Evaluation of the Key Odorante in a Thermally Treated Solution of Ribose and Cysteine by Aroma Extract Dilution Techniques

Application of the aroma extract dilution analysis on a solvent extract isolated from a thermally treated solution (145 °C; 20 min) of cysteine/ribose led to the identification of 2-furfurylthiol, 3-mercapto-2-pentanone, 2-methyl-3-furanthiol, 5-acetyl-2,3-dihydro-l,4-thiazine, 3-mercapto-2-butanone, and bis(2-methyl-3-fiιryl) disulfide showing the highest flavor dilution factors among the 29 odor-active volatiles. HRGC/olfactometry of decreasing headspace volumes established especially 2-furfurylthiol and 2-methyl-3-furanthiol as important odorante and revealed 2-thenyl mercaptan and ethyl mercaptan as further key contributors to the overall roasty, meatlike, sulfury odor of the model mixture. 5-Acetyl-2,3-dihydro-l,4-thiazine, identified for the first time among the volatiles of Maillard model reactions or foods, exhibited an intense roasty, popcorn-like odor at the low odor threshold of 0.06 ng/L of air, which was of the same order of magnitude as those reported in the literature for the roasty-smelling odorants 2-acetyl-1-pyrroline and 2-acetyl-2-thiazoline.