Preparation of free-standing films from kafirin protein microparticles: mechanism of formation and functional properties.
A method of preparing free-standing films using kafirin microparticles made by phase separation from acetic acid is described. Film preparation involved the suspension of the microparticles in acetic acid solution containing plasticizer. On evaporation of the acetic acid, a complete, smooth, flexible, transparent film was formed. A minimum concentration of acid was required to form a cohesive film relative to the concentration of kafirin. This was approximately 10.8:1, percent acetic acid to percent kafirin. Film formation appears to be by controlled aggregation of kafirin microparticles, followed by dissolution of the microparticles in acetic acid and drying into a cohesive film. The functional properties of microparticle films were generally superior to films cast directly from a solution of kafirin, at the same protein content. Kafirin microparticle films were very thin (<15 microm), relatively strong but not very extensible, with better water barrier properties and lower protein digestibility than conventionally cast kafirin films.
Taylor
Janet
J
Department of Food Science, University of Pretoria, Pretoria 0002, South Africa. janet.taylor@up.ac.za
Taylor
John R N
JR
Belton
Peter S
PS
Minnaar
Amanda
A
D001704:Biopolymers / Q000737:chemistry*; D008863:Microspheres; D010316:Particle Size; D010940:Plant Proteins / Q000737:chemistry*; D010968:Plasticizers / Q000737:chemistry; D045868:Sorghum / Q000737:chemistry*; D013499:Surface Properties; D013718:Tensile Strength
D001704:Biopolymers; D010940:Plant Proteins; D010968:Plasticizers; C080615:kafirin protein, Sorghum bicolor