金针菇纳米纤维素复合凝胶的制备及结构表征

Preparation and Structural Characterization of Composite Gels Containing Flammulina velutipes Cellulose Nanofibril

采用热处理制备明胶(gelatin,GN)-结冷胶(gellan gum,GG)复合凝胶,通过持水性和溶胀度的测定优化GN和GG的添加量,在此基础上为进一步改善复合凝胶的性能,添加金针菇纳米纤维素(cellulose nanofibril,CNF)制得CNF-GN-GG复合凝胶,探究CNF对复合凝胶持水性、溶胀度、质构及流变性能的影响,并对其结构进行表征。结果表明:当GN添加量为5%、GG添加量为0.4%时,复合凝胶具有较好的持水性和溶胀度;CNF的添加增加了复合凝胶的持水性和溶胀度,提高了储能模量和损耗模量,同时也增大了复合凝胶的硬度、咀嚼性和胶黏性;通过测定复合凝胶的ζ电位和红外光谱发现,添加CNF使ζ电位绝对值增大、凝胶体系内的氢键增强、蛋白交联度增加,微观结构也显示CNF促进了凝胶网络的形成并使结构更加均匀、致密。由此表明,CNF的添加能够提升复合凝胶的性质并使凝胶体系更加稳定,CNF添加量为0.6%时较为适宜。

In this study,gelatin-gellan gum(GN-GG)composite gels were prepared by heat treatment,where the addition levels of GN and GG were optimized based on water-holding capacity(WHC)and swelling degree(SD).Furthermore,GN-GG composite gels added with Flammulina velutipes cellulose nanofibril(CNF)were prepared to improve the performance of GN-GG composite gels.Also,we investigated the effect of CNF on the WHC,SD,texture,rheology and microstructure of the composite gel.The results showed that the composite gel with 5%GN and 0.4%GG had good WHC and SD.The addition of CNF increased the WHC and SD and improved the storage and loss moduli,hardness,chewiness and gumminess of the composite gel.By measuring theζ-potential and infrared spectrum of the composite gels,it was found that addition of CNF increased the absolute value of theζ-potential,strengthened the hydrogen bond in the gel system,and increased the degree of protein crosslinking.The microstructure showed that CNF promoted the formation of gel networks and made the structure more uniform and compact.These findings show that the addition of CNF can improve the properties of composite gels and make the gel system more stable,and the suitable addition level of CNF is 0.6%.