Physical and mechanical properties of peanut protein films

The properties of peanut protein films were modified using physical and chemical treatments, and their effects on color, mechanical strength, water solubility and barrier to water vapor and oxygen of the films were investigated. Physical treatments consisted of heat denaturation of film-forming solution for 30 min at 60degreesC, 70degreesC, 80degreesC and 90degreesC, ultraviolet irradiation of films for up to 24h, and three ultrasound processes of film-forming solution. Chemical treatments consisted of addition of aldehydes and anhydrides. Heat curing at 70degreesC, ultraviolet irradiation for 24h, ultrasound for 10 min in a water-bath, and formaldehyde and glutaraldehyde addition caused a significant increase in the tensile strength of the films. The water vapor permeability (WVP) and oxygen permeability (OP) of the films decreased after heat denaturation and aldehyde treatment. OP also decreased with UV treatment. Heat curing was the most effective treatment, making the films stronger, more resistant to water and less permeable to water vapor and oxygen. (C) 2004 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.