High pressure homogenization of mechanically deboned chicken meat protein suspensions to improve mechanical and barrier properties of edible films

The effect of high pressure homogenization (HPH) on edible films obtained from mechanically deboned chicken meat proteins (MDCM-P), a by-product of poultry industry, was investigated. Film forming suspensions (FFS) were prepared at 4% protein concentration and homogenized up to 150 MPa. FFSs were characterized in terms of particle size and steady shear rheology, whereas optical, barrier, mechanical and microstructural properties of resulting films were determined. Particle size of suspensions decreased as homogenization pressure increased, and suspensions treated up to 50 MPa showed shear thinning behavior with higher yield stress, while higher HPH treatment caused Newtonian flow. Shear stress-shear rate data were fitted to Herschel-Bulkley model. HPH treatment improved film appearance, and all films displayed good barrier properties against UV light which induces lipid oxidations in foods. The decreasing particle size of HPH treated MDCM-P suspensions up to 100 MPa caused lower water vapour permeability (WVP) and higher tensile strength (TS), and these results were also confirmed by film micrographs which had homogeneous, non-porous and un-cracked surface images. However, porous cross sectional images were observed from 150 MPa HPH treated films. FTIR spectra of films showed similar backbone structure, and the secondary structure of films was analyzed from the area of the deconvoluted Amide I peak, which changed significantly. ss-sheet and ss-turn contents of films showed high correlation coefficients with TS and EAB values. It can be concluded from this study that HPH applications up to 100 MPa can enhance the mechanical and barrier properties of films.