Study On Vacuum Impregnation Technology Of Date

Jujube is one of the characteristics fruit of China, which as a good flavorand rich nutritious, but also has a high medicinal value. It is the high-qualitysupplements in nutritious and health care. However, Jujube is not only easy tosave, the processing methods are backward, nutritional content and flavor ofjujube has suffered from serious loss, long processing time made economicefficiency is also low. How to change the processing methods to improve thepreservation of the nutritional content of jujube products, to reduce the loss offlavor substances to improve the sensory quality, to short the processing time,was the focus of the study. The raw material of this subject is Shaanxi andNingxia jujube, the impregnation performance of the different varieties of jujubein the vacuum conditions, compare the processing time, the Vc retention rate andthe sensory assessment of the concentrated vacuum impregnation, vacuumimpregnation and atmospheric pressure impregnation; study the impact factor ofthe condensed vacuum impregnation, and optimize the process; at last study theprocessing and formulation of solid jujube tea and health candied, tooptimization of the formulation, development of a new solid jujube tea andhealth candied. The results are as follows:1）The impregnation speed of seven fresh jujubes results showed that, Waterjujube is the fastest, followed by Zhong Ning small jujube, Ling Wu long jujube,Ling Wu round jujube, the Yellow River Beach jujube, Tong Xin orbicular jujube,Jing Yang jujube is the slowest. As the candied to products, the condensedvacuum impregnation have the shortest processing time, only need2～3h, havelower degree of browning, the least nutrient loss.2）The quality of fresh jujube will change after pretreatment, sensory qualitychanges and Vc losing is more serious by smoked sulfur, followed by frozenprocessing, and sensory quality of fresh jujube by the vacuum of low-temperature drying is relatively good, the maximum limits retain the Vccontent and the jujube original color and luster. However, the sugar permeabilityrate increased by the three methods.3）Processing conditions in the concentrated vacuum impregnation processfactors, the results showed that the most suitable process conditions of jujubewere determind to be: the mass ratio of the impregnating fluid and jujube is8,concentration of initial sugar is30%, the vacuum time is10min, the vacuum is0.09MPa, the temperature is55℃, the vacuum impregnation time is3h, theweight gain rate is175.34%； the most suitable process conditions of jujubeslices were determind to be: the quality of the impregnating fluid and jujube is6,the concentration of initial sugar is40%, the vacuum time is10min, the vacuumis0.09MPa, the temperature is55℃, the vacuum impregnation time is40min,the weight gain rate is164.62%.4）As to the preparation of impregnation fluid, the most suitable formulationof solid jujube tea were determined to be: concentration of initial sugar is40%,concentration of hawthorn is7%, concentration of lemons is4%, concentrationof CaCl2is4mg/ml. The conditions of vacuum impregnation were determind tobe: the vacuum is0.0904MPa, the temperature was55.7℃, the vacuumimpregnation time is42.6minutes.5）Analysis the quality of final product solid jujube tea, it has highernutrients than the processing of brittle jujube sclices, which content of Vc andflavonoids increased more.6）As to the preparation of impregnation fluid, the orthogonal experimentsruslts showed that the most suitable formulation of solid jujube tea weredetermined to be: concentration of sucrose is30%, concentration of hawthorn is6%, concentration of wolfberry is2%, concentration of honey is10%. Theconditions of vacuum impregnation were determind to be: the vacuum is0.09MPa, the temperature is55℃, the vacuum impregnation time is3h, vacuumlow-temperature drying time is1.5h, the health candied which color is bright,appearance is plump, taste is sweet and sour, fragrance is pleasant.7）Base on the quality of health candied, the results showed that addnutrition and functional ingredients in impregnation fluid, the candiedappearance color is more bright and nutrition is more higer than ordinary candied, which content of Vc and flavonoids is increased considerably, also has a certainamount of lycium barbarum polysaccharides, to improve the nutritional valueand health effects of candied.