Estimation of beer stability by sulphur dioxide and polyphenol determination. Evaluation of a Laccase-Sonogel-Carbon biosensor

The traditional methods used to evaluate parameters related to beer ageing have been tested, revised and criticised. With this aim, a sampling of lager beers has been carried out. Sulphur dioxide, polyphenols and antioxidant capacity have been determined in fresh and aged beer. Only sulphur dioxide concentration showed relevant differences after the ageing process. These results together with a correlation study provided information about the selectivity of the methodologies used and have made it clear that sulphur dioxide has an important role and polyphenols have an indirect role. Laccase-Sonogel-Carbon biosensor is proposed to determine polyphenols in beers instead of Folin–Ciocalteu assay due to its better selectivity, sensitivity and short assay times.