Nutmeg tree ( Myristica Fragrans) gives two important spices namely nutmeg and mace. The peak harvesting period is June to August which coincides with our monsoons. The fruits are ripe and ready for harvest when the pericarp splits open. The split fruits are either plucked from the tree or collected after they drop on the ground. After harvest, the rind is removed from the fruit and nut and mace should be separated manually. Both these two spices need to be washed with clean water. The well drained nut and mace should be put in the drying unit or yard on the same day of harvest.
The quality of all spices including nutmeg and mace depends to a large extend upon the post harvest operations. Post harvest operation in nutmeg includes separation of nut and mace, washing, grading and drying. Among the various operations drying remains the most important especially because; nutmeg is being harvested during the monsoons in Kerala. The time taken for bringing the moisture level to the desirable level is most important.
Sun drying is more prevalent in Kerala. Harvested nutmegs are spread on cement floors, rooftops, mats for drying and exposed to direct sunlight. While sun drying, care must be taken for not to expose the nutmegs to excessive heat and to avoid contamination by domestic animals, rodents and birds.
Nutmeg and mace are dried separately as the moisture content of wet nutmeg is higher than that of mace and time required for drying is different. Mace takes four to five days for drying and nutmeg takes 10 to 12 days depending upon the intensity of the sun light. Nutmegs are dried in the sun until the seeds inside rattle on shaking. In sun drying, the disadvantages are the products are exposed to direct sunlight, no uniformity in drying, presence of mould and infections and contamination.
Mechanical drying is the right answer to tide over the Aflatoxin problem in Nutmeg and mace. Mechanical and firewood based driers can be used for drying both nutmeg and mace. In case of nutmeg drying, a temperature of 40 degree Centigrade may be adopted for about 6 to 8 hours for three days. Continuous drying may be avoided. Mace will take only 5 hours to dry at 40 degree centigrade. Mechanically dried nutmeg is clean, free from extraneous matter and conserves the basic qualities like aroma, flavor and appearance. Maintenance of better quality, drying even in unfavorable climatic conditions at reduced drying time are the main advantages of mechanical drying. Care should be taken to see that shell is not broken nor the nutmeg oil oozes out due to excess heat during drying. Both nutmeg and mace need to be dried to a maximum moisture level of 10 percent.
Spices are hygroscopic and interact with moisture in the atmosphere. The risk of mould growth is natural and therefore it should be protected from relative humidity. The mace can be stored for more than a year in thick plastic barrels with airtight lid and sealed with cellophane tape around the lid. Nutmeg is usually packed in polythene bags and such bags in jute bags weighing up to 50 kilos. Care must be taken to avoid sweating and mould development while storage. Nutmeg and mace should be stored away from compound wall and goods which are sensitive to moisture and humidity. The ideal temperature for storing nutmeg is 20 to 25 degree centigrade and at higher temperature essential oil may be lost.
World Spice Organisation (WSO) in association with Spices Board, Government of India has conducted awareness programs at major producing centers of nutmeg to address Aflatoxin contamination in nutmeg. The campaign stressed the need of Good agricultural practices, post harvest practices including mechanical drying and proper packaging and storage.
