Abstract: 【Objective】 Phenols are the most important substances of wine, which not only affect the sensory quality of wine, but also determine the function of the physiological activity of wine. The contents and types of phenolic compounds, as well as the differences of phenolic compounds in different parts of grape fruits in 20 red wine grape varieties, which were taken from areas of the Shanxi Loess Plateau, were studied in order to acquire more effective improvement in wine making process, and provide a theoretical basis for the breeding of wine grapes. 【Method】 Using 20 red grape varieties collected from Pomology Institute of Shanxi Academy of Agricultural Sciences, grape resources garden (Taigu) as materials, berry size and its shape index, mass and percentage of different parts, soluble solids content (TSS), titratable acid content, TPC, TFA, CGE and monomer phenol content were measured. 【Result】 The result indicated that the fruit shape index of 20 grape varieties were higher than 0.95, and the fruit shape was oval or conical. There was a significant difference between the proportion of grape peels, seeds and pulps. The ‘Cabernet Sauvignon’ with a higher quality was the first cultivar in China, its proportion of peels and seeds were the highest and reached 31.3%; whereas the proportion of peels and seeds of ‘Cabernet Gernischet’ was lower, only 10.62%, meanwhile the wine fermented by ‘Cabernet Gernischet’ had a lower content of polyphenols and a supple texture. Titratable acid content of 20 varieties of grapes was 3.97-9.00 g·L^-1 and the content of soluble solid was 14.5-25.4 g·L^-1. Different grape varieties and different parts of the grape fruit (skin, seed and pulp) were significantly different in the polyphenols content. TPC (total phenolic content) of grape peel was 12-125 mg·100g^-1FW (fruit fresh weight), TFA (total flavanol content) was 1-27 mg·100g^-1FW; TPC of grape seed was 17-456 mg·100g^-1 FW, TFA was 22-505 mg·100g^-1FW, TPC of grape pulps was 1.24-3.24 mg·100g^-1FW, that TPC in grape seed was 3-4 times of grape peel, TFA in the seed was 10 times more than the peel. Anthocyanin mainly existed in grape peels and the content of anthocyanin of grape peels was 1-34 mg·100g^-1FW. Among the 20 varieties of grape, ‘Cabernet sauvignon’ exhibited the highest anthocyanin content, which was followed by ‘Ruby cabernet’, ‘Marselan’ and ‘Cabernet gernischet’. The grape cultivars such as ‘Marselan’ and ‘Cabernet sauvignon’ had higher phenolic compounds, meanwhile the grape cultivars such as ‘Cabernet gernischet’, ‘Heihuxiang’ and ‘Cinsaut cehco’ had lower phenols content. The content of phenolic compounds in different parts of various grapes was significantly different. The order was that grape seeds was the highest, followed by the grape skins, and the pulp was the lowest. The phenolic compounds content in pulp was much lower than that in skins and seeds, and pulp mainly contained phenolic acids. A total of 12 kinds of monomeric phenols in grape pulps were identified by HPLC, including 4 kinds of flavonoids, 7 kinds of phenolic acids and resveratrol. 【Conclusion】 Characters of grape affected not only the quality of wine, but also the phenolic compounds in wine. The final content of phenolic compounds in wine was determined by the size of fruit, the proportion between peels and seeds, the phenolic content and variety of grape peels, seeds and pulps. By controlling the polyphenols content of the grape skin, seed and pulp through wine making technology, the quality of red wine can be improved. Based on the characteristics of grape polyphenols, a selective grape breeding work should be carried out.

Key words: grape, varietal characteristic, phenolic compounds, brewing