properties of a new edible film made of faba bean protein isolate

there has been a renewed interest in edible films made of renewable and natural polymers such as protein, polysaccharide and lipids. natural polymers derived from natural sources like food protein, offer the greatest opportunities because of their biodegradability and their ability to supplement nutritional value of foods. faba bean is a valuable source of protein and is cultivated in large quantities in iran. therefore, in this study, we investigated the potential of faba bean protein isolate (fpi) as a new protein source for preparation of an edible film and determined the effects of film forming solution ph and plasticizer concentration on the film properties. results showed that increasing the ph improved mechanical properties (tensile strength and elongation) and solubility of the films, but, caused the water vapor permeability (wvp) and lightness of the films to decrease. plasticizer concentration did not affect wvp over the studied range. elongation and solubility of the films increased and the tensile strength decreased by increasing plasticizer content of the film forming solutions. the lowest wvp and the highest tensile strength were observed at ph 12 and 40% (w/w of fpi) glycerol concentration.