Characterization of the Key Odorants in Raw Italian Hazelnuts (Corylus avellana L. var. Tonda Romana) and Roasted Hazelnut Paste by Means of Molecular Sensory Science

Abstract

The concentrations of 19 odorants, recently characterized by GC-olfactometry and aroma extract dilution analysis as the most odor-active compounds in raw hazelnuts, were quantitated by stable isotope dilution assays (SIDA). Calculation of odor activity values (OAV) on the basis of odor thresholds in oil revealed high OAVs, in particular for linalool, 5-methyl-4-heptanone, 2-methoxy-3,5-dimethylpyrazine, and 4-methylphenol. A model mixture in sunflower oil containing the 13 odorants showing OAVs above 1 in their natural concentrations resulted in a good similarity compared to the overall nut-like, fruity aroma of the raw hazelnuts. Quantitation of the 25 most odor-active compounds in roasted hazelnut paste by SIDA showed clear changes in the concentrations of most odorants, and formation of new odor-active compounds induced by the roasting process was observed. The highest OAVs were calculated for 3-methylbutanal (malty), 2,3-pentanedione (buttery), 2-acetyl-1-pyrroline (popcorn), and (Z)-2-nonenal (fatty), followed by dimethyl trisulfide, 2-furfurylthiol, 2,3-butanedione, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone. The aroma of a model mixture containing the 19 odorants with OAVs above 1 in their actual concentrations in the roasted nut material was judged to elicit a very good similarity to the popcorn-like, coffee-like, and sweet-smoky aroma of the roasted hazelnut paste. New SIDAs were developed for the quantitation of 5-methyl-4-heptanone, 5-methyl-(E)-2-hepten-4-one, 2-thenylthiol, and 3,5,5-trimethyl-2(5H)-furanone.

Chemical Characterization of Virgin Almond and Hazelnut Oils and Their By‐Products

“…For the VHOs, their volatile content was much lower than that measured in the VAOs, and their profile (Table ) featured aldehydes (31–40%), acids (30–31%), and alcohols (16–28%). Hexanal was the main aldehyde, ranging in concentration from 0.99 mg kg –1 (“Pauetet”) to 1.27 mg kg –1 (“Negret”), consistent with previous work . It is important to remark that hexanal is not only a marker of secondary oxidation but an intrinsic characteristic of certain virgin oils aroma .…”

Simultaneous removal of multiple odorants from source water suffering from septic and musty odors: Verification in a full-scale water treatment plant with ozonation

“…Odor activity value (OAV), which was calculated by dividing the odorant concentration by the corresponding OTC, was employed to evaluate the contribution of different odorants to the odor profile (Burdack-Freitag and Schieberle, 2012). The odor characteristics and OTC values of the odorants are listed in Table S1 (Guo et al, 2015).…”

Identification of complex septic odorants in Huangpu River source water by combining the data from gas chromatography-olfactometry and comprehensive two-dimensional gas chromatography using retention indices

“…Odor activity value (OAV), which was calculated by dividing the odorant concentration by the corresponding OTC, was employed to evaluate the contribution of different odorants to the odor profile (Burdack-Freitag and Schieberle, 2012). Odorants with an OAV equal to or above one are considered to be responsible for odor, and the greater their OAV is, the more they contribute to the odor profile (Pang et al, 2012).…”