Study On The Fermentation Process And Quality Of Fruit Wine Based On Zymomonas Mobilis

With the improvement of living standards,people gradually begin to pursue healthier eating habits,and the choice of drinking wine is more focused on fruit wine with low alcohol content and rich nutrition.In recent years,China has also vigorously promoted winemaking with fruits instead of grains,so fruit wine has a good development prospect.Blueberry is rich in nutrients such as vitamins,SOD and anthocyanins.It has anti-oxidant,protect eyesight,improve resistance,anti-cancer and other effects.So blueberry is called the “King of Berries” and widely used in the food field.Fermentation of fruit wine using blueberries as raw materials can retain its own nutrients to a large extent.In addition,it can also produce esters,higher alcohols,organic acids and other substances during the fermentation process.Zymomonas mobilis,isolated from palm wine,is a gram-negative,facultative anaerobic spore,and is recognized as a GRAS strain.Compared with Saccharomyces cerevisiae,it has the advantages of high ethanol production rate and simple metabolism,but it is seldom used in fruit wine research.In this study,we chose the blueberry from Yunnan as raw materials,ZMD95 obtain by Biomass Energy Technology Research Centre of Biogas Institute of Ministry of Agriculture and Rural Affairs as a fermentation strain,honey as carbon source to explore the optimal fermentation process.The volatile compounds and clarification process were also been investigated.This experiment provides a theoretical reference for Z.mobilis in the field of fermented fruit wine.The main research contents and results are as follows:1.Initial pH,initial sugar content,inoculum size and fermentation time were determined as dependent variables by single factor experiment,and the ethanol content,anthocyanin content,and sorbitol content as response values.A four-factor three-level response surface experiment was designed based on the Box-Behnken principle.The final optimal fermentation process as follow: initial pH 4.40,initial sugar 20° Brix,inoculum 10.5%(v/v),fermentation time 6 d.Under this condition,the ethanol content of honey-blueberry wine fermented by Z.mobilis is 8.61%vol,anthocyanin content 69.87 mg/L,sorbitol content 33.94 g/L,which were close to the predicted values.2.Using HS-SPME-GC-MS technology to detect and compare the volatile compounds of honey-blueberry wine and commercial blueberry wine.The results showed that a total of 48 volatile compounds were detected in two wine samples,of which 22 were detected in the experimental wines,accounting for 89.67% of the total peak area,and 28 were detected in the commercial blueberry wines,accounting for 93.46% of the total peak area.There are only two kinds of volatile compounds that are common to both,namely phenethyl alcohol and 2,4-Di-tert-butylphenol.The terpenes was the main volatile compounds of the experimental wine,accounting for 72.03%,and the esters was the main volatile compounds of the commercial wine,accounting for 59.56%,but no ester was detected in the experimental wine.3.Three methods,natural clarification method,centrifugal clarification method and bentonite method,were used to clarify the honey-blueberry wine obtained from the experiment.The result showed that adding bentonite solution had the best clarification effect,and 1.2 mg/mL was the optimal added amount.The degree of clarification can reached 72.55%,and the bentonite clarification method has simple operation,short time consumption and low cost.