Preparation And Properties Of Chitosan/ Tea Polyphenol Coated Non-woven Fabric As Active Packaging Material

With the improvement of life quality and the diversification of food in the production,circulation,storage and consumption,consumers have higher requirements of food safety quality,packaging,flavor and convenience and so on.Therefore,the research and development of new technology are quickly conducted.Meanwhile,active packaging has become a major trend in the field of research at home and abroad,because of its unique advantage that the active packaging material is not only the barrier between the product and the external environment,but also combines advanced food packaging and material science and technology,and maintains the quality of the packaged food to the utmost.At present,scholars at home and abroad have been done many research to the development of active packaging materials with plastic film substrate,and they mainly study on the antibacterial activity of packaging materials,however the antioxidant activity is relatively small,what is worse,the application of active packaging in China’s commodity packaging has not yet been popularized.Besides,in the study of active packaging materials,the commonly used substrates are plastic film,edible materials,paper and so on.However,it has not been reported that the non-woven fabrics has low price,excellent performance and wide adaptability of environmental protection.Therefore,the preparation and properties of chitosan/tea polyphenols coated non-woven fabric as a new type of active packaging materials are still a new research topic.And it takes into account antibacterial,antioxidant,mechanical strength and other performance indicators,the development of antioxidant,antibacterial and other complex active function of packaging materials,comprehensive inhibition of food spoilage,extend the shelf life of food,enhance the mechanical properties of the material,so that it is more widely applied to the actual life.In this paper,the first stage,hydrophilic modified on hydrophilic polypropylene non-woven fabric modified as active packaging base material to improve the hydrophilic properties of the substrate,which is more convenient to combine with chitosan and tea polyphenols.In this stage,the hydrophilic modification scheme of the corrosion solution formed by sulfuric acid and ferric chloride was used for reference.The water absorption and contact angle were used to evaluate the hydrophilic properties of the substrate.The hydrophilic properties,mechanical properties and barrier properties of the modified base materials were compared.The experimental results show that the water absorption of the modified base material is bigger,and the contact angle is smaller.The hydrophilicity of the substrate is obviously improved.The mechanical properties of the modified hydrophilic modifier before and after hydrophilic modification have no obvious change,and the barrier property is slightly weakened.The SEM showed that the surface modification of polypropylene non-woven fabric before the relatively smooth and clear etching and surface sediments of the concave,more suitable for attachment of chitosan and tea polyphenols.The FTIR showed that the hydrophilic group hydroxyl group（-OH）was introduced into the corrosive liquid after the action of the corrosive solution,which further explained the reason for improving the hydrophilicity of the substrate.In a word,the hydrophilic modification of the substrate does not weaken other excellent properties of then on-woven fabric while improving the hydropili-city.The second stage,preparation of composite material of chitosan and polypropylene non-woven fabric by dipping shaking table,and then,to study the effects of chitosan content（0%,1%,1.5%,2%,2.5%）on the properties of the materials were investigated by means of hydrophilic test,FTIR,TAG,SEM,tensile strength test,barrier test and other characterization methods.The results show that the content of chitosan has obvious influence on the properties of the composite.In detail,hydrophilic properties were improved with the increase of chitosan content,without chitosan,the contact angle of the material was 64.25 degrees.As chitosan was added,the contact angle changed to 35.23 degrees.Compared with the blank control,the tensile strength of chitosan decreased from 1.05 KN/m to 0.85 KN/m,and then decreased with the increase of chitosan content.When the content of chitosan is 1.5%,the tensile strength of the material is 0.99 KN/m,and the barrier property also increases with the increase of chitosan content.SEM showed that the surface of the composite formed uniform coating with the increase of chitosan content,the smoothness was improved obviously,and the reason for the improvement of barrier property was explained.The results show that when the content of chitosan is 1.5%,the composite has the best comprehensive properties.The third stage,the preparation of chitosan/TP coated non-woven active packaging material under constant temperature and humidity conditions by dipping method.Then,the chitosan content is fixed,change the content of tea polyphenols（0%,1%,1.5%,2%）.Then test the binding fastness of materials,adding amount of tea polyphenols obtained the influence of the compound degree of mixing liquid on the non-woven fabric.And the antioxidant,mechanical,thermal stability and barrier properties of the tea polyphenols were tested,and the influence of the amount of tea polyphenols on the properties of the materials was analyzed and compared.At the same time,SEM,FTIR,TAG and other means were used to analyze the influence of different ratio of chitosan/tea polyphenols on the properties of the material.Finally,to test the activity of this material that the red bayberry fresh-keeping test,antibacterial test of Escherichia coli,compared to the content of tea polyphenols on the active packaging freshness,antibacterial effect.The results indicate that there is an obvious effect,the performance of the content of tea polyphenols on the activity of packaging materials as follows:with the increase of TP content,antioxidant activity increased significantly when the content of TP to 1.5%after the free radical scavenging rate tends to slow.The permeability and pore size of the material are smaller,the barrier property is improved,and the tensile index of the material decreases.FTIR showed that the addition of chitosan to the new hydrophilic group-OH and-NH₂,and the addition of tea polyphenols did not appear new absorption peaks.They existed in the form of dispersion and adsorption without bond reaction,but increased the compatibility between chitosan and substrate.The experimental results showed that the preservation effect of the materials was obvious,during waxberry preservation at room temperature from the 4d extended to 8d to 10d.It also has a good antimicrobial activity,and when the TP content is 1.5%,the antibacterial rate is highest for99.1%.It is concluded that the performance of the active packaging material is the best when the content of tea polyphenol and chitosan is 1.5%.