Comparative study on the functional properties of the pearl oyster (Pinctada martensii) protein isolates and its electrostatic complexes with three hydrophilic polysaccharides

Abstract

Pinctada martensii protein isolates (PPIs) and polysaccharide complexes of different mixing ratios (10:1, 10:2, 10:3) were prepared at the optimal pH. The characteristics of PPIs and complexes were compared by determination of solubility, emulsifying properties, surface hydrophobicity, thermal properties, rheological behavior, and fourier transform infrared (FT-IR) spectroscopy. Compared with PPIs, the solubility of complexes changed to different degrees, and 10:3 PPI-pectin complex had the highest solubility (10.02 ± 0.68%). The emulsion properties of 10:2 and 10:3 PPI-alginate complexes were significantly higher than produced from other systems. The conjugation of PPI and pectin evidently reduced surface hydrophobicity of PPI. Denaturation temperatures of complexes were generally higher than that of PPIs. The gel network of PPI and complexes was formed within 70–80°C at pH 7.0 and G′ values of complexes were lower than that of PPIs. FT-IR spectroscopy showed O-H stretching of water absorption, C-C and C-O stretching and C-H bending of colloidal polysaccharides were improved in complexes.

Keywords

• pinctada martensii
• protein isolates
• pectin
• alginate
• functional property