Effects of Biodegradable Liquid Film on Cabernet Sauvignon (V. vinifera L.) Grape Quality

Abstract

Biodegradable liquid film (BLF) improves soil structure and increases plant freezing tolerance after spraying on the surface of soil and plant. In this study, the effects of BLF on grape composition and volatile compounds in Cabernet sauvignon (Vitis vinifera L.) grapes were determined by spraying BLF during the dormant periods over three years. The aim of the study was to evaluate the potential impact of BLF as an overwintering protection measure on grape fruit quality. In 2020 and 2021, BLF spraying increased reducing sugar content and 100-berry weight, decreased titratable acid content, and improved the maturity factor. Compared with the vines not sprayed with BLF, the content of total phenols and total anthocyanins in grape skins showed an increase over the three-year period, with the largest increases of 31.92% and 48.38%, respectively, and the content of total tannins and total flavan-3-ols increased in 2020 and 2021. BLF treatment also increased the total phenolic content in seeds for all three years, reaching a significant level in 2019, 16.38% higher than control treatment (CK). HPLC analysis showed that BLF treatment affected the content and composition of monomeric anthocyanins in grape skins, especially in 2021, BLF treatment significantly increased the content of nine monomeric anthocyanins, and the proportion of acetylated and coumaroylated anthocyanins. However, GC-MS analysis indicated that BLF had little effect on volatile compounds. These results suggest that BLF can be used as an overwintering protection measure in cold regions to promote the accumulation of sugars and polyphenolics, thereby improving overall grape quality.