Tastes and Odors of Water—Quantifying Objective Analyses: A Review

Abstract

Usually, organoleptic criteria have to be fulfilled for tap water in order for it to be considered safe to drink. This can be achieved at three levels: chemical analysis, sensory analysis, or through electrophysiology. While chemical analysis has been quite extensively discussed in the literature and as consumer perception is of vital importance, we propose a review of the latter two levels, namely sensory analysis and electrophysiology. We first recall some basics of perception and how it can be influenced by stimuli properties, human intrinsic factors and contextual factors, which are critical for an efficient measurement. Next, we present sensory analysis methods, as these are usually carried out in order to measure consumer appreciation of water. The drawbacks of such methods are then discussed before introducing the alternative of electrophysiological measurements. Some evidence that activity from the central and autonomic nervous systems can be measured in response to gustatory and olfactory stimuli in water is first described. Then, a review of objective physiological methods in the literature, developed to assess the emotional aspect of these reactions, is detailed. Finally, the possibility of correlating and predicting the quality, intensity, and hedonic dimension of a stimulus in water with sensory self-report and nervous system responses is discussed.