New insight on the genesis and fate of odor-active compounds in vanilla beans (Vanilla planifolia G. Jackson) during traditional curing

Green vanilla beans were subjected to the traditional curing process in Mexico. Odor-active potential from beans including 23 compounds was monitored through the analysis of both free and glucosidically bound volatiles. 8 of them were aliphatic aldehydes, acids, alcohol and ketone. 15 molecules were shikimate derivatives in which 13 were detected in glucosylated form. Some glucosides were efficiently hydrolyzed while some others partly or not at all after 90 days of curing. Moreover kinetics of hydrolysis of glucosides were not the same. A major part of glucovanillin was hydrolyzed at the first stages of curing while some other glucosides at the advanced stages. Data support hypothesis that hydrolysis of glucosides during curing is rather enzymatic origin than chemical one. Free shikimate derivatives or those liberated from glucosides are prone to chemical or enzymatic interconversions leading to a significant change in the aroma profile of cured vanilla. (Résumé d'auteur