Studies On The Improvements Of Flavor And Texture Of Low-fat Processed Cheese By Enzyme-modified Cheese And Inulin

Enzyme-modified Cheeses (EMCs) are obtained by enzymatic hydrolysis of natural cheese. The low production costs and high flavor intensity make the enzyme modified cheeses as a good cheese flavors seasoning in food, and the time for formation of its cheese flavor is significantly shorter compared to the natural cheeses. And inulin (Inulin), as a new fat substitute, is not only beneficial to human health, but also play a role in improving the texture of cheese. This study used the fresh cheddar and butter as the main raw material to prepare enzyme modified cheese by two-step enzymolysis method. This study also investigated the effects of adding the enzyme modified cheddar and inulin on the cheese flavor and of texture.(1) The key process parameters of cheddar cheese enzymolysis by flavourzyme was studied.The optimized process parameters are as follows: the flavourzyme level was 0.02% (m/m), the hydrolysis temperature was 50 degrees, the hydrolysis time was 12 hours. In this condition, the soluble nitrogen content (at pH4.6) accounted for 56% of total nitrogen content, reaching the level of commercial enzyme modified cheese. The content of free amino acids in enzyme modified cheddar was 20mg/g. The composition of free amino acids in enzyme modified cheddar was compared with that in the commercial enzyme modified cheese by high-performance liquid chromatography analysis.(2) The key process parameters of butter enzymolysis by lipase was studied.The optimized process parameters are as follows: the lipase level was 1% (m/m), hydrolysis temperature was 35 degrees, hydrolysis time was 5 hours, and stirring speed was 500rpm. In this condition, the butter hydrolysate obtained the best sense score, the FFA content was about 12% (in terms of oleic acid). The fatty acid value reached the levels of commercial enzyme modified cheese.(3) The hydrolysates of fresh cheddar and butter were mixed at a ratio of 20:1. In this way, the enzyme-modified mixture was provided with a rich aroma and flavor like mature cheese. The flavor was soft and balanced. Its'moisture content was slightly higher than the commercial enzyme modified cheese, but the proportion of protein and fat was similar with commercial enzyme modified cheddar. The addition of enzyme-modified mixture at about 6% provided a good natural cheese flavor in processed cheese.(4) The results from the replacement of butter by inulin in cheese showed that, inulin-addition at the level of 4% can effectively reduce the hardness of the processed cheese, and permitted better sensory score. However, the melting of cheese was significantly reduced due to the reduction of fat content (P<0.05).(5) Butter in the processed cheese was replaced with Inulin (as a fat substitute) at different proportions, with other formula ingredients and processing conditions unchanged. The results showed that the addition of inulin can significantly change the hardness of cheese, make the cheese more flexible, and reduce the chewing activity. After replacing the original formula of 40% butter by inulin, the new cheese and the control had the most closed physical properties and little sensory differences.