Plum Wine Yeast Efficient Isolationscreening And Efficient Yeast Fermentation Technology Research

By measuring the physical and chemical characteristics of green plum juice,the results show that the soluble solids in juice is 5.8%,the reducing sugar content is 2.5%,and total acid content is 5.6414%,and the tannin content is 0.21%.Because of the green plum juice with high acid content,some of special yeasts such as acid tolerance strains should be screened in green plum wine fermentation.Thirty yeast strains were isolated from the pericarp and pulp of green plums in different maturity which were grown in Dali,and these yeasts were identified by methods of morphology and molecular biology.The results show that these yeasts were classified in five species,and 4 among them were known species,namely Pichia guilliermondi,Candida oleophila,Hanseniaspora guilliermondii,Clavispora lusitaniae.By Duchenne tube fermentation,26 yeasts were proved alcohol producing.According to the ethanol yield,fruit wine sensory evaluation,and tolerance of SO₂,acidity,alcohol and sugar content,the stain PG19（Pichia guilliermondi）and CL1（Clavispora lusitaniae）were confirmed as the green plums wine producing yeast strains.By single factor experiment and 4 factors and 4 levels orthogonal experimental,and scoring by fermentation starting time and gas production in Duchenne tube fermentation test,the optimum fermentation conditions were determined,For the strain CL1 the optimum fermentation conditions are 7% sugar content,40 ppm of SO₂,pH 5.5 and 28℃.For the strain PG19,as follows,4% sugar content and 50 ppm SO₂,pH5 and 28 ℃.