Handbook of Vanilla Science and Technology

McCormick & Co., Baltimore, Maryland, was granted two US patents for curing vanillaby new and radically different curing methods. The first, apatentauthoredbyTowt(1952), describes a protocol for an accelerated curing process, in which green beans are ground to a thick pulp of puree-like consistency and heated to about 48° to 54°C in a tank, ventilated with forced air and with constant agitation for about 48 hours. After the pulp is cured, it is spread on trays and dried in the oven at 59° to 61°C to a final moisture content of 20%. The dried pulp is then ground, packed, and shipped for use in various vanilla products. A second patent (Graves et al. 1958) deals with the curing of an aqueous extract from green beans. Mature green beans are chopped to fine consistency and agitated with water at room temperature for 3 minutes. Next, the pulp is filtered, followed by repeated washing with pure water and repeated filtration. The filtrates are combined and the extract concentrated under hypobaric condition at 29° C and is then allowed to cure at 70°C for 6 hours. After the curing is over, enough alcohol is added to obtain a single or multi-fold extract. Commercial enzymes could also be added to facilitate the curing process. According to the authors, the extracts produced by this process result in retention of vanilla flavor and odor to a far greater degree than conventional curing protocols.

Kaul (1967) describes a rapid curing method, in which whole or cut green vanilla beans are subjected to temperatures ranging from 35° to 60° C and high humidity (80-100%), carried out in a closed system from 1 to 7 days. Cured beans are then dried at room or slightly higher temperature. This process claims to produce a more uniform curing without mold problems. In another rapid curing method, green vanilla beans are chopped into approximately one-half inch segments, and cured for about 70 to 78 hours in perforated trays within a closed tank maintained at about 140°F(60°C). Tissue exudates are returned to the curing beans and the mixture dried in a rotary drier at about 140°F to a moisture content of about 35 to 40% by weight, transferred to a conditioner and dried with air at room temperature until moisture content is reduced to about 20 to 25% by weight (Karas et al. 1972). This method uses forced air for the removal of moisture much more rapidly than a method described by Kaul (1967). On the commercial scale, the entire curing and drying operation is said to be completed in 4 to 5 days.

Theodose (1973) described a curing method developed at the Antalaha Station in Madagascar, in which green beans are killed by scalding at 63 to 65°C for 2 to 3 minutes, and allowed to sweat in closed chests for about 48 hours. The killed beans are cut into about 1 inch pieces and dried in a hot air drier at 65°C for 3 hours each day for about 12 days. Each day, after the drying cycle is completed, the beans are placed in isothermal chests for accelerating enzymatic actions. After about 12 days, the beans are uniformly cured and have a moisture content of 20 to 25%. According to the US extract manufacturers, the quality of beans produced by this process is good and the vanillin content is higher than the conventionally produced Bourbon beans.

REFERENCES

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Ansaldi, G.M., Marseille, G.G. and Aubagne, J.L.P. (1990) Process for obtaining natural vanilla flavor by treatment of green vanilla beans, and the flavor obtained. US Patent No. 4,956,192.

Arana, F.E. (1943) Action of b-glucosidase in the curing of vanilla. Food Research, 8, 343-351.

Arana, F.E. (1944) Vanilla curing and its chemistry. USDA Fed. Expt. Station, Mayaquez, Puerto Rico, Bulletin No. 42, Washington, DC, USDA.

Arana, F.E. (1945) Vanilla Curing. USDA Fed. Expt. Station, Mayaguez, Puerto Rico, Circular No. 25, Washington, DC, USDA.

Balls, A.K. and Arana, F.E. (1941a) The curing of vanilla. Industrial and Engineering Chemistry, 33, 10731075.

Balls, A.K. and Arana, F.E. (1941b) Determination and significance of phenols in vanilla extract. Assoc. Off.

Agr. Chem., J24, 507-512.

Balls A.K., and Arana F.E. (1942) Recent observations on the curing of vanilla beans in Puerto Rico.

Proceedings of the 8th American Science Congress 1942, Physics and Chemistry Science, 7, 187-191. Ben-Aziz A., Grosssman S., Ascarelli I., and Budouiski P. (1971) Carotene bleaching activities of lipoxygenase and heme proteins as studied by a direct spectrophotometric method. Phytochemistry, 10, 1445-1452.