| Silver carp, one of the main fresh-water fish species, accounting for15%to20%of fresh-water fish production, is a low-value fish. The gel strength of silver carp surimi is much less than that of marine fish surimi.So,we should study how to improve the gel strengthing of silver carp. In this paper,using silver carp and pike eel as raw materials,we determined the amino acid composition and the interactions,analyzed the relationship,optimized the process and developed a formula for strengthen gel strength of silver carp surimi.The results were as follows:1. Determined the the amino acid contents of the two kinds of fishes of washed surimi and the actomyosin from the two kinds of fishes and calculated the ratio of each amino acid to total amino acids.. The results showed that:the ratio of cystine, glutamic acid, lysine, tyrosine, valine, aspartic acid, threonine and methionine in washed pike eel surimi and in actomyosin from pike eel surimi were all higher than that in silver carp’s. The ratio of cystine in washed pike eel surimi and washed silver carp surimi were respectively0.833and0.992, The ratio of glutamic acid were respectively18.754and19.040, The ratio of lysine were respectively9.461and9.834, The ratio of tyrosine were respectively3.864and4.085, The ratio of valin were respectively3.905and4.186, The ratio of aspartic acid were respectively10.523and10.775, The ratio of threonine were respectively4.775and4.905, The ratio of methionine were respectively2.588and2.721. The ratio of same amino acid in two kinds of fishes are significant (P<0.05).Determined the gel strength of silver carp surimi gel and pike eel surimi gel with TA-XTPlus and the results were1099.910g.cm and4905.818g.cm (P<0.05).Determined the contents of the interactions during gel forming procedure. The results showed that:hydrogen bonds and ion bonds decreased significantly, while hydrophobicity,disulfide bonds and non-disulfide covalent increased significantly with surimi gel forming. So,hydrophobicity,disulfide bonds and non-disulfide covalent bonds were the main interactions to maintain surimi gel network.The contents of disulfide bonds in surimi gel of pike eel and silver carp were respectively1.68mol/106g and mol/106g (P<0.05), protein dissolving rate were respectively were74.53%and69.51%(P<0.05)(The contents of non-disulfide covalent bonds was inversely proportional to protein dissolving rate), The contents of hydrophobicity were respectively10.26g/L and6.42g/L (P<0.05).Therefore, the ratio of cystine was positively related with the contents of disulfide bonds, the ratio of glutamic acid and lysine was positively related with the contents of non-disulfide covalent bonds, the ratio of aspartic acid, valine, tyrosine, threonine and methionine were positively related with the contents of hydrophobicity. So, the ratio of cystine, glutamic acid, lysine, aspartic acid, valine, tyrosine, threonine and methionine were positively related with gel strength of surimi gel.2. Optimized silver carp surimi process with single factor and orthogonal experiments. The results showed that:the optimizing process was using0.1%CaCl2solution at6-7℃wash the surimi for3times;blending with nothing for5min and then blending with2.0%NaCl for10min;40℃suwari for60min and then90℃heating for30min.The gel strength of silver carp surimi gel with optimizing process was2145.378g·cm which was1.95times compared with the surimi gel for genenal process.3.Develop a formula for strengthen gel strength of silver carp surimi gel by quadratic general rotary unitized design. The results showed that:TGase had the best beneficial effect for strengthen gel strength of silver carp surimi gel,followed by egg albumin powder, hydropropylated starch and carrageenan.The strengthening agent which had best eneficial effect for strengthen gel strength of silver carp surimi gel was as follows:egg albumin powder of6.81%, hydropropylated starch of8%, carrageenin of0.4%, and TGase of0.99U/g. The gel strength of silver carp surimi gel with the strengthening agent was4804.751g.cm,2.2times compared with the surimi gel of no formula.4.Using scanning electron microscopy observe surimi gel microstructure.The results showed that:the structure of surimi gel of pike eel,silver carp surimi with optimizing process and silver carp surimi with strengthening agent were all more fine and dense and had smaller hole。... |
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