Sensory detection of cooked flavor development during pasteurization of a guava beverage using R-index

Kinetics of cooked flavor development (CFD) during thermal treatment of a guava beverage was evaluated within a temperature range of 85 degrees C to 90 degrees C. The guava beverage (pH 3.2, 10.8 degrees Brix, and 0.68% titrable acidity) made with 40% juice, 55% water, and 5% sugar was subjected to selected pasteurization treatments. A trained sensory panel and R-index test were used to determine the temperature dependence of CFD. Logarithm of maximum and minimum heating times that resulted in positive and negative sensory detection at each treatment temperature were plotted to calculate the z value (15.1 degrees C). At 90 degrees C, the treatment time required for the panel to detect a change in flavor was 119 s, whereas 184 s and 248 s were needed for detecting the flavor change at 87.5 degrees C and 85 degrees C, respectively. This result allows estimating the effects that Pasteurization treatments will have on guava flavor.