Effects Of Salt Content And Drying Temperature On Physicochemical Properties Of Dry-cured Chicken During Processing

Dry-cured chicken,one of the traditionally cured meat products in China,is popular among consumers due to its unique flavor.The traditional method of dry-cured chicken is composed of marinating,sun drying,fermenting,and ripening.However,the traditional process has the disadvantages that affected by climate and temperature,long production cycle,and hard to control,which is difficult to adapt for industrialized production.At present,wet-curing and hot-air drying are common marinating and drying methods,which can effectively solve the above problems.In the production process,salt content and drying temperature are important process parameters,which are closely related to the moisture,quality,color,lipid and protein oxidation of dry-cured chicken,and have an important impact on the quality.The objective of this work was to explore the effects of different salt content on the mass transfer characteristics,physicochemical properties,lipid and protein oxidation of dry-cured chicken during the wet-curing process.Meanwhile,we investigated the effects different salt content and drying temperature on drying characteristics,physicochemical properties,lipid and protein oxidation of dry-cured chicken during drying process.The conclusions are as follows:1.During wet-curing process,the effects of different salt concentrations on mass transfer kinetics,shearing force and water-holding capacity of dry-cured chicken were analyzed.The results showed that salt content have a significant effect on the mass transfer characteristics.With the increase of salt content,the total weight and water content gradually increased and decreased thereafter,and the change of salt content was directly proportional to the salt concentration.Shearing force,cooking loss and crushing loss showed a decreasing trend as the curing time prolonged.All mass transfer prediction models had a good linear relationship for wet-curing process,which could be used to predict the changes of weight,water content and salt content.2.The changes of lipid oxidation,protein oxidation and edible quality of dry-cured chicken marinated with different salt mass fractions were studied.The results showed that with the increase of salt content,the carbonyl content and surface hydrophobicity increased significantly,the sulfhydryl contents decreased significantly,TBARS and protein solubility gradually increased and decreased thereafter.SDS-PAGE electrophoresis showed that increased in salt content could promote the formation of disulfide bonds,which indicated that salt may lead to protein cross-linking.As for the edible quality,with the increase of salt mass fraction,pH and moisture content increased first and then decreased,cooking loss first decreased and then increased,L^*showed a significant downward trend,and a^*was increased significantly.Overall,increased in salt content could promote lipid and protein oxidation,which in turn affected the edible quality.3.To study the effects of different salt content and drying temperature on drying characteristics and quality of dry-cured chicken during drying process.The results showed that an increase in temperature could accelerate moisture evaporation and mass transfer,thereby increasing the drying rate and reducing the drying time.Increasing the salt content could delay moisture migration in the muscles,thereby enhancing water-holding capacity.D_eff was inversely proportional to salt content and directly proportional to drying temperature.E_a was affected by salt content.As salt content increased,E_a showed a downward trend.Six common kinetic models were used to fit the drying curve of dry-cured chicken,and the results showed that Page model was the best mathematical model for evaluating the drying dynamics,which was according to the change of R²?RMSE and?².4.The effects of different salt content and drying temperature on lipid and protein oxidation during the drying process were investigated.Lipid and protein oxidation were significantly affected by salt and temperature.Increased in salt content and temperature led to significantly increased level of indicators,including CD,TBARS,and carbonyl contents.Conversely,the sulfhydryl contents and surface hydrophobicity significantly decreased.The changes of these indicators illustrated that the increased in salt content and drying temperature promoted lipid and protein oxidation.SDS-PAGE analysis revealed that protein oxidation may lead to cross-linking and aggregation,thereby reducing the surface hydrophobicity.