Preparation Of SPI/PVA/MMT Film And Its Application In Flammulina Velutipes And Beech Mushroom

As a natural organic raw material,soy protein isolate?SPI?has been widely used in food and other fields.With the increasing awareness of environmental pollution,the development of degradable materials has become a hot spot.SPI has become one of the raw materials of degradable materials because of its wide source and good film-forming properties.Polyvinyl alcohol?PVA?has become one of the methods to improve the properties of biomaterials.Montmorillonite?MMT?,due to its special structure,has strong adsorption and fixation and has been widely used in packaging materials.SPI,glycerol,PVA and MMT were used to prepare the composite membrane,which was used in the storage and preservation of agricultural products.It is of great significance to improve the technical level of preservation of agricultural products.SPI,glycerol,PVA and MMT were used as raw materials to prepare SPI/PVA/MMT films.The tensile strength,elongation at break,water vapor transmittance,oxygen transmittance,carbon dioxide transmittance,light transmittance,color,contact angle,moisture absorption curve of the film were taken as indexes by single factor test and orthogonal test.The optimum technological conditions for the addition of SPI,glycerol,PVA and MMT were obtained.Scanning electron microscopy?SEM?,X-ray diffraction?XRD?and thermogravimetric analysis?TGA?were analyzed.The film was applied to the storage and preservation of F.velutipes and Beech mushroom.The sensory quality and weight loss rate of mushroom during storage were measured.The changes of browning degree,soluble solids content,soluble protein content,ascorbic acid content and malondialdehyde content were studied.The main contents of the study are as follows:?1?The preparation of SPI/PVA/MMT films were studied.The results showed that the optimum conditions for the films were as follows:the content of soybean protein was 5%,the content of glycerol was 2.5%,the content of polyvinyl alcohol was 0.7%and the content of montmorillonite wa 0.7%.On the basis of single factor test,the comprehensive score index of order orthogonal experiment optimized the influences of various factors on the composite film.Finally,the optimum technological parameters of composite membrane were determined as follows:the content of soybean protein was 5%,the content of glycerol was 2.5%,the content of polyvinyl alcohol was 0.6%and the content of montmorillonite was 0.8%.The microstructure of SPI/PVA/MMT film was characterized by scanning electron microscopy?SEM?,X-ray diffraction?XRD?and thermogravimetric analysis?TGA?.A more compact three-dimensional and more smoother structure was formed in film with higher compatibility and thermal stability.?2?Selecting F.velutipes as the research object,the application of SPI/PVA/MMT film in F.velutipes was studied.The results showed that the sensory quality,soluble solids content,soluble protein content and ascorbic acid content decreased during storage.While weight loss rate,browning degree and malondialdehyde content increased during storage.Compared with the control group?SPI film?,the sensory quality,soluble solids content,soluble protein content and ascorbic acid content of F.velutipes were significantly higher,and weight loss,browning degree and malondialdehyde content were significantly lower.Sensory quality was 23.12,weight loss was0.82%,browning degree was 0.97,soluble solids content was 4.02%,soluble protein content was 5.73%,ascorbic acid content was 18.42?g·mg^-1and malondialdehyde was 17.94 nmol·mg^-1.?3?Selecting Beech mushroom as the research object,the application of SPI/PVA/MMT film in Beech mushroom was studied.The results showed that the sensory quality,soluble solids content,soluble protein content and ascorbic acid content decreased during storage.While weight loss rate,browning degree and malondialdehyde content increased during storage.Compared with the control group?SPI film?,the sensory quality,soluble solids content,soluble protein content and ascorbic acid content of Beech mushroom were significantly higher,and weight loss,browning degree and malondialdehyde content were significantly lower.Sensory quality was 23.21,weight loss was 0.82%,browning degree was 0.92,soluble solids content was14.02%,soluble protein content was 9.73%,ascorbic acid content was 5.42?g·mg^-11 and malondialdehyde was 1.80 nmol·mg^-1.