Emulsification properties of groundnut protein.

The ability of groundnut protein to emulsify soybean oil was studied under various experimental conditions. The emulsification capacity (EC) of groundnut protein isolate was highest at 5 mg/ml protein concn. The EC vs. pH profile resembled a typical protein solubility curve and the EC of groundnut protein isolate was greatest at pH 10.0. NaCl at low concn. (0.05-0.2M ) increased the EC of protein dispersed, in the pH range 7-10. Groundnut protein isolate showed poor emulsifying properties in water (pH 6.8) in contrast to casein or soybean protein. Results with groundnut flour indicated that it was a less effective emulsifier than the protein isolate. EC increased with the fineness of the flour, indicating the influence of particle size. A smaller amount of oil was emulsified at higher mixing speeds.