Development Of Low Fat Cheddar Cheese Made Using Polymerized Whey Protein And Adjunct Culture

Cheese products are considered as high fat, high protein and high energy foods.Especially the Cheddar cheese is popular with consumers due to the special flavors.However, taking in high fat may cause diseases such as obesity, high cholesterol and heart disease. As consumers’ health consciousness improving, people prefer to eat low-fat Cheddar cheese. Traditional low-fat Cheddar cheese usually performs as hard texture, insipid flavors, even prominent bitter taste because of reducing fat. To solve this problem, this study combined polymerized whey protein and adjunct culture to make low-fat Cheddar cheese, in order to improve the taste qualities and enhance flavors as well as acceptability.Firstly, According to the single factor experiments and response surface experiments, optimized the preparation technological parameters of polymerized whey protein: the whey protein solution concentration was 10%, the solution p H value was 8.5, the heating temperature was 85℃. The regression equation was: R =3379.67 + 84.38 * A + 54.75 * B + 19.13 * C + 0.75 * A * B + 319.00 * A * C-194.25 * B * C- 385.08 * A2- 1189.33 * B2- 518.08 * C2. The predicted whey protein particle size by the model was 3379.67 nm. The results of rheological behaviors showed that the polymerized whey protein was a kind of non-Newtonian fluid which had high thermal stability.Then, by measuring the growth abilities, growing abilities, acidogenicities,viscosity producing abilities, autolysis degrees, exopolysaccharides(EPS) producing abilities, protein hydrolysis abilities and peptidase activities, selected an adjunct culture from seven kinds of lactobacilli including lactobacillus bulgaricus(LB),Lactobacillus acidophilus(LA), Lactobacillus paracasei ET-22(LPC), Lactobacillus casei CS-773(LC), Lactobacillus helveticus RE-88(LH),Lactobacillus plantarum(LP) and Lactobacillus rhamnosus CT-53(LGG). The growing abilities of strains were LA > LP > LH > LB > LPC > LC > LGG. The acidogenicities of strains were LPC > LH > LB > LA > LP > LC > LGG. Theviscosity producing abilities were LP > LH > LPC > LC > LA > LGG > LB. The autolysis degrees were LH > LGG > LB > LP > LC > LPC > LA. The EPS producing abilities were LP > LH > LGG > LC > LB > LA. The protein hydrolysis abilities were LH > LGG > LA > LC > LPC > LB > LP. The peptidase activities were LA > LH > LPC > LP > LGG > LB > LP. Results indicated that LH had high acidogenicity, viscosity producing ability, autolysis degree, protein hydrolysis ability and peptidase activity which meant it might be suitable for as an adjunct culture to make low fat Cheddar cheese.Finally, made low fat Cheddar cheeses using polymerized whey protein and adjunct culture individually or together, the full fat cheese(FFC) and semi-skimmed cheese(SSC) were as controls. The cheese samples were analyzed for chemical,microbiological properties, protein hydrolysis, texture, rheological properties, T2 distribution of moisture, free amino acids(FAA), volatile compounds, microstructure and sensory characteristics. The results showed that there weren’t significant effects on cheese yield by adding polymerized whey protein and adjunct culture.Polymerized whey protein might improve the moisture content of low-fat Cheddar cheese. While the adjunct culture might improve the protein hydrolysis degrees of low fat Cheddar cheese. Both polymerized whey protein and adjunct culture could improve the texture qualities of low fat Cheddar cheese. The adjunct culture could raise the free amino acids content. and volatile compounds of low fat Cheddar cheese. The results show that the low fat Cheddar cheese which adding both polymerized whey protein and adjunct culture had similar characteristics as FFC and might replace FFC.