CAST FILMS FROM SOY PROTEIN ISOLATES AND FRACTIONS

Glycerol-plasticized soy protein films were cast from alkaline aqueous film-forming solutions of laboratory-prepared 7S, 11S, and soy isolat e (LSI) fractions and from commercial soy isolate (CSI). Tensile stren gth (TS), elongation at break (E), water vapor permeability (WVP), tot al soluble matter (TSM), protein solubility (PS), and Hunter L, a, and b color values of these films were determined. The 11S films had grea ter TS and 7S films (P < 0.05), while LSI films had greater TS than CS I films (P < 0.05). No significant differences were detected among mea n E values and among mean WVP values of all films (P > 0.05). The 7S f ilms had higher TSM and PS values than 11S films (P < 0.05). CSI films were significantly darker (lower L value) and more yellow (greater po sitive b value) than LSI films (P < 0.05).