Study On Selection Of Higher Quality Acetic Acid Bacteria,Fermentative Pattern And Enzyme Activity In Vinegar Fermentation Of Apple Juice

The study on the vinegar fermentation in apple juice mainly focused on selecting high quality Acetic Acid Bacteria, fermentative pattern * making fruit vinegar and drink of fruit vinegar. The results showed as follow.1. One strain of high quality CP| was selected from solid vinegar fermentation; Two strains of high quality AM} and AM4 were selected from the vinegar liquid fermentation from American. Result of determination strain is: CPi belonged to Ace.rancens; AM: and AM* belonged to Ace.mesoxy'dans. The four strains produced vinegar well and good flavor of apple vinegar. The acid rate and flavor of apple vinegar were better then that of AS1.41.2. Study on fermentation regular pattern showed that (1) there were three factors: temperature, turning frequency, relative filling capacity on the effect of acetic acid fermentation during Shaking Culture of Acetobacteria AS. 1.41. Results Showed that the main factor affecting on acid growing speed was the relative filling capacity, the best condition was 1/4 relative filling capacity, 30"C and 90 r/min; also, the main factor influencing the transformation rate of alcohol into acetic acid was the temperature, of which the best is 27'C > 1/4 relative filling capacity and 120r/min.(2). Under the same condition of fermentation of five different strain of AM^> AM<, CPi, AS 1.41 and 101. The result showed that all five strain produced acidification rate range 0.305~0.399g/L.h and alcohol yield range 53-61%. acid Production , the rate of acidification in production and alcohol yield of Strain AM2 was higher than those of the others strains.(3). The effect of oxygen-vector on the fermentation production was studied in the vinegar systems. It was demonstrated that addiction of 2% n-dodecane in the vinegarfermentation might increase the yield. It was demonstrated that dissolved oxygen waslimit factor in the vinegar fermentation.(4). The higher content of alcohol and sugar restrained fermentation. The cider containing5% alcohol fermented apple vinegar. The cider containing 3% alcohol and 7.5% sugar fermented the drink of apple vinegar.3. Study on change of the alcohol dehydrogenase from Acetic Acid Bacteria ir fermentative pattern show that the enzyme activity increased before production acid, Enzyme attained the highest activity in approximate 60 hours of fermentation . Production of acid attained the highest amount in approximate 84 hours.4. GC-MS analysis of the flavor composition in fermented broth showed the main flavor composi lion were ethyl acetate> ethyl acetate, acetaldehyde-. glycerine, butyleneglycol in fermentation product.