Olfactometric and sensory evaluation of red wines subjected to ultrasound or microwaves during their maceration or ageing stages

Abstract

In the present work, we have studied the effect that some extraction techniques, such as ultrasound or microwaves, produce on the aroma of red wines, when applied to processes of extractive nature, such as pre-fermentative maceration or ageing with oak chips (Spanish oak – Quercus pyrenaica and French oak – Quercus robur). The volatile profile has been studied by means of gas chromatography coupled with olfactometric and mass spectrometric detection. Sensory analysis of all the wines produced has also been conducted. Although no indications were found to show that the pre-fermentative treatment with microwaves or ultrasound modified the sensory profile of the wines, the application of such energies during the ageing phase showed some positive trends at sensory level, also confirmed by the olfactometric measurements. The application of ultrasound during the ageing of the wines resulted in a greater contribution of red fruits, aromatic intensity and wood than that obtained through microwaves. Regarding the type of oak chips, Spanish oak provided more volatile compounds than French oak and with a lower proportion of undesirable aromas. At the sensory level, Spanish oak also showed greater aromatic intensity and higher values for the wood descriptor, being preferred by the panel of judges.