| Jujube(Ziziphus jujuba) fruit is widely consumed as a kind of wholesome food and traditional Chinese medicine in Asian countries due to its potential effects on tonifying spleen stomach, comfortable resting to restore energy, and sweating thirst. However, with the high sugar content, jujube fruit couldn’t be accepted by some groups such as diabetics and people who are not suitable for having too much sugar. To solve this problem, a newly compound fermentation which in the role of the jujube juice with Saccharomyces cerevisiae and domesticated Lactobacillus plantarum(Lp-5) were studied by designing experiments. In this way, jujube juice was endowed with the characters like low sugar content and preserving the original fermentation liquid nutrients by the compound fermentation which based on the mechanism that microbe mainly consumed monosaccharide(especially glucose) in fermentation process. The main results are as follows:In the first experiment, the process of jujube juice preparation was studied by the comparison of the content of cyclic adenosine monophosphate(c AMP), total flavone, and vitamin C which extracted in different ways, and the Microwave assisted hot water extraction was finally been selected. The preparation conditions were considered as follows: the extraction time was 2h, the extraction temperature was 75℃,the ratio of material to water was 1:7, the microwave heating time was 75 s, these conclusions were optimized through the single factor experiments and orthogonal test. According to the screening of yeast fermentation carbohydrate utilization capacity under the same conditions of jujube juice,Angle dry wine yeast SY was considered to be the most suitable fermentable strain. Acid producing ability and tolerance of the Lactobacillus plantarum(Lp-5) were improved after the reasonable domestication.The fermentation was composed of two parts in the second experiment which is also the mainly important part in the whole study. In the first part, optimizational conditions of fermentation were as follows: fermentation time was 10 h, fermentation temperature was 33℃, inoculating quantity was 1%, single factor experiments and orthogonal test were used to obtain the optimum result. Through single factor experiment and response surface optimizational experiments, the fermentable conditions of second part were as follows: fermentation time was 22h40 min, fermentation temperature was 39.6℃, inoculating quantity was 6.3%. After the compound fermentation, the total sugar content was 8.09mg/m L, which reduce the amount of 97%. The content of glucose was 0.97mg/m L, much lower than the national standard of sugar content for low sugar foods.Comparing the change of physicochemical properties and functional components in jujube juice before and after the compound fermentation was the main idea of the third experiment. It can be found through the study that the juice after fermentation, saccharide content itself was significantly reduced. The soluble solids content and p H decreased, and the juice was much brighter than before. The total c AMP was 21.1 g/m L, which maintain well. The content of total flavonoids and vitamin C decreased a little, but remained at a rate above 90%. Four kind of amino acids were found in the fermentable jujube juice. The content of Lysine which knowed as a kind of essential amino acid, increased obviously after the compound fermentation. Besides, there were five kind of organic acids, which had a changing content during the fermentation time. Among the different organic acids, the content of tartaric acid and citric acid almost unchanged. Promotion is quite obvious on lactic acid andacetic acid content,and a significant decline in malic acid content.Through the determination of low sugar jujube juice concentration under the conditions of different income concentrated liquid nutrient content, determine the conditions of concentration to prepare concentrated low sugar products was 60 C and the vacuum concentration time was 30 min. Studying on formula with neotame, sodium citrate, ginger powder as auxiliary material. The results of studying were as follows: Neotame 0.01%;Sodium citrate 1.2%;Ginger juice 10 %... |
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