Employment of κ-carrageenan and high pressure processing for quality improvement of reduced NaCl surimi gels

摘要

The effects of high pressure (100-500 MPa) pretreatment on the properties of reduced salt (1.5% of NaCl, w/w) surimi (RSS) containing 0.8% (w/w) kappa-carrageenan (RSS-K) gels were investigated. Results showed that the gel strength and water-holding capacity of RSS-K gels obtained the maximum value at 300 MPa. The low-field nuclear magnetic resonance revealed that pretreatment at 300 MPa shortened the T-2 spin-spin relaxation time of RSS-K gels and increased the proportion of immobilized water in gels. Scanning electron microscopy imaging suggested that the 3D network structure of RSS-K gels became smoother, more continuous and uniform, and denser at 300 MPa. These results indicated that pretreatment at 300 MPa could improve the gel properties by changing the water state and microstructure of RSS-K gels. Practical applications Consumers' growing awareness of the reduction of NaCl intake has led the aquatic product processing industry to develop healthier surimi-based products with lower NaCl. However, the gel-forming ability of surimi is reduced by less NaCl, so effective technologies are required to facilitate gelation for the improvement of the gel properties. Adding kappa-carrageenan (dietary fiber) and high pressure processing can be a potential method to improve the gel quality of reduced NaCl surimi gel.