Effect of air frying and baking on physicochemical properties and digestive properties of scallop (Patinopecten yessoensis) adductor muscle

In this study, the effects of dry heat treatments including air frying and baking on the physicochemical and digestive properties of proteins in scallop adductor muscle (SAM) were evaluated. After heat treatments, the proteins in SAM exhibited different degrees of oxidation, aggregation and degradation. For both heat treatments, the increase of carbonyl and dityrosine contents and the decrease of free sulfhydryl groups and surface hydrophobicity of proteins in SAM were observed along with increasing heat temperature. Meanwhile, with increasing heat temperature, there was a progressive transition from α-helix to β-sheet in protein secondary structure. However, the protein solubility first increased and then decreased with increasing temperature. Among which, the solubility of 160°C-treated samples was the highest, which were 21.02% and 20.32% for air frying and baking. The protein digestive properties which reflected by the degree of hydrolysis (DH), soluble amino groups and soluble peptides showed a trend of increasing first and then decreasing with increasing temperature. After gastrointestinal digestion, the DH, soluble amino groups and soluble peptides of 160°C-treated SAMs cooking by air frying were 69.96%, 61.14% and 39.33%, respectively, which were significantly higher than all other samples including the fresh ones. Correlation analysis showed that the protein digestive indexes were positively correlated with solubility, free sulfhydryl content and surface hydrophobicity, and negatively correlated with protein carbonyl content, dityrosine content and protein aggregation degree. These results provide evidence for knowing more about the effects of dry heat treatments on physicochemical and digestive properties of aquatic muscle food.