Protein–protein interactions: Their importance in the foaming of heterogeneous protein systems

Abstract

Analysis of egg albumen foams by electrophoresis showed that the basic protein lysozyme (PI 10.7) was strongly retained. Addition of low concentrations (0.01-0.10% wiv) of the basic proteins clupeine (PI 12) and lysozyme to solutions (0.50% wiv) of several acidic proteins (PI 4.7-6.0) greatly improved their foaming properties at pH values between the isoelectric points. Sucrose strongly enhanced the action of the basic proteins, while not significantly affecting the foaming of the acidic proteins alone. Basic proteins did not enhance the foaming of ovalbumin and egg albumen in the absence of sucrose. Clupeine enhanced foaming more effectively than lysozyme under all conditions studied. Lysozyme was least effective near the isoelectric point of the acidic protein, where electrostatic interactions were weakest. Sodium chloride ( 0 . 1~) had a detrimental effect on the action of lysozyme.

Some Functional Properties of an Enzymatically Phosphorylated Cowpea (Vigna unguiculata)Globulin Isolate

“…The absorbance of each diluted emulsion was immediately measured at 500 nm to calculate EAI, while the reading obtained after 30 min was used to calculate ES. Foaming capacity (FC, ml) and percentage foam stability (FS, %) were determined according to the method of Poole et al 14) as modified by Aluko and Yada,6) except that FS was expressed as the volume of foam (ml) instead of the percentage foam expansion.…”

Effect of Sodium Chloride on Rheological Properties of Foams Obtained From Powdered High Whip Albumin

“…Właściwości pianotwórcze białka jaja kurzego są wynikiem wzajemnych oddziaływań między pięcioma frakcjami białek, które są w nim obecne [16,23]. Duże znaczenie ma fakt, że właściwości pianotwórcze poszczególnych frakcji białka jaja kurzego są słabe w porównaniu z ich mieszaniną, co powoduje, że specyficzne oddziaływa-nia międzybiałkowe pełnią ważną rolę w tym układzie.…”

Foam Fractionation of Binary Mixtures of Lysozyme and Albumin

“…32,38 The stability of whipped foam of egg albumin and lysozyme has also been attributed to electrical interaction. 40 Taken as a whole, the data in Tables 3 and 4 FOAM FRACTIONATION OF LYSOZYME AND ALBUMIN MIXTURES indicate that under those conditions that BSA and lysozyme may potentially interact electrically (low ionic strength), BSA is recovered in the retentate in greater amounts. Since drainage of the film is unaffected by pH or ionic strength, the putative interaction of the BSA with the lysozyme could be preventing BSA from adsorbing strongly to the interface.…”