Study On The Fermentation Technology Of Kiwifruit Wine By Mixed Aspergillus Niger And Aspergillus Oryzae Koji

In this paper, the fermentation method of kiwifruit wine with Aspergillus Niger and Aspergillus Oryzae koji was studied, which four aspects were systematically analyzed: starter-making technology of Aspergillus Niger koji, exclusive yeast-starter preparation of kiwifruit wine, fermentation technology of kiwifruit wine, the rapid aging technology and dynamic changes of aroma components in kiwifruit wine during storage. The main research results were as follows:(1)In order to maintain the heat balance and good ventilation, the appropriate turning was necessary. The culture temperature of Aspergillus Niger koji was generally controlled about 35℃. Through single factor experiment and orthogonal analysis, results indicated that the optimal culture parameters were soaking rice time 10 h, steaming rice time 30 min under 112℃, inoculation quantity 0.35g/Kg, culture temperature 35℃, culture time 65 h. Under the above conditions, the moisture content 24.4%, glucoamylase activity 803.5U/g, liquifying enzyme activity 33.1U/g, total acid 3.85 m L/10 g, pectinase activity 2260.5U/g.(2)By tracking and detecting physical and chemical indicators, four different yeast strains were studied in order to ascertain the effect on fermentation process of kiwifruit wine, confirming Kagoshima Ⅱ was suitable. Exclusive yeast-starter preparation of kiwifruit wine by traditional method, the optimal fermentation conditions were Aspergillus Niger and Aspergillus Oryzae koji amount 1:3, koji and water amount 1:1.4, yeast inoculums quantity 0.45%, fermentation temperature 29℃, fermentation time 8d. Under the above conditions, alcoholic content 15.3%vol, total acid 8.2g/L, yeast count 8.30×108个/m L, budding rate 24.1%, the physical and chemical indexes were in line with national standards.(3)Wild kiwifruit from Shen Nongjia was used as raw materials with homemade purebred Aspergillus Niger and Aspergillus Oryzae koji, Kagoshima Ⅱ yeast as yeast-starter to brew kiwifruit wine. Through single factor experiment and response surface analysis, the optimal fermentation conditions were yeast-starter addition amount 32%, Thiazote amount 0.2g/L, fermentation temperature 25℃, fermentation time 9d. The wine was relatively prominent, the fermentation flavor and fragrance was very rich and nice, alcoholic content 11.2%vol, total sugar 5.4g/L, total acid 8.75g/L, VC 572.5mg/L, methanol 8.35mg/100 m L, higher alcohols 12.54mg/100 m L, sensory evaluation 95, accuracy 98.2%.(4) 61 kinds of aroma components were detected in new kiwi fruit wine by GC-MS, there were 28 kinds of esters, mainly consists of ethyl acetate and ethyl octanoate, as aging time extension, the species of esters were increased, reaching 33 species while 240 d, the relative content increased from 26.656% to 40.25%. Alcohols increased from 14 to 19 kinds, mainly consists of isobutyl alcohol, isopentyl alcohol and benzene ethanol, the relative content decreased from 59.435% to 41.051%. When 240 d, 71 kinds of aroma components were detected, the kiwifruit wine was transparency, aroma coordination.(5) Microwave and ultrasonic technology had a certain role in promoting aging effects of kiwifruit wine, the ultrasonic technology could improve the esters content better, accelerate oxidation and esterification reaction, substances such as esters, alcohols, acids, aldehyde and others presented coordination and unity, constituted the complex characteristics of the kiwifruit wine.