Formula And Process Optimization Of Stretching Processed Cheese

Mozzarella cheese,as the main ingredient of Pizza,is loved and accepted by young consumers for its unique melting,stretching and browning properties.Mozzarella cheese mainly relies on imports from New Zealand and Australia due to the high price of raw milk in China and the unprocessable whey,which leads to high production costs.Mozzarella cheese needs 2-4 weeks to ripen before it has baking characteristics.During the shelf life of the product,protein degradation can cause the baking properties to become unstable,resulting in a shorter time in the market.At present,many domestic researches use processed cheese as an alternative to Mozzarella cheese,but these researches mainly focus on lowshear melting process,which has a poor texture and baking characteristics and low marketing competitiveness.Therefore,it is urgent to develop a stretchy processed cheese product.Based on the above background,this study innovated the equipment technology of Mozzarella processde cheese processing,changing the low-shear process to screw stretching process.The effects of different phosphate types,p H value,sterilization temperature,emulsification temperature,emulsification time and stretching speed on the product quality were investigated,and the physical and chemical characteristics of the product during shelf life were monitored.The main findings were as follows:(1)Different kinds of emulsified salt and p H were screened by texture,baking characteristics,proteolytic gel,rheology and other characteristics after single factor screening.Basedon the single-factor test,the regression equation model of emulsified salt and p H value was established by response surface optimization,and the key formulations was determined as follows: sodium citrate 0.94%,sodium hexametaphosphate 0.43%,disodium hydrogen phosphate 0.82%,p H value 5.78.The stretched processed cheese prepared under the conditions of this formulationl had the highest overall score of 79.95 points.(2)By adding a new stretching process,the sterilization temperature of 81℃,emulsification temperature of 76℃,emulsification time of 6 min and stretching speed of 200 rpm were determined.The quality index and microstructure of the resulting products were similar to those of Mozzarella cheese,it showed a linear protein fiber structure arranged in parallel,with fats and minerals shrunk into(3)On the basis of single-factor text,the regression equation models of sterilization temperature,emulsification temperature,emulsification time and stretching speed were established by response surface optimization,and the key process parameters were determined as follows: sterilization temperature 80.4℃,emulsification temperature 75.5℃,emulsification time 5.8 min,and stretching speed 215.78 rpm.The stretched stretched processed cheese prepared under this process condition had the highest overall score of 76.94 points.(4)During the storage period of 90 d,the colour and physicochemical indexes met the design requirements.Its microorganism indicator corresponds to t the requirements of the national standard for the processed cheese.There is little change in the product quality,the GC-MS detection of the product flavor substances were relatively stable.it can be concluded that the shelf life of the product can be up to 90 days under refrigerated conditions at 2-8℃.