Study On The Rheological Properties And Water States Of Alginate-fish Protein Mixture Gel Systerm

The aim of this work was to analyze the influence of the alginates methods of making surimi from low price fish on the gel and rheological properties, in terms of the rheological properties of surimi and definitive-gels. This rheological study is explained in terms of the chemical and structural analyses performed. The water states of mixture gels was analysed by DSC method for the based researches of improving marine resources.1. The alginate gels were thermally nonreversible gel. Its breaking force was increased with the alginate addition adding, but its deformation was increased firstly and then decreased when the alginate concentration was more than 8%. The gel strength of alginate gels reached the maximum, when the alginate concentration was 8%. The linear viscoelastic range of alginate gels was 0%-5%. Strain was increased rapidly as stress applied, with the stress time the strain trend change a little. When the stress was undid, strain recovered rapidly amd at last, a part of strain was unrecovered. The phenomenon above was creep and recovery of alginate gels. Stess was decreased rapidly as strain applied, with the strain time the stress trend change a little. At last, stress was retained for a certain level. The phenomenon above was stress relaxation of alginate gels. The frequency sweep of alginate gels showed that values of the storage modulus and the loss midulus were no significant changes. Those results indicated that alginate gel was elastic and stable.2. The addition of kanjac gum, carrageenan and guar gum could improve the breaking force and deformation of alginate gels. The addition of xanthan gum had no significant effect on the gel properies. The gel strength of alginate gel achieved the maximum when addition level of kanjac gum, carrageenan and guar gum were 4%, 5% and 4% respectively. The addition of xanthan gum and gellan gum had the negative effects on the gel strength of alginate, furthermore, the gel strength decreased with the addition added. All the food hydrocolloids could improve the water holding capacity, but reduce the whiteness.3. Effects of calginate at different concentrations on rheological and gel properties of jumbo squid surimi were investigated. Alginate (1-3% w/w) exhibited enhance effects toward gel strength, especially when alginate concentration increased. When 3%(w/w) alginate was added, breaking force and deformation of gel was increased by 566.9% and 89.7%, respectively. The cross-link of alginate was the main cause for increasing the gel strength and water-holding capacity. The microstructure of surimi gel showed that ordered structure became more evident with the calcium alginate content increased. The rheological properties of surimi-alginate mixture gel were studied by the time sweep, frequency sweep and temperature sweep. The storage modulus G' of alginate-jumbo squid surimi mixture was increased with the time for 4 hours. The frequency sweep shows that G' was greater than G" for all the mixture gels with different calcium alginate concentration, and values of n' and n" for all samples were low (<0.15), indicating the elasticity of mixture gels. The values of storage modulus G' decreased during heating process and increased with the temperature decreasing. In general, the addition of alginate could increase the gel strength of surimi gel.4. Temperature had obviously effects on the gel and rheological properies. The gel strength and storage modulus decreased with the temperature increased. The gel strength and storage modulus increased with the recovery of temperature. Compared to the non-heatd mixture gels, the gel strength and storage modulus of heated gels decreased, but the difference was not significant. The creep and stress relaxation of heated mixture gels indicated that structure of gel matrix was destroyed in some extent, but the recovery of temperature made the rheological properties recover.5. Water states of alginate gel systerm was studied by DSC, DTG, and infrared spectrum. The content of bound water increased with concentration of alginate increased. The addition of kanjac gum, carrageenan guar gum and xanthan gum could increase the content of bound water, but the bound water decreased with the gellan gun added. Bound water of alginate-fish protein mixture gel could be hold more with the fish protein added.6. The structure of an imitation surimi gel with low protein content was developed by replacing part/all of the surimi with alginate-calcium carbonate-glucono-delta-lactone and konjac glucomannan in the formula. Calcium alginate was partially joined as gel to provide gel properties, and KGM was used to provide to improve the gel elasticity and water-holding ability. Formulation studies were carried out to obtain gel properties and water-holding ability of commercial surimi. Response surface method was used to determine the effects of ALG, KGM and surimi on the gel properties of the imitation surimi products. Gel properties of the imitation surimi were affected positively by KGM and ALG and negatively by surimi concentration. A formula was determined by multiple response optimization method that would provide gel strength, stiffness and water-holding ability in the developed surimi similar to those of the commercial surimi used as targets. Results obtained from a trial imitation srumi gel produced according to the determined formula confirmed that the values of physical properties estimated by the optimization can be achieved.