Research On Optimum Processing Of Low-Fat Mozzarella Cheese And The Effect Of Fat Replacer On The Quality

Mozzarella cheese is a casein gel system containing water and fat,which has unique meltability and stretchability after blanching and stretching treatment.Mozzarella cheese can meet the standard of pizza ingredients only after water reduction and part skim.In this thesis,low moisture part-skim Mozzarella cheese was successfully produced by optimizing the process and reducing the raw milk fat content.The indexes of cheese composition,protein hydrolysis,texture,functional properties,rheological properties and microstructure were tested to study the effect of fat reduction on the quality of Mozzarella cheese at the ripening stage.The effects of fat replacer on the quality of low-fat Mozzarella cheese were studied by adding egg yolk granules,carrageenan and their composite gel.1.Preparation of low-moisture Mozzarella cheese and optimization of technological parameters.Select the cooking temperature,cooking duration and hot stretching temperature for single factor experiment,and then through the response surface analysis test of three factors and three levels,get the best process conditions:cooking temperature 42 ℃,cooking duration 31 min,hot stretching temperature 65 ℃,sensory evaluation score 92.08 points,the cheese produced is milky white,fine texture,smooth surface,rich flavor,and good quality.2.The effect of reducing the fat content of raw milk on the quality of Mozzarella cheese in ripening.With the decrease of fat content,the moisture content,fat content,protein hydrolysis,whiteness,yellowness,meltability,and free oil formation of cheese decreased,and the protein content and hardness increased.The casein matrix in the microstructure was denser and the pores were fewer.With the extension of ripening duration,the protein hydrolysis,yellowness,meltability and free oil formation of low-fat Mozzarella cheese increased,the hardness and whiteness decreased,the softening point of cheese advanced,the casein matrix expanded and the pores decreased.The stretchability of part-skim cheese reached the maximum value in10 days ripening.3.The effect of adding fat replacer on the quality of low-fat Mozzarella cheese.The egg yolk granules improved the hardness,cohesion and yellowness of cheese by filling and destroying the casein gel network.Carrageenan retained water and fat for cheese by attaching to and cross-linking with casein micelles,and improves the whiteness and free oil formation of cheese.The egg yolk granules-carrageenan composite gel improved the moisture,fat content,yellowness,free oil formation and stretchability of cheese by reducing the interaction between proteins in the casein matrix,and reduced the cohesion,hardness and improved the rheological properties.The protein chain in its microstructure became smaller,with more obvious water oil channels and fiber layered structure.