Comparative Study On Quality And Fungal Diversity In Two Kinds Of Fermentation Methods For Vitis Amurensis Wine

Vitis amurensis Rupr from Changbai Mountains area in Jilin Province were used as experimental materials to study the effects of natural fermentation(NF)and controlled fermentation(CF)for the chemical composition,volatile flavors and fungal diversity during the fermentation.The experiment was to confirm the relationship between fermentation methods,fungal microorganisms and volatile flavor components;realize the composition of fungal diversity of Vitis amurensis Rupr from Changbai Mountains area,which to provided a basis for the formation of the "regional" style forVitis amurensis wine.The results were as follows:1?Study on chemical composition during the two kinds of fermentation of Vitis amurensis wine.(1)Different fermentation methods could affect the metabolism of sugar and alcohol in Vitis amurensis wine.The alcohol of NF was lower than CF,but the fermentation process could be completed in NF,fully.Total solubie solids without sugar of Vitis amurensis wine from Changbai Mountains area was around 6.5%(2)The difference of pH and total acid was small between NF and CF.The pH was increase and the total acid was decrease in the overall fermentation.But the content of tartaric acid and citrate in NF was higher than that in CF.The difference of malic acid and succinic acid was not significant between the fermentation mothods,and malic acid-lactic acid fermentation cannot be carried out in NF.(3)Different fermentation methods had little effect on total phenolic content,and had different effects on monomeric phenols.The content of chlorogenic acid,p-coumaric acid and ferulic acid of CF in the pre-fermentation period was higher than that in NF,and the content of epicatechin and resveratrol was higher in post fermentation stage.The content of quercetin,gallic acid and ferulic acid of NF was higher than CF in post fermentation stage.(4)Different fermentation methods affected the total anthocyanins and total pigment content of mountain wines.The total anthocyanins and total pigments in CF were higher than NF in post fermentation stage;the resistance to SO2 of NF was better in the middle and post stages of fermentation.2?Study on volatile flavors during the two kinds of fermentation of Vitis amurensis wine(l)The 122 volatile composition of Vitis amurensis wine from NF and CF were determined by using headspace solid phase micro extraction(HS-SPME)coupled with gas chromatography-mass spectrometry(GC-MS).Esters and alcohols are the main flavor substances,accounting for 63.11%.(2)The types of flavors in both fermentation methods reached the maximum in the main fermentation stage.The total content of flavor substances in the NF continued to increase.While it was increased first and decreased later in the CF.Compared with the two fermentation methods,the CF showed a higher flavor content,and its aroma was rich and monotonous.The NF had a lower flavor content but a rich and mild aroma.(3)Further analysis of the volatile flavors of the five samples by principal component analysis(PCA)revealed that the sample of zero fermentation stage was different from the other stages because of the alcohol and ester compounds.The difference between the two groups in the main fermentation stage was mainly caused by esters.The difference between the two groups is small in the post-fermentation stage.3?Study on fUngal diversity during the two kinds of fermentation fermentation of Vitis amurensis wine(1)A total of 109 OTU were detected by high-throughput sequencing technology,with the largest number of NFZ.Specimen annotation analysis found that the main microorganisms were Ascomycetes,Basidiomycetes and Mortierella;and Saccharomyces and Hanseniaspora accounts for 91%,and others account for 9%.The differential microorgaJisms in the main fermentation stage were Saccharomyces and Hanseniaspora,also includes Sporobolomyces in the post fermentation stage.(2)Saccharomyces exhibited a strong correlation with volatile flavors by the Partial Least Squares Regression(PLS)model.