Evaluation of Process Parameters Governing the Aroma Generation in Three Hazelnut Cultivars (Corylus avellana L.) by Correlating Quantitative Key Odorant Profiling with Sensory Evaluation

Abstract

The majority of the world hazelnut crop is roasted, thus developing a unique aroma that depends on the cultivar used and on the roasting conditions applied. Although several studies have investigated the volatile fraction of different cultivars and have correlated the data with overall sensory profiles, studies establishing a correlation between key odorants among the bulk of odorless volatiles and the respective aroma profiles are not yet available. On the basis of recently published stable isotope dilution assays (SIDAs) using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS), differences in concentrations of key odorants in different hazelnut cultivars roasted under defined conditions were monitored and compared with sensory data obtained by projective mapping, aroma profile analysis, and triangle tests. The results showed that the aroma-active compounds 2-acetyl-1-pyrroline, 2-propionyl-1-pyrroline, 5-methyl-(E)-2-hepten-4-one, 2,3-diethyl-5-methylpyrazine, 3,5-dimethyl-2-ethylpyrazine, and 2-furfurylthiol are appropriate marker odorants to differentiate the various nut aromas. In particular, the appreciated roasty, nutty aroma of optimally roasted hazelnuts was developed if both 5-methyl-(E)-2-hepten-4-one and 3-methyl-4-heptanone were >450 μg/kg, whereas the sum of the two 2-acyl-1-pyrrolines and two pyrazines should not exceed 400 μg/kg to avoid an over-roasted smell. Such a desired aroma can be obtained for each cultivar, but obviously specific roasting times, temperatures, and roasting techniques had to be applied.

Parallel dual secondary‐column‐dual detection comprehensive two‐dimensional gas chromatography: a flexible and reliable analytical tool for essential oils quantitative profiling

“…Most quantitative methods validated for targeted analysis by GC×GC are based on MS detection [high frequency Time‐of‐Flight MS (ToFMS) or fast quadrupole MS (qMS)] because this approach commonly is mandatory for regulated substances (xenobiotics, residues, contaminants, suspected allergens, etc.). In addition, for trace and ultra‐trace analytes, as with several aroma compounds present in a food at sub‐mg/Kg level, with MS detection, diagnostic ions can be used to increase Signal‐to‐Noise (S/N) ratios and thus method sensitivity.…”

Sense of smell and volatile aroma compounds and their role in the evaluation of the quality of products of animal origin – a review

“…In this case, a carrier gas that contains analytes is split off into two flows after exiting the column: one flowing to a chromatographic detector, and the second to an olfactometer. By using this technique, one may evaluate the smell of odour-active compounds flowing out of the column and determine aroma profiles, which may be additionally associated with the sensory evaluation of a test product (Chin et al, 2011;Robinson et al, 2011a;2011b;Kiefl and Schieberle, 2013). The recent set-ups of these types of analytical techniques include multidimensional gas chromatography integrated with an olfactometer and mass spectrometer.…”

“…in nuts (Cordero et al, 2010;Kiefl et al, 2012;Kiefl and Schieberle, 2013), olive and oils (Purcaro et al, 2014;Tu et al, 2014), coffee (Majcher et al, 2013), cocoa (Nicolotti et al, 2013), strawberries (Samykanno et al, 2013), mushrooms (Grosshauser and Schieberle, 2013;Usami et al, 2014), teas and herbs (Baba and Kumazawa, 2014;Lv et al, 2014;, as well as in beverages (Butkhup et al, 2011;Avellone et al, 2013;Inui et al, 2013;Langos et al, 2013).…”

Inlet backflushing device for the improvement of comprehensive two dimensional gas chromatographic separations

“…GC × GC is considered an established separation technique and for the last decade focus has shifted away from the development of modulation technology to applying the technique to an ever increasing number of analytical challenges. Fields in which GC × GC applications are popular include petroleum and petrochemicals [6][7][8][9][10][11][12][13][14][15][16]; food, flavours and fragrances [17][18][19][20][21][22][23][24][25][26][27][28][29][30]; metabolomics [31][32][33][34][35][36][37][38][39][40][41][42] and environmental analysis [43][44][45][46][47][48][49]. Although GC × GC has never been more widespread, there are some applications that remain challenging for a chromatographer to perfect.…”