“…Several Maillard by-products, such as sotolon, 2-furfural, 5-methyl-2-furfural, 5-(ethoxymethyl)-2-furfural, methional, and phenylacetaldehyde were detected, which clarify the baked, brown sugar, and nutty aroma descriptors of Madeira wine. From these studies [4,77], sotolon, due to its low OT (10 µg/L), is reported as a key odorant on the conventional aroma of aged Madeira wines [36,78,79]. The formation pathways of sotolon are not well elucidated [79], although many precursors and pathways have been suggested for its formation in wines, namely oxidative degradation of ascorbic acid in the presence of ethanol, aldol condensation, peroxidation of acetaldehyde, and the Maillard reaction, among others [36,78].…”