Analysis and Sensory Evaluation of Volatile Constituents of Fresh Blackcurrant (Ribes nigrum L.) Fruits.

Abstract

Volatile constituents of fresh blackcurrant (Ribes nigrum L.) berries were isolated via vacuum-headspace extraction and analyzed by capillary gas chromatography-mass spectrometry. In agreement with previous studies with frozen fruits, short-chain esters and terpenes were major compound classes. However, rather high concentrations of C6-compounds (e.g., (E)-hex-2-enal, (Z)-hex-3-enal) constituted a striking difference to data reported for frozen fruits. Frozen storage of blackcurrant berries was shown to result in drastically reduced concentrations of C6-compounds and a shift of the volatile profile in favor of terpenes. The time-dependent enzymatic formation and isomerization of C6-compounds adds an additional element of variability to the spectrum of fresh blackcurrant volatiles. Nevertheless, blackcurrant cultivars can be classified according to the major classes of the volatiles of the fresh fruits, if prerequisites, such as the same growing location and the same state of ripeness, are met. The sensory contributions of volatiles of blackcurrant berries were assessed by gas chromatography-olfactometry in combination with aroma extract dilution analysis. 4-Methoxy-2-methyl-2-butanethiol, (Z)-3-hexenal, ethyl butanoate, 1,8-cineole, oct-1-en-3-one, and alkyl-substituted 3-methoxypyrazines were among the volatiles showing the highest aroma activity values.