Functional properties of the protein isolates of hyacinth bean [Lablab purpureus (L.) Sweet]: An effect of the used procedures

This study investigated the effect of protein isolate preparation procedures on functionality and characterization of protein isolates using salt-extraction dialysis, micellization and isoelectric precipitation. Micellization produced the highest protein content and yield (87.78 and 72.60 g/100g) followed by isoelectric precipitation and salt-extraction dialysis. Isoelectric precipitation gave a significantly higher digestibility (88.47 g/100g) than micellization and salt-extraction, as well as higher water and oil holding capacities (2.48 and 2.99 g/g). However, emulsion capacity (88.89-100%) and stability (20.15-37.00%) were not found to be significantly affected by the extraction method. Salt-extraction gave the highest foaming capacity but lowest foaming stability (123.33 and 27.32%) than isoelectric and micellization precipitation. Isoelectric and micellization precipitation gave better gelling abilities (16%) than salt-extraction. Arginine and lysine contents of isolates were high (12.70-16.59) with protein efficiency ratios for the isolates greater than 2 (2.61-6.66), indicative of a high protein quality. Protein isolates may be useful in supplementing foods that require improved functionality and protein qualifies, but extraction procedures play a significant role in the functional properties of the final product.