Development of a new method for determining beer foam and haze proteins by using the immunochemical method ELISA

Beer proteins derived from malt are considered to be very important factors for foam and colloidal stability of beer. Foam proteins have to be retained as much as possible to realize good foam stability or foam adhesion, but at the same time, haze proteins have to be kept below a certain level to avoid haze problems. A specific analytical method for each protein had not been developed yet, and the development of such a method was thought to be of value in the control of these proteins during the brewing process or to evaluate malt quality. For this purpose, we attempted to apply an enzyme-linked immunosorbent assay (ELISA) method for the determination of haze and foam active protein and established a specific analytical method for each protein. The new method was compared with conventional analytical methods for nitrogen or protein in beer. The foam-active and haze-active protein levels determined by the new method were found to agree better with foam adhesion and haze stability than did the conventional method.