Cooking evaluation of crayfish (Procambarus clarkia) subjected to microwave and conduction heating: A visualized strategy to understand the heat-induced quality changes of food

The evaluation of food cooking process is an important way to understand the heat-induced quality changes and optimize the heating process. To understand the quality changes in crayfish tail heated by microwave (MW) and boiling water (BW), the protein denaturation, cooking uniformity and overheating degree of tails were visually evaluated based on the theories of reaction kinetics and maturity value in this work. Protein denaturation analysis showed that heat-induced protein denaturation in crayfish tails heated by MW and BW followed first-order reaction kinetics and had similar one-dimensional denaturation patterns and temperatures, but their distributions were non-uniform and with reverse trends. Moreover, strong correlations between protein denaturation degree and heat-induced qualities changes were observed in crayfish tail during heating. The cooking uniformity and overheating degree of crayfish tail heated by MW and BW were evaluated by the maturity value (Mv) and overheating value (Ov), respectively. Evaluations showed that the profiles of Mv and Ov in the crayfish tail were non-uniform and with reverse trends, and there was lower ΔMv and O¯v for crayfish tail heated by MW than by BW, but higher Ov occurred in the centre, which corresponded to the texture of crayfish tails heated by MW was more susceptible than by BW when proteins had completely denatured. The general patterns of cooking process in crayfish tail during microwave heating and boiling have been visually evaluated and compared based on the theories of reaction kinetics and maturity value, which enriched the knowledge for the application of microwave in the industrial thermal processing of crayfish and reaction kinetics in the analysis of cooking (especially microwave heating). Furthermore, the theory of maturity value was introduced into the evaluation of the cooking uniformity and overcooked degree in crayfish tail during the heating, which provided a new strategy for the cooking evaluation of food.