| Apple vinegar has a wide range of markets due to its rich organic acids,phenols and antioxidants.Apple vinegar prepared by submerged fermentation are reported more,but moderate fermentation of apple vinegar reports are scarce.In this paper,the optimum conditions for the fermentation of vinegar were optimized.The dynamic changes of total phenols,organic acids and aroma components of moderate fermention and entire fermention were studied.The total phenol,antioxidant capacity,organic acids,aromatic components of apple juice,apple wine and apple vinegar prepared by different materials were analyzed,the results were as follows:1,Based on the total phenols as index,The process of apple wine and apple vinegar optimal conditions were studied by the the orthogonal experiment and response surface methodology(RSM).The results were as follows: the sugar added 4%,the inoculation volume of yeast 0.04 %,PH 3.5,fermentation temperature 28?.The inoculation volume acetic acid bacteria(GIM1.152)7%,shaking speed 160 r /min,fermentation temperature 32?,the acetic acid bacteria(GIM 1.848)added volume 3%.Under this condition,the total phenol content of apple wine and apple vinegar wre 64.57mg/100 mL and 59.23mg/100 m L.2,The total phenols content in moderately fermented sample was 21 % higher than that in entirely fermented one.The organic acids profiles in two vinegar samples were exactly the same,but their contents were different.The moderately fermented vinegar had higher contents of tartaric acid,citric acid and fumaric acid,and the entirely fermented vinegar had higher contents of pyruvic acid,malic acid,?-ketoglutaric acid,lactic acid,acetic acid and succinic acid.3,Moderate fermentation and entire fermentation were identified 42,30 kinds of volatile components respectively,which 3 alcohols,5 esters and a ketone were not detected after moderate fermentation,and 3 alcohols,a acid,7 esters,a ketone,and terpene were lost after entire fermentation.Esters were characteristic flavor substance of apple vinegar prepared by moderate fermentation.Phenylethyl contributed greater on the aroma of apple vinegar prepared by entire fermentation.4,The total phenol content of freeze-concentration apple juice,wine and apple vinegar were 58%,66% and 60% higher than that of evaporation concentrated juice and its fermentation products;and were 25%,33%,26 % higher than that of juice addition of sugar and its fermentation products.This method has been well-known as the concentration method with the best quality The antioxidant capacity of apple juice,cider and apple cider vinegar was significantly higher than that of concentrated juice and its fermentation products and juice of chaptalization and its fermentation products.In the DPPH and ABTS assay,apple wine was significantly higher than apple juice,and vinegar.The reduction of Fe3+ in apple juice was significantly higher than that of apple wine and vinegar,and the correlations between antioxidative activity and total phenol content were very significant The contents of organic acids in apple juice,wine and vinegar prepared by different materials were no significant differences of which showed the relationship of accumulation,metabolism and transformation.5,From different materials of apple juice,wine and vinegar 58,69,61 kinds of aroma components were identified.The aroma composition and content were significantly different between evaporation concentrated apple juice and freeze-concentration ones.6-methyl-5-hepten-2-ol,ethyl 3-methylbutyrate,4-methyl-3-hexyl acetate,phenylethyl acetate,2,4-dimethyl-3-hexanone,phenylacetaldehyde,6-methyl-5-hepten-2-one and other characteristic ingredients have not been detected in concentrated apple wine.Some volatile substances in vinegars decreased or even disappeared,such as ethyl caproate,ethyl octanoate,ethyl 9-decenoate,ethyl decanoate,ethyl laurate,6-methyl-5-hepten-2-ol,6-methyl-5-hepten-2-one,2,4-dimethyl-3-hexanone,etc. |
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