|Title||Changes of structural and physical properties of semi-gel from Alaska pollock surimi during 4 °C storage|
|Author(s)||Liu, Xiangyu; Zhang, Tao; Xue, Yong; Xue, Changhu|
|Source||Food Hydrocolloids 87 (2019). - ISSN 0268-005X - p. 772 - 782.|
|Department(s)||Physical Chemistry and Soft Matter|
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Cold semi-gelation - Gelation differences - Heat-induced gelation - Surimi gels|
This study compared the semi-gel system of Alaska pollock surimi formed at a low temperature with a heat-induced gel system. The cold semi-gel and heat-induced gel were found to have obvious differences in their degrees of protein unfolding, aggregation, and gel network structures. Microscopic observations and an analysis of their fractal dimensions revealed different degrees of compactness and uniformity in the two network structures. Rheological parameters, including the least permanent deformation, equilibrium stress, and frequency exponent, confirmed the non-total aggregation and lower degree of cross-linking in the cold semi-gel. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the myosin heavy chain (MHC) value gradually decreased, but the light meromyosin (LMM) value remained stable during cold storage. Furthermore, a decrease in the α-helix and an increase in the β-sheet and random coil values, as revealed by Fourier-transform infrared (FT-IR) spectroscopy, indicated that the proteins unfolded differently in the two gel systems. By comparing the times required for the cold semi-gel and heat-induced gel to form, we concluded that the formation process of heat-induced gel is intertwined while it is temporally separated in cold storage. Overall, myosin was selected as the starting point for establishing a schema chart to characterize the gelation processes of the cold semi-gel and heat-induced gel. These findings are helpful for understanding the gelation process of surimi in refrigerated storage.