Pomegranate seed protein isolate obtained from isoelectric
precipitation: functional and physicochemical characteristics
Abstract
The aim of the present study was to evaluate the functional and
physicochemical characteristics of pomegranate seed protein isolate
(PSPI) obtained by an isoelectric precipitation process. The extracted
isolate had a desirable nutritional value as the contents of its
essential amino acids (except for valine and isoleucine) exceeded those
recommended by FAO/WHO for adults. The molecular weights of the protein
fractions of PSPI were found to be within 15-60 kDa range. According to
thermal analysis data, PSPI could be denatured at 90 °C. Surface
hydrophobicity of PSPI was determined at 774 level. PSPI showed high
solubility both in alkaline and acidic media with the highest solubility
at pH 12 (96.6%). Solubility of PSPI at pH 7.0 was at 39.5%.
Furthermore, PSPI had good oil- and water-holding capacity (3.7 and 4.3
g g-1, respectively), emulsifying and foaming properties, and in-vitro
digestibility. The lowest emulsifying activity index (14.1 m2/g) and
emulsion stability index (8.18%) were obtained at the isoelectric pH.
Overall, PSPI as a novel protein source shows a potential for future
industrial applications.