Effects Of Tea Polyphenols And Carvacrol On The Properties Of Soybean Protein Film

Plastic packaging film has excellent mechanical properties and low prices,widely used in food,pharmaceuticals and other fields of packaging,but because it is not easy to degrade,easily lead to "white pollution" and other issues,therefore,the study of biodegradable bio-packaging materials instead Plastic is very necessary.Soy protein has become a best film-forming substrate for plant proteins because of its good film forming ability and biodegradability.However,because soybean protein is rich in nutrients,it is easy to breed bacteria and mold,and the antibacterial effect of protein film is poor,which greatly limits its application in biodegradable packaging materials.By adding bacteriostatic substances,the antibacterial ability of the protein film can be improved,the growth and reproduction of microorganisms on the surface of the packaged food can be effectively suppressed,and the shelf life and safety of the food can be improved.The inhibitory intensity and inhibitory spectrum of different antibacterial substances are different for microorganisms.Therefore,selecting suitable antibacterial substances for compounding can complement each other's deficiencies and play a synergistic role.Soybean protein isolates are used as the matrix,and tea polyphenols(TP)and carveol(Car)are added to them respectively.The water barrier properties,mechanical properties,and appearance of protein films with different concentrations of tea polyphenols or carvone are studied.Nature and influence of infrared light spectrum and other properties.Based on this,the effects of tea polyphenols and carvacrol MTPs on film properties,antioxidation and antibacterial properties are studied.The purpose is to improve the antibacterial properties of the protein film,and provide a theoretical basis for the research and application of soybean protein film.The main findings are as follows:(1)The addition of tea polyphenols increased the solubility and swelling index of the protein film;adding carvacrol reduced the solubility and swelling index of the protein film.The combination of tea polyphenols and carvacrol reduced the solubility and swelling index of the protein film.(2)With the increase of the amount of tea polyphenols,the water vapor transmission rate of the protein film first decreased and then increased;the addition of carvacrol increased the water vapor transmission rate of the protein film significantly(p< 0.05).In the compound film,the water vapor transmission rate of the protein film increased significantly with the increase of the amount of carvacrol(p<0.05);with the increase of the amount of tea polyphenols,the water vapor transmission rate decreased significantly(p<0.05).(3)The addition of polyphenols or carvacrol significantly reduced the elongation at break of the protein film(p<0.05).With the increase of the amount of tea polyphenols,the tensile strength of the protein film first decreased and then increased.With the increase of the amount of carvacrol,the tensile strength of the film first increased and then decreased.The combination of tea polyphenols and carvacrol can reduce the effect of tea polyphenols on the tensile strength and elongation at break of the protein film.(4)With the increase of the amount of tea polyphenols,the opacity of the protein film increased gradually;adding carvacrol made the opacity of the protein film decrease first and then increase.Compared with the caraway film,tea polyphenols and carvacrol combined to improve the opacity of the protein film.(5)With the increase of the amount of tea polyphenols,the brightness of the protein film gradually decreased,and the redness and yellowness gradually increased.The combination of tea polyphenols and carvacrol reduced the brightness of the protein film,and the a* and b* values increased significantly(p<0.05).(6)The addition of tea polyphenols,carvacrol and tea polyphenols and carvacrol did not significantly change the chemical structure of the protein film.(7)The addition of tea polyphenols,carvacrol and tea polyphenols and carvacrol combined significantly increased the total phenolic content and DPPH free radical scavenging rate of the protein film.(8)The addition of 0.5% tea polyphenols or 1.5% to 2.0% carvacrol had inhibitory effects on Escherichia coli and Staphylococcus aureus.The combination of tea polyphenols and carvacrol has a synergistic effect on the bacteriostatic properties of soybean protein films.In summary,compared with tea polyphenols or carvacrol protein films,the composite film has better physical properties,chemical structure,anti-oxidation and antibacterial properties.Comprehensively,when the protein film is supplemented with 1.0% Carotenol+0.3% tea polyphenols,the soybean protein film has good performance,and has a certain anti-oxidation and antibacterial ability.It can be used for food preservation and soybean protein film application.There's important meaning.