ABSTRACT Sixteen commercially wet‐extracted protein isolates and 13 commercially air‐classified protein concentrates were evaluated for their particle size, physicochemical properties (protein solubility, differential scanning calorimetry, surface hydrophobicity, and surface charge) and functional properties (water holding capacity, oil absorption capacity, emulsifying capacity and stability, foaming capacity and stability, and least gelling concentration). Protein concentrates exhibited lower average values for particle size, surface charge, surface hydrophobicity, and water holding capacity, but higher values for oil absorption capacity, protein solubility, emulsion capacity and stability, as well as foaming capacity and stability, compared to protein isolates. Intensive processing appeared to denature proteins in most isolates, leading to reduced functional properties. Changes in pH and the addition of 2% NaCl influenced the properties of both protein isolates and concentrates. Protein solubility, emulsion capacity and stability, and foaming stability of the protein samples were superior at pH 10, followed by pH 3. The addition of 2% NaCl enhanced foaming capacity and reduced the least gelling concentration. A significant interaction between sample and treatment conditions ( p < 0.001) in protein isolates and protein concentrates was observed. Crop type differences in protein solubility, oil emulsion capacity and foaming stability of protein concentrates under certain conditions were detected using maximum likelihood factor analysis (MFLA). However, these differences were not evident in protein isolates, possibly due to more variable processing conditions.
Fenn et al. (Fri,) studied this question.