%0 Journal Article %A Ye, Xinchen %A Junel, Kristina %A Gällstedt, Mikael %A Langton, Maud %A Wei, Xin-Feng %A Lendel, Christofer %A Hedenqvist, Mikael S. %D 2018 %T Protein/Protein Nanocomposite Based on Whey Protein Nanofibrils in a Whey Protein Matrix %U https://acs.figshare.com/articles/journal_contribution/Protein_Protein_Nanocomposite_Based_on_Whey_Protein_Nanofibrils_in_a_Whey_Protein_Matrix/6019925 %R 10.1021/acssuschemeng.8b00330.s001 %2 https://acs.figshare.com/ndownloader/files/10830638 %K hydrogen-bonded β- sheets %K Whey Protein Nanofibrils %K extent exfoliation %K nanocomposite films %K β- sheets %K nonfibrillar protein matrix %K content %K Tensile tests %K glycerol-plasticized films %K protein film %K glycerol distribution %K X-ray diffraction %K undulation %K Whey Protein Matrix %K PNF material %K protein nanofibrils %X This article describes nanocomposite films with separately grown protein nanofibrils (PNFs) in a nonfibrillar protein matrix from the same protein starting material (whey). Tensile tests on the glycerol-plasticized films indicate an increased elastic modulus and a decreased extensibility with increasing content of PNFs, although the films are still ductile at the maximum PNF content (15 wt %). Infrared spectroscopy confirms that the strongly hydrogen-bonded β-sheets in the PNFs are retained in the composites. The films appear with a PNF-induced undulated upper surface. It is shown that micrometer-scale spatial variations in the glycerol distribution are not the cause of these undulations. Instead, the undulations seem to be a feature of the PNF material itself. It was also shown that, apart from plasticizing the protein film, the presence of glycerol seemed to favor to some extent exfoliation of stacked β-sheets in the proteins, as revealed by X-ray diffraction. %I ACS Publications