Kinetic modelling of the mass and heat transfer of a plant-based fishball alternative during deep-fat frying and air frying and the changes in physicochemical properties

Abstract

The mass and heat transfer of a plant-based fishball alternative (PFB) and the changes in physicochemical attributes within frying were researched. The effective moisture diffusivity Deff and thermal diffusivity α of PFB in deep-fat frying (DF) were larger than in air frying (AF), where the Deff and α of DF-PFB were 2.95 × 10−8 and 7.56 × 10−6 m2/s, respectively, while those of AF-PFB were 2.34 × 10−8 and 6.89 × 10−6 m2/s, respectively, indicating a more effective moisture and heat transfer in DF. The oil uptake of DF-PFB was significantly higher than fishball (FB), with the equilibrium oil content Oeq of 0.120 and 0.039 g/g, respectively; AF would reduce the oil uptake of PFB considerably (0.067 g/g). PFB had a similar trend for texture and gel strength development to FB; the hardness, chewiness, resilience, and springiness during DF developed more rapidly than in AF. Besides, DF induced a larger ΔE (total color difference) than AF, where the surface ΔE of DF-PFB was 32.25, while that of AF-PFB was 26.74. Microstructural observations illustrated that DF-PFB formed a rougher structure than DF-FB, causing more oil absorption in PFB. These results could provide a fundamental understanding of transport phenomena and physicochemical attributes of PFB during frying, demonstrating that the AF could be an alternative way to produce healthier PFB products with less oil absorption while having equal qualities.