A high molecular mass emulsifier derived from lentil seeds: The role of polysaccharide and protein in its...

A water-soluble lentil polysaccharide (SLPS) extract was obtained from lentil fiber, at pH 10, after heating at 120 °C for 90 min, with a recovery as high as 16.5 %. SLPS had a weight average molecular mass of 1975 kg/mol, and contained 47 % glucose, 42 % arabinose, and 7 % uronic acid. Objective of this work was to evaluate the potential of SLPS to be employed as a natural emulsifier, by measuring its interfacial properties, as well as emulsifying capacity on a model emulsion system. Acidic emulsions were prepared with 5 % oil and 5 % SLPS and their particle size distribution was evaluated by light scattering and complementary microscopy, to determine their stability. SLPS showed the ability to reduce interfacial tension at oil/water interfaces, and the emulsions were stable under acidic conditions. Two different molecular weight fractions (SLPS-H and -L were investigated), and while the high molecular weight fraction (SLPS-H; 1567 kg/mol) was effective at stabilizing interfaces, emulsions prepared with low molecular weight fraction (SLPS-L; 2.3 kg/mol) showed aggregation and coalescence of oil droplets. Addition of pectinase caused aggregation of the droplets as measured by dynamic light scattering, demonstrating that adsorbs on the surface of oil droplets, and prevents aggregation of the oil droplets.