Hibiscus rosa-sinensis as Flavoring Agent for Alcoholic Beverages

The present work is an evaluation of the chemical composition of the aroma and the sensorial characters of a beer flavored with Hibiscus rosa-sinensis flowers. Moreover, the total polyphenol, flavonoid and anthocyanin contents and the antioxidant activity of the plant materials and beers were assessed. A comparison with a liqueur flavored with the same hibiscus flowers was also performed. Non-terpene derivatives constituted the main class of components of the aroma of both samples, representing 96.4% of the whole volatilome in the control beer and 99.0% in the hibiscus one. Among this class, esters were the most abundant compounds, being significantly higher in the treated sample (77.6%) than in the control (68.4%), followed by the alcohols (20.9% in control beer and 18.8% in hibiscus beer). From a sensorial point of view, the control beer was characterized by malty and hoppy notes, attributable to the noticeable content in myrcene and α-humulene in its headspace, while in the hibiscus beer, floral and fruity notes, typical of esters and alcohols, prevailed. The polyphenol content was significantly higher in the treated beer (143.96 mg/g) than in the control, as well as the total flavonoids and the total anthocyanins, and, consequently, the antioxidant activity (DPPH-assay).