UV-B Radiation Induced the Changes in the Amount of Amino Acids, Phenolics and Aroma Compounds in Vitis vinifera cv. Pinot Noir Berry under Field Conditions

Abstract

High UV-B radiation can challenge Pinot noir growth in the wine-making region of the Southern Hemisphere. The aim of this work was to determine UV-B effects on amino acids, phenolic composition and aroma compounds of Pinot noir fruit. Sunlight exposure with or without UV-B did not affect fruit production capacity, °Brix and total amino acids in the vineyard over the two years. This research reported increased contents of skin anthocyanin and skin total phenolics in berry skins under UV-B. The research showed that there were no changes in C6 compounds. Some monoterpenes concentrations were decreased by UV-B. The information also indicated how important leaf canopy management was for vineyard management. Therefore, UV radiation potentially affected fruit ripeness and crop load, and even stimulated the accumulation of phenolic compounds that may affect Pinot noir quality. This research reported that canopy management (UV-B exposure) may be a good way for vineyard management to increase the accumulation of anthocyanins and tannins in berry skins.

Keywords: UV-B radiation; Vitis vinifera ‘Pinot noir’; amino acids; aroma compounds; phenolic compounds.

Figure 1

Vineyard experimental design. Data showed the trial design of this study. SC (green): shade cloth treatment; LR (yellow): leaf removal treatment; PETG (blue): polyethylene terephthalate screen treatment.

Figure 2

Effects of UV-B exposure/exclusion on skin anthocyanins, skin total phenolic substances, skin tannins and seed tannins in Pinot noir berries during ripening in the 2015–2016 vineyard trials. Data showed the mean ± standard error of four replicates. p-values for statistical significance compared the different treatments according to one-way ANOVA and LSD test at the 5% level. Different letters indicate significant differences at p < 0.05.

Figure 3

Effects of UV-B exposure/exclusion on skin anthocyanins, skin total phenolic substances, skin tannins and seed tannins in Pinot noir berries during ripening in the 2016–2017 vineyard trials. Data showed the mean ± standard error of four replicates. p-values for statistical significance compared the different treatments according to one-way ANOVA and LSD test at the 5% level. Different letters indicate significant differences at p < 0.05.