Study On Color Protection And Preparation Of Green Vegetables Of Chinese Style Fast Food Of Cold Chain

With the accelerated pace of life, the demand for fast food is growing, and therequirements for their nutritional features are also increasing. Currently, green vegetables inChinese style fast food dishes are relatively few, mainly owning to facts that green vegetablesdishes in Chinese style fast food Enterprise are still prepared with stir frying method, which isnot suitable for quantitative and standardized production in large scale. In order to furtherexpand Chinese style fast food’s scale of production, simplify the preparation process andcater to consumers’ favorite dishes, joining more green vegetables, the industry hopes todevelope new ways of process suitable for factory production.Therefore, based on colourprotection principles of green vegetable, this research focused on technology of greenvegetable dish preparation in large scale for cold chain supplying, and investigating thequality change of the dishes under cold storage. The main research contents are as follows:Firstly, blanching time for Pakchoi and green peppers dish preparation had beeninvestigated. The optimal blanching time of Pakchoi and green peppers were both45s.Underthis condition, within the accepted range of products sensory evaluation, the peroxidaseactivity was minimum, and it was the most conducive to the storage of the product. Colorprotection of Pakchoi with zinc ions and salt had been studied. The results showed that: zincion and the salt’s color protection effect were not obvious for the Pakchoi product of Chinesestyle fast food of cold chain.Secondly, impacts of different types of starch on Pakchoi preparation behaviors hadbeen studied. The results showed that potato starch and sweet potato starch were the best forretention of weight loss rate, etiolating rate, reducing Vc residual rate, but sweet potato starchwas cheaper than potato starch, so we chose it. Different ways of starch gelatinization werestudied. The best way was: pre-gelatinized raw starch suspensions, and then pour hot oil, inorder to together cover the surface of Pakchoi. The cell shrinkage rate was38.18%, lowerthan the control group’s56.05%.Then, the optimal process of starch gelatinization sizing was stuided. The results showedthat: the best condition of Pakchoi was: starch slurry concentration5%, the ratio betweenPakchoi and starch slurry was1:0.4, the ratio between Pakchoi and hot oil was1:0.06. Underthose conditions, the weight loss rate decreased65.11%, cell shrinkage rate decreased35.4%,reducing Vc residual rate increased2.56times, and the storage period was extended to7days.The optimal condition of green pepper was: starch slurry concentration5%, green peppers/starch slurry was1:0.5; green pepper/hot oil was1:0.08. Under those conditions, and theweight loss rate decreased57.75%, reducing Vc residual rate increased2.14times. Thequality of product was still edible after cold storage for7days. Next, different cooling ways’ influences on the product storage stability were studied.We investigated relationships between centre temperature and etiolated rate of Pakchoi dishesover time. The results showed that: the etiolated rate was significantly increased whilePakchoi dishes were piled after heat treatment. The optimum cooling way was cooled by coldair. The residual enzyme peroxidase activity was the lowest (under20%) after this coolingprocess during cold storage time.Lastly, permeation rate of salt in Pakchoi and starch slurry stable behavior during coldstorage time were observed. The results showed that: The permeation rate of salt becamestabilized in refrigerated after8h. During the whole refrigerated period, starch paste were notaging occurs, and the traits were stable.