| Natural wine,it is generally believed that the grape raw materials are grown organically,commercial yeast,SO2 and other auxiliary materials are not added as much as possible during the production process,and human intervention is reduced to produce a wine with the characteristics of the terroir of the producing area.The wine quality from the Eastern Foothill of Helan Mountain is good,but there are problems such as single product structure and homogenization of style;'Merlot' is the second largest wine grape variety in the world and is widely planted in the Eastern Foothill of Helan Mountain.In this study,'Merlot' in the Eastern Foothill of Helan Mountain in Ningxia were used as test materials to analyze the physical and chemical indicators,flavor substances,sensory quality,microbial flora and aging stability of natural wines,and clarify the natural wines from the Eastern Foothill of Helan Mountain.The quality and characteristics of the fermentation process,microbial changes and safety,provide a theoretical basis for the development of new wine varieties in the production area.The main results of this study are as follows:1.Natural wine can completely complete alcohol fermentation at a potential alcohol content of 14.5°,Compared with traditional technology,there is no significant difference in alcohol content,residual sugar,dry extract,pH and other indicators,while natural wine has higher volatile acid and lactic acid content.,The content of glycerin,total phenols,tannins,and anthocyanins is low;the total aroma components of natural wine are lower than traditional craft wines,and there are fewer short-chain and medium-chain fatty acid esters with fruity characteristics,and the proportion of alcohols High,long-chain fatty acid ethyl esters above C10 and high volatile phenol content,aroma cluster analysis can distinguish natural wines from traditional craft wines,showing unique aroma characteristics of the production area;sensory,natural wine color chroma Lighter,weaker fruit aroma,with more complex aroma characteristics such as almond,pepper,vanilla,etc.The taste characteristics and overall score are not significantly different from traditional craft wines2.The results showed that the fungal flora was the most abundant in the early stage of fermentation.39 genera of fungi(15 genera of yeasts)were detected,and the dominant flora was Hanseniaspora and Saccharomyces became domnant as the fermentation progressed.Flora,the higher proportion of the flora include non-Saccharomyces such as Filobasidium,Metschnikowia,and non-yeast fungi such as Alternaria,Cladosporium,Aureobasidium,Gibberella,etc;bacterial flora abundance first decreases and then increases It reaches the highest at the end of fermentation,and the dominant bacterial group Fructobacillus accounts for more than 80%.The relatively high proportion of bacteria include Rhodococcus,Massilia,Lactobacillus.At the beginning of fermentation,the types and quantities of aroma substances are relatively small,and gradually increase as the fermentation progresses.Phenylethyl alcohol,isoamyl alcohol,ethyl caprylate,and ethyl caprate are the main aroma substances.The content of aroma substances varies significantly in different fermentation stages.3.Natural malic acid-lactic acid fermentation(MLF)can completely convert malic acid into lactic acid.Compared with fermentation with added strains,there is no significant difference in physical and chemical indicators and sensory quality between the two.After the MLF,a large number of lactic acid bacteria and microorganisms were detected in the wine.There are hidden dangers to stability.4.The content of biogenic amine in natural wine is between 4.60?5.21 mg/L,slightly higher than that of traditional craft wine(4.12?4.50 mg/L),which is formed during alcohol fermentation and MLF process. |
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