Identifier: TDX:4356
Authors: De Lima E Silva, Ana Carolina
Abstract:
Beer is an alcoholic fermented beverage produced from water, malted barley, hops and yeast. Generally, beer quality and shelf life are determined by its appearance, aroma, taste and texture, and are conditioned by its microbiological, colloidal and flavour stability. During the ageing process, the sensory quality attributes of a beer change due to alterations in its chemical composition. These changes are directly correlated to the parameters of the brewing process and are affected by the type of packaging used and the storage conditions. To achieve quality and maintain the stability of the product during its shelf life, it is necessary to understand and control all the parameters involved in the brewing process, from the raw material to the storage and transport conditions.
In this Doctoral Thesis, we studied the quality and stability of beer focusing on the evolution of its volatile compounds during its shelf life in terms of the type of packaging used, aluminium cans or glass bottles, and the type of conservation process applied, microfiltration or pasteurization. To understand and monitor the main parameters that influence beer sensory quality and stability we correlated physicochemical measurements and data obtained with techniques such as gas chromatography - mass spectrometry (GC-MS), to microbiological and sensory analyses. To facilitate the extraction, connection and interpretation of the acquired data, we applied multivariate analysis techniques, mainly Principal Component Analysis, Partial Least Squares Regression and Partial Least Squares Discriminant Analysis.
Our results show that the use of multivariate analysis in combination with the GC-MS technique , and physicochemical, microbiological and sensory analyses appear to be a valuable tool to better understand, manage, monitor and predict beer quality and shelf life stability.
Repositori URV