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Aliphatic γ- and δ-lactones with 9–12 carbons (γ-C9–12 and δ-C10&12) possess rich peach and coconut odors and could be a potential source of fruity, especially stone fruit (i.e., peach and apricot), aroma in beers. To assess the influence of these lactones in a complex beer matrix, low levels (µg/L) of these lactones in combination with oxygenated terpenes (linalool and β-damascenone) and ethyl esters (ethyl 2- and 3-methylbutanoate) were evaluated by a descriptive analysis panel in addition to group olfaction detection best estimate threshold (BET) determination. Descriptive analysis demonstrated that lactones enhanced the final overall fruity aroma profile and contributed stone fruit and peach aromas when combined with the terpenes and esters. Group BETs were calculated to be 376 µg/L (γ-C9), 239 µg/L (γ-C10), 238 µg/L (γ-C12), 750 µg/L (δ-C10), and 256 µg/L (δ-C12) in an unhopped ale base according to ASTM E679 methodology. Headspace solid-phase microextraction methodology was applied to commercial and controlled dry-hopped beers in which levels of γ-lactones ranged from 1.2 to 2.3 µg/L and δ-lactones ranged from 1.8 to 3.9 µg/L. Concentrations of detected lactones were well below group BET and appeared to play a minor role in overall beer fruit aroma. Keywords: Aliphatic lactones, Fruit aroma, Beer aroma, Oxygenated terpenes, Synergistic sensory effects
