Papaya Wine Yeast Isolation, Screening And Fermentation Characteristics

In this study, wild aroma-producing yeast was isolated for papaya wine from orchard soil in Hainan. And the best papaya variety was chosen for papaya wine brewing. Papaya fruit juice yield was improved by pectinase treatment, papaya wine fermentation conditions were optimizated, Finally, Analysis of effective composition and aroma components in papaya wine. Results are as follows:(1) The isolation and screening of wild aroma-producing yeast for papaya wineFrom a variety of fruits and orchard soil,120 strains were isolated (including 83 strains were from the peel and flesh, and 37 strains were from the soil). Especially,a strain of yeast P3-4 isolated from pericarp of mature papaya produced aroma componds perfectly in papaya fruit wine. Yeast P3-4 could ferment excellently at 16% volumteric concentration alcohol,300 mg/L SO2, pH 2.1 and it made papaya fruit wine with particular fruit aroma, The strain was identified by morphological and biochemical biolog as Candida albicans.(2) The determination of the raw material papaya wineThe juice yield of papaya, physicochemical properties and the response signal of the electronic nose were used to determine the variety and maturity of papaya wine materials, Finally determine the best raw materials of brewing papaya wine is eight mature of Daqing.(3) Optimization of pectinase enzymatic papaya fruit pureeBy single factor and orthogonal experiments to determine the best pectinase hydrolysis papaya pulp conditions:pH 3.5, temperature 30℃ under hydrolysis 45min, the juice yield is highest.(4) Papaya wine fermentation process optimizationPapaya wine fermented optimum conditions:Angel of active dry yeast inoculated with 0.7%, the optimum pH of 3.8, the sugar content of 24% SO2 concentration to 100 mg/L(5) Oleanolid acid,Vc and total flavonoids in fermentation processBefore papaya wine fermentation,Oleanolic acid content is 69 mg/100 g.Vc content is 45mg/100g, Total flavonoids content is 2.214%(m/m),After the end of the fermentation,oleanolic acid is 6mg/100mL,the Vc content is 3mg/100ml and total flavonoids content is 0.143%(m/m), before and after fermentation oleanolic acid and total flavonoid content has decreased significantly.(6) Papaya and papaya wine aroma components analysisAcetic acid,5-(hydroxymethyl) furfural, linoleic acid, palmitic acid, naphthalene, hydroxylamine, stearic acid, furfural, butyric acid decyl ester and 3,4-Diacetylfurazan, n-pentadecyl acid were detected in Papaya fruit, esters, acids and aldehydes constitute the papaya fruit flavor, papaya wine fermented by Angel Yeast were detected 20 volatile compounds, including seven kinds of alcohols, esters, acids, alkanes, papaya wine fermented by Angel Yeast and yeast P3-4 were detected a total of 30 kinds of volatile compounds, including 15 esters,8 alcohols,5 acids,1 aldehydes, lketones, their common volatile compounds were isoamyl alcohol,3-ethyl alcohol, acetic acid,2-butylene glycol, ethyl acetate, benzyl alcohol, phenethyl alcohol, ethyl stearate and 16 carbon enoate. The characteristic aroma of papaya wine component of isoamyl alcohol, phenethyl alcohol,2,3-butanediol and ethyl acetate, isoamyl alcohol with bitter and sweet, more full bodied, phenethyl alcohol with a soft, pleasant and long-lasting rose fragrant, ethyl acetate with fruit flavor, pleasant characteristic aroma of papaya wine contribute a great deal, in addition, papaya wine fermented by Angel and P3-4 were detected 3-hydroxy -2-butanone, this substance has a strong creamy smell and fat aroma, After highly diluted it has a agreeable milk aroma, malonate with apple flavor, aroma of benzaldehyde having similar bitter almonds, these constitutents have contributed to the complexity of papaya wine aroma.