Malt and wort bio-acidification by Pediococcus acidilactici HW01 as starter culture

Abstract

In a previous study, indigenous bacteriocin-producing Pediococcus acidilactici HW01 was isolated from malt. The bacterium was chosen as it is properly adapted to the malting conditions, and it showed a strong antagonistic effect against beer-spoilage lactic acid bacteria (LAB) in the previous study. Strain HW01 was added to the malting process for bio-acidification and bio-preservation of LAB. Changes in the microorganisms, enzymes, pH, total soluble nitrogen, free amino nitrogen, colour, filtration time and viscosity of wort were compared with the control. The LAB starter culture improved several characteristics of malt modification, such as microbiological stability, viscosity and filtration time. Especially, the starter culture protected the malt from the beer-spoilage bacteria of the genus Pseudomonas, by producing several acids and antimicrobial substances. The potential of using HW01 strains for bio-acidification and the bio-preservation of LAB are discussed.