Section III - Post harvest handling

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1. Harvesting
2. Post harvest handling operations in the field - preparation for marketing to GCNA
3. Yield patterns
4. Handling operations in the receiving and processing station

 

1. Harvesting

The ripe or mature fruit splits open at the groove while still on the tree and the seed surrounded by the red aril falls to the ground after two days. Harvesting involves collecting the seed or seed with aril from the ground. Sometimes fruits with partially opened pods may be picked from the tree using a long pole "rodding". The latter method affords a better quality aril, and pods that could be used in agroprocessing. This procedure may also lead to excessive dropping of flowers and young fruits.

The frequency with which nutmegs are harvested is dependent on the location of the field, the availability of labour, the level of production, and the price offered to farmers. Most farmers collect the fallen seeds daily during the two peak production periods - January to March and June to August, and every two to three days during the rest of the year. Once the field is readily accessible nutmegs are harvested with a higher frequency. In the cases where farmers are part-time, fields located in distant areas, or when the farm is comprised of several plots of land at different locations, then the collection rate may be as low as once per week. Observations show that a larger proportion of women are usually involved in harvesting.

2. Post harvest handling operations in the field - preparation for marketing to GCNA

In the case where rodding was used, open fruits may fall to the ground intact. The seed with the surrounding red aril is removed from the pod which oftentimes is discarded. The collected seeds, and seeds with mace are transported from the field by workers, on their heads or assisted by animal (donkey) or vehicle to the boucan or farmer's residence where the mace is carefully separated from the seed, graded and allowed to dry directly in the sun. Care is taken so that drying mace does not get wet. Wetting will encourage mould growth and such mace will have to be discarded.

The seeds are usually delivered green (fresh), within 24 hours after harvesting to the receiving station. However, depending on the distance from the receiving station and the quantities of nutmegs involved, deliveries may be made once weekly or at a much later period if the nutmegs are being delivered in the dry state. This is usually the situation with large estates with adequate drying facilities. Mace is always delivered to receiving station dried.

3. Yield patterns

A tree from seedling usually "declares" in five to eight years. Trees propagated vegetatively by marcots may fruit as early as in three years. Yields increase gradually and at 25 - 30 years the plant may have peaked to its maximum production level. It continues to bear up to 100 years and over (personal communication - Reynold Benjamin). However, after age 70 -15 yields tend to decline.

In Grenada it is not easy to ascertain the yield per acre since most fields are heavily intercropped and there are variations in the number of trees planted per acre. It is estimated that the tree population may be in the vicinity of 400-450 thousand. There are only a few locations with pure stance nutmeg trees in moderate acreage.

There is no serious documentation to support tree yields. However, a good producing tree may give on an average a yearly production in the vicinity of 30-50 lbs (14-22 kg) green nutmegs (15-25 lbs - 7-11 kg of shelled, dry nutmegs). The proportion of dried shelled nutmeg to dried mace is approximately 20:3. During drying nutmeg loses about 25% of its weight. Yields vary greatly between trees, and between plantations or field locations.

4. Handling operations in the receiving and processing station

Fig. 3 outlines the main stages in the processing of nutmeg and mace.

Following the postharvest operations in the field and at home, the farmer delivers the nutmeg products to a GCNA (Grenada Cooperative Nutmeg Association) receiving station. There are 16 GCNA receiving stations well distributed around the island as shown in Fig. 4. Additionally, there are 3 processing stations at Grenville, Gouyave and Victoria. These 3 also carry out receiving stations activities.

FIG. 3. Stages in the processing of nutmeg and mace at receiving and processing stations

Fig. 4 Location of GCNA Received and Processing Stations

The GCNA purchases both nutmeg and mace products from the farmers. Three types of nutmeg are purchased:.

1. Fresh or green nutmegs (undried and still in their shells)
2. Dry nutmegs (dried but still in shells)
3. Grinders (dried and shelled)

Mace is bought dried, either as No. I or No.2, the No. 1 being of better quality, dark red, unbroken, dried and unblemished.

Although the term nutmeg is used very loosely to cover fruit, seed or kernel, the spice nutmeg for commerce is solely the dried seed kernel, and the spice mace is the dried and cured aril.

Since for the GCNA annual production is expressed in terms of commercial nutmeg, then the purchased green nutmegs need to be dried and shelled and the dry nutmegs need to be shelled. A conversion factor is therefore used at arriving at a commercial production figure, this is calculated by multiplying the weights of green nutmegs by 0.5, dry by 0.6667 and grinders by 0.98.

