Development and characterization of egg yolk and egg yolk fractions edible films

摘要

New edible films were developed using egg yolk, yolk fractions (granules and plasma) and their purified protein fractions as a raw material. All films were characterized by means of texturometry, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TGA). Regarding texture analysis, protein content was the key parameter in case of films prepared with non purified yolk and yolk fractions, whereas the conformation of the proteins was the significant factor when purified yolk and yolk fractions were employed. FTIR measurements proved that heating steps during the film preparation had a determinant effect on the secondary structure of plasma and its protein fraction. In all films, micrographs were similar showing heterogeneous surfaces with round-shaped particles, excepting purified granule film, which exhibited rough surface organized by layers. TGA indicated a decrease in the thermal stability of non-purified yolk and fractions in comparison to the purified ones. (C) 2017 Elsevier Ltd. All rights reserved.