Corylus avellana L. Aroma Blueprint: Potent Odorants Signatures in the Volatilome of High Quality Hazelnuts
Simone Squara, Federico Stilo, Marta Cialiè Rosso, Erica Liberto, Nicola Spigolon, Giuseppe Genova, Giuseppe Castello, Carlo Bicchi, Chiara Cordero
Abstract
The volatilome of hazelnuts ( Corylus avellana L.) encrypts information about phenotype expression as a function of cultivar/origin, post-harvest practices, and their impact on primary metabolome, storage conditions and shelf-life, spoilage, and quality deterioration. Moreover, within the bulk of detectable volatiles, just a few of them play a key role in defining distinctive aroma (i.e., aroma blueprint) and conferring characteristic hedonic profile. In particular, in raw hazelnuts, key-odorants as defined by sensomics are: 2,3-diethyl-5-methylpyrazine ( musty and nutty ); 2-acetyl-1,4,5,6-tetrahydropyridine ( caramel ); 2-acetyl-1-pyrroline ( popcorn-like ); 2-acetyl-3,4,5,6-tetrahydropyridine ( roasted, caramel ); 3-(methylthio)-propanal ( cooked potato ); 3-(methylthio)propionaldehyde ( musty, earthy ); 3,7-dimethylocta-1,6-dien-3-ol/linalool (citrus, floral); 3-methyl-4-heptanone ( fruity, nutty ); and 5-methyl-(E)-2-hepten-4-one ( nutty, fruity ). Dry-roasting on hazelnut kernels triggers the formation of additional potent odorants, likely contributing to the pleasant aroma of roasted nuts. Whiting the newly formed aromas, 2,3-pentanedione ( buttery ); 2-propionyl-1-pyrroline ( popcorn-like ); 3-methylbutanal; ( malty ); 4-hydroxy-2,5-dimethyl-3(2H)-furanone ( caramel ); dimethyl trisulfide ( sulfurous, cabbage ) are worthy to be mentioned. The review focuses on high-quality hazelnuts adopted as premium primary material by the confectionery industry. Information on primary and secondary/specialized metabolites distribution introduces more specialized sections focused on volatilome chemical dimensions and their correlation to cultivar/origin, post-harvest practices and storage, and spoilage phenomena. Sensory-driven studies, based on sensomic principles, provide insights on the aroma blueprint of raw and roasted hazelnuts while robust correlations between non-volatile precursors and key-aroma compounds pose solid foundations to the conceptualization of aroma potential .