Effects Of Freezing On Flaxseed Gum-Soybean Protein Edible Film And Its Mechanism

Soybean protein isolate(SPI)has excellent processing and film-forming ability,but its alone film-forming performance is poor,and it is often compounded with polysaccharides.Flaxseed gum(FG)has high viscosity and weak gel properties,and is widely used in meat processing.In this paper,SPI was used as the film-forming matrix to explore the effect and mechanism of different FG additions on the film.The film-forming liquid and film were frozen to study the effect of freezing on the film function,and to determine the mechanism of the change of film properties after freezing and the process of freezing.The change.Finally,the application of film-forming fluid in frozen meatballs was studied.The main results are as follows:First,the mechanical properties,stability,barrier properties,and optical properties as the measurement indicators,the fuzzy comprehensive evaluation method was used for cumulative weighting to explore the effect of FG addition on the functional properties of the membrane.When the addition amount of FG was 3%,the film thickness,tensile strength and elongation at break were increased by 80.00%,85.38%,and 285.78%,respectively,compared with the SPI film without FG.And the transmittance decreased by27.58%,130.08%,10.06%;its membership value was 0.2827,and the comprehensive performance of the film was the best.To explore the mechanism of action of different amounts of FG on SPI membranes.By exploring the characteristics of the film-forming fluids,it is found that all the film-forming fluids belong to pseudoplastic fluids,the elastic behavior is greater than the viscous behavior,and the storage modulus G’ is greater than its corresponding loss modulus G’;the infrared results show that when the addition of FG was 3%,the protein molecules formed hydrogen bonds with FG,and the electron microscope results showed that the change made the network structure of the membrane more compact;the maximum thermal decomposition temperature increased(317.84℃);when the addition of FG was 4 % and 5%,the excess FG affected the interaction between protein molecules,resulting in the appearance of lines on the membrane section,and the maximum thermal gravimetric decomposition temperature decreased.The effects of two different treatment methods,freezing of the film-forming solution and freezing after film-forming,on the membrane were investigated.Both freezing treatments were found to decrease the barrier capacity of the films.The highest tensile strength and elongation at break of the film-forming solution freezing group were 13.27MPa(FG-4)and 21.42%(FG-3),and the film-forming freezing group was 10.04 MPa(FG-3)and 19.49%(FG-5).The microscopic results show that freezing makes the film’s cross-section no longer tight,resulting in an increase in water solubility.The apparent viscosity showed an upward trend with the increase of FG addition.The infrared and particle size results indicated that large-sized insoluble aggregates were formed in the film-forming liquid after freezing.Finally,the film-forming solution was applied to study the properties of frozen meatballs in two ways: pouring and adding.The study found that the cooking and thawing loss rates of the addition group were lower than those of the untreated group(1.14%)and the maximum value of the pouring group(0.04%),and were positively correlated with the addition of FG in the film-forming solution.During thawing,the frost on the surface of the meatballs melted and combined with FG,resulting in an increase in the loss rate.The hardness of meatballs in the untreated group was 106.2 g,and the maximum hardness of the pouring group and the added group was 405.17 g and 108.93 g,which was related to the self-thickening property of FG and the weak gelatinity of the formed solution.In conclusion,the addition of FG improves the overall performance of the SPI film,And the application of its film-forming liquid in frozen meatballs improved the quality of frozen meatballs.Therefore,this study can provide a certain theoretical reference for expanding the application of FG in food,especially for the preservation of food frozen packaging and future research on the mechanism of action between polysaccharides and SPI.