Institute of Nutritional Science, Chair of Food Science, and TransMIT Center for Effect-Directed Analysis, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany; On leave from Università degli Studi di Modena e Reggio Emilia, Facoltà di Farmacia, Via Giuseppe Campi 203, 41125 Modena, Italy.