Development Of Soy Protein Isolate/Chitosan Edible Films And Their Shape Memory Properties

This thesis mainly studied the preparation technics and intelligence of the compound edible film based on soy protein isolate and chitosan, which was part of the project"Investigation of Intelligent Structure of Protein-Based Edible Biopolymers". This project was financially supported by Grant from Hi-Tech Research and Development Program of China and International Corporation Project of Jilin Provincial Science&Technology Department Development Program.Recently, the polymeric materials of good environmental acceptability have received increasing attention. Edible packaging films have become a major hot spots in food, pharmaceuticals and packaging, and other fields because of their extensive source of raw materials, edible property, non-polluting, and other advantages. Modern packaging materials have been developing in intelligent investigation, which is the materials have certain intelligent properties, in addition to some essential project characters, such as shape memory, self diagnosis, adaptive, self restoration and so on.In this thesis, the author take the soy protein isolate and chitosan as film-forming material, by the effect assisting the agent and technologic conditions, develop out the advantageous function intelligence composite film, satisfied wrapping material.The main contents and conclusions are as follows:1) The concentration of the film-forming liquid plays an important role in determine film'performance, too big or too small concentration all go against film-forming. In this experiment, the choosing of its concentration is 2%.2) Through the single factor experiment, the study ascertain the technical conditions of film's preparation as follows: the commercial mix of the soy protein isolate and chitosan is 3:3, the proper glycerin dosages are 2.0%, proper film liquid pH value is 3, the best drying temperature is 60℃. 3) The author used computer to test that design procedures carries out an optimization on composite film system film handicraft directly, adopt the SPSS software to carry out regression analysis on test result, gets two return models taking tensile strength and tearing elongation rate as index and. Be informed that two return models and experiment data fit from verifying an experiment, fairly good. Owe the experiment having tested design procedures, having fallen off number of times, may get fairly good system film technological conditions.4) The author tested the expanding rate designing dissolving getting the composite film under different pH value by homogeneous orthogonality, the expanding rate curve diagram makes an explanation the composite film has the flexibility principle, comes to a conclusion and according to dissolving: This is that are what self's molecular structure decides from composite film mainly, the soy protein isolate and chitosan forms the big molecule polymer after getting together, owe a polymer the network structure taking form in the film, electrified condition of base group in network structure is different, the hydrophily leading to a film is different, and then can by the fact that changing pH value makes the composite film display flexibility under different pH value.5) The study give the optimum factor level combination as A2B3C2D2, which is takes the water-preserve rate as test index. The most important factor for water-preserve rate is glycerol content, the next is commercial mix of film-forming material and the drying temperature. However, pH has less effect within the range of experiment.6) The study give the optimum factor level combination as A1B2C3D2, which is takes deformation preserve rate as test index. The most important factor for deformation preserve rate is the pH of film liquid; the next is glycerol content and commercial mix of film-forming material. However, drying temperature has less effect on deformation preserve rate within the range of experiment.7) Methods used to measure the glass transition temperature (Tg) of food system were reviewed in this article including theory calculate, differential scanning calorimetric (DSC), dynamic mechanical thermal analysis (DMTA), nuclear magnetic resonance (NMR), and etc.8) The author passed the single factor experiment, taked the deformation recovery rate as testing index. The single factor experiment showed that the deformation recovery rate was affected by the amount of soy protein isolate, glycerol concentration and recovery temperature. The more soy protein isolate, glycerol content and recovery temperature, the bigger deformation recovery rate. The deformation recovery rate is more than 95%.The innovation points of the thesis:1) This thesis studied the film-forming mechanism based on soy protein isolate and chitosan, then analysed the best technical conditions of film-forming.2) The author optimized of preparation conditions for composite film using random-arranged experimental designs with aid of computer3) The author studied the soy protein isolate / chitosan composite film temperature sensitive property and pH sensitive property.