Peanut Bouquet Molecules Identified

Grab a handful of peanuts, and you’re probably thinking more about satisfying your urge for a snack than the volatile molecules that give peanuts their characteristic smell. This is not the case for Peter Schieberle of the Technical University of Munich, whose research team has figured out the subset of molecules emanating from raw and roasted peanuts that make them so enticing (J. Agric. Food Chem., DOI: 10.1021/jf1026636). Using a combination of analytical chemistry and professional aroma assessors, Schieberle and coworkers found that of the hundreds of volatile molecules in raw peanuts, only 11 contribute significantly to peanut aroma, with 3-isopropyl-2-methoxypyrazine (which smells earthy), 3-isobutyl-2-methoxypyrazine (with a bell-pepper-like scent), and trans-4,5-epoxy-(E)-2-decenal (which has a metallic odor) acting as the most important fragrance ingredients. For roasted peanuts, the team found that 27 molecules contribute to the nutty smell, including 2-acetyl-1-pyrroline (a common aroma noted in popcorn, crusty wheat bread, and basmati rice) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (which has a caramel-like fragrance). The goal of the work is to help the food industry know which molecules contribute to tasty roasted snacks, Schieberle says. Next up, the team will study almonds.