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 Viti culture in Anaheim, California (June 1994). She specializes in sensory and chemical analysis of wines and other systems. Her projects includ e evaluation of temporal properties of specific attributes, the role o f saliva in taste perception, and the effect of geographical, viticult ural, and enological facto rs on must and wine composition and wine se nsory properties. The text of her presentation has been edited for pub lication. Temporal evaluation has important applications for character izing wine sensory properties, such as astringency and bitterness, whi ch are very persistent. Factors influencing perception in time-intensi ty 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 durat ion increase, whereas only small differences in time to maximum occur. Little difference is observed between evaluation of bitterness or sou rness by sipping versus swallowing. No differences in perception of sw eetness or sourness have been found as a function of salivary flow, de spite lower oral concentrations of stimuli in high-flow judges after e xpectoration. In contrast, large differences are observed in perceptio n of bitterness and astringency. Low-flow subjects perceive both attri butes more intensely throughout the evaluation, and persistence lasts longer than for high-flow subjects.