APPLICATION OF TIME-INTENSITY PROCEDURES FOR THE EVALUATION OF TASTE AND MOUTHFEEL

*Professor Noble presented the ASEV 1994 Honorary Research Lecture at the 45(th) Annual Meeting of the American Society for Enology and Viticulture in Anaheim, California (June 1994). She specializes in sensory and chemical analysis of wines and other systems. Her projects include evaluation of temporal properties of specific attributes, the role of saliva in taste perception, and the effect of geographical, viticultural, and enological facto rs on must and wine composition and wine sensory properties. The text of her presentation has been edited for publication. Temporal evaluation has important applications for characterizing wine sensory properties, such as astringency and bitterness, which are very persistent. Factors influencing perception in time-intensity studies include mode of evaluation, structure and concentration of compounds, and individual variation such as in salivary Row rates. As stimulus concentration is increased, maximum intensity and total duration increase, whereas only small differences in time to maximum occur. Little difference is observed between evaluation of bitterness or sourness by sipping versus swallowing. No differences in perception of sweetness or sourness have been found as a function of salivary flow, despite lower oral concentrations of stimuli in high-flow judges after expectoration. In contrast, large differences are observed in perception of bitterness and astringency. Low-flow subjects perceive both attributes more intensely throughout the evaluation, and persistence lasts longer than for high-flow subjects.