Carbohydrate and nitrogenated compounds in liquid smoke flavorings

Commercial smoke flavorings were extracted with dichloromethane and the rem aining aqueous phase was evaporated at room temperature; the residues obtai ned were dissolved in methanol and studied by gas chromatography/mass spect rometry. The composition of these residues was totally different from that of the dichloromethane extracts, constituting a small number of compounds t hat were also detected in the dichloromethane extract, as well as a large n umber of compounds not described before as components of either smoke for f ood smoking or smoke flavorings. Among those compounds not previously descr ibed there are some furan, pyran, and phenolic derivatives, as well as some pyridine and carbohydrate derivatives. The main component of these fractio ns is 1,6-anhydro-beta -D-glucopyranose, or levoglucosan. Likewise, aqueous residues of liquid smoke flavorings, prepared at a laboratory scale from b eech, vine shoots, thyme, and sage, were studied in the same way. These con tained compounds of the same groups cited above, but showed clear differenc es. The aqueous residue of beech smoke flavoring was the most similar to th at of the commercial smoke flavorings. The aqueous residues of vine shoots, thyme, and sage smoke flavorings contained a lower number of furan, pyran, and carbohydrate derivatives and a higher number of nitrogenated derivativ es. Instead of levoglucosan, the main component was an unidentified compoun d, present in all samples, included in the carbohydrate derivatives group. In the samples studied, the influence of the vegetal source on the composit ion of the aqueous fraction has been shown. In the future, attention must b e paid to the functionality of these smoke components.