Jujube Powder Processing Technology And Change Of Aroma Components

Cultivation area of Jujube of Xinjiang is nearly400million acres, dry dates as the main product, which species are single and not convenient to consume. Researching and development of deep processing product of jujube,which is in wide use in the field of food, is the basis of healthy development of Jujube industry. The jujube powder made by fresh dates is low loss of nutrients,unique flavor and a wide range of applications, which has a good market prospect. The fresh jujubes of Hami, Xinjiang were used as raw material to study peeling of fresh jujubes, color protection technology, jujube powder processing technology and process parameters in this paper. The effects of simultaneous distillation and extraction, steam distillation and extraction, solvent extraction on extraction efficiency of volatile components of date syrup were studied. Correlation of heating temperature, heating time, the formation of flavor substances and the stability of flavor substances in the storage were studied. The results showed that:1. The effects of alkali concentration, temperature and peeling time on the peeling of jujube were studied by orthogonal test, the best process parameters of peeling were obtained:alkali concentration was4%, the temperature of alkali concentration was90℃～95℃and the processing time was3min.2. The influence of sodium hydrogensulfite-and ascorbic acid with different concentration on the effects of color protection of jujube pulp. The result showed that the effect of sodium hydrogensulfite was better, the optimal concentration was0.2%,under these conditions L was53.76,b was24.78.3. The analysis of jujube powder made by spray drying and freeze-drying were that:the nutrients of jujube powder made by freeze-drying remained high, but the cost is high. Spray drying has some influence on the color and lustre and nutrients, and the the technology was mature. The effects of air inlet temperature, outlet air temperature and feeding temperature on the the dates powder spray results, the optimum spray drying process parameters are:inlet air temperature145℃, outlet air temperature of70℃, the material temperature is40℃.4. Extraction efficiency of simultaneous distillation and extraction, steam distillation and extraction, solvent extraction on volatile aroma of jujube pulp was studied, the result showed that:large consumption of solvent, long extraction time and tedious process of extraction were the feature of solvent extraction; Simultaneous Distillation and Extraction of aroma types derived and effective aroma compounds relative was more, however, due to the need of high temperature treatment, resulting in a difference with the original jujube aroma is substance; Extracted by steam distillation of the aroma components and effective types of aroma substances are more, the best way is steam distillation and extraction method.5. In order to satisfy the requirements of different consumers for the aroma component of jujube powder made by the raw material of fresh jujube, the correlations of temperature, time of treatment and the formation of flavor were detected. The effects of different dealing temperature and dealing time on the composition and relative content of aroma was studied, the optimal conditions were obtained as followed: heat treatment temperature was115℃, dealing time was6h, the followed team was120℃,2h. The aroma component of jujube pulp dealed with heat treatment was analyzed by SPME-GC-MS, the kinds of aroma component were to110, the main characteristic components were alkanes and aromatics and their derivatives, aldehydes, lipids, acids, ketones, and alcohols were followed,88.04%of the total relative content. The contents of lipids and acids were increased, but aromatics and their derivatives were decreased.6. The effects of heating treatment temperature and time on the color and lustre of jujube pulp were studied, the results showed that:with the heating temperature increased and the heating time extended, L became smaller that was the color was deeper.7. The changes of aroma component of jujube powder with different processing and dealing conditions were analyzed, the result showed that:the aroma component of jujube powder dealed with freeze-drying was less, the aroma component of jujube powder dealed with spay drying was more and the flavor was rich, the flavor compounds of jujube powder was close related to the dealing conditions. Based on the above analysis, the reality of different flavors of jujube powder made by jujube pulp dealed with different heating treatment condition was possible.