Study On The Fermentation Of Haihong Fruit-Jujube Compound Wine

Haihong fruit is a kind of rare fruit produced in the northwest region of China, which has the characteristics of rich nutrition. Jujube with rich nutrition, is known as the king of the vitamin. Currently, the research on Haihong fruit and jujube is mainly focused on the single-type products processing. The study about the compound products of Haihong fruit-jujube have rarely reports. Based on the characteristics of high acidity and high tannis in Haihong fruit and high saccharide content in jujube, Haihong fruit and jujube are used as raw materials to fermente compound wine, which can increase the wine's nutrition, flavor and color.The main research content of this paper were as follows:(1)The pectinase enzymolysis technology was used to extract composite jujube juice. The single factor experiment and orthogonal experiment were used to optimize the mass ratio of Haihong fruit to jujube, the ratio of material to water, dosage of pectinase, enzymolysis time and temperature. (2)The suitable fermentation process for the Haihong fruit-jujube compound wine was selected from two kinds of fermentation process, one was fermentation-after-extraction and the other was the brewing by the conbination of the fermentation and the extraction. The yeast suitable for the Haihong fruit-jujube compound wine fermentation was screened from seven kinds of yeasts. The optimal parameters for alcoholic fermentation such as the yeast inoculum, the SO2 content and the fermentation temperature were determined by the response surface methodology. (3)The techniques including a natural clarification, centrifugal clarification, low temperature clarification and clarifying agent clarification were applied to clarify the Haihong fruit-jujube compound wine. Seven kinds of clarifying agents were used to clarify the Haihong fruit-jujube compound wine, and two of them were selected to make a compound clarifying agent. The response surface methodology was used to optimize the compound ratio, clarification temperature and clarification time. And the stability test of compound wine was also carried out after clarification. The results obtained were as following:(1) The optimal enzymolysis conditions were the pectinase dosage of 0.7g/L, the mass ratio of Haihong fruit to jujube of 1:4, the ratio of material to water of 1:3, the enzymolysis time of 48 hours, the enzymolysis temperature of 55? Under these conditions, the obtained composite jujube juice had a total saccharide content of 169.70g/L, total acid content of 6.63 g/L and tannin content of 2.73 g/L, respectively. The resulting compound juice was orange red, clear, and rich in fruity aroms.(2)The suitable fermentation process for the Haihong fruit-jujube compound wine was fermentation-after-extraction. The suitable yeast for the Haihong fruit-jujube compound wine was XF15. The optimal conditions were the yeast inoculum of 0.26g/L, the SO2 content of 60ppm, the fermentation temperature of 20?. Under these conditions, the compound wine's average scores reached 93.4, with bright color, outstanding aroma, pure taste, full-bodied wine flavor, rich nutrition.(3)Seven clarification tests showed that the natural clarification, centrifugal clarification and low temperature clarification were disadvantageous in effiency cost and the protective nutrition of wine respectively. So, the three methods could not be used in clarifying. However, on the basis of single clarification experiment, bentonite and chitosan were proved to be better compound clarifying agent. The optimal conditions were the bentonite addition amount of 0.08g/L, the chitosan addition amount of 0.12g/L, the clarification temperature of 20? and the clarification time of 18h. Under these conditions, the compound wine's transmittance reached 93.87%. After the natural clarification, the centrifugal clarification, the low temperature clarification and the compound clarification, Haihong fruit-jujube compound wine had normal oxygen, copper, iron and tartar stability.