Vanilla curing under laboratory conditions

A laboratory model curing is described in which the cured vanilla beans are analysed for enzyme activity and aroma. The activity of the enzymes was highest in green beans. β-Glucosidase (β-Glu) could not be detected after 24 h of autoclaving. Peroxidase (PER) and protease (PROT) activity decreased, but were still present (20%) after 29 days. Phenylalanine ammonia lyase (PAL) survived autoclaving, but was not detected later in the process. Beans that were scalded for 20 min at 80 °C showed no detectable β-Glu and PAL activity, but PROT and PER were still active. Under traditional curing conditions glucovanillin (GV) and glucovanillic acid (GVA) were hydrolysed to vanillin and vanillic acid, respectively. Upon scalding for 20 min at 80 °C the concentration of glucosides was still high (after 16 day: GV 2000 ppm, GVA 700 ppm). This may be an indication that the normal scalding leads to inactivation of a non-specific glucosidase, while the prolonged scalding also inactivates a specific glucosidase.