Effect Of Sous Vide Cooking On Nutrients And Flavor Of Scallop

Sous-Vide has been used in abroad as early as in1974.As a new kind of cooking, itis energy-saving and environment-friendly, simple and easy to use, with the minimumlevel of reduced the loss of water and nutrients, retained the original taste of food etc.Sous-Vide has been widely used in the dishes of the western restaurant, but has not getattention at home.Put the vacuum-packed food into lower temperature water bath about60℃for along time to make the food cooked is Sous-Vide. Search the cooking temperature,cooking time and the vacuum became the key of this technology. We studied the loss ofthe nutrients and the taste of the food after cooking to search the best cookingtemperature and time, at last we determined its safety after microbiological laboratory.First of all, the nutrients in the shellfish including taurine, collagen, protein, fat, ect.The experiment explored the changes of the taurine and collagen in the scallop to searchthe best cooking temperature and time. Collect the taurine in the scallop with waterextraction, purify it by cation exchange restin, then determine its content with UVspectrophotometry. When the cooking temperature is less than65℃,the loss of thetaurine is fewer, but when it exceeded65℃,the loss of the taurine is obvious. The effectof the cooking time and the vacuum of packing to the loss of taurine is not so obvious.The content of the collagen in the scallop is determined by the content of L-hydroxyproline. The conversion factor is0.081.We get the highest content of collagen,10mg/g,with the cooking temperature65℃,cooking time20min and the vacuum70s by theorthogonal test, then observed the change of the content of collagen in the organizationstructure by staining technique of VG. In this condition, the content of taurine in the dryweight of scallop is4.76mg/g,protein626mg/g, fat62.5mg/g, more than the nutrients inthe scallop after cooking by boiled water.After Sous-Vide cooked, we determined its best taste by combining the textureprofile analysis and sensory evaluation. As the cooking temperature and time changing,the hardness, elasticity, chewiness and cohesiveness of scallop can be reflected by texture profile analysis. The vacuum of scallop packing have great influence on the rateof water loss of scallop, as well as the profile of scallop. If the time for evacuate is morethan80s,the rate of water loss will be obviously high, so we determined the time forevacuate is70s.The chewiness and cohesiveness of scallop changed obviously as thecooking temperature and time changing. The variation treed of hardness and elasticitywas relatively stable. The sensory evaluation of scallop showed that, the fishy taste isfull-bodied and tastes terrible. When the cooking temperature is under60℃,it tastes welland seems plumpy when the cooking temperature reached65℃.If it is overtemperaturedor overtimed, the rate of water loss will be higher and is bed to its appreance and taste.Finally considering the microbial safety of Sous-Vide. The CNS of the green foodrequest that the coli group of fresh shell should be less than or equal to230MPN/100g,and the CNS of instant trepan request that the total plate count should be less than orequal to30000cfu/g, the coli group should be less than or equal to30MPN/100g.Evaluate the food safety including the totle plate count and the coli group ofscallop which is under65℃,20min Sous-Vide cooking by experiment on microbiology.