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A relationship between EPR and spectrophotometric parameters related to beer staling and antioxidant activity, was identified. AUC (area under the curve), intensity at 150 min (T150), radical scavenging activity (RSA), total phenolic compounds (TPC), hydroxyl radical scavenging capacity (HRSC) and one parameter linked to staling degree of beers (thiobarbituric index, TBI) were related. Temperature was modified to find the proper working conditions for EPR spin-trapping experiments and it was found that it affected the kinetic of PBN adduct evolution. For the samples reaching a maximum intensity signal, the higher the heating temperature, the shorter the time interval needed to reach it. No linear relationship was detected among parameters obtained with EPR spin trapping experiments and RSA, TPC, TPI, and HRSC when correlating one parameter with another. On the contrary, a good linear relationship was found among AUC or T150 and a combination of RSA, TPC, TPI, and HRSC (R2 = 0.9562 and 0.9694, respectively). The goodness of fit increased to R2 = 1 when a combination of AUC and T150 was related to a combination of RSA, TPC, and TPI, and HRSC. [ABSTRACT FROM AUTHOR]

The hop has been used for centuries in brewing because of its aroma and bitterness; it is mainly cultivated in Northern Europe and in the United States; to date, few data are available about its performance in the Mediterranean environment. The hop contribution to the final taste of beers is related to the chemical composition of resin and essential oils resulting from both genetic material and environmental conditions. In the last decade, the rising of interest in craft beer has led brewers to use local ingredients to produce beers with a stronger identity. In this paper, the quality parameters of hop Var. Cascade recently introduced in Sardinia have been investigated. The hop fields were sampled for three crop seasons (2015, 2016 and 2017); the yield and the chemical composition of essential oil as well as the alpha- and beta-acids were evaluated by GC–MS and UV-HPLC techniques. The obtained data demonstrate that features of Cascade hop grew in Sardinia are in the same range of those cultivated in USA. [ABSTRACT FROM AUTHOR]