| The maturity of grape is the most critical indicator to evaluate the quality of the grapes.The monitoring of berry maturity includes the content of sugar,acid,phenolic compounds,and aroma components.In order to determine the optimal ripen condition of the Meili grape in brewing wine,the content of sugar,acid,phenol,aroma of Meili grape and the quality and sensory analysis of Meili wine which were brewed by grapes harvested on different time were monitored during the grape growth period.For the purpose of study the application of saignée in the Meili variety,the saignée treatment was added to tradition Meili wine-making process,and measured the quality of wine in this treatment.Optimized the craft of Meili.(1)In 2017,the version time of Meili grape in Yangling region was about 21 July,and mature time was in late August.The best physical and chemical maturity period was 28 August.At this time,the content of sugar in berry was 185±2.05 g/L,and acid content was5.45±0.62 g/L.M(maturity degree)reached 33.9 which was the max value during growth period;The best phenol maturation time of Meili was 24 August,and the condition of the grapes was SMI=0.061,CMI=0.521,TPI=9.6.(2)The results of the fruit aroma determination in the ripening of berry fruit showed the green fruit rich in volatile alcohol and aldehyde.During red fruits period,the main aroma were also alcohols and aldehyde.However alcohols components content were increased.The proportion of esters and alcohols in the mature black fruit period were larger.Compared with the 28 August fruit aroma and the results of 24 August fruit aroma,the fruit aroma varieties were same in 28 August and 24 August,but there were 12 kinds of substances decreased slightly in the fruit of 28 August.(3)The grapes harvested on different times(19 August,24 August,28 August)were make wines.The index of quality in this wine showed that the fruit harvested on 24 August with best color,aroma,phenolic content and other indicators.Indicating that the quality of grape of 24 August was more suitable for brewing wine.the color of wine in 24 August was deeper than the others.This wine with 41 kinds of aroma compounds,and the total contentwas 471.75 mg/L.The content of phenolic was 756.34 mg/L.That means the quality of the wine produced by the best phenol maturation is better than that of the wine brewed at the best physical and chemical maturity.(4)The total score of the sensory analysis of wines which grapes at the different maturity levels(19 August,24 August,28 August),were 75.69,80.69,68.92.The highest wine sample was 24 August.There were 28 aroma features in the aroma description,among which the smell quantification values(M)were larger,such as orange,strawberry,litchi,rose,and violet,and these odors were mostly distributed around the load chart of 24 August.(5)Three proportions of saignée were set,at 0%,15%,and 30%,respectively.In red wine with the increase of saignée ratio,the color of Meili red wine became deeper showed ruby.However the pink wine showed light orange.Also the contents of total phenols,flavonoids and the property of antioxidant increased significantly.Moreover,the highest levels of these compounds were 830.41 mg/L,149.46 mg/L,1.53 mol/L Trolox(ABTS)and0.64 mol/L(DPPH),respectively.The volatile compounds in red wine,such as3-methyl-butyl acetate,ethyl nonanoate,and ethyl laurate,also had obviously growth,which displayed the rose and fruity aroma in wine.(6)The sensory analysis results of the Meili wine in the saignée process showed that dry red wine with a saignée proportion of 30% had the highest total score(86).The quantification results of aroma characteristics showed that the aroma of red fruit and the intensity of floral aroma were significantly positively correlated with the proportion of juice,while the aroma of citrus fruit was significantly negatively correlated with the proportion of juice. |
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