| Biodegradable packaging materials are green packaging materials developed from natural materials,such as polysaccharides and proteins.Packaging based on natural materials can be completely degraded by microorganisms in a certain period of time and under certain conditions.It is not any burden to the environment.Therefore,the development of biodegradable packaging materials is very important to solve the problems of resources and ecological environment.Soluble soybean polysaccharide(SSPS)is a kind of water-soluble dietary fiber extracted from bean dregs,which has good emulsification,film-forming,acid,alkali and heat resistance,and is widely used in lactic acid drinks,protein drinks,baking and other food industries.Because of this excellent film-forming properties,soluble soybean polysaccharide has been concerned in the field of packaging materials.However,the mechanical properties of pure soluble soybean polysaccharide films are poor,without antibacterial,and poor water resistance.To overcome these shortcomings,this study from the application requirements of food packaging,add gelatin was studied the influence of physical and chemical properties of soluble soybean polysaccharide composite films,Relationship between heat sealing condition and heat sealing performance of soluble soybean polysaccharide composite films,the effect of microfibrillated cellulose and nano-zinc oxide on the physical properties and antibacterial properties of composite films were discussed,sodium periodate was used modified for soluble soybean polysaccharide,explored its ability to crosslinked gelatin.The main contents of this paper are as follows:The effects of gelatin on the structure and properties of soluble soybean polysaccharide composite films were studied,the relationship between composition and mechanical properties,barrier properties,thermal stability and other physical properties of the composite films were emphatically investigated.The results showed that the tensile strength of soluble soybean polysaccharide/gelatin composite film was significantly higher than that of pure soluble soybean polysaccharide film.At thesame time,the addition of gelatin also enhanced the thermal stability of the composite films,and improved the water sensitivity and water vapor transmittance of the pure soluble soybean polysaccharide film.With the increase of gelatin content,the heat sealing strength of composite film has been increased obviously.The effects of pig skin and fish skin gelatin on the heat sealing properties of soluble soybean polysaccharide film was studied.The effects of heat sealing temperature,heat sealing time and heat sealing pressure on heat sealing strength and heat sealing efficiency of gelatin/soluble soybean polysaccharide composite films were investigated by single factor experiment.The results show that the heat sealing temperature and heat sealing time have significant effects on the heat sealing strength and heat sealing efficiency of the composite films,but the heat sealing pressure has little effect on the heat sealing strength and heat sealing efficiency.With the addition of gelatin,the thermal stability and flexibility of composite films were improved,so the heat sealing strength and heat sealing efficiency of composite films were improved.Soluble soybean polysaccharide film was modified by microfibrillated cellulose and nano-zinc oxide,the enhancement effect of microfibrillated cellulose on soluble soybean polysaccharide film was studied,the influence of nano-zinc oxide on antibacterial properties of composite film was analyzed,and the structure and properties of composite films were studied.The results showed that the mechanical properties,thermal stability and UV barrier properties of composite films were improved by the addition of microfibrillated cellulose.The addition of nano-zinc oxide made the composite films show obvious antibacterial activity against escherichia coli and staphylococcus aureus.The oxidized soluble soybean polysaccharide was obtained by using sodium periodate.The effects of oxidation time and sodium periodate dosage on the content of aldehyde in the oxidized soluble soybean polysaccharide was investigated.The results showed that the prolongation of oxidation time and the increase of the amount sodium periodate significantly increased the content of aldehyde group in the oxidized soluble soybean polysaccharide.The oxidation time was 4 hours,and the content of aldehyde group was the highest when the mass ratio of soluble soybeanpolysaccharide to sodium periodate was 1:2.The presence of aldehyde group was also confirmed by Fourier infrared spectroscopy.The effects of oxidized soluble soybean polysaccharide on the structure and properties of gelatin films were studied.The crosslinking gelatin film of oxidized soluble soybean polysaccharide was prepared and the effects of the amount oxidized soluble soybean polysaccharide on the mechanical properties,light transmittance and other physical properties of gelatin films were investigated.The results showed that the aldehyde group of oxidized soluble soybean polysaccharide and the amino group of gelatin occured Schiff base reaction.With the increase of the amount oxidized soluble soybean polysaccharide,the mechanical properties of crosslinked films were improved significantly and the deformation recovery ability was excellent. |
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