The foaming of mixtures of albumin and hordein protein hydrolysates in model systems

Although hydrolysed albumin and hydrolysed hordein derived from barley are independently capable of stabilising foams in model beer solutions, when both are present together, the net foam stability is less than anticipated. In particular, it seems that hordein, even in an unhydrolysed state, interferes with the ability of albumin-derived polypeptides to stabilise foam. It appears, therefore, that the observed foam stability of a product such as beer is not only dependent on the absolute level of individual foam-stabilising polypeptides but also on the relative proportions of polypeptides derived from the albumin and hordein protein subsets. (C) 2004 Society of Chemical Industry.