Optimization Study Of Fermentation Technology Of Hawthorn And Litchi Fruit Vinegar

In order to further enhance the value of hawthorn and litchi and develop their vinegars in the study the raw materials, hawthorn and litchi, were selected to be devoted to the development of fruit vinegar, which were indispensable to get through two fermentation phases, namely ethanol fermentation and acetic acid fermentation. Based on above,hawthorn vinegar was selected to study the change of active compounds in the fermentation.To sum up, as follows was what to be studied in the study.(1) After all, the changes of surface sugar degree and alcohol degree with alcoh ol fermentation processing were tested and monitored in real-time in order to determ ine the most suitable fermentation period of alcohol fermentation of hawthorn vinega r, then a single factor experiment was designed and carried out to explore the effect of surface sugar degree, inoculation amount of active bacterial liquid, fermentation t emperature and fermentation p H on alcohol fermentation. Based on the favorable ach ievement, the technology optimization of alcohol fermentation of hawthorn vinegar w as carried out in assistant with Box-Behnkan response surface methodology, which in cluded optimization parameters of surface sugar degree, inoculation amount of active bacterial liquid, fermentation temperature and fermentation p H. Results showed as f ollows. Fermentation period of alcohol fermentation was 8 d, meanwhile response su rface optimization experiment presented the optimal fermentation technology of alcoh ol fermentation of hawthorn vinegar including surface sugar degree of 17.0%, inocul ation amount of active bacterial liquid of 4.5%, fermentation temperature of 30 °C a nd fermentation p H of 4.0 and predicted the optimal alcohol degree of 7.47% in the optimal technology which was near to the actual alcohol degree of 7.42%.(2) A single factor experiment was designed and carried out to explore the effec t of original alcohol degree, inoculation amount, fermentation temperature and fermen tation p H on acetic acid fermentation. Based on the favorable achievement, the opti mization of acetic acid fermentation of hawthorn vinegar was carried out using respo nse surface methodology, which composed of optimization parameters of original alco hol degree, inoculation amount, fermentation temperature and fermentation p H. Result s showed the optimal fermentation technology of acetic acid fermentation of hawthor n vinegar was presented by response surface optimization experiment, which composed of original alcohol degree of 8%, inoculation amount of 10%, fermentation temper ature of 30 °C and fermentation p H of 4.0, the optimal acetic acid yield was also p redicted as 51.77 g/L in the optimal technology which was near to the actual acetic acid yield of 51.69 g/L.(3) Changes of vitamin C, total flavonoid, crude protein and polypeptide in fermentation process of hawthorn juice were revealed by comparing their contents between hawthorn juice and hawthorn vinegar. Results showed that in the fermentation of hawthorn juice, vitamin C decreased by 673 mg/100 m L, total flavonoid decreased by 16.46mg/100 m L, crude protein decreased by 15.26 mg/100 m L and polypeptide contrastly increased by 27.10 mg/100 m L. In a word the contents of vitamin C, total flavonoid and crude protein would decrease in the treatment and fermentation of hawthorn juice because of oxidation and metabolic, on contrast, polypeptide content would increase because of bacterial metabolic.(4) Alcohol fermentation of litchi vinegar had superior fermentation technology including sugar content of 16%, inoculation size of 5%, fermentation p H of 3.5 and fermentation temperature of 30~32 °C. Acetic acid fermentation of litchi fermentation had the highest yield of acetic acid of 52.45 g/L with inoculation size of 10%, original alcohol degree of 7% and fermentation temperature of 30 °C, actual experiment showed that acetic acid yield of 52.47 g/L was near to the predicted value.Hence, response surface methodology can afford to optimize fermentation technology of hawthorn vinegar and litchi vinegar with better model of good fit and low error, and their yields of acetic acid were high. In fermentation process active compounds such as vitamin C,flavonoid and protein would lose, polypeptide would increase, and fruit vinegar had great development value for abundant active compound and various functions.