Application of Enzyme-Linked Immunosorbent Assay to Quantitative Evaluation of Foam-Active Protein in Wheat Beer

We previously reported the development of a new method to determine foam-active protein in barley by enzyme-linked immunosorbent assay (ELISA). We have recently succeeded in obtaining a polyclonal antibody to foam-active protein in wheat beer. By using two different antibodies, one for barley and one for wheat, the behavior of foam-active protein from wheat and barley was investigated during the brewing process and the following results were obtained: 1) the molecular weight of foam-active protein in wheat was smaller than that in barley and their iso-electric points were different; 2) the wheat and barley foam-active proteins showed different behavior during the brewing process, which reflected their different iso-electric points; and 3) the bubble size of wheat beer was much smaller or finer than that of barley beer.