Study On Screening Of Excellent Acetobacter Strains For Hippophae Rharmmoides L. Vinegar And The Making Of Vinegar Beverages

Hippophae rhaxnnoides L. juice was used as the acetobacter source. The method of liquid fermentation included alcoholic fermentation and acetic fermentation was used, procured 177 acetic acid bacterias and three superior acetobacter acetic strains A-4, A-18, A-23 were selected. A-4 was selected by comprehensive comparison. Through physiological and biochemical identification and molecular biology identification, it was identified as Acetobacter sp.434.The optimum strain growth conditions were optimized by single factor test and central composite uniform precision experiment. The optimum medium was glucose 1.32%, yeast extract 1.27%, acetic acid 1.02%, alcohol 2.77%, K2HPO4 0.18%. The optimal growth conditions were at 32℃, pH5, starter age 22h, inoculating amount 10%, revolving amount 150r/min, volume of medium 1/5. After optimizing experiment, the highest growth amount could increase by 19.2%. The time that strain reached the highest point of logarithmic phase was shortened 4h.The Hippophae rhaxnnoides L. juice was used to brew vinegar, which was developed by A-4. According to the Plackett-Burman experimental design to choice notable factors and experimentize by Box-Benhnken center-united experimental design principles, the method of response surface analysis was adopted to determine optimal fermentation conditions of Hippophae rhaxnnoides L. vinegar. The optimal fermentation conditions were at 32℃, inoculating amount 7%, initial amount of sugar 5oBX, alcohol 5.5%(v/v), initial pH value 4.0, volume of medium 96mL/500mL, revolving amount 125r/min.The aroma compounds of Hippophae rhaxnnoides L. vinegar were extracted by solid phase micro extraction. The aromatic compounds were analyzed by GC/MS and identified by mass spectra database searching technology and were quantified by using peak area normalization method. There were 82 compounds identified and 35 aroma compounds of matching score above 80 and the percent of the peak areas was 84.57%. These 35 aroma compounds including 11 kinds of esters, 2 kinds of acids, 17 kinds of hydrocarbon, 1 kinds of alcohols, 2 kinds of ketones and 2 kinds of phenols. Ester is of the highest content 56.35%, followed by hydrocarbon 12.58%, acids 11.33%, ketones 1.93%, phenol 1.57%, alcohols 0.81%.The optimal composition of Hippophae rhaxnnoides L. vinegar beverage formula was determined by single factor test and orthogonal test. The results were as follows: Hippophae rhaxnnoides L. vinegar 8mL/100mL, Hippophae rhaxnnoides L. juice 15 mL/100mL, honey 1g/100mL, sugar 10g/100mL. The Hippophae rhaxnnoides L. vinegar beverage possess bright color, gratifying fruit savory, harmonious sourness and sweetness, and clarity.