d) Formación de agregados moleculares de proteínas lácteas puras e industriales

LARSEN GERALDINE; OSTORERO ELIANA; KIVATINITZ SILVIA CLARA

Córdoba

Congreso; d) Formación de agregados moleculares de proteínas lácteas puras e industriales; 2016

Caseins (s1, αs2, β and K) represent 80% of total dairy proteins and whey proteinsa re the remaining 20%, mainly β-lactoglobulin (β-LG) and α- lactalbumin (α- LA).Oligomer formation induced by ultraviolet irradiation was studied, using pure β-CN and β-LG , and the industrial fractions; whey protein isolate (WPI) and caseinate (CN). The purpose was to determine if the product of the photooxidation was similar when pure proteins or industrial fractions were used, which cost is lower.SDS-Gel analysis showed that the rate of disappearance of the monomeric protein was faster with the pure proteins than with the industrial ones.Tryptophane loss was faster in WPI and caseinate than in the pure proteins.This results are in accord with the fact that the structural mobility of the protein influences its oxidation pathway and that the less pure the protein fraction is, more resistant to fragmentation and therefore remains intact longer to form covalent oligomers and aggregates. The tryptophan disappearance does not seem related to fragmentation, as industrial proteins showed a faster disappearance.In the instance of caseinate the aggregation -fragmentation pattern was completely different from the isolated protein (β-CN), while in the case of β-LG differences were by the speed in the apparition of fragments and polymer / aggregate