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Combined effect of pH and temperature during electroreduction of whey proteins

Bazinet, L., Lamarche, F., Boulet, M., Amiot, J.
Journal of agricultural and food chemistry 1997 v.45 no.1 pp. 101-107
whey protein, electrical treatment, reduction, pH, temperature, sulfhydryl groups
Electroreduction was conducted at various pH values (4, 6, and 8) and temperatures (25, 45, and 65 degrees C) to evaluate the effect of these parameters on the structure of whey proteins. A preliminary study with cystine as a disulfide bond (S-S) reduction model indicated that the use of a reticulated vitreous carbon cathode and an anode/cathode voltage difference of 6 V was suitable for the electroreduction of whey proteins. Up to a 39% reduction of whey protein S-S bonds was obtained by electroreduction for 3 h at pH 6.0 and 65 degrees C, with pH and temperature accounting for 33% and electroreduction for 67% of the result. New molecules were formed by alpha-lactalbumin aggregation or co-aggregation with p-lactoglobulin or fragments of bovine serum albumin. The contribution of pH and temperature would be to produce free SH in addition to the ones released by electroreduction, and to increase thiol-disulfide interchange reactions.