Determination of Flavor Threshold Levels and Sub‐Threshold, Additive, and Concentration Effects

Abstract

SUMMARY— The flavor threshold concentrations were determined for 23 compounds composing an artificial peach beverage base. The threshold levels ranged from 52 ppm to 0.4 ppb. The threshold values were used in sub‐threshold, additive sub‐threshold, and concentration trials. Sub‐threshold and additive sub‐threshold effects resulted from only a few of the flavor combinations tried. Change in concentration of one compound in a mixture of six compounds was not readily detectable organoleptically. The difference in concentration could be detected gas chromatographically, but only if the mixtures were extracted with pentane and concentrated. By dividing the respective threshold values into the amount of each compound present in the beverage, a factor was calculated, called the “unit flavor base,” which indicated the relative importance of each compound as a flavor substance in the peach beverage. By dividing the gas chromatographic peak heights by the respective threshold values, gas chromatographic response was weighted for flavor importance. When the unit flavor base and weighted gas chromatographic response were converted into logarithms, the relation between the values was nearly linear. The correlation coefficient was 0.8691 (significant @ 0.01).

Odour and flavour thresholds for key aroma components in an orange juice matrix: terpenes and aldehydes

“…Compounds whose odour thresholds were within the same order of magnitude as those in published studies were vanillin 31 and trans-2-pentenal. 32 Odour threshold for hexanal was between the values found by Larsen and Poll 33 and Tandon et al 16 In general, population thresholds were higher than experienced panel threshold, and orthonasal were higher than retronasal odour thresholds.…”

“…33,42 Finally, different levels of error are accounted for in threshold studies. With one spiked and two reference samples, 31,34,39 there is 33% chance of guessing which is the spiked sample, while with a paired comparison test, 35,36 there is a 50% chance of guessing correctly. Larsen and Poll used a modified duo-trio test, with a 1/6 chance of correct guess.…”

“…42 Vanillin odour threshold was similar in the present study to that published by Keith and Powers. 31 These authors presented samples in a decreasing order of concentration, which is known to induce a fatigue or habituation effect in perception. Therefore, this explains why the threshold value found for vanillin in water in that study is higher than other studies (Table 2).…”

“…28 Most studies reporting odour or flavour thresholds use 10-20 panel members. Some panels are selected for their reproducibility, 31,34 others for their sensitivity and reproducibility.…”

Revisiting psychophysical work on the quantitative and qualitative odour properties of simple odour mixtures: a flavour chemistry view. Part 1: intensity and detectability. A review.

“…Compounds in a peach beverage 1968 [70] In most of the combinations they fail in finding sub-threshold additivity*, but the methods used for measuring threshold were very rough to get precise conclusions…”