Effects of Shading Treatment on Occumulation of Anthocyanin in Grape Fruit of 'Cabernet Sauvignon' at Harvest

In this paper, Cabernet Sauvignon grapevines during two growth stages: from the beginning of veraison to full maturation (I), and from full veraison to full maturation (II) were shaded with 50% and 20% shading nets. Normal growth conditions were considered as the control. Changes in the composition and contents of anthocyanins in grape skins at maturity were determined by high performance liquid chromatography-mass spectrometry (HPLC-MS). The experimental results showed that a total of 15 anthocyanins were detected in the 20% shading net group during stage I, while 14 anthocyanins were detected in each of the other four treatments. Pe-coumaroylglucoside (cis or trans) was not detected. The total amount of anthocyanins in the shading treatments was higher than that in the control, but methylated anthocyanins were still the main anthocyanins, and the 50% shading net significantly increased the content of methylated anthocyanins during stage II. With the shading treatments, the composition of anthocyanins was changed: the 20% shading net significantly improved the content of coumarin-modified anthocyanins during stage I and increased the content of acetylated anthocyanins during both stages. The four shading treatments significantly reduced the content of Dp-coumaroylglucoside in both cis and trans. During stage I, the ratio of 3'-methyl anthocyanin acetylated glucoside to total anthocyanins was increased; during stage II, the proportions of cyanidin-O-glucoside and peonidin-O-glucoside were significantly lower than in the control group. © 2020, China Food Publishing Company. All right reserved.