Preparation and surface active properties of coconut and sunflower protein-based diethanolamides

Protein isolates were extracted from sunflower and coconut deoiled cakes employing alkaline extraction method. Diethanolamides were synthesized by transamidification reaction of sunflower and coconut protein isolates and diethanolamine and evaluated for their surface active properties such as wetting ability, foaming properties, surface tension, emulsion stability, and critical micelle concentration (CMC). Diethanolamides exhibited better emulsion stability (276-570 s) compared to sodium lauryl sulfate (SLS, 224-480 s). Surface-active properties like wetting ability, foaming properties, surface tension lowering ability, and CMC values of these diethanolamides were inferior compared to SLS. These surfactants can be commercially exploited since they are prepared from less expensive oilseed proteins compared to oils and fats.