| Carrageenan is a kind of linear sulfated polysaccharide,which is widely used in surimi and other foods.The application properties of carrageenan are closely related to the source of raw materials and the strength of alkali treatment.However,there are few studies on how alkali treatment strength affects properties of carrageenan,and the production process of carrageenan was not optimized for its application requirements in surimi products.In this study,κ-carrageenan products with different strength of alkali treatment were prepared by alkali treatment of Eucheuma auricula at different time based on the traditional extraction process of carrageenan by the alkali method.The effect of different alkali treatment of κ-carrageenan on the quality of surimi products were compared.(1)Alkali treatment strength(time)has a significant effect on the elements inκ-Carrageenan.κ-Carrageenan polysaccharide and Cl increased significantly,while N decreased significantly when alkali treatment time was between 2-3 h.The texture,water holding capacity and transparency of κ-Carrageenan were significantly different within 0-3 h after alkali treatment.Infrared spectrum analysis showed that alkali treatment removed part of sulfuric acid group ofκ-Carrageenan molecular structure,and did not form a new chemical bond.(2)The results of dynamic rheology show that the storage modulus G ’and loss modulus G’of different carrageenan with different alkali treatment intensity change with increasing or decreasing temperature,and the trend of gel temperature and thaw temperature decreases first and then increases.The storage modulus G’ and loss modulus G" of κ-carrageenan without alkali treatment(K0)and alkali treatment for 1 h(K1)are similar at 0-40℃.The dynamic viscoelastic experimental results show that alkali treatment can significantly enhance the storage modulus G’ of carrageenan,and enhance gel capacity.The gelation ability of carrageenan and other carrageenan without alkali treatment(K0)and alkali treatment for 2 h(K2)were significantly different.(3)DSC analysis showed that there were no other physical and chemical changes inκ-carrageenan system from-20℃ to 90℃,and the transition temperature increased with the increase of alkali treatment strength,in which the K0 transition temperature was-2.06℃,and the K5 transition temperature was-1.68℃.Low field NMR analysis showed that the water binding capacity of κ-Carrageenan without alkali treatment was higher than that of alkali treatment group.With the increase of alkali treatment strength,the water mobility became weak.(4)Alkali treatment time had a significant effect on the quality of surimi.With the increase of alkali treatment intensity during the extraction process of carrageenan,the whiteness and water holding capacity of surimi showed a downward trend after adding carrageenan.The hardness,adhesiveness and chewiness of surimi showed an upward trend,but the breaking force,gel strength,elasticity,cohesiveness and recovery of surimi had no significant effect.(5)The differences of water holding capacity(WHC)and repeated freeze-thaw results in surimi products with K1 and K-carrageenan were compared.The addition of K1 carrageenan to surimi products can improve the WHC of surimi in freezing-thawing.In addition,the protective effect of K1 carrageenan on hardness of surimi is better than that of commercial κ-carrageenan,so K1 carrageenan is more conducive to the preservation of texture in surimi frozen storage.In this paper,the effect of different alkali treatment intensity on the application properties ofκ-Carrageenan was studied,which provided experimental basis for optimizing the application properties of carrageenan in surimi products. |
PDF Full Text Request