2.7. Emulsion activity index
Emulsion activity index (EAI) was measured following
the procedure of Pearce and Kinsella (1978). The
EAI was determined on the total soluble protein extract
adjusted to 4% protein. To prepare the emulsion, 5 ml
of 4% protein extract was homogenised at 20 500 rpm
for 1 min with 2 ml safflower oil using an Ultra Turax.
Of the emulsion, 15 ml were immediately diluted with 3
ml of 0.3% SDS solution, the mixture was vortexed to
obtain a uniform dispersion, and the absorbance was
read in a 1-cm pathlength cuvette at a wavelength of 500
nm and a bandwidth of 10 nm.
2.8. Emulsion stability
The same samples read for absorbance in the EAI
determination were held at room temperature for 2 h
and then read again. The emulsion stability was calculated
as the difference between the initial absorbance
of the emulsion and the absorbance of the
same after 2 h.