The Study On Brewing Technology For Improving Polyphenol Content In Oat Vinegar

Oats is a whole grain food,the whole grains contain external bran and internal germ.Therefore,the bioactive substances such as polyphenols can be effectively retained.Oats are good source of polyphenols with dual nutritional and health values.Polyphenols in oats have strong antioxidant capacity as well as a variety of biological activities,such as reducing bacteriostasis,anti-aging and inhibiting tumor cells.Vinegar is widely used as a condiment in cooking.Besides,it has other physiological functions.The use of oat to make vinegar can combine the health functions of both and produce oat vinegar with high edible and medicinal value.In this study,the process parameters of oat vinegar production were optimized,and the polyphenol content in oat vinegar was increased to maximize the health efficacy of oat vinegar.The main research results are as follows:1.In the stage of oat germination,through single factor experiment,we keep the soaking time,temperature and relative humidity of oat germination the same,and change the time of oat germination.It is concluded that the polyphenol content is the highest when the time of oat germination is 6 days.2.The content of polyphenols was the highest when oats were treated under five roasting conditions(50,110 min),(70,90 min),(90,70 min),(110,50 min),(130,30 min),(90,70 min),respectively.3.Enzymatic saccharification and koji saccharification were carried out to obtain the highest content of polyphenols in the saccharified products.4.In the alcoholic fermentation stage,the optimum technological parameters of alcoholic fermentation were obtained by single factor test and orthogonal test:yeast dosage was 0.1%,initial pH value was 4.0,fermentation temperature was 30 C,fermentation time was 4 days.5.In the acetic acid fermentation stage,the optimum technological conditions of acetic acid fermentation were obtained by combining single factor analysis with orthogonal experiment analysis:liquid loading 1/4,fermentation temperature 35 C,initial alcoholicity 7.0%vol,acetic acid bacteria addition 2.0%,fermentation time 5 days.6.Oat vinegar was clarified by four different clarifiers.The clarification results were as follows:chitosan(transmittance 87.78)>diatomite(transmittance 82.14)>bentonite(transmittance 72.63)>gelatin(transmittance 70.28).The clarification effect of Chitosan on Oat vinegar was the best.The optimum clarification conditions are:the dosage of chitosan is 2.5 g/L,the clarification time is 16 h,the clarification treatment pH is 3.5,and the clarification temperature is 35 C.7.For the blending of oat vinegar,the sensory evaluation showed that the optimum formula of oat vinegar was 40 mL/100 mL of vinegar,20 mL/100 mL of acetic acid and 6.0 g/100 mL of honey.The main factors affecting the taste of oat vinegar were:the addition of vinegar>the addition of acetic acid>the addition of honey.