Characterization of the Key Aroma Compounds in a Freshly Prepared Oat (Avena sativa L.) Pastry by Application of the Sensomics Approach

Oat flour has a weak cereal-like, powdery aroma, which is significantly changed by a thermal process. Application of an aroma extract dilution analysis on a distillate obtained from oat pastry prepared under defined conditions led to the detection of 43 odor-active areas in the flavor dilution (FD) factor range of 2-8192. Among them, 3-(methylthio)propanal (cooked-potato-like), 2-acetyl-1-pyrroline (roasty, popcorn-like), vanillin (vanilla-like), 2-methoxy-4-vinylphenol (clove-like), 1-octen-3-one (mushroom-like), 2-propionyl-1-pyrroline (roasty, popcorn-like), and (E,E,Z)-2,4,6-nonatrienal (oat-like) were identified with the highest FD factors. Nine aroma compounds were identified for the first time in oats or oat products, and (E,E,Z)-2,4,6-decatrienal, also showing an oat-like odor quality, is reported for the first time in foods. Quantitation of the 36 most important compounds by means of stable isotope dilution assays followed by a calculation of odor activity values on the basis of odor thresholds in corn starch revealed 2-acetyl-1-pyrroline, vanillin, the tautomers 2-acetyl-3,4,5,6-tetra-hydropyridine and 2-acetyl-1,4,5,6-tetrahydropyridine, 3-(methylthio)propanal, 2-propionyl-1-pyrroline, and methanethiol as the key aroma-active compounds. An aroma recombinate prepared in odorless oat pastry material containing 30 odorants in the concentrations determined in the oat pastry was able to successfully mimic the overall aroma profile of the original oat pastry.