Study On Production Process And Quality Of Coconut Water Vinegar Based On Metabolomics

Mature coconut water is usually discarded as a by-product of coconut milk processing.In order to make use of it,we brewed coconut water vinegar with mature coconut water,and studied the fermentation process,aroma components and metabolites of coconut water vinegar.In this study,odor activity value and metabolomics were used to characterize coconut water vinegar comprehensively for the first time,and metabolic substrates with potential effect on flavor and nutritional value were found,which provide a theoretical basis for improving the quality of coconut water vinegar.The main results were as follows:Mature coconut water was used as the fermentation substrate and yeast D254 was used as the fermentation strain,the alcoholic fermentation process was optimized and the fermentation conditions were adjusted to 16°Brix,pH 4.5,temperature 30℃ and yeast inoculation amount 0.07 %,after 5 days of fermentation,the alcohol content was 7.9%.Coconut water wine was used as the fermentation substrate and AAB(Difa)was used as the fermentation strain,the acetic acid fermentation process was optimized and the fermentation conditions were adjusted to alcohol content of 7.8%,pH 3.6,and fermentation temperature of 30.8 ℃ and the AAB inoculation amount 10%,speed 180 rpm,the total acid content was6.21% after 7 days of fermentation.The aging process of coconut water vinegar was optimized,and the suitable process for aging coconut water vinegar was as follows: the aging temperature was 36-40 ℃,the aging time was 6 months,and the aging container was ceramic bottle.The process for the coconut water vinegar drink was optimized and the process conditions for the coconut water vinegar drink were 12% coconut water vinegar,30%coconut water,and 4% xylitol.SPME-GC-MS was used to detect and analyze aroma in coconut water vinegar during fermentation.The alcohols and esters content of coconut water and coconut water wine was higher,but the content of each substance changed a lot.The higher content of aromatic components in coconut water vinegar was acids and esters.Analysis of the OAVs during the fermentation of coconut vinegar showed that coconut water has a lighter aroma and usually has a fruity and oily taste.Coconut water wine has 13 OAVs of aroma were greater than 1,and the aroma was strong,which was fruity,winey,fatty and malt flavors.Coconut water vinegar contained 16 substances with OAV more than 1.Typical aromatic compounds were isovaleric acid,acetic acid,ethyl acetate,isoamyl acetate,benzaldehyde,etc.It had the sour taste of almonds,bananas or pears.LC-MS was used in combination with metabolic technology to analyze change of nontarget metabolites during coconut water vinegar fermentation.It was found that metabolites with higher content in coconut water were amino acids and peptides;The content of amino acids in coconut water wine were decreased sharply,and the content of organic acids were increased;In coconut water vinegar the content of amino acids and peptides were sharply increased,and the content of organic acids were slightly decreased.Coconut water vinegar was rich in essential amino acids,accounting for about 60% of the total amino acid content,especially the essential phenylalanine content,which reaches 1011.54 mg/L.Metabo Analyst4.0 was used to analyze the metabolic pathways of various metabolites during the fermentation of coconut water vinegar,and 17 major metabolic pathways were identified.The network diagram of metabolic pathways was constructed based on metabolic pathways and metabolites,and three important metabolic substrates,aspartic acid,pyruvate and glutaminewas were discovered by analysis of metabolic pathways.