Optimization Of Fermentation Process For Malt Vinegar

Vinegar has been widely used in daily life and production,it varied in the aspect of raw material based on different regions,because of the features of good quality,rich nutrients and widely accepted and loved by people,barley possesses an immense benefit of market as raw material to make vinegar,Malt is mainly made from barley through the process of barley production,and then through crushing,glycosylation,alcohol fermentation,acetic acid fermentation and other processes the malt can finally be the malt vinegar.The experiment is mainly to optimize the technology parameters in the process of malt vinegar production.it mainly includes saccharification stage of malt,the alcohol fermentation and acetic acid fermentation.in the stage of saccharification,it mainly optimize the time and temperature of different saccharification stage.The process includes proteolysis and amylohydrolysis.The temperature depends on the optimum temperature range of different enzyme.The two stages are measured by the content of alpha amino nitrogen and reducing sugar.the optimize ressults are as follows:the hydrolysis stage should maintain for 60 minutes at 50?,the amylohydrolysis stage should maintain for 60 minutes at 65?.Alcohol fermentation stage includes screening of different yeast,it measures by the alcoholic strentgth,the alcoholic strentgth of the strain d is apparently higher than the strain a?b?c,and the fermentation period is the shortest.the single factor experiment results show that the optimum condition are fermentation temperature 30?,the inoculum size 6.0×10~7cfu/mL,pH 5.5.The optimum fermentation parameters of respond surface are pH 5.5,temperature 30?,inoculum size 7.5×10~7cfu/m L.The experimental results are consistent with the predicted results.The stage of acetic acid fermentation in the table concentrator are measured by the content of total acid.the ability of acid production of AS1.41 bacterial strain is more stronger than the other one,the single factor experiment results show that the optimum condition are the inoulum size 10%,the loaded volume 50 mL,temperature 30?,the rotate speed 160 rpm.the optimum fermentation parameters of respond surface are rotate speed 187 rpm,loaded volume 50 mL,temperature 29?.The experimental results are consistent with thepredicted results.In the process of fermented in fermentation tank,the period of fermentation is long and the yield is low,by adding fermentation liquid to the initial fermentation broth can shorten the period from 15 days to 10 days,through the process of fermentation in the tank for several days then changing to static fermentation can increase the content of total acid from 2.21g/100 mL to 3.51g/100 mL.The difference of sensory are analysed between malt vinegar fermentated in table concentrator and in tank combined with static fermantation,it shows that each vinegar has its own advantages,Overall the evaluation is nearlly no difference.The difference of organic acid content are detected through liquid chromatography.