New Proline-Specific Endoprotease for Improved Colloidal Beer Stability and Gluten Reduction

Abstract

Chill-haze is a well-known concern for brewers and most commonly involves polyphenols that interact with proline-rich hordein proteins in beers. An effective haze-suppressing effect has previously been established by a proline-specific endoprotease (PEP). In the present study, the protease action of a new Trichoderma reesei expressed PEP enzyme, available as the product BCLEAR™ was studied by assessing its impact on colloidal as well as foam stability and gluten reduction in beer. All malt beers treated with the BCLEAR™ enzyme or beers produced using BCLEAR™ at low dosage levels during fermentation, showed improved colloidal and foam stability when compared to the benchmark PEP investigated. In addition, gluten reduction was investigated using the BCLEAR™ enzyme and was found to have a very good correlation with the observed haze reduction, suggesting that the PEP enzyme dosage can accurately be determined from the calculated gluten content of the given raw materials. Thus, for optimal PEP enzyme use, the brew processes may most efficiently be controlled by following the gluten content, which was demonstrated with use of Lateral Flow Device (LFD) analysis technology.