An Immunochemical Analysis of Beer Foam

Abstract

Beer foam produced in a continuous foaming tower in volumes representative of commercial dispense, was analysed by immunoelectrophoretic and immunoblotting techniques to identify antigens involved In foam structural stability. In crossed immunoelectrophoresis (CIE), only one antigen precipitated from foam in the homologous foam antiserum. This antigen was shown to be of malt origin by rocket-line immunoelectrophoresis and was also present in 11 commercial beers (5 bitters, 4 lagers and 2 stouts). However, the foam preparation separated into more than 20 polypeptides by SDS polyacrylamide gel electrophoresls. Immunoblotting showed that at least 12 of these reacted with foam antiserum and that they originated from either malt or yeast. Similar polypeptides were also identified in the antigen precipitated in CIE, suggesting that these polypeptides were probably present in the foam as a complex. It is concluded that the stability of foam reflected molecular interactions between these polypeptides (and possibly other components such as carbohydrates) in the liquid film of the bubble structure.

Variation of saturated surface density of ovalbumin on bubble surface in continuous foam separation

“…This technique has been studied in many fields, such as chemical/biochemical engineering [1][2][3][4][5][6], analytical chemistry [7,8], wastewater treatment [9][10][11] and so on.…”

Adsorption of Water-Soluble Proteins onto Bubbles in Continuous Foam Separation

“…Recently, it appears that the separation of proteins by this method has been studied based on interest in applicability to food and biochemical industries (3)(4)(5)(6)(7). For the optimal design and operation of industrial processes, it is necessary to determine the adsorption and enriching mechanism of protein onto bubble surface in this technique.…”

Polipeptídeos e proteínas com influência na qualidade da espuma da cerveja e métodos analíticos utilizados no seu estudo

“…Outro método imunológico bastante utilizado é o "western blot", que tem sido aplicado no estudo de proteínas da espuma da cerveja 55,56 , da proteína Z da cerveja e dos seus percursores na cevada 17,19 e ainda da LTP1 16,29 . Mills e colaboradores 45 utilizaram este método para testarem a eficácia de um painel de 15 anticorpos monoclonais específicos para uma fracção proteica da cerveja.…”