Preparation And Film-forming Proerpties Of Polysachahride Nanoparticles From Flammulina Velutipes

Nanoparticles shows the distinctive properties compared with ordinary particles,making a large potential in nanotechnology and nanomaterials. In food industry,nanotechnology in food process and packing has become an important role.In this study, by following three different pretreatments (hot water, cold alkali, hot alkali), insoluble polysaccharide nanoparticles were prepared from Flammulina velutipes by wet milling and high pressure homogenization and their properties were investigated. The resultant nanoparticles were characterized by Scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray (XRD), Fourier transform infrared (FTIR), viscosity, and thermal gravimetric analysis (TGA). Flammulina velutipes nanoparticles can be obtained by alkali pretreatment with wet milling and high pressure homogenization, and the diameter of the majority particles nearly ranged from 100 to 300 nm. The three nanoparticle dispersions presented non-Newtonian, shear thinning fluids with viscosity. At 68-100 Hz, the cold alkali and hot alkali sample showed the inferior storage moduli (G’) and loss moduli (G") than hot water sample. Moreover, these particles showed a decrease in thermal stability after alkali treatment.Furthermore, influence of enzyme treatment on these particles (hot water, proteinase and amylase; (3-glucanase) were also studied. Flammulina velutipes nanoparticles can be obtained by enzyme pretreatment with wet milling and high pressure homogenization, the diameter of the majority particles nearly ranged from 50 to 300 nm. The three nanoparticle dispersions presented non-Newtonian, shear thinning fluids with viscosity. At 7-100 Hz, the glucanase sample showed the larger storage moduli (G’)and loss moduli (G") than proteinase-amylase and hot water sample, suggesting a superior viscoelasticity. The thermal stability were inferior but an elevated in cation exchange capacity after enzyme treatment.Flammulina velutipes edible film was prepared by the hot water pretreatment after three different treatment: PFI (2 times), colloid mill (2 times), low pressure homogenization (20 mPa), high pressure homogenization (100 mPa). The obtained edible films were detected with the Scanning electron microscopy (SEM), DSC (differential scanning calorimetry),thermal gravimetric analysis (TGA), tensile strength (TS), elongation (E), light transmission and water vapor permeability (WVP). The results showed that the film with high homogenization treatment has an elevated in appearance, light transmission, water resistance and thermo properties. Furthermore, the tensile strength, elongation, water vapor permeability was 0.230±0.005a Mpa,2.697±0.132a %, 0.900×10-5±0.030x10-5c g/(m2·24h)respectively. Moreover, the DSC and TG results showed an elevated in thermal stability after homogenization treatment.All in all, FNP prepared by alkali and enzyme treatment with wet milling and high homogenization showed nanoscale, and the edible film, had excellent mechanical and barrier properties, suggesting potential applications in the food industry.