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J Agric Food Chem

Title:		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
Author(s):		Burdack-Freitag A; Schieberle P;
Address:		"Deutsche Forschungsanstalt fur Lebensmittelchemie , Lise-Meitner-Strasse 34, 85354 Freising, Germany"
Journal Title:		J Agric Food Chem
Year:		2012
Volume:		20120502
Issue:		20
Page Number:		5057 - 5064
DOI:		10.1021/jf300908d
ISSN/ISBN:		1520-5118 (Electronic) 0021-8561 (Linking)
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"
Keywords:		"Chromatography, Gas Corylus/*chemistry *Hot Temperature Humans Indicator Dilution Techniques Isotopes Italy Nuts/*chemistry Odorants/*analysis Plant Oils Smell Sunflower Oil Volatile Organic Compounds/analysis;"
Notes:		"MedlineBurdack-Freitag, Andrea Schieberle, Peter eng 2012/04/21 J Agric Food Chem. 2012 May 23; 60(20):5057-64. doi: 10.1021/jf300908d. Epub 2012 May 2"