Deciphering the impact of air frying vs. oven roasting on crayfish (Procambarus clarkii) quality: A multiscale journey from water migration and protein denaturation to texture, flavor, and digestibility

Crayfish are valued for their culinary appeal and nutritional profile. This study compares air frying (AF) and roasting (RO) impacts on crayfish muscle. We investigated water migration, protein structural changes, microstructure, sensory attributes, digestibility, and volatile compounds. Dry-heat processing induced significant protein oxidation and aggregation, as evidenced by a 3.6-fold increase in carbonyl content, a 48 % rise in the myofibrillar fragmentation index, and a reduction in free sulfhydryl groups. AF promoted protein oxidation due to rapid heating, whereas RO enhanced proteolysis. AF samples retained bound water within compact matrices, restricting water mobility, whereas RO formed porous networks that increased free water content, yielding smaller digesta particles (367.9 nm). AF enriched volatile compounds through dehydration-driven concentration, with tetrahydro-2-furanmethanol as a discriminant marker. AF at 170 °C/10 min achieved optimal sensory acceptance. Our findings elucidate multiscale mechanisms linking water-protein dynamics to texture, flavor, and digestibility, providing a scientific basis for optimizing crustacean processing. • Dry-heat causes oxidative degradation, higher carbonyl and MFI, lower sulfhydryl. • Air frying oxidizes proteins, roasting degrades them. • Air frying retains bound water via compact matrices, concentrating volatiles. • Roasting boosts digestibility with porous architectures via proteolysis. • Tetrahydro-2-furanmethanol acts as an authentication marker for air-fried crayfish.