School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
Int J Biol Macromol. 2019 Apr 1;126:1266-1272. doi: 10.1016/j.ijbiomac.2018.12.254. Epub 2018 Dec 27.
Whey Protein Concentrate (WPC) has been researched as food packaging materials in recent years. However, WPC films own the drawbacks on the barrier ability to water vapor and mechanical properties. In the presented work, Transglutaminase (TGase) and different concentrations of nanocrystalline cellulose (NCC) (0-15% wt. of WPC) were incorporated into the WPC matrix to prepare WPC-NCC composite film, their transmittance, mechanical properties, water vapor permeability and microstructures were investigated and compared with that of WPC films. Results illustrated that NCC as fillers in the protein network blended with WPC markedly improved the mechanical properties. The tensile strength of composite film increased from 1.3 to 3.15 MPa as NCC increased to 15% wt. of WPC. Moreover, TGase took a promoted effect on mechanical properties. The composite film achieved a maximal elongation value of 86.7% when TGase was added at 9 U/g of WPC. SDS-PAGE confirmed that TGase positively facilitated the formation of the protein polymers. FTIR analysis observed conformational changes caused by TGase in the films and implied the interaction between WPC and NCC. Results suggest NCC and TGase have a synergy effect on mechanical properties of WPC based film, and TGase-crosslinked WPC-NCC composite film can be applied as an alternative packaging material.
近年来,乳清蛋白浓缩物(WPC)已被研究用作食品包装材料。然而,WPC 薄膜在水蒸气阻隔能力和机械性能方面存在缺陷。在本工作中,将转谷氨酰胺酶(TGase)和不同浓度的纳米纤维素晶体(NCC)(0-15%wt.WPC)掺入 WPC 基质中,制备 WPC-NCC 复合膜,研究并比较了它们的透光率、力学性能、水蒸气透过性和微观结构与 WPC 膜。结果表明,NCC 作为填料在蛋白质网络中与 WPC 混合显著提高了力学性能。随着 NCC 增加到 WPC 的 15%wt.,复合膜的拉伸强度从 1.3 增加到 3.15MPa。此外,TGase 对力学性能有促进作用。当 WPC 中添加 9U/g 的 TGase 时,复合膜达到了 86.7%的最大伸长率。SDS-PAGE 证实 TGase 有利于蛋白质聚合物的形成。FTIR 分析观察到 TGase 在薄膜中引起的构象变化,并暗示了 WPC 和 NCC 之间的相互作用。结果表明,NCC 和 TGase 对 WPC 基膜的力学性能具有协同作用,并且 TGase 交联的 WPC-NCC 复合膜可用作替代包装材料。