Study On Preparation And Properties Of Indica Rice Nano-starch/sodium Alginate Blend Edible Films

This paper took Indica Rice,sodium alginate as the research objects,explored the preparation of rice nano-starch,the properties of nano-starch/sodium alginate solutions and blend edible films,provided some ideas for the deep processing of the main crops-Indica Rice in Hunan and theoretical basis for the preparation of a new type edible film based on nanocomposite polymer.The main results of this paper are as follows:1.Optimal extraction of Indica Rice starchThe Indica Rice starch was extracted and purified by alkali,enzymatic,ultrasonic assisted enzymatic methods.Ultrasonic assisted enzyme raised the rice starch extraction yield significantly to 93.6%and the protein reduced to 0.18%.2.Characterization of Indica Rice nano-starchStarch was debranched and recrystallized by pullulanase to prepare starch nanoparticle,the NS15 can be dispersed uniformly in water.The influence of different starch concentration on nano-starch was compared:the highest yield was 65.68%,when starch concentration was 15%;the surface morphology of nano-starch was analyzed through SEM,the particle sizes of the NS5,NS10,NS20 were higher and nonuniform;NS15 had smaller and uniform particle size;the particle sizes were analyzed by Nano Measurer 1.2 software,the average size of NS5 was 191.5 nm;the average size of NS10 was 199.2 nm;the NS15 had the minimum average size 94.6nm;the average size of NS20 was 198 nm.The structure of nano-starch was analyzed by FTIR,the hydrogen bonding force was strong between molecules,the nano-starch had a tight structure.The intermolecular force of NS15 was the strongest.3.Study on Indica Rice nano-starch/sodium alginate blend film forming solutions4%sodium alginate film forming solutions were prepared,then added 0%,10%,20%,30%wt nano-starch to the solutions,the static and dynamic rheological properties on blend film forming solutions were investigated:in the steady shear rheological test,the BFS0 didn't exist thixotropy,at the same shear rate,BFS10,BFS20,BFS30 were thixotropic;the static rheological datas of nano-starch/sodium alginate blend film forming solutions were model fitted by Power Law model,4 kinds of solutions in steady shear rheological tests were shear thinning,which showed pseudoplastic characteristics and increased with the increase of nano-starch concentrations,BFS30 was the strongest;the effect of temperature on nano-starch/sodium alginate blend film forming solutions was investigated by Arrhenius equation:the activation energy of pure sodium alginate solution(BFS0)was 22.27 kJ/mol,the activation energy were significantly lower than the BF0 when joined the nano-starch(BFS10,BFS20,NFS30),it meaned the apparent viscosity of BFS0 was more sensitive to temperature than that solutions with nano-starch,BFS30was the lowest.4.Study on the properties of Indica Rice nano-starch/sodium alginate blend filmsNanocomposite edible films were prepared by adding a certain proportion of nano-starch to the sodium alginate solutions,the improvement of mechanical and barrier properties of blend edible films was investigated.The results were as follows:the adding of nano-starch had no significant effect on film thickness;the water solubility,transmittance of the NSF10 showed good performance,water vapor transmission rate was low for 0.6511×10~-1212 g·m·(m~2·s·Pa),the mechanical property was improved.The tensile strength of NSF20 was the highest for 72.1106 MPa,about1.5 times of the NSF0;and oxygen barrier of NSF30 was highest.The microstructure of blend films was characterized by FTIR,there were good compatibility with strong hydrogen bonding between the components of nano-starch/sodium alginate blend edible films,the interaction of components of blend films NSF10 was the strongest,and had the best compatibility.