Preparation And Characterization Of Nanofiber Cellulose-protein Gels

Nanofiber cellulose(NFC),a new nano material,has attracted much research interest in hydrogel related areas.Due to its nano size and related distinguished characteristics,such as its high aspect ratio,specific surface area,excellent mechanical,physical and chemical properties,NFC has potential applications in food processing,drug delivery and other industrial fields.This paper studied the reinforcement of NFC in gelatin and salt-soluble protein systems,the characterization of these gel systems was investigated,thereby providing technical reference for the application of NFC in food gel.In this paper,the rheological properties and structure of NFC aqueous dispersion were studied firstly.A pseudo-plastic(shear thinning)behavior was confirmed for the NFCdispersion,and this behavior was more obvious as NFC concentration increased.The impact of NFC on gelatin hydrogel performance involving strength,rheology,microstructure was investigated as the gelatin-NFC gels were produced with 5%,10%,and 15%of NFC on the gelatin solution basis.A marked influence of NFC on gelatin gel performance was observed in this study,based on the percolation mechanism.The addition of NFC significantly enhanced compactness of three-dimensional network structure of gelatin gel,however,an NFC amount of 15%and higher caused more inhomogeneous aggregation.Depending on NFC concentration(?10%),the addition of NFC increased the hardness but reduced the elasticity of gelatin gel at 10? and gelatin solution transformed from the Newtonian action into pseudoplastic behavior at 60?,with a marked increase of viscosity.For dynamic rheology,NFC changed the temperature of the sol-gel and gel-sol transition of gelatin,and even no obvious transformation occrued as ?10%NFC used.NFC at concentrations of 0%,2.5%,5%,7.5%,and 10%was introduced into salt-soluble protein(SSP)for chicken breast.The effects of carboxylated nanofiber cellulose(NFC)on SSP model system with or without transglutaminase(TG)crosslinking were investigated.The results indicated that NFC contributed to the improvement of water-holding capacity of gels,but this effect was insignificant when TG was added into the composite gel.The presence of NFC enhanced gel strength in the model system with TG.Based on scanning electron micrographs(SEM)and confocal laser scanning micrographs(CLSM),the addition of NFC to SSP produced a hydrogel in the form of a semi-IPN(Interpenetrating Polymer Network).In the presence of TG,this structure was more compact.No strong intermolecular interaction between SSP and nanocellulose was evident from FTIR spectra,suggesting the occurrence of physical entanglement of NFC in the composite gel.E4M and E15LV,two kinds of hydroxypropyl methyl cellulose(HPMC)with different molecular weights,were introduced into salt-soluble protein with 7.5%NFC.The impact of this reversible thermoforming matieral on SSP performance was investigated.E4M and E15LV had different influence on the texture of gels,especially on hardness.The higher concentration of HPMC,the higher cooking lose rate of the gel.The addition of E4M,HPMC with higher molecular weights,led to the higher cooking loss rate.The increasing of cooking loss rate caused by HPMC could be alleviated by working with NFC.In conclusion,the presence of NFC can improve gelation properties of gelatin and chicken salt-soluble protein,depending on its concentration and the gel structure,thereby providing potential applications in the food industry.