Preparation Of Nano Modified Polyvinyl Alcohol (PVA) Anti Oxygen Composite Packaging Film And Its Application In Fresh Cut Yam

In recent years,with the promotion of China’s supply side reform,the improvement of food quality is also more and more concerned by consumers,high-quality food is a strong guarantee for the health and safety of the people.Food processing of fresh cut fruits and vegetables is a new commercial,very good conforms to the efficient and convenient demand,how to improve the efficiency of fresh cut production,but also can ensure the health and safety of fresh cut fruits and vegetables more,the food processing is the main development direction in the future.The fresh cut yam cut after exposure to the air,it is prone to browning,affecting food quality,the main reason is that the oxygen and enzymes under the action of phenolic compounds in yam browning,so if they can effectively isolate oxygen and inhibit the activity of enzymes,can be very good to solve the browning of fresh cut yam the problem.According to the characteristics of the process of fresh cut yam,combining with the research direction of the postgraduate stage,isolation on oxygen for fresh cut yam production and processing stage of the pretreatment liquid cleaning preservation stage and the final packaging stage,and the activity of enzymes were inhibited.In the pretreatment stage,a new preservative solution was prepared with salt,sucrose and acetic acid.In the packaging stage,using nano mica powder(Ser)modified PVA substrate to enhance the mechanical strength of PVA film and improve its breathable,and then add a certain proportion of 4-hexylresorcinol(4-HR)and citric acid(CA)on PVA nano materials prepared by anti oxidative modification agent.The preparation of nano modified polyvinyl alcohol(PVA)antioxidant composite packaging film,and explores the two kinds of antioxidant effects on properties of nano modified polyvinyl alcohol packaging materials,and its application in the experiment of preservation of fresh cut yam,under normal temperature,to study its preservation effect.The main conclusions are as follows:(1)The use of domestic common seasoning(salt,sugar,vinegar reagent)on the preservation of fresh cut yam color,can be seen from the experimental results,the compound use of sucrose,vinegar and salt dipping liquid color keeping effect is obvious,at the end of the experiment of complex data analysis of the best combination group,i.e.with sucrose,salt,vinegar concentrations were 4,2 and 3 g/L mixed solution for 10 min after the treatment liquid has the best color keeping effect.(2)PVA/Ser nano modified thin films were successfully prepared by solution casting method.SEM characterization proves that moderate mica powder and PVA good compatibility when mica powder addition is 3%,the maximum tensile strength of nano composite films,is 26.4% higher than that of pure PVA film strength,mica powder was added to reduce the optical properties of PVA thin films,the addition of mica powder can enhance the barrier properties of PVA thin films.When the content of Ser is 5% nm PVA film modified O2 transmission rate to a minimum,the water vapor permeability is the minimum.The thermal stability of pure PVA films was improved by addition of mica powder.(3)Respectively adding a certain proportion of 4-hexylresorcinol(4-HR)and citric acid(CA)containing 4% mica powder of nano modified PVA thin film oxidation modification,were prepared with 0.6%CA,0.6%4-HR and nano 0.3%CA+0.3%4-HR modified PVA composite thin film anti oxygen,mechanical properties of nano modified PVA antioxidant composite films the same without oxidation treatment of nano PVA film modified by comparison,and verify the anti oxygen performance of anti oxygen composite films modified by nano,through the experimental results can be obtained: 4-HR and CA are compatible with the PVA film is very good,without causing too much influence on the tensile strength of the case,but also a certain reduced O2 film transmittance and water vapor permeability theory,make the film better antioxidant properties.The DPPH radical scavenging rate test showed that the nano modified PVA oxidation resistant composite film had antioxidant activity,and the antioxidant property of the 4-HR film was better.(4)The prepared nano modified PVA composite thin film anti oxygen applied to fresh cut yam fresh color protection research,under the condition of normal temperature,with the increase of packaging of fresh cut yam days,weight loss rate,Vc content,hardness,soluble solids,color and polyphenol oxidase(PPO)activity determination of relevant indicators and found that the nano modified PVA antioxidant composite film compared with the control group with anti oxygen fresh-keeping effect is very good,from the comprehensive anti oxygen fresh-keeping analysis,CA nanoparticles containing 0.3% 4-HR and 0.3% modified PVA composite thin film anti oxygen fresh-keeping effect optimal.