Thus processing by GCNA involves the production of the spices of commerce Nutmeg and Mace.

In summary, this includes all aspects of quality control, sorting, curing, grading, packing, shipping and marketing.

The processing of nutmeg and mace will be outlined separately.

4.1 Nutmeg

Sorting

On delivery at the receiving station the green nutmegs are emptied into sorting trays. These trays are wooden and four sided, 5 ft (152 cm) long by 2 112 ft (76 cm) wide and 9 inches (23 cm) deep with a slightly perforated wooden base and angled gently towards an emptying hole at one end, and standing on legs about 3 ft (91 cm) off the floor.

The inspector or inspectors spread out the seeds with a wooden pallet, and hand select out broken seeds, slightly discolored seeds, water-logged seeds, empty or rotten seeds, mouldy seeds, very light seeds and germinating seeds. These are usually returned to the delivering farmer (photographs 15 a,b)

The remaining seeds are scooped into a receiving bag. When all of that particular farmer's consignment is sorted, the bag or bags are weighed and the weight entered into the farmer's assigned book and recorded at the station. The farmer is given a bill and is paid at what ever is the then rate per pound. At the end of the day all collected nutmegs are reweighed and checked against the weight paid out for, and this weight is entered in the "reweighed book" at the station.

Drying

Bags with about 100 lb (45.5 kg) of seeds are hand sewn at the top and carted to the hoisting area for lifting to the drying floors. Smaller quantities may be handled at the smaller receiving stations. Also at the peak periods or times of very high deliveries, nutmegs are transported from the receiving stations to the processing stations daily.

For drying, the fresh seeds are spread on large trays to a depth of 2-3 inches (5-7.5 cm). The seeds are turned daily with wooden rakes or spades. Seeds are shade dried in the buildings at a temperature of 85-90F (29-32C) for six to eight weeks. Drying trays have wooden bottoms and wooden sides with periodic trap doors. Trays vary in size according to the station, but are usually arranged in tiers with about 4-8 trays above each other separated by 1 ft (or 30.5 cm) between trays. Trays are arranged so that there is always easy passage between stacks of trays to afford ready access to all seeds. However, for the higher trays workers have to climb up to gain access.

The energy for drying comes from the sun on the large galvanized roof of the station and the warm circulating air. Seeds closer to the roof tend to dry much faster. Drying completion is indicated by simple inspection. Usually after 6 weeks a sample of seeds is taken, these are cracked, cut with a knife and inspected for moisture. The characteristics looked for are rattling in shells, difficulty or ease to cut, degree of oiliness and intensity of the aromatic smell.

After the drying period and satisfaction with the inspection, the seeds are heaped in the trays close to a trap door which on raising allows easy scooping into bags. Each bag carrying 150 lbs (68 kg). Bags are sewn and dried nutmeg in shells are stored until an order is received (photographs 16 a, b, c, d)

Photo. 15a. Delivery and sorting at Grenville Receiving/Processing Station
Photo. 15b. Sorting at Grenville Receiving/Processing Station
Photo. 16a. Hoisting of hagged fresh nutmegs to upper drying floors
Photo. 16b. Stirring drying nutmeg
Photo. 16c. Collecting dried nutmeg
Photo. 16d. Storage of dried nutmeg
Photo. 17. Worker loading cracking machine
Photo. 18. Sorting nutmegs that have passed through the cracking machine

The preceding is the limit of processing that can take place at a receiving station.

Cracking and Sorting

The other stages of the processing are carried out on the receipt of an order.

Most cracking is now done by cracking machine. The loaders empty bags of 90 lbs (50 kg) into the feeder (photograph 17), the machine cracks the seed coat and these are channeled to the right and left of the machine from where they are spread manually with a wooden spade so that the entire length of the sorting area could be supplied. As many as (90 - 100 bags) could be cracked in a day (Grenville Processing Station)

Sorting is done manually. Workers seated at stools have cracked seeds fed to their work stations, via their individual trap doors which they operate.

