US EPA

5220879 

Journal Article 

Physical characteristics of emulsified soy protein fatty acid composite films 

Rhim, JW; Wu, Y; Weller, CL; Schnepf, M 

1999 

1 

Sciences des Aliments
ISSN: 0240-8813 

19 

1 

57-71 

WOS:000079740800003 

Degradable composite films composed of soy protein isolate (SPI) and fatty acids were prepared. The effect of different types of fatty acids, i.e., lauric acid (LA), palmitic acid (PA), stearic acid (SA), and oleic acid (OA) at different concentrations (0, 10, 20, 30 or 40% w:w of protein) on color, tensile strength (TS), percentage elongation at break (E), water vapor permeability (WVP) and water solubility (WS) was studied. Generally, incorporation of fatty acids into SPI resulted in films that were thicker, more whitish, and less susceptible to shrinkage upon drying than the control SPI films. All composite films with more than 20% of fatty acids were heal sealable. Other physical properties of SPI-fatty acid composite films were greatly influenced by the type of fatty acid added and its concentration. TS decreased by adding fatty acids up to 20%, then increased with addition of fatty acids at more than 20%. Independent of type of fatty acid, E decreased as concentration of fatty acid increased. WVP of SPI film was significantly (P < 0.05) decreased by the incorporation of fatty acids with a reduction of about 260% for films with 40% PA and SA, respectively. WS of films with LA, unlike those with PA, SAI or OA, was adversely affected and the effect became more severe as the concentration of the fatty acid increased. 

biodegradable film; soy protein isolate; fatty acid; composite film