Analysis Of The Change Trend Of Phenolic Compounds During The Ripening Of Red Wine Grapes In Different Sub-Producing Areas Of Helan Mountain In Ningxia

Phenolic compounds are important flavor substances in grapes and wines,which have important effects on the sensory quality of wines,such as color,aroma,taste and stability.Therefore,it is of great significance for brewing high-quality wine to accurately grasp the changes of grape phenols during the maturation of wine grapes.In this study,the red wine grape varieties from five subproducing areas of Jinshan,Yongning,Qingtongxia,Pingjipu and Yuquanying were used as research materials.The fruit quality of five sub-producing areas in the eastern foot of Helan Mountain in Ningxia was measured during the period from color to maturity,and the change trend of each substance content was clarified,which provided theoretical basis and reference basis for wine brewing in different sub-producing areas of Ningxia.The main results are as follows:1.The pH and total sugar content of red wine grapes in the five sub-producing areas showed an overall upward trend during ripening,and the total acid content showed a downward trend.Among them,the total sugar content of wine grapes in Jinshan and Yongning producing areas was generally higher than that in Qingtongxia,Pingjibao and Yongning producing areas during ripening.The results of the last sampling showed that the total sugar content of Marselan varieties in Yongning producing area was the highest,27.86 ° Brix;the total acid content in Yongning Malbec decreased from 11.83 ±0.06 g/L to 3.52 ± 0.04 g/L during the whole maturation process.The fruit of Pingjibao Malbec grape is larger than that of other varieties,and the 100-grain weight of Pingjibao Malbec grape is generally higher than that of other varieties during the whole ripening process.2.During the ripening process of red wine grapes in five sub-producing areas,the contents of total phenols,tannins and anthocyanins in grape peel and seed increased first and then decreased,and tended to be stable in the later stage.At the last sampling,the total phenol content of grape peel in Yongning was the highest among the five sub-producing areas,which was 137.55 mg/g,while the anthocyanin content of grape peel in Yongning was generally lower than that in the other four subproducing areas.In the studied wine grapes,the content of polyphenols in fruit seeds was higher than that in peel,and the content of polyphenols in fruit seeds was about 2 times higher than that in peel.3.The average degree of polymerization of tannin in the skin of red wine grape in the five subproducing areas showed a downward trend during the ripening process,while the average degree of polymerization of tannin in the fruit seeds did not change significantly during the ripening period.The average degree of polymerization of tannin in the fruit seeds was between 2.19 and 3.00 at the last sampling,and the average degree of polymerization of tannin in the skin of the grape was higher than that of the fruit seeds during the whole ripening process.