Characterisation of flavour compounds in Biska - a herbal spirit produced with mistletoe

Mistletoe (Viscum album) is mostly used in its herbal form owing to its content of diverse biologically active substances. In Croatia's Adriatic region, it is used for production of Biska, a strong alcoholic beverage produced by maceration of mistletoe in spirit or brandy, with or without the addition of honey. In this work, Biska was characterised by analysis of aroma compounds and physicochemical parameters and is the first study of the aroma profile of a strong alcoholic beverage produced with mistletoe. The aroma of 14 samples of Biska - five commercial and nine homemade - was analysed using GC/MS with solid-phase microextraction. A total of 166 aroma compounds were detected. Major components were ethyl esters (medium and long chain fatty acids), fatty alcohols, isopropyl myristate, aldehyde decanal and some terpenes. The distribution of aroma compounds was evaluated by principal component analysis. Some significant differences in physicochemical properties were observed including ethanol concentration (28-44% v/v) and pH (4.4-6.5). Although the colour of Biska was light brown with greenish reflections, there were differences in chromatic parameters. The commercial samples were darker and were less transparent than homemade Biska, perhaps reflecting more extensive maceration/extraction or the addition of caramel. (C) 2018 The Institute of Brewing & Distilling