Effect of citrate on the composition and enzymic coagulation of colloidal bovine casein aggregates

ESTELA M. ALVAREZ; PATRICIA H. RISSO; CARLOS A. GATTI; MARTÍN S. ARMESTO; MARIANO BURGOS; VERÓNICA M. RELLING

COLLOID AND POLYMER SCIENCE

Springer-Verlag

Lugar: Heidelberg; Año: 2006 vol. 284 p. 1016 - 1023

0303-402X

Q2 según Scimago a la fecha de publicaciónColloidal casein aggregates (CCA) prepared from soluble whole bovine caseinates in the presence of Ca2+ and phosphate (Pi) ions by addition of different citrate (Cit) concentrations showed different mineral and proteic composition. Citrate concentration conditions the Ca and Pi concentrations incorporated into CCA, probably due to the complexing effect of this anion on calcium. A significant change in the incorporated Ca/Pi ratio at 8 mM citrate could very likely be associated to changes in CCA net charge. The incorporation of individual caseins to the colloidal particles obtained, as well as their average size and size distribution, depended also on the Cit concentration used [Cit]P. Alpha S- and beta-caseins assembled in the CCA structure sharply decreased at a [Cit]P higher than 15 mM, i. e. at a low Ca2+ concentration in the aggregates, showing that the presence of this cation is necessary for the incorporation of these caseins. An inverse relationship between the aggregation step rate in CCA enzymic coagulation and their average size was observed. The aggregation rate vs. the average size curve obtained at [Cit]P 8 mM clearly differed from the curves obtained at 10 and 12 mM respectively, a fact probably related to a change in the CCA net charge. This behavior showed the effect of citrate concentration on CCA functional properties.