Interactions of soy protein fractions with high-methoxyl pectin.
A protein-binding technique was employed to visualize, using scanning electron microscopy, the soy protein as well as the association between HMP and soy protein fractions. Image analysis indicated that at pH 7.5 and 3.5 soy protein isolate showed a bimodal distribution of sizes with an average [ d(0.5)] of about 0.05 microm, but at pH 3.8 the proteins formed larger aggregates than at high pH. Addition of HMP at pH 3.8 changed the surface charge of the particles from +20 to -15 mV. A small addition of HMP caused bridging of the pectin between soy protein aggregates and destabilization. With sufficient HMP, the suspensions showed improved stability to precipitation. The microscopy images are the first direct evidence of the interactions between soy proteins with high-methoxyl pectin (HMP).
Department of Food Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
Monica
M
Lam
Paul
P
Paulsen
Milena
M
Corredig
D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D010368:Pectins / Q000737:chemistry / Q000378:metabolism*; D030262:Soybean Proteins / Q000737:chemistry / Q000378:metabolism*; D055672:Static Electricity
D030262:Soybean Proteins; D010368:Pectins