Hyphenated Headspace-Gas Chromatography-Sniffing Technique:  Screening of Impact Odorants and Quantitative Aromagram Comparisons

Abstract

A new headspace-GC-sniffing method is proposed. Using a recently developed headspace cell, the vapor phase is collected under conditions that mimic well those of an aroma above a food. Data treatment is based on detection frequency, rather than on perceived intensity or successive dilutions as used in other approaches. Repeatability appears satisfactory, and independent panels are even able to generate similar aromagrams, without training prior to the analysis. Using a minimum of six assessors, this technique seems to be more reliable than classical ones. To compare detection frequencies between two aromagrams, an estimation of the least significant difference is given. A theoretical justification of this approach is suggested, on the basis of determination of detection thresholds. Keywords: Headspace-GC-sniffing; impact odorants; detection frequency

Gas chromatography-olfactometry

“…These methods are based upon different principles and can be placed into one of the three categories: (i) detection frequency [2,3], (ii) dilution to threshold (CharmAnalysis TM [17,29] and aroma extract dilution analysis (AEDA) [5]) and (iii) direct intensity (posterior intensity method [6], Osme [7,28,30] and the finger span method [8,31,32]). …”

“…The proportion of the panel that is able to detect an odorant at a particular retention time is counted [3,23,33]. Compounds that are detected more frequently are concluded to have a greater relative importance and this is assumed to be related to actual odour intensity perceived at the concentration of compound present in the extract [32].…”

“…Compounds that are detected more frequently are concluded to have a greater relative importance and this is assumed to be related to actual odour intensity perceived at the concentration of compound present in the extract [32]. In addition, the duration of the odour occurrence can be measured, and this can be used to calculate a peak area when multiplied by the number of odour detections [3].…”

“…van Ruth and Roozen [34] and van Ruth et al [35] used the same method but also did not discuss methodology or results in detail. The detection frequency method was further developed and formalised by Pollien et al [3]. The authors' objectives were to develop a method that did not require training a panel and produced repeatable results with the minimum required number of GC runs.…”

“…Based upon this, various GC-O techniques have been developed that can be classified into three types: detection frequency [2,3], dilution to threshold [4,5] and direct intensity [6 -9].…”