Cryoprotective Effects Of Water-soluble Soybean Polysaccharides On Myofibrillar Protein Of Aristichthys Nobilis Surimi

Surimi myofibrillar protein is easily denaturated during frozen storage,leading to the decrease of functional characteristics of surimi and its products.In this paper the effects of different concentrations and molecular weight of water-soluble soybean polysaccharides?SSPS?on the stability of Aristichthys nobilis surimi myofibrillar protein were investigated during frozen storage.The mechanism of SSPS freezing-resistance was preliminarily explored.Finally,the synergistic effect of liquid nitrogen freezing and SSPS was explored to develop a new freezing method for surimi.?1?The cryoprotective effect of SSPS with different concentrations?0%,1%,3%,5%?was studied by physicochemical indexes such as whiteness,water holding capacity?WHC?,protein solubility,total sulfhydryl content,Ca²⁺-ATPase activity as well as fluorescence spectra and Raman spectra.The results showed that SSPS could alleviate the freezing denaturation of Aristichthys nobilis surimi myofibrillar protein,and the positive effect was increased with the increase of SSPS concentration,but the difference between 3%and 5%was not significant.Besides,the addition of 5%SSPS could largely increase the yellow value b*of surimi.Taking costs and other factors in consideration,3%was the best addition.?2?SSPS-U and SSPS-H were obtained by ultrasonic degradation and hydrogen peroxide combined with untrasonic degradation respectively,whose molecular weight were smaller than SSPS.The molecular weight of SSPS,SSPS-U,SSPS-H was 5025.24 kDa,4384.77 kDa,3218.14 kDa,respectively.Compared with non-degraded SSPS,three kinds of SSPS with different molecular weight were used to study the cryoprotective effect on Aristichthys nobilis surimi.Results showed that the lower the molecular weight was,the better the cryoprotective effect of SSPS was,of which SSPS-U was the best.?3?The free water content and infrared spectra of surimi showed that the hydroxyl group?-OH?of SSPS could convert the free water of Aristichthys nobilis surimi into binding water.As the SSPS concentrations and hydroxyl group content increased,free water content decreased and binding water content increased.The cryoprotective effect of SSPS-U and SSPS-H on Aristichthys nobilis surimi was better than that of SSPS.?4?The experimental result of surimi with SSPS by liquid nitrogen freezing showed that liquid nitrogen freezing can significantly improve the freezing rate,shorten the time for maximum-ice-crystal formation zone,and the addition of SSPS did not have a significant impact on the freezing rate?p>0.05?.SSPS combined with liquid nitrogen freezing was superior to liquid nitrogen freezing or SSPS.