Heating surimi products using microwave combined with steam methods: Study on energy saving and quality

Moisture content plays an important role in aspects of the food processing such as energy transfer, food yield, and quality. This study investigated the effects of the moisture content of surimi on its electromagnetic characteristics. At moisture contents between 78% and 80%, both the dielectric constant and the dielectric loss increased, but gradually decreased with the increase of frequency. The strongest microwave absorption appeared at a thickness of 8 mm at 2.45 GHz. A moisture content of 0.45% was supplied to surimi using steam as an auxiliary heating method. The gel strength was obviously improved by a combination of microwave treatment (35 kW) and steam heating, and scanning electron microscopy showed that the network structure was also denser. In addition, the new heating mode with medium microwave power received the highest score on the comprehensive sensory evaluation after frying. The combination of microwave and steam preparation can save 11.68% ± 1.8% of the energy used in the conventional heating method, even when taking into account the combustion of methane produced during the wastewater treatment process.