Effect of Physical State of Fatty Acids on the Physical Properties of PGP-Based Emulsified Edible Film


1 Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran. P.O.Box:91775-1163

2 Department of Food Science and Technology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran. P. O. Box 51666-16471.


Many factors influence physical properties of edible composite films fabricated from hydrocolloids and lipids.
Novel edible emulsified films were made using PGP, glycerol and stearic (SA) or oleic (OA) fatty acids by Tween-80
addition and emulsification of filmogenic solutions. In this study, the effect of physical state of fatty acids on the pistachio
globulin protein (PGP) edible film properties was investigated. There were significant differences (p < 0.05) in the water
vapor permeability (WVP), tensile strength (TS) and opacity of emulsified films containing SA and OA. SA was more
effective than OA in WVP diminishing. The decrease values of 42 and 26.5% were observed for films with SA and OA,
respectively. TS and elongation at break values of films containing OA were lower than SA ones. Oxygen permeability
(OP) was evaluated indirectly applying peroxide value measurement. No significant difference was observed in the OP of
the films. Water solubility was not affected by the physical state of fatty acids either. The solid state of SA at the room
temperature caused the resultant films to be more opaque than OA containing films. Our findings indicated that PGP films
modified with SA had better physical properties special in WVP reduction than OA ones and could be potentially used for
primary packaging of foods with high water loss problem.