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Electron spin resonance (ESR) spectroscopy was used to determine the effect of dry hopping on the oxidative stability and antioxidative potential of beer. Commercial beer was dry-hopped at 5 °C and 20 °C with six hop varieties (Polish and American). The rate of radical formation and lag time were found to depend on the variety of hop used. An increase in the lag time and a decrease in the rate of radical formation occurred when dry-hopping was performed at 20 °C for all hop varieties (at 5 °C in some varieties). The lag time had a strong correlation with the TPC (total polyphenols content) in beer. The rate of radical formation was correlated with the iron content of the beer. A decrease in iron concentration was observed after dry-hopping at 20 °C. Overall, the evaluation of free radical formation using ESR is useful for predicting oxidative changes in beer during storage.

Treball desenvolupat dins el marc del programa 'European Project Semester'., The Autonomous Acoustic Buoy (AAB) has been designed and manufactured by Laboratori d’Aplicacions Bioacústiques (LAB) with the assistance of Universitat Politècnica de Catalunya (UPC) over the past two years. This is due to the need to measure and control the correlation between human activity and presence of marine mammals in the marine environment. The buoy is used for recording sound patterns in the underwater environment, specifically referring to the physiological and neurophysiologic processes by which sounds are produced, received and processed [42]. Furthermore the AAB has an important role in monitoring and identifying the communication between marine mammals. This paper presents the further advancements and improvements of the design and functionality of the AAB as well as a concise introduction into the buoy capabilities and a brief overview of the history, purpose and organisation of the LAB. With regards to the improvements made this article gives details of elaborate research undertaken into dolphin whistles analysis and a well structured marketing plan. The mechanical and electrical features concerning the safe operating conditions of the buoy offshore are also presented within this report.