| Smoked meat products are loved by consumers all over the world,but the traditional processing of smoked meat products not only causes environmental pollution,but also produces carcinogens such as benzo(a)pyrene,which endangers consumers’ health.Curing is an important part of meat processing,and although salt can provide flavor and improve the quality of meat products,too high salt intake is not good for human health.In recent years,liquid smoke has gradually replaced the traditional smoking process because of its ability to reduce environmental pollution and the production of harmful substances.In order to promote the application of liquid smoke with low sodium salt in meat processing,to obtain the optimal concentration range of liquid smoke cured meat products,to reveal the quality changes of meat products under liquid smoke curing,as well as the connection between the main components of liquid smoke and protein in cured meat and its molecular mechanism.In this paper,tea branch liquid smoke was prepared by processing tea branches and cured pork tenderloin at different concentrations,and its effects on meat product quality,antioxidant properties,protein structure and proteomics were investigated to scientifically understand the mechanism of liquid smoke effects on meat products,and to provide theoretical guidance for improving the traditional smoking process and traditional curing process and enhancing the quality of smoked meat products.The research contents and results are as follows:1.Study of the effect of the addition of tea branch liquid smoke with low sodium salt at different concentrations on the quality of tenderloins.The effects of tea tree branch liquid smoke in combination with low sodium salt on the quality of cured meat products were investigated by examining p H,color,water retention,microstructure(SEM)and low-frequency NMR at different concentrations over four days.The results showed that the p H and water-holding capacity of cured pork tenderloin performed best when the concentration of tea branch liquid smoke in pork tenderloin was 5 m L/kg during the curing process,but the water-holding capacity was reduced when too high or too low concentrations were involved in the curing process.The results of SEM revealed that the addition of tea branch liquid smoke at a concentration of 5 m L/kg resulted in a better network structure of pork tenderloin.According to the results of LF-NMR,tea branch liquid smoke could increase the proportion of bound water,resulting in a denser network structure and stronger water binding ability of pork tenderloin.2.Study on the antioxidant effect of curing with tea branch liquid smoke in combination with low sodium salt on tenderloin proteins at different concentrations.The changes of protein antioxidant properties of cured meat products by tea branch liquid smoke with low sodium salt at different concentrations over four days were investigated by examining the surface hydrophobicity,carbonyl content,total sulfhydryl content and differential scanning calorimetry(DSC)of the proteins in meat samples.The results showed that when the concentration of tea branch liquid smoke in pork loin was 5 m L/kg,the hydrophobicity of myogenic fibrous protein surface in cured pork tenderloin improved,the rate of carbonyl generation decreased,the rate of total sulfhydryl decomposition slowed down,and its antioxidant capacity tended to increase significantly,but too high or too low liquid smoke concentration accelerated the oxidation of protein.Combined with the results of DSC,the addition of 5 m L/kg of tea branch liquid smoke could improve the thermal stability of porcine tenderloin protein.The antioxidant capacity of the liquid smoke depends mainly on its composition,especially on the phenolic compounds.When the concentration of the liquid smoke is moderate,its antioxidant effect is greater and can improve the stability of cured tenderloin.Thus,the oxidation of myogenic fibrous protein could be delayed when the concentration of tea branch liquid smoke was 5 m L/kg.3.Study of the effect of curing with different concentrations of tea branch liquid smoke in concert with low sodium salt on the protein structure and molecular docking of tenderloin.The effects of tea branch liquid smoke on the protein structure of tenderloin at different concentrations were investigated through protein solubility,endogenous fluorescence spectroscopy,Raman spectroscopy,and molecular docking studies of several guaiacols and furfural with myosin,which accounted for a higher proportion plus in the tea branch liquid smoke.The results showed that the solubility of myofibrillar proteins increased with the increasing concentration of tea branch liquid smoke;it was found by endogenous fluorescence spectroscopy that the concentration of tea branch liquid smoket at 5 m L/kg would inhibit the unfolding of myofibrillar proteins,while too high or too low concentration changes would enhance the effect on myofibrillar proteins and cause the unfolding of myofibrillar proteins,expose more tryptophan residues,and reduce the fluorescence intensity;as shown by Raman spectroscopy,higher concentrations of tea branch liquid smoke reduced the disruption of hydrogen bonds and hydrophobicity,and the protein secondary structure was stabilized after its curing,but curing with moderate concentrations of liquid smoke also had the potential to enrich the functionality of the protein.Molecular docking of2-methoxy-4-methylphenol,4-ethyl-2-methoxyphenol,2,6-dimethoxyphenol,o-methoxyphenol and furfural with myosin revealed that hydrogen bonding was the main driving force for carrier-ligand binding.Meanwhile,the different structures of guaiacol and furfural in tea branch liquid smoke bind to myosin both with π-stacking interactions,which can enhance the binding of myosin to its material carriers.4.Study on the proteomics of tenderloin meat by curing with tea branch liquid smoke in synergy with low sodium salt.The effects of different tea branch liquid smoke additions(0m L/kg,5m L/kg)on the proteomics of tenderloin were investigated by dry curing.The results showed that a total of 1455 differential protein expressions were identified,including 291 up-regulated proteins and 1164 down-regulated proteins.The differential proteins were screened and annotated,and then analyzed for GO enrichment,and the differential proteins were classified into three biological functions: biological processes,cellular components,and molecular functions.The results showed that tea branch liquid smoke muscle had significant effects on cytoplasm,mitochondria,metabolic enzyme-like proteins and their activities,and ligase proteins and their activities inside the lining meat cells,and were dominated by down-regulated proteins.By KEGG enrichment analysis,the differential proteins had significant effects on the metabolic pathways of tea branch liquid smoke on tenderloin meat.The main focus is on biometabolic pathways in human disease categories(biometabolic pathways such as neurodegenerative degeneration-multiple disease pathways,amyotrophic lateral sclerosis,Alzheimer’s disease,Huntington’s disease,Parkinson’s disease,prion diseases,diabetes,Salmonella infection,non-alcoholic fatty liver disease,dilated cardiomyopathy,African trypanosomiasis,etc.),metabolism(oxidative phosphorylation glycolysis/gluconeogenesis,valine,leucine and isoleucine degradation),organismal systems(metabolic pathways such as thermogenesis and reverse endogenous cannabinoid signaling),and genetic information(pathways such as protein processing,proteases,and protein export in the endoplasmic reticulum)have also been improved.Tea breach liquid smoke curing is characterized by strong activity of membrane linker proteins and protein phosphatases,allowing them to produce peptides and amino acids through plasmids and protein ligases in concert with other kinases.These proteins may be the main reason for the altered meat quality.Through this study,it may provide new ideas research direction for the molecular mechanism of liquid smoke on the processing of meat products. |
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