Importance of thickness in electromagnetic properties and gel characteristics of surimi during microwave heating

Abstract To better apply microwave technology to surimi industry, surimi gels of different thicknesses were investigated. According to the determination of electromagnetic properties of surimi paste, both the maximum penetration depth and absorption peak are less than 1 cm. The results of temperature distribution shown that the highest temperature point of the surimi shifted from the center to the periphery. The coefficient of variation (COV) was the minimum and the temperature distribution the temperature distribution was the most uniform when the surimi thickness was 2.0 cm. Surimi paste with a thickness of 2.0 cm heated by microwaves (2450 MHz) had higher gel properties (16.42 ± 0.22 MPa) and water holding capacity (73.59 ± 0.26%) compared to that heated by the traditional water bath method. Scanning electron microscopy revealed that an ordered and dense network structure formed at a thickness of 2 cm. The optimum thickness (2 cm) for microwave heating was determined based on the electromagnetic characteristics and the temperature distribution of surimi, which provided basis for the application of microwave in surimi products.