Influencing Factors Of Surimi Of Freshwater Fish And Process Optimization Of Its Frozen Products

Fish balls is deeply loved by people as one of the most representative of surimi traditional products, with its rich nutrition, taste delicious, edible convenience in China. Auxiliary materials usually are added in the surimi in order to improve the gel strength of surimi products, whiteness and water retention in producing the surimi gel products with low-value freshwater fish; however in actual production, the unstable temperature has highly effect on the quality of surimi in the condition of storage, transportation and processing. Because of the unstable temperature, it is easy to appear many times freeze-thaw phenomenon. Based on this, this test mainly research the influence of the product ingredients, gel strength, whiteness, water retention, TBARS and other indicators of the surimi by the different freshwater fish species, accessories add and repeated freezing and thawing with three kinds of freshwater fish with carp, grass carp, silver carp. And the frozen surimi products formula was optimized. From what has been studied above, the conclusions can be drawed:1. There are some differences in nutrition and physical and chemical indicators of the boiled production of the Grass carp, carp, silver carp, three kinds of minced fish balls(every 100.00 g minced fish only add 2.00 g of salt, don’t add other auxiliary materials). In this three types of all minced fish pill gel products, The moisture content of silver carp fish balls is(80.82 ± 1.20) %,significantly higher than that of the grass carp fish balls(78.33 ± 0.56) % and the carp fish balls(77.65 ± 1.65) %(P<0.05); the content of protein of the carp fish balls was the highest(19.04 ±0.68) %, the second were the grass carp fish balls(18.75 ± 1.04) %, silver carp fish balls were the minimum(17.42 ± 0.85) %. The content of the fat of grass carp fish balls was(2.78 ± 0.48) %,significantly higher than the carp fish balls(2.39 ± 0.87) % and the silver carp fish balls(1.23 ±0.64) %(P<0.05); the gel strength of the carp fish balls was the biggest(2289.37 ± 59.01) g·mm,significantly higher than that of the grass carp fish balls(1835.02 ± 44.11) g·mm and the silver carp fish balls(1255.29 ± 42.71) g·mm(P<0.05); the whiteness value of the silver carp and grass carp fish balls was higher, respectively(70.73 ± 0.29),(70.19 ± 0.18); while the whiteness value of carp fish balls was(69.21 ± 0.14), relatively lower; the grass carp and carp fish balls were better in the three kinds of fish ball productions in sensory evaluation and the flex experiments, the silver carp was the worst; the cooking loss of the silver carp fish balls was(10.30 ± 0.49) %,significantly higher than that of the grass carp(8.97 ± 0.20) % and the carp(8.66 ± 1.01) %(P<0.05); the water retention of the grass carp fish balls was the highest(94.63 ± 0.36) %, the carpfish balls were the second(92.87 ± 0.64) %, the silver carp fish balls were the minimum(92.01 ±1.09) %.2. Adding auxiliary materials could soy protein solate, potato starch, egg white protein and water improve the gel strengths of three surimi products, and it also enhanced grass carp and carp surimi’s whiteness(P<0.05), but the silver carp products. The grass carp products had no changes,but carp and silver carp products decreased in sensory evaluation and flex experiment(P<0.05).Adding auxiliary materials reduced cooking loss of three surimi products and enhanced water retention of three surimi products(P<0.05).3. Repeated freezing and thawing reduced the gel strength of three surimi products(P<0.05),but when grass carp was repeated freezing and thawing in one time, its gel strength increased but the overall downward trend; in addition, three surimi products’ s whiteness and water retention decreased but cooking loss of three surimi products continued to increase with repeated freezing and thawing frequency increasing(P<0.05), meanwhile freeze-thaw accelerated fat oxidation of three surimi products(P<0.05).4. The main factors of affecting quality of frozen surimi which were soy protein solate, potato starch, egg white protein and water. They were added together to make L9(34) orthogonal tests and used sensory evaluation and gel strength as the evaluation index to determine frozen surimi products optimum parameters. The optimized conditions were: potato starch dosage 6 g, egg white protein dosage 6 g, soy protein solate dosage 8 g, water dosage 6 g. Gel strength of frozen surimi products was 3240.18 g.mm and sensory scores were 19.7 points under these conditions.