Effect of pressure-shift freezing treatment on gelling and structural properties of grass carp surimi

The damage of conventional freezing (CF) to the quality of surimi products is an urgent problem in the food industry. In the study, the effect of different freezing treatments [CF, pressure shift freezing (PSF), pressure-shift freezing pretreatment (Pr-PSF), unfrozen control] on gelling properties [gel strength, texture profile analysis (TPA), color], water-holding capacity (WHC) and protein structure characteristics of the grass carp surimi gel were evaluated and compared. Compared with other freezing treatment groups, surimi gel strength was increased three to four times after PSF treatment, which was mainly caused by the change in the microstructure and the WHC of the surimi gel. The study showed that PSF treatment could significantly improve the quality of the surimi gel and overcome the negative effect of freezing on the surimi gel. This indicates that PSF technology has a wide application prospect in the surimi gel processing industry, food processing and related material fields. Industrial relevance: PSF can enhance the commodity value of low-value freshwater fish products and has potential in surimi gel new product development. The development of new products and the use of new resources are very important in addressing the global food crisis and resource shortages. In addition, PSF units with self-cooling systems offer opportunities for scale-up and commercialization.