Research On The Key Technologies In The Fermentation Of High-acid Apple Vinegar

High-acid apple vinegar had so many advantages,such as without the fear of bacterial contamination,low cost of storage and transportation.Most of apple vinegar for beverage that had low market share was less than 6.0g/100 mL in total acid at present.The main reasons of that phenomenon were the equipment defects,immature fermentation technology or lack of special acetic acid bacteria.So it was difficult to produce high-acid apple vinegar that limited development of apple vinegar and apple vinegar beverage.According to the company's fermentation strain and equipment for producing apple vinegar,this paper would establish method for determination of organic acid and explore the effect of apple juice concentrate on organic acid in apple vinegar for beverage to determine the control standards of organic acid in apple juice concentrate,and study feed fermentation to determine the key technical parameters of fermentation,and establish the hazard analysis and critical control points of industrial production process,so as to realize the industrial production of apple vinegar for beverage from 4.6-5.2g / 100 mL to more than 7.0g/100 mL in total acid.A method for the determination of six organic acids in apple juice concentrate,apple vine,apple vinegar by RP-HPLC-UV with two coupled columns was established.The results showed that the method was accurate and reliable by analyzing in two coupled C18 columns(4.6mm×250mm×5?m),0.01mol/L(NH4)2HPO4 buffer(pH2.7)of mobile phase,1.0mL/min flow rate,and 210 nm detection wavelength.The correlation coefficient of six organic acids were greater than 0.999 in linear range.The precision of the six organic acids(RSD)was less than 5.0%.The recoveries were in the range of 92.82-108.39%,and the limit of detection was in the range of 0.1-0.7mg/L.The effect of four different apple juice concentrates(3 batches)on organic acids in apple vinegar was investigated.The results showed that malic acid,tartaric acid and citric acid decreased,and succinic acid and acetic acid increased during fermentation.The content of tartaric acid,malic acid,lactic acid,acetic acid,citric acid and succinic acid in apple juice concentrate for fermentation was 10.58-403.81mg/L,13061.12-21248.32mg/L,32.15-1934.25mg/L,0-467.21mg/L,25.86-549.81mg/L,15.39-309.12mg/L respectively.It was recommended that the organic acids of apple juice concentrate should meet above range,and as much as possible screening high malic acid,low lactic acid of apple juice concentrate for fermentation.The effects of acetic acid strain on the tolerance of ethanol and acetic acid,the growth of strain in seed tank and ventilation factor on strain growth were studied to determine the parameters of fermentation in seed tank.The results showed that the concentration of alcohol and acetic acid were 4.5-5.5%(v/v),0-2.0g/100 mL,the feed quantity was more less than 80%,and the ventilation in first and second seed tank were 0.8-1.2m3/h?4.0-6.0m3/h respectively.It was suitable for transferring seed when the acidity of fermentation liquid reached2.0g/100 mL.The effects of the proportion of raw materials,the concentration of alcohol,the amount of inoculation and the feeding schedule on the fermentation of high-acid vinegar were studied to determinate those parameters.The results showed that the fermentation efficiency was the highest when the the concentration of alcohol,the proportion of raw materials,the amount of inoculation was 6.0%(v/v)?60%?20% in start-up fermentation respectively.According to the ingredients should not exceed 80% of the fermentation tank,it could achieve a kind of apple vinegar that total acid was more than 7.0g/100 mL through split volume feed plan.And it was the best way of that plan that the concentration of fruit wine for fed and split volume ratio was10.0%(v/v)?25% respectively.To ensure the quality and food safety of high-acid apple vinegar for industrial production,we established industrial production procedure and hazard analysis and control system.The critical control points were confirmed that they were the acceptance of raw materials(fruit wine,water,bacteria strain),acetic acid fermentation,sterilization and storage.Continuous production of 5 batches reached the requirements of the standard.