Effects of Protein Concentration, Plasticiser, and pH on the Properties of Protein Films from Whitemouth Croaker (Micropogonias furnieri) Residues

Abstract

ABSTRACTProteins have been used extensively because of their relative abundance, nutritional qualities, and film-forming ability with a good structural integrity and mechanical properties. This study investigated the effects of protein isolate and glycerol concentration and pH on the properties of protein films obtained from Whitemouth croaker (Micropogonias furnieri) residues. The films were evaluated for mechanical properties, thickness, water solubility, water vapor permeability (WVP), and morphological properties. The lowest water solubility of the films occurred at low pHs and low glycerol concentrations. The films had high elongation and higher tensile strength when prepared with higher concentrations of protein isolate, lower concentrations of glycerol, and at lower pHs. The WVP and thickness of the films had a low correlation coefficient. The films were rough and had irregular surfaces. These results indicated that protein isolates from fish of low commercial value can be used as a component of new polymeric films for packaging. However, more studies are needed to assess their barrier action against oxygen, thermal behaviors, and their performance in different types of packaging.