Preparation And Characterization Of Chitosan-plant Protein Composite Films

In the food field, with the demand for food quality increasing and environmentalpollution problems caused by polyethylene and other plastic packaging, the development ofbiodegradable packaging has become a hot food industry research. This study aims to usechitosan and plant protein to make films, to improve poor mechanical properties of a singleprotein film. Prepare composite proteins film with antibacterial properties by adding Nisin,composite proteins film with a controlled release of Thymol and lysozyme，protein emulsionfilm with a good water vapor barrier properties.To study the relationship betweenmacroscopic mechanical properties, thermal properties, controlled release properties,antibacterial properties and microstructure.The main contents are as follows:At the conditions of pH=3, prepared composite antibacterial protein film successfullyby ultrasound technology. Observed by CLSM and SEM found that:when the CH: KPI is0.2to0.4, there remains a phase separation phenomenon. Tensile strength of CH-KPI compositefilm increases from2.96MPa to3.96MPa compared to the simple KPI film, elongation atbreak increases from5.68%to75.65%. CH-KPI film has antibacterial properties both toBacillus subtilis and Staphylococcus aureus, inhibition zones are increased from10mm to12.75mm,9.25mm increases to12mm respectively. Experiments show that its antimicrobialactivity is co-produced by Nisin and CH.Prepared CH-zein composite protein film, and the surface of the film is smooth.Observed by CLSM and SEM, the phenomenon of phase separation structure exists, when theratio of CH: zein is1:5, there is a clear structure of the microspheres. CH-zein film compositefilm combines the advantages of both CH and zein,tensile strength increases gradually from1.52MPa to17.71MPa, elongation at break increases from0.38%to29.94%, and thermalstability is between CH and zein. Thymol has a lower release proportion, lysozyme has ahigher release proportion, achieved the controlled release of both things.In order to improve the barrier properties of the CH-zein composite film, the soybean oilis added to prepare the CH-zein emulsion film. The results show that: when the oil rate is10%and50%, the film has best moisture barrier properties. Soybean oil not only improves the water vapor barrier properties of CH-zein film, also enables CH-zein emulsion film has alow wettability. The effect of soybean oil is decided by the distribution. The oil in the surfacehas a good barrier effect of the water, and the oil within the film expands the diffusion path ofthe water.In sμmmary, CH-KPI composite film and CH-zein composite film are very good toimprove poor mechanical characteristics of the single protein film.And adding Nisin made thecomposite film has a good antibacterial properties; CH-zein composite film has a goodcontrolled release effect; added oil to prepare emulsion film, which significantly increasesthe moisture barrier properties. The research is not only prepared plant protein compositefilms having antibacterial properties, controlled release properties and good water vaporbarrier properties respectively.And it is a theoretical guidance for the field of the films.Because all the substances are food grade, it has a broad prospect.