RELATIONSHIPS BETWEEN ADSORPTION AND EMULSIFYING OF ACETYLATED PROTEIN ISOLATES FROM FABA BEANS (VICIA-FABA L)

The influence of acetylation on surface adsorption and emulsifying pro perties of faba beans protein isolates (FBPI) was studied. Generally, acetylation improved the interfacial activity of FBPI. The plateau val ue of the GIBBS' adsorption isotherms measured with the WILHELMY-plate was between 22.97 and 24.22 mN/m. The critical association concentrat ion (CAC), i.e. the inflection point of the adsorption isotherms, was shifted from 2.06 . 10(-5) to 5.35 . 10(-7) g/ml with progressive acet ylation, The dependence of the CAC on the degree of acetylation was fo und to be significant For FBPI stabilized n-decane/water emulsions wit h varying volume fraction of oil (phi) the emulsifying activity index increased from 166 to 593 m(2)/g whereas the droplet size decreased fr om 7.79 to 3.4 mu m with acetylation. The correlation between emulsify ing activity of FBPI and both degree of acetylation and adsorption beh aviour was only significant for emulsions with phi = 0.4.