Effects Of Thymol And Carvacrol On The Properties Of Peanut Protein Film

For the past few years,with the increasing environmental pollution,people began to study biodegradable biofilms instead of plastic packaging films.Protein membrane is a biological macromolecule membrane,because of its good physical properties,at the same time has the good nutritional value of people's attention.Peanut protein has become a good packaging material due to its abundant source,remarkable functionality,high protein content,and a great quantity chemical bonds in the molecule.As the protein membrane itself is rich in nutrients,which easy to breed microorganisms,causes the mechanical properties of the product during storage and barrier properties decreased.The study shows that by adding antimicrobial agents can enhance the antimicrobial function of edible film,preventing food and film itself,which could be contaminated by microorganisms,thereby extending the shelf life of food.In this study,peanut protein isolate was extracted by alkali solubilization.This work was undertaken to optimize the constituents of peanut protein isolate using transglutaminase for improvement of its mechanical properties,and then added thymol and carvacrol as antimicrobial and antioxidant agents.To study the effects of thymol and carvacrol on the physical and structural properties,total phenolic content,and antioxidant and antibacterial properties of peanut protein films.The main results are as follows:?1?The addition of thymol and carvacrol had no significant effect on the thickness of the protein film?p>0.05?.?2?With the increase of the thymol content,the tensile strength and elongation at break of the film increased first and then decreased.With the increase of the content of carvacrol,strength first increased and then decreased,the elongation at break decreased.Thymol and carvacrol added in an amount of 0%to 1.0%,the mechanical properties of the protein film are better.?3?With the increase of thymol and carvacrol,the water resistance of the protein membrane gradually increased,but the transparency decreased.The water resistance of thymol protein membrane is better than carvacrol membrane,but its transparency is lower than that of carvacrol membrane.When the content of thymol and carvacrol was 0%¹.5%,the color of the protein film showed almost no change.?4?The addition of thymol and carvacrol did not significantly change the structure of peanut protein isolate,but the addition of thymol and carvacrol resulted in the rough structure of the membrane.The thymol protein film with the same added amount has a more compact structure than the added carvacrol film,indicating that the thymol has better compatibility with the peanut protein isolate.?5?The content of total phenolics increased with the addition of thymol and carvacrol,and the content of total phenols gradually increased with the increase of thymol and carvacrol.Thymol and carvacrol at 0%¹.5%,the total phenolic content of protein film was significantly different?p<0.05?.?6?The addition of thymol and carvacrol significantly increased the DPPH,ABTS free radical scavenging ability and the ability of reducing Fe³⁺,and with the increase of thymol and carvacrol,the DPPH and ABTS of the protein membrane were free base scavenging ability and Fe³⁺reduction capacity gradually increased.?7?Under the same addition,the content of total phenols,DPPH and ABTS free radical scavenging ability and Fe³⁺reduction ability of thymol protein membrane was higher than carvacrol protein membrane.?8?By comparing the data of minimum inhibitory concentration,thymol has better bacteriostatic effect than carvacrol,and achieves a complete antibacterial effect at a lower concentration.However,compared with the data of the minimum bactericidal concentration,the germicidal activity of carvacrol is better than that of thymol.?9?The addition of the peanut protein film of thymol and carvacrol has the good effect of inhibiting the common spoilage bacteria and pathogens in the food.The effects of Staphylococcus aureus,Lactobacillus plantarum,Pseudomonas aeruginosa and Escherichia coli have inhibitory effect.Thymol and carvacrol at the dosage of 0.5%¹.5%,the antifungal ability of protein membrane on four kinds of bacteria was significantly enhanced?P<0.05?.Thymol peanut protein membrane on Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa and Lactobacillus plantarum antibacterial effect is better than the same amount of added carvacrol film.And the antibacterial effect compared:Staphylococcus aureus>Lactobacillus plantarum>Escherichia coli>Pseudomonas aeruginosa.In summary,peanut protein film added thymol compared with peanut protein film added carvacrol has good physical and structural properties and antioxidation and antibacterial properties.When the content of thymol is 1.5%,the performance of peanut protein membrane is good,and it has certain antioxidation and antimicrobial ability.It is important for the application of food preservation and peanut protein membrane.