Study On Enhancement Of Gel Strength Of Surimi-based Products

Surimi products with low fat and cholesterol contain abundance of protein which can easily digested by consumers. What's more, surimi products are usually producted by low-value fish for unlimited by raw materials'size. This thesis use frozen surimi from low value fish as raw material to research the effect of adding three non-muscle proteins as well as carrot juice, transglutamnase and starch on the quality of surimi products, and obtain the optimum adding process. Then the main components and flavor of surimi-based products in optimum technics are analyzed and compared with the traditional surimi products. During30days, the surimi-based products are put in different temperature to measure the changes of their quality. The main contents of this research are as follows:(1) The addition of tree non-muscle proteins can enhance the gel strength and reduce the expressible moisture of surimi-based products. But it will decrease the whiteness and the smell of protein will cover the unique flavor of surimi. Then the optimum process is obtained by using response surface methodology. The best combination of three non-muscle proteins is9.7%SPI,9.9%GP and7.6%WPC. Emulsion can also significantly improve the gel strength of surimi-based products, and the best oil-water emulsion content is10%oil and10%water.(2) The addition of carrot juice, transglutaminase and starch can enhance the gel strength and texture of surimi products. However, adding carrot juice will increase the expressible, mosture; adding transglutaminase will be not obviously effect the expressible moisture; and adding starch can significantly reduce the expressible moisture of surimi-based products. The optimum process is obtained by using response suface methodology. The best combination of three additive is13%carrot juice,2U/g trans-glutaminase, and20%starch.(3) Compound of fatty acids in surimi-based products ia mainly unsaturated fatty acids which account for72%, and surimi-based products have a highe level of DHA and EPA; the contents of moisture and ash in surimi-based products are64.76%and1.24%, and lower than those in the traditional surimi products of which the contents are75.68%and1.65%. The contents of crude protein and crude fat in surmi-based products are21.32%and3.76%, and higher than those in the traditional surimi products of which the contents were16.92%and1.36%. The content of total sugar is11.34%, and higher than its in the traditional surimi products of which the content is7.26%. The surimi-based products is a low cholesterol food for the content of cholesterol is16.74%, but the content of cholesterol content in traditional surimi products is22.11%. The level of alkane compounds contnent in the traditional surimi products is30.19%, and higher than its in the surimi-based products of which the content is23.62%. The contents of Nitrogen compounds, Aldehydes and Esters in traditional surimi products are much larger than others, resching10.54%,10.46%and8.62%. While the level of Lipid Compounds, Nitrogen Compounds and Aldehydes content in surimi-based product is higher, resching9.83%,8.45%and8.02%. What's more, the traditional surimi products do not contain Furan. Carrot juice and non-muscle proteins change the flavor of surimi products, what make the surimi had a unique flavor.(4) Freezer storage can effectively prevent the surimi-based products from spoilage and inhibit microbe growth and protein degradation. But in15days of the storage period, the gel strength of surimi-based products decreased significantly, but turned to flatten later. The surimi-based products do not obvious decay during the storage lasting30days.