Impact of pH on the interactions between whey and egg white proteins as assessed by the foamability of their mixtures

Item Type Journal Article
Author Malgorzata Kuropatwa
Author Alexander Tolkach
Author Ulrich Kulozik
URL http://www.sciencedirect.com/science/article/B6VP9-4W9XDY4-1/2/73ab8c9e2b8b129456f41d949252c849
Volume 23
Issue 8
Pages 2174-2181
Publication Food Hydrocolloids
ISSN 0268-005X
Date Diciembre 2009
DOI 10.1016/j.foodhyd.2009.05.001
Accessed 2009-10-07 11:42:11
Library Catalog ScienceDirect
Abstract The impact of protein-protein interactions on foaming properties of mixtures consisting of egg white proteins (EWP) and whey proteins (WP) with total protein content of 60 g/L was examined at pH 5, 7 and 9. The ratio between EWP and WP in the mixtures was varied between 67:33, 50:50 and 33:67 (in %; w/w). The ionic strength was adjusted to that of milk (I = 176 mM). The foamability of the protein products was characterized by the foam capacity, stability and firmness. In addition, the hydrophobicity in the protein solutions was assessed as a measure for the physical behaviour and ability of proteins to adsorb at the air-water interface. The individual egg white proteins and whey proteins each showed the best foaming properties at pH 5 and pH 9, respectively. At pH 9 a synergism was observed in the capacity and stability of the foams from EWP/WP-mixtures. This effect appears to be caused by the electrostatic interactions between egg white and whey proteins which occur in the bulk solution after the pH adjustment prior to the foaming. In contrast, at pH 5 no positive influence of foaming the components in a mixture as well as no indication of intermolecular interactions was found. At pH value near the pI of ovalbumin the protein interactions occur when the proteins have adsorbed at the air-water interface. The protein systems foamed at pH 7 showed intermediate foamability compared to the values obtained at alkaline and acidic pH.
Title Impact of pH on the interactions between whey and egg white proteins as assessed by the foamability of their mixtures
Date Added 2009-10-07 07:42
Date Modified 2009-10-07 07:42

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