Effects Of Thymol And Carvacrol On The Properties Of Peanut Protein Film Treated By High Temperature

Compared with the plastic,protein films have edible,high nutrition and biological characteristics.The mechanical properties and water resistance of peanut protein films is no good.Moderate modification is the prerequisite of protein films.The denaturation temperature of peanut globulinis 102℃,and atmospheric heating treatment cannot make its modest degeneration.Thymol and carvacrol are natural antioxidant and antibacterial material.Antimicrobial substances was added in protein films,microorganisms on the surface of the food was suppressed effectively,and the shelf life of food was improved.Different antibacterial material has different bacteriostasis intensity and bacteriostatic spectrum.Antibacterial material were compound can make up for their shortcomings and has synergy effects.Peanut protein isolate(PPI)was used as film-forming substrate,and thymol(Thy)and carveol(Car)were respectively added to the film-forming liquid which was treated by high temperature(100 ~ 120 ℃).Effects of thymol and carvacrol addition on properties and antimicrobial activity of PPI films treated by high temperature(HPPIF)was studied.Based on this,Effects of compound thymol and carvacrol on properties and antimicrobial activity of PPI films treated by high temperature was studied.The main findings are as follows:(1)The optimum process conditions for the preparation of HPPIF were determined by single factor and orthogonal test: protein concentration 8%(w/v),p H value 9.0,heating temperature of 110℃,heating time 15 minutes and glycerin concentration 35%(w/w).Under the conditions,the HPPIF has the tensile strength of 4.42 ± 0.05 Mpa.(2)After high temperature treatment,the difference of the thickness and brightness of protein films was little(p>0.05),the tensile strength,water resistance and water soluble increased significantly(p<0.05),the elongation at break and transparency significantly reduced(p<0.05).(3)Adding thymol and carvacrol alone,the opacity and water resistance of protein films were reduced,effects on the thickness was little.When Adding the same thymol and carvacrol,the color of carvacrol protein films was yellower than thymol protein films(p<0.05),the transparency of carvacrol protein films was bigger than thymol protein films(p < 0.05).(4)Compared with the control films,adding 0.5~1.0% thymol and 0.5% carvacrol,the mechanical properties of the protein films change little,the difference of color was not significant(p>0.05).(5)Compared with single films and control films,the watertightness,water soluble and brightness of compound thymol and carvacrol protein films were decreased significantly(p< 0.05),the color was darker(p < 0.05),the effects on the thickness was little(p>0.05).(6)Under the low concentration,thymol and carvacrol can inhibit staphylococcus aureus and escherichia coli,both of them had inhibitory effects on escherichia coli was worse than that of staphylococcus aureus.The inhibition effects of thymol on staphylococcus aureus bigger than that of carvacrol.(7)Thymol and carvacrol compound films has synergistic inhibition on escherichia coli and staphylococcus aureus.In summary,compound 1.0% thymol and 0.5% carvacrol was used to make HPPIF,high water solubility,tensile strength,resistance to wet and antimicrobial activity protein films was used as good packaging materials,which has a good application prospect in the future.