Screening And Wine-Making Characteristics Of Excellent Lactobacillus Plantarum From Eastern Foothill Of Helan Mountain

At present,the MLF starter used by wine enterprises of Eastern Foothill of Helan Mountain in Ningxia mainly depends on imports,but the widespread use of commercial MLF starter makes the native microbial resources threatened,and also brings problems such as wine homogenization.The cultivation area of wine grape cultivation in the Eastern F oothill of Helan Mountain in Ningxia is vast,and the difference of local conditions is obvious.Therefore,the development and utilization of native wine microbial resources can not only highlight the characteristics of wine "local customs ",but also gradually screen out the wine microbial suitable for the local environment to solve the problems existing in wine fermentation.In this experiment,malolactic acid bacteria were isolated from Cabernet Sauvignon dry red wine with natural malolactic acid fermentation by modified MRS medium.The lactic acid bacteria were screened by physiological and biochemical identification,molecular biology identification and fermentation tolerance,and wine fermentation test was carried out.Comprehensive measurement of their MLF capacity,the strains of growth,content of L-malic acid and aroma components before and after MLF were measured.In order to provide theoretical basis and technical support for the collection and application of native maloactic acid bacteria in the Eastern Foothills of Helan Mountain,Ningxia.The main results are as follows:1.196 wild strains of Cabernet Sauvignon red wine were isolated from three sub-producing regions in the Eastern Foothills of Helan Mountain,Ningxia,Using morphological identification,physiological and biochemical identification,species specificity identification and 16S rRNA sanalysis,indicating that 47 strains were Lactobacillus plantarum,139 strains were Oenococcus oeni,8 were Acetobacter okinawensis,1 was Lactobacillus hilgardii,1 was Leuconostoc mesenteroides.2.The excellent strains with good tolerance to ethanol,pH,SO2 were screened from 47 wild Lactobacillus plantarum strains H18,H19,H21,Q7,Q18,which were able to maintain activity in a culture environment alcohol content of 17%(v/v),pH 3.3,total SO2 concentration of 60 mg/L.3,In this study,the selected strains of L.plantarum H18,H19,H21,Q7,Q18 were used for brewing experiments.L.plantarum H18,H19,H21,Q7 showed good acid-reducing ability,starting MLF for 28 days,can completely degrade L-malic acid to 0.2 g/L.L.plantarum Q18 compared with other strains,the acid-reducing ability is weaker in fermentation 28 days,degradation of L-malic acid to 0.49 g/L.4.Compared with commercial strain O.oenol,5 strains of L.plantarum could increase the species of volatile aroma compounds in the MLF,the H21,Q18 of the strains also increased the content of volatile aroma compounds.Comprehensive analysis,the strain H21 fermented wine contents of phenylethanol,isoamyl butyrate,ethyl octanoate,ethyl decanoate,eleven aldehyde,benzaldehyde and terpenes were increased,which gave wine unique aroma characteristics such as flower fragrance and fruit aroma,and had the potential to be developed as commercial starter.