COLLECTION AND STUDY OF SOME ACETIC ACID FORMING BACTERIA CHARACTERISTIC-PRELIMINARY APPLICATIONS TO MAKING VINEGARS FROM FRUIT JUICE

Abstract

Collected Acetic acid producing bacteria from the vinagar sample in some areas around Hồ Chí Minh city and some neighboring provinces have been isolated. A total of 12 strains of Acetic acid forming bacteria have been identified as Acetobacter.sp (A1,A2....,A12) and Gluconobacter.spg. (G9, or Gluc.sp9). The cultural of Acet.spy and Gluc.spg were inoculated into a medium consisting of 5% ethanol, (NH4)2SO4, KH2PO4 at 30°C for 8-10 days. The samples were found to have relatively low total acid concentrations: 2,78% and 2,89%, respectively. Mixing the wine of fruits as from bananas (containing 9% ethanol), grapes (containing 10% ethanol), cherries (9% ethanol) a ratio of 20% (v/v) with the above samples at 30°C, it has been found that after 8 to 10 days the grape vinegar has the highest degree of limpidity with most flavor and a total percentage of acid of 2,88% and 3,04%, respectively. In addition, with grape juice (1kg/10 1 of water), and ethanol added at intevals (5%, then 2,5%, and 2,0%,...) the over all acid concentration in vinegar sample reach 5,8% and 6,3% in 22 days (under static fermentation).