Sorting and shelling generates four products which are compartmentalized by the sorter. The products are:

1. Whole kernels
2. Cracked kernels or pieces
3. Escapes - seeds with unbroken testa
4. Shells

Sorting is done by women and there may be as many as thirty two working simultaneously. The expected output is 170 lbs (77 kg) per worker per day. However, most workers average 350-450 lbs (159-204 kg) daily (photograph 18)

Grading and Flotation

The first grading of shelled kernels is effected by flotation in water using the principle of varying density. The procedure is to place 20-30 lbs (914 kg) kernels in a wicker basket. The wicker basket is then immersed in water held in a concrete trough to a level just about I inch (2.54 cm) below its rim. The kernels are then agitated by hand. Once stirring stops, some kernels are seen to remain at the bottom of the basket while others float. All "floats" are removed as defectives along with any kernels seen to be moving or in suspension (doubtfuls). Workers (female) try to effect this in as short a time as possible. The kernels remaining at the bottom are classified as Sounds. The detectives (floats) are grouped, basketed and spread on trays to dry for 48-72 furs. The sounds are spread usually on the upper trays to dry for 24 furs. Both grades are turned twice daily while drying.

When detectives "floaters" are inspected by cutting in half, they usually show incomplete kernels (large airspaces, or whitish cork tissue with reduced brownish endosperm) (photograph 19 d).

Sorting Sounds

The dried sounds are gathered and bagged, 150 lbs (68 kg) and then manually sorted (photograph 20). This sorting is usually performed by female workers and each worker is expected to sort a minimum of 21/2, 100 lbs (45.5 kg) bag per day. The sorter spreads the kernels in a wooden tray held in her lap and proceeds to separate three products, which are placed in three separate bags which surround her. The products are genuine sounds "heavies", defective heavies and shells. Constituting these detectives are kernels with pin holes, cracks or breaks (pieces). The sounds could be classified as sound "unassorted" (Suns).

Metal Sieve Grading

Using large metal sieves with uniform regular circular perforations and sieves of different sizes, workers pour on hand-graded sounds and gently massage them. The appropriate kernels fall through the appropriate holes into collecting bags (photograph 21).

The grades collected are:

110 S (110 to the lbs) (242 to the kg)
80 S (80 to the lbs) (176 to the kg)
60/65 S (60/65 to the lbs) (132/143 to the kg)

Inspection of Grades

As an additional quality control measure, before putting into new labelled bags, sound graded nutmegs are further inspected visually. The worker will spread the nutmegs of a particular grade in a small wooden tray and hand remove any broken pieces, cracked nutmegs or shrivelled and discoloured. Such a worker is expected to handle a minimum of 2 (150 lbs 68 kg) daily (photograph 22).

A typically labelled bag is shown in photograph 23.

Photo. 19a. Flotation: nutmegs in basket prior to flotation
Photo. 19b. Flotation: workers agitating nutmegs in immersed baskets
Photo. 19c. Flotation: three baskets, sounds, flotation, floats
Photo. 19d. Cross section through sounds (lower) and floaters (upper)
Photo. 20. Sorting and inspecting sounds
Photo. 21. Metal sieve grading for selected nutmegs
Photo. 22. Inspection of sound selected nutmegs
Photo. 23. Typically labelled bag with nutmeg for export (included in text)

Fumigation

The final processing step for nutmegs before export is fumigation of the bagged nutmegs with methyl bromide in a special fumigation chamber over night.

Defectives

Sometimes the defectives "heavies" are sorted and exported separately.

The "floats" after drying are heaped, then packed in bags and stored until an order for that class of product is received. For export they are then packed in labelled bags and fumigated.

4.2 Mace

The mace delivered at the receiving station though preclassified by the farmer as No. I or No. 2 is still carefully inspected on delivery and classified as No. 1 or No. 2. The mace is weighed and the weight entered in the farmer's book and the book at the receiving station and the farmer is paid.

The mace is then bagged according to grades and at the end of the day the separated grades are reweighed, the weights noted, and the mace placed in separate wooden curing bins (6' long by 4' wide and 4' deep) - 1.83 x 1.22 x 1.22 m. Each bin may be loaded to the level of 1600 - 1700 lbs (727 - 772 kg) and left for 3 months. Into each bin is suspended a bottle with carbon disulphide (CS2) to keep away any insect pest (photographs 24 a,b,c).

After the three months curing period the mace is now ready for export. The cured graded mace is bagged accordingly and fumigated (photographs 25a, 25b and 26)

Photo. 24a. Mace. Uncured No. 1
Photo. 24b. Mace. Uncured No. 2 in wooden bin
Photo. 24c. Mace. Wooden curing bins
Photo. 25a. Mace. Cured No. 1
Photo. 25b. Mace. Cured No. 2
Photo. 26. Mace. Bag labelled for export


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