (5min,10min,15min) and three different adaptation times (12h,24h,48h) on the carbohydrates,polyphenols,MDA content and the PAL,CHI activity of developing blueberries.The major findings are listed as following:1.During the developmental of blueberry, the soluble sugar content increased, and reached 92.713 mg/g FW when it matured. The total phenol content increased after the initial decreased at the beginning; the flavonoid content of fruits reduced; the anthocyanin accumulated after 40d, and reached 3.649 mg/g FW when it matured,increased nearly 80 times,and PAL activity was also reduced while CHI activities increased slowly after the initial decreased at the beginning.2.After UV-A, UV-B, UV-C ultraviolet treatment, the content of total phenols, flavonoids, anthocyanins and PAL activity had increased at different developmental stages. CHI activity was also increased, but decreased significantly in young fruit. PAL and CHI certainly had a negative correlation with soluble sugar, fructose, glucose and sucrose content except UV-A treatment The veraison blueberry had higher sensitivity to UV irradiation, the content of MDA had increased significantly. UV-C treatment had more significant effects on increasing blueberry’s phenols, especially anthocyanin. 3.After UV-A, UV-B, UV-C three different UV treatments to ginkgo Blueberries, at the time of 12h adaptation time soluble sugar, fructose, glucose, and sucrose content increased except UV-A treated 5min and UV-C treated 15min. Total phenolic and flavonoid contents increased after 12h adaptation time. Anthocyanin contents increased significantly after 12h adaptation time except UV-A treatment then showed upward trend. PAL and CHI activity both increased after 12h adaptation times. MDA content did not change significantly comparing with control at 12h adaptation time except UV-B treated 15min. Basically all the content of carbohydrates and polyphenols.changed at 12h, this kind of rapid response shows a rapid and effective protection mechanisms to UV radiation exhibited in blueberries.