The kinetics of protein precipitation by different reagents

Abstract
The kinetics of precipitation of soya protein has been examined in a tubular flow reactor with the precipitants, ammonium sulfate, ethanol, divalent calcium, and sulfuric acid. The precipitate growth profiles obtained in all cases showed the rapid formation of a precipitate phase and the attainment of a final size within 16 s. The final mean particle diameter dm varied with precipitating agent used in the order: sulfuric acid (12.5 μm) > ethanol (7.5 μm) ≈ calcium ion (7.2 μm) > ammonium sulfate (3.1 μm). In the case of ethanol precipitation, changes in the design of the contacting section of the reactor led to differences in the precipitate growth curve. Protein solubility curves are also presented, and with the reactor data, they provide a convenient method for assessing the effect of precipitating agent on the design of protein precipitation reactors.
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