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 fromα-helix toβ-sheet in protein secondary structure.However,the protein solubility first increased and then decreased with increasing temperature.Among which,the solubility of 160℃-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℃-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.

Glycation of whey protein isolate and stachyose modulates their in vitro digestibility: Promising prebiotics as functional ingredients

Glycated conjugates have recently been designed to be targeted to probiotic in the colon.However,the underlying mechanisms of regulating the prebiotic properties and digestibility of conjugates through glycation have not been fully elucidated.In this study,WPI-stachyose conjugates were prepared through Maillard reaction and proposed as functional ingredients with prebiotic characteristics.The effect of glycation on the in vitro simulated gastrointestinal fate of WPI-stachyose conjugate was further evaluated.The results showed that the glycated conjugates of stachyose covalently bound to whey protein exhibited a characteristic cross-linked structure,which enhanced their inhibition ofα-amylase activity and retardation of glucose dialysis.Besides,simulated digestion analysis demonstrated that stachyose-conjugated WPI was more resistant to pepsin and trypsin digestion than unconjugated WPI.Compared with native WPI,the protein digestibility and degree of hydrolysis of WPI-stachyose conjugates were reduced by 12.5%±0.66%and 5.30%±1.02%,respectively.In addition,rat intestinal extracts were used to detect the in vitro digestibility of stachyose.The hydrolysis rate of stachyose in the glycated conjugates was 70%lower than that of stachyose.Therefore,the resulting WPI-stachyose conjugate may be used as functional ingredients to achieve the sustained-release effect in the gastrointestinal tract.These findings demonstrate the possibility of modulating proteins and carbohydrates digestibility through glycation,and have implications for the design and manufacture of potential prebiotic molecules with controlled digestibility in food and related healthcare fields.