Effect of pH and defatting on the functional attributes of safflower, sunflower, canola, and hemp protein concentrates

Background and objectives The effect of defatting four oilseed protein concentrates (safflower, sunflower, canola, and hemp) on the surface and functional properties of the proteins was investigated as a function of pH (pH 3, 5, 7). The functionality of commercial protein concentrates (soy, faba bean, lentil, pea, northern great bean, whey) already in the marketplace was also tested for comparative purposes. Findings Defatting with hexane increased the protein content from 77.3% to 92.9% for safflower, 67.5 to 75.5% for sunflower, 58.0-66.0% for canola, and 71.0-83.2% for hemp. The approximate isoelectric point (pI) of safflower increased with defatting (5.4-5.8), whereas for canola the pI decreased with defatting (4.7-4.3), and sunflower and hemp protein concentrates had similar pI for defatted or full fat. Certain functional properties were improved with defatting, whereas others showed the opposite trend; this was highly dependent on protein type and pH. Conclusions The oilseed concentrates were comparable to the concentrates in the marketplace with canola and sunflower proteins having the greatest oil-holding capacity and defatted safflower having the highest foaming capacity of all the proteins tested. Significance and novelty Based on their functionality, the oilseed protein concentrates have potential to be used by the food ingredient industry.