The Research And Utilization Of Red Date Vinegar

Red dates, (Zizphus jujuba Mill) with a homology of food and Chinese medicine,is favored by many. The vinegar made from red dates by the method of liquid fermentation is a new kind of beverage with multi-nutritional and health promotional functions to meet increasing demand, and has a great potential value. The basic composition of the fresh date was determined in the present study. The Vc and sugar contents of the fruit were much higher than other kinds of fruit, which are more favorable for microorganisms such as yeast and lactic acid bacteria for growing and producing organic acid (lactic acid) by their metabolism,which also enables protection of the Vc content of the date, so as to maintain the red date vinegar with a high level of Vc. The method of uniform design and orthogonal design were employed to determine the processing technology of the date vinegar. For the determination of pectinase hydrolysis in terms of temperature,pH value,time length, and enzyme dosage,a four- factor with ten- level uniform design table U10(100) was created to be a test guide for the solid substance determination.. The optimal conditions for hydrolysis of pectinase were found: temperature 36.61℃,pH Value 4.19,time length 1.50h,and enzyme dosage 0.12%. In terms of temperature of fermentation,sugar concentration,dosage of Saccharomyces cerevisiae(2.1421) and dosage of Leuconostoc mesenteroides (1.20), a four-factor with four-level of orthogonal design L16(45) table for the ethanol fermentation test was built. After four days of fermentation,according to the amount of ethanol and lactic acid obtained, the optimal conditions for the ethanol fermentation were set at temperature 28℃,with sugar concentration of 16%,inoculating dosage of Saccharomyces cerevisiae(2.1421) of 3%,and inoculating dosage of Leuconostoc mesenteroides (1.20)of 2%. In terms of fermentation temperature,ethanol concentration,inoculation dosage,and initial pH value,a four-factor with four-level orthogonal design L16(45) table was also built to guide the acetic fermentation test. After 18 days of fermentation , the optimal acetic fermentation conditions were obtained: temperature 32℃,ethanol concentration of 6%,inoculation dosage of 10% , and .initial pH value at 4.4. The combined gas chromatography-mass spectroscope was employed to determine the aromatic components of red date vinegar. A total of 29 components were identified. Among them were esters 9,acidic substances 8,alcoholic substances 7,ketones 2, aldehydes 2,and heterocyclic substances 1. Benefiting from inoculating heterofermentative species,the lactic acid and ethyl lactate contents of the vinegar were enhanced effectively. The sharp taste of the product was reduced and a mild flavor was developed. Based on present research findings,the organoleptic, physic-chemical, and microbiological indicators of the vinegar product made from the red date met the National Standards of Diet Vinegar of the People's Republic of China (GB2719-2003).