The Research Of Spray-ability Of Soy Protein Liquid And Hot-seal Performance For Vegetables Composite Paper

The heat sealability of fennel and celery based edible wrapping paper were studied, therheological properties and spray conditions of soy protein spray coating dispersions(SPSCD) were also investigated in this work.The main content and work are as follows:1) The vegetable composite paper was prepared under the condition of the pilot withthe raw materials of celery, fennel and soy protein. In order to seal edible wrapping paperbetter, multifunctional vertical packaging machine was used to heat sealing on vegetablecomposite paper with the method of transverse vertical extrusion sealing at the same time.Through the single factor test of temperature, the range of heat sealing temperature ofvegetables composite paper was determinated. And the heat sealability of soy protein-fennel and celery composite paper were studied at different temperatures.The results provedthat the heat sealing temperature of celery composite paper should choose below105℃when using double roller heating device of the packing machine for sealing the paper. Theoptimum heat sealing temperature of different vegetables composite paper are different.Theheat sealability of horizontal sealing and vertical sealing of soy protein-vegetable compositepaper bags have certain difference at the same temperature.The heat sealing performance ofsoy protein-celery composite paper was significantly better than that of soy protein-fennelcomposite paper, the average heat sealing strength of the former is generally3.245times asthat of the latter.2) The influence of polycarboxylic salt, sodium carboxymethyl cellulose (CMC) andglycerol addition on the rheological behaviour of soy protein spray coating dispersions(SPSCD) in steady and dynamic state were investigated by means of the response surfacemethod (RSM). The SPSCD showed a shear-thinning behaviour when the shear rate wasless than the200s-1, and the apparent viscosity of all the samples decreased with theincreaseof shear rate but the curve appeared undulate phenomenon between300s-1and1000s-1. The viscosity value reached an extreme again in the500s-1. The addition of CMChad significant influence on the flow index nHand storage modulus G. Polycarboxylicsalt had a significant effect on theloss tangent. The regression model of flow index and losstangent about three kinds of additives was obtained. It will be a reference for theperformance of the SPSCD which was prepared with different ratio of additives. These willprovide a basis for rheological parameters in spraying coated and then get uniform qualityvegetable composite paper.3）The influence of temperature and storage time on the steady shear flow propertiesand dynamic viscoelastic properties of the SPSCD were evaluated. The rheologicalproperties of SPSCD was determinated respectively under30,40,50and60℃. Thesteady state and dynamic rheological behavior of SPSCD were measured every half an hour in theprocess of constant temperature storage for three hours under40,50and60℃. The studyshowed that the consistency coefficient of SPSCD decreased and non-Newtonian indexincreased with the increasing of the temperature. There was no regularity of the influence ofstorage time on apparent viscosity of the SPSCD. The best formula of spraying liquid isobtained by dynamic rheological test. The distilled water is400g. Soybean protein isolatedis30g. Poly carboxylic acid salt is70g. CMC is70g and glycerin is30g. In terms ofcoating process, SPSCD should be according to the different performance to grasp thereasonable spraying time so as not to affect the fluidity of the SPSCD when it flowsthrough the nozzle.4) The calculation method of spray angle for SPSCD of the vegetable composite paperin the spraying process and the influence of spraying process parameters on atomizationangle of SPSCD were investigated. The spray angle of SPSCD for vegetable compositepaper was calculated using MATLAB software based on the image processing method. Theeffect of process parameters on the spray angle produced during spraying process was alsostudied based on response surface methodology analysis. Among the single factors, thespray flow rate and pressure had a significant effect on SPSCD. The interaction of sprayflow rate, air pressure and hydraulic pressure had a very significant effect on the sprayangle(0.0008＜0.05). The relational model between spray angle and process parameterswas built by analysis software and the optimal spraying conditions were identified. Thespray angle of SPSCD could reach138.26°, when the flow rate was48.04cc/min, the airpressure was1.99bar, and the hydraulic pressure was1.51bar.