Analysis and comparison of the phenolic compounds of Chardonnay grape in different terroir

【Objective】The objective of this study was to explore the changes of phenolic compounds in grapes and wines of Chardonnay under different terroirs in the eastern foothills of Helan Mountain. 【Methods】The phenolic compounds in grapes and wines of Chardonnay were determined in 2021 and 2022 by high performance liquid chromatography- mass spectrometry (HPLC- MS) and other techniques, and the phenolic compounds characteristics of grapes and wines under different terroirs were investigated by partial least squares discrimination analysis (OPLS-DA).【Results】At the ripening stage, the 100-grain mass of grapes in ZH plot was the largest, reaching 158.21 g and 158.15 g in 2021 and 2022, respectively, and the mass of 100 grains in ZH were 29.51%, 42.15% and 14.11% higher than those of YQ, YM and XG in 2021, and 18.43%, 45.82% and 29.22% higher than those of YQ, YM and XG in 2022. For two consecutive years, the soluble solids content of grape fruit in plot XG was higher,and YQ was the lowest, respectively, but there was no significant difference. In 2021, there was a significant difference in the titratable acid content between grape fruits in YQ and ZH plots, which was 25.42% lower than that in ZH plots, and there was a significant difference in titratable acid content between YQ and XG plots in 2022, which was 43.75% higher than that in XG plots, and the total phenolic content of grape fruits in each plot in 2021 was higher than that in 2022, and the total phenolic content of YQ in 2021 was the highest , 6.24 mg·g-1 , and ZH was the lowest , 3.61 mg·g-1 , YQ was 72.9% higher than that of ZH. A total of 14 phenolic compounds were detected in the grape fruits of Chardonnay, including 2 flavanols, 6 flavanols and 6 phenolic acids, and the contents of catechins and gallic acid in the phenolic substances of grape fruits in the four plots were the highest, and the catechin content of the YQ plot at the ripening stage in 2021 was higher than that in other plots, which was 52.37 mg·kg-1 , and YM was the lowest , 30.11 mg · kg- 1 , and YQ was 73.93% higher than that of YM. The difference was significant. In 2021, the gallic acid content of YQ, YM, XG and ZH accounted for 68.92%, 89.69%, 93.55% and 86.24% of the total acid content, respectively, and in 2022, it accounted for 79.65% , 59.24%, 73.87% and 75.69% of the total acid content. The orthogonal partial least squares discriminant analysis (OPLS- DA) was used to distinguish the four plots, and the most significant differences between the four plots were catechin, epicatechin, and gallic acid, among them catechin was the most significant. Additionally, the grape berries from the YQ plot were characterized by catechin and rutin as their distinctive components, while the wine was predominantly marked by catechin and gallic acid. The grape berries from the YM and XG plots featured quercetin, kaempferol, and myricetin as their characteristic compounds, whereas the wine was distinguished by quercetin and morin. In the ZH plot, gallic acid was the primary phenolic compound in the grape berries, while rutin was the characteristic substance in the wine. The main phenolic compounds in grape berries were largely consistent with those in the corresponding wines.【Conclusion】The main characteristic phenolic compounds of Chardonnay grapes in the eastern foothills of Helan Mountain in Ningxia were phenolic acids and flavanols, and the phenolic compounds in the grapes and wines of Chardonnay in different plots were significantly different depending on the terroir conditions. It would provide a theoretical basis for the production area style and product design of Chardonnay wine in the eastern foothills of Helan Mountain in Ningxia, China.