Turbidity and ?-potential measurements were used to examine the formation of complex coacervates from soy protein isolate (SPI) and gum Arabic (GA) as a function of pH (6.5-2.0), NaCl (0-1000 mM), SPI/GA ratio (1/4-8/1 w/w) and GA concentration (0.0125-0.20% w/v). At the SPI/GA ratio (1:1) in absence of NaCl, critical pH values (pHc, pHf1, pHopt and pHf2) of the mixture were appeared at 4.40, 3.55, 3.15, and 2.40, respectively. The critical pH values were increased with SPI/GA ratio. When SPI/GA mixing ratios changed from 1/4 to 8/1, the turbidity curve shifted to larger pH. When SPI was 0.05% and GA changed from 0.0125 to 0.20%, the turbidity curve shifted to lower pH. <5.0 mM NaCl had little effect on SPI/GA interactions, while =10 mM NaCl promoted complex coacervate formation. When NaCl was =100 mM, complex coacervate formation was suppressed. It was extremely suppressed at 1000 mM NaCl.

pH, NaCl, biopolymer ratio and concentration effects on the complex coacervate formation from soy protein isolate and gum arabic

244th National Meeting (2012)

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