The impact of grape variety on the aromatic chemical composition of non-aromatic Peruvian pisco

Pisco is a common beverage, originating in some South American countries (such as Peru and Chile), which is obtained by distillation of wine made from different varieties of grapes. In this paper, thirty one commercial Peruvian pisco samples made with Negra Criolla, Mollar and Uvina grapes have been analyzed by gas chromatography-flame ionization (GC-FID) and mass spectrometry detection (GC-MS). A representative sample of each variety was also evaluated by gas chromatography-olfactometly (GC-O). A sensory descriptive analysis also was carried out to evaluate the effect of these varieties on the sensory properties of pisco. All these analyses provide a novel and complete information about the aromatic composition of these three varieties of piscos. It is the first time that the aromatic profiles of Negra Criolla, Mollar and Uvina piscos have been evaluated. The Negra Criolla grape gave a neutral aroma to pisco with no particular aromatic notes. The Mollar variety was notable for the presence of beta-phenylethyl acetate in high concentrations and low levels of volatile phenols and some esters. The Uvina samples showed significantly high levels of esters, cinnamates and terpenes and low levels of beta-phenylethyl acetate. The Uvina piscos received the highest score in the sweet descriptor, which could be related to their high levels of esters, acetates and terpenes. In addition, the odor thresholds of 35 compounds have been estimated for the first time in a solution consisted of a 40% ethanol/water (v/v) mixture, simulating a real sample of pisco. Thirteen compounds were found in higher concentrations than their corresponding thresholds in some of the piscos analyzed. Four of these had aroma values higher than or equal to unity in more than 70% of all the non-aromatic varieties of piscos. These compounds are: ethyl isovalerate, 2-methyl-1-butanol, 3-methyl-1-butanol and beta-phenylethanol. It is worth noting the low odor threshold of ethyl isovalerate, being only 5 mu g L-1. (C) 2013 Elsevier Ltd. All rights reserved.