Content of 4-ethylcatecol and other volatile phenols in dressings, beverages and spirits

Recently, in addition to the already known 4-ethylphenol and 4-ethylguaiacol, 4- ethylcatechol (a-EC) was found to be associated with Brettanomyces. These off-flavouring ethylphenols are also produced by Lactobacíllus plantarum or other micro-organisms. 4-EC has been described as phenolic and horsey, and its olfactory threshold ranges between 50 and 800 mg/l. depending on the type of wine. The "volatile phenols" class also includes 4- vinylphenol and 4-vinylguaiacol, both playing a remarkable sensory role in several products. This work mainly surveys the content of 4-EC in beverages, dressings and spirits in order to round out the few published data regarding agri-food field. Moreover, the content of the other volatile phenols is investigated. Samples of traditional balsamic vinegar of Modena P.D.O. (N.:14), apple (10) and wine (6) vinegar, soy sauce (1), apple (8) and peer (10) juice, commercial (3) and lab-scale produced (16) apple cider, not-decaffeinated ground coffee (15), tea (7), beer (28), grapp a (12) and fruit distillate (5) available in the Italian market were analysed using an HPLC approach with coulometric electrochemical array detection. 4-EC was at noteworthy concentrations in apple fermented products, reaching maximum values of above 2200 and 4600 mg/L in cider and vinegar respectively, and concentration high up to 43.5 mglkg powder were also found in aqueous extracts of not-decaffeinated ground coffee. In these products, in the light of the 4-EC sensory threshold reported in the literature, an organoleptic role of the compound is very likely.