| The grapes and wines of Cabernet Gernischt,Cabernet Sauvignon and Marselan in Changli,Hebei Province were used as experimental materials.The quality parameters and fungal community changes and differences in the fermentation process of different varieties of grape mash were studied,and the antioxidant activity and metabolites of 3 kinds of wines were determined.Clarified the impact of variety on these four aspects,and the results of the study were as follows:1.Research on the quality parameters of different varieties of grape mash during natural fermentation(1)Different varieties affect the sugar metabolism of wine.The main fermentation process of Cabernet Gernischt grape mash was basically completed in about 7 days,and the reducing sugar content was reduced to 2.20 g/L.The main fermentation process of Cabernet Sauvignon and Marselan grape mash was basically completed in about 8 days,and the reducing sugar content was reduced to 2.30 g/L,2.70 g/L,respectively.(2)Different varieties affect the alcohol metabolism of wine.At the end of the main fermentation,the alcohol levels of Cabernet Gernischt,Cabernet Sauvignon and Marselan were 10.6%vol,11.4%vol,and 11.9%vol respectively.(3)There are differences in the total acid content of different varieties of grape mash.The initial values of the total acid content of Cabernet Gernischt,Cabernet Sauvignon and Marselan were 6.08 g/L,6.80 g/L and 6.67 g/L,respectively.The total acid content of Cabernet Sauvignon is slowly increasing during the fermentation process,and it is as high as 8.97g/L at the end of the alcohol fermentation.The total acid content of Cabernet Gernischt and Marselan showed a slow downward trend during the fermentation process,and it decreased to 5.09 g/L and 6.11 g/L respectively at the end of alcohol fermentation.2.Study on the diversity of fungi community during the fermentation of grape mash(1)Taking samples of different varieties of grape mash before,during and after fermentation as the research object,the Illunina HiSeq high-throughput technology was used for sequencing and analysis of the ITS1-ITS2 region.The results showed that:The 128 genera of fungi were Hanseniaspora,Saccharomyces,unidentified genera,Aureobasidium,Mortierella and so on.The 331 OTUs were identified,mainly Saccharomyces cerevisiae,Hanseniaspora uvarum,Hanseniaspora osmophila,and Hanseniaspora vineae.Aureobasidium Pullulans,Mortierella alpina,Mortierella elongata,Stachybotrys Microspora and Guehomyces Pullulans were in small amounts.(2)The Hanseniaspora in grape juice was the dominant strain in the early fermentation stage of the three grape wine varieties,and Saccharomyces Cerevisiae was the dominant strain in the middle and late fermentation stage.There are differences in the species and abundance of fungi in different samples.There are differences in fungal species and abundance in different samples.3.The difference of active substance content and antioxidant activity of different varieties of wine(1)There were significant differences in the phenolic content of the 3 wines.The wines of Cabernet Sauvignon The contents of total phenols,total flavonoids,and total anthocyanins were the highest,which were 1909 mg GAE/L,1107 mg/L,and 660 mg/L,respectively;the total anthocyanins content of Cabernet Gernischt wine was the highest,207 mg/L.(2)The copper ion reduction ability,DPPH scavenging ability and ABTS+scavenging ability of the three wines were measured,and it was concluded that the antioxidant activities of the three wines had significant differences.Among them,the three indicators of Cabernet Sauvignon wine were the highest,respectively.It is 18347 μmol/L,8072 μmol/L,9298μmol/L.4.Analysis of Nutritional Metabolites of Different Varieties of WineThrough 1H NMR pattern recognition analysis,the differences of the three wine metabolites in the Changli,Hebei were studied.The three types of wine nutritional metabolites were not significantly different,but the relative content of the three wines was not significantly different.Through partial least squares discrimination(PLS-DA)and content analysis,it was concluded that the content of citric acid,lactic acid,succinic acid,and ethyl acetate were higher in Cabernet Gernischt wine.The content of malic acid,gallic acid,and choline were higher in Cabernet Sauvignon wine.The content of tartaric acid,glycerin and proline were high in Marselan wine.During the fermentation process,the fermentation index and the abundance of fungal community of different varieties of grape mash are different,and the antioxidant activity and the content of metabolites measured after the fermentation are also different,which proves that the grape mash from the same production area Different vinified varieties have different effects on the overall quality of wine,in order to provide a theoretical basis for reasonable brewing and reasonable selection of wine. |
