Emulsifying properties of chickpea, faba bean, lentil and pea proteins produced by isoelectric precipitation and salt extraction

The physicochemical properties of legume protein isolates and their ability to stabilize oil-in-water emulsions with and without genipin

“…Similar solubility for legume protein isolates prepared by isoelectric precipitation has been reported in literature for CPI (>80 %) by Sánchez- Vioque et al (1999), and for CPI, FPI and LPI (all >80 %) by Carbonaro et al (1997). Solubility is mediated by the balance of proteinprotein and protein-solvent (aqueous phase) interactions, the latter promoting solubility, which can further be influenced by environmental factors (e.g., temperature, pH, ionic strength) (McClements 2007;Can Karaca et al 2011) and by processing (e.g., extraction or post-extraction treatments) (Kinsella 1979). High surface charges are important for fostering sufficient electrostatic repulsion between proteins, such that they can overcome electrostatic and van der Waals attractive forces, to remain dispersed in solution.…”

“…(p<0.05). Surface hydrophobicity values were different from those reported in literature for these particular legume proteins (potentially due to the use of different protein concentrations in generating the slope), but Can Karaca et al (2011) reported the same pattern of decreasing hydrophobicity with: CPI > LPI = SPI > FPI. However, Tang and Sun (2011) report a similar surface hydrophobicity magnitude, as determined in Fig.…”

“…Protein levels in the present study were comparable to others found in literature. For example, Can Karaca et al (2011) using similar legumes and a similar extraction method reported protein levels of 85.4 %,~84.1 %,~81.9 %, and~87.6 % for CPI, FPI, LPI and SPI respectively. In addition, protein levels on a dry weight basis of~90.2 % and~78.0 % have been reported for LPI (Joshi et al 2012) and CPI (Sánchez- Vioque et al 1999) respectively, when prepared using similar isoelectric precipitation extraction procedures.…”

“…Emulsifiers are comprised of both hydrophobic and hydrophilic moieties that become integrated into the oil-water interface to lower the interfacial tension (Bos and van Vliet 2001). The effectiveness of protein-based emulsifiers is dependent on properties of the protein (e.g., source, size, solubility, concentration, conformation and surface characteristics) (Schwenke 2001;McClements 2007); emulsification conditions (e.g., level and duration of shear, oil/water ratio, and type of homogenizer) and solvent effects (e.g., temperature, pH and the presence of salts) (McClements 2004;Can Karaca et al 2011). Proteins are ideal materials for improving emulsion stability due to their amphiphilic nature (i.e., having both hydrophilic and hydrophobic moieties), enabling them to align at, or unfold at the oil-water interface to lower interfacial tension and form a cohesive viscoelastic coating/film around the droplets (Tcholakova et al 2006).…”

“…While soy is the current market standard for vegetable proteins, several legume proteins are becoming of interest as ingredients due to their nutritional value, renewability, availability, low cost and functionality. Can Karaca et al (2011) investigated the emulsifying properties of chickpea, faba bean, lentil and pea protein isolates prepared by isoelectric precipitation and salt extraction, to find both the legume source and production method to influence their performance. Emulsion capacities for the various protein solutions at pH 7.0 ranged between 476 and 542 g oil/g protein, with the lentil proteins giving the highest measured values.…”