Jujube Residues Fruit Vinegar Fermentation Technology Research And Nutrition

The jujube fruit planting area in China is large, high yield and increase with years, butthe jujube fruit deep processing is relatively backward. As its nutrition is rich, it has agreat value of further processing. Jujube residues can be brewed into fruit vinegar,which not only can solve a lot of jujube processing wastes that caused environmentalpollution and resource-wasted problems, but also promote the added value of jujubefruit processing, and enhance the development of the jujube fruit industry. Jujube fruitbrewed from jujube residues using solid-state fermentation was studied in this thesis,including pre-processing technology, optimization of fermentation conditions, thechange rule of main parameters in jujube residues vinegar fermentation process,evaluation of the quality of fermented jujube residues vinegar and flavor compositionsof the fermented jujube vinegar, which could be a theoretical support for the deeplyprocessing of jujube vinegar and its industrialization. The results showed that:Firstly, the fermentation technology of jujube residues fruit vinegar was studied andestablished. Rice starch saccharification process, the rice starch and water mixed ratiowere1:3, heating gelatinization, adding α-amylase for liquefaction when thetemperature rised to90℃(heat-resistant α-amylase adding amount of12U/g, pH valueof6.0, liquefied temperature of90℃, liquefied time for60min), destroy enzyme andcooling, adding saccharifying enzyme for saccharification when the temperature to55℃(saccharifying enzyme adding amount of160U/g, pH value of5.0, saccharifiedtemperature55℃, glycosylated time for30min), then got the rice starchsaccharification liquid. Fermentation process, the ratio of the rice to the jujuberesidues was the rice and jujube residues adding ratio was1:4after when the jujuberesidues and rice starch saccharification liquid was enzymed, the amount of yeastinoculum was1.2‰, rice and accessories adding ratio of1:1, at room temperature(22±2℃) fermentation23d. Sterilization condition, using the pap instantaneoussterilization, vinegar was sterilized at95℃for2min, got jujube vinegar product.Secondly, the change rules of main physiochemical and microorganism index infermentation process of jujube vinegar had been studied and analyzed. During thejujube vinegar fermentation process, total sugar, reducing sugar content presenteddecrease gradually, alcohol content remained unchange basically after a slight increase, and the total acid content increased gradually. The number of yeast, lacticacid bacteria and acetic acid bacteria overall present the first growth and thendisappeared gradually. Total sugar, reducing sugar content of rice raw materialfermented jujube vinegar was lower and decline slowly, alcohol content was low andremained the same level, the total acid content increased gradually. Total sugar,reducing sugar content of alcohol fermented jujube vinegar was always in the lowerlevel, alcohol content present a gradual declined trend, total acid content increasedslowly.Thirdly, the content of nutrients of different jujube vinegar products were analyzedand compared. The results showed that, the total content of eight organic acids injujube vinegar were higher than rice vinegar, the proportion of nonvolatile of cookingsaccharification rice fermentation jujube vinegar was the highest.18kinds of freeamino acids of jujube vinegar were analyzed, included7kinds of essential aminoacids, the content of total free amino acids of three jujube vinegar were markedlyhigher than that of the rice vinegar, the cooking saccharification rice fermentationjujube vinegar was the highest, and the content of essential amino acids was higherthan rice raw materials and alcohol jujube vinegar. Aroma omposition of jujubevinegar mainly contained alcohols, ketone, acids, aldehydes, esters, alkane. Cookingsaccharification rice fermentation jujube vinegar was detected87kinds of volatilecompound, the rice raw materials and alcohol jujube vinegar were each61kinds,volatile compound of three jujube vinegar were all higher than rice vinegar(52kinds),and the relative content of characteristic ingredients in jujube vinegar such as esters,acids and other were higher than rice vinegar. In addition, in different jujube vinegar,the content of Vc and polyphenol of cooking saccharification rice fermentation jujubevinegar were the highest, the content of total flavonoids of rice raw materials jujubevinegar were the highest. We can see the nutrient contents of jujube vinegar whichadding jujube residues were higher than rice vinegar, among the three jujube vinegar,the cooking saccharification rice fermentation jujube vinegar was better than the riceraw materials and alcohol jujube vinegar, and the proportion was suitable, which hadsour taste mellow and good taste.Fourthly, With reference to the national standards of solid-state fermentation vinegar,each indicators of jujube vinegar product were all up to the technical standards, andthe fermentation process can be applied to actual production.