Pea soluble polysaccharide improves stability of acidic pea protein dispersions

Soluble pea polysaccharide (PPS) is an acidic extract from the by-product of pea protein processing. It was hypothesized that this polysaccharide, which is negatively charged, may be able to stabilize acidic protein dispersions at acidic pH. Model dispersions were prepared with PPS and commercial pea protein isolate (PPI), at ratios ranging between 0 and 1, and at pH 3.8, and at two protein concentrations, 1 and 2%. With increasing the ratio of PPS/PPI, there was a shift in the surface charge from +21 to -4 mV. Stable complexes were formed at ratios >0.25, as shown by an increase of unsedimented proteins, in spite of the low overall charge at these ratios. There was an effect of concentration, with 2% showing less stability than 1%. Transmission electron micrographs confirmed the presence of complexes, and the ability of PPS to limit the acid-induced aggregation of PPI at low pH.