Pigeon Peas Processing

Purchase at farm-gate, village aggregation points and regional markets.

Volume is assembled from smallholder production through village aggregators, regional traders and warehouse operators in the producing districts. Buying is organised around the harvest window for each origin, because the widest choice of crop-year, colour and size is available while the crop is moving. Lots are assessed on arrival at the buying point for visible moisture, obvious admixture, insect activity and off-colour material before purchase.

Sampling, moisture check and lot identity on receipt at the processing point.

Incoming trucks are sampled with a probe or by drawing from multiple bags across the load, and the composite sample is checked for moisture, foreign matter, damaged and immature grains, admixture of other varieties and live insect infestation. Each accepted delivery is given a lot identity so it can be traced through cleaning to the final packed consignment. Loads outside the intake tolerance for the intended contract are either rejected or set aside for a lower specification.

Applied when incoming moisture is above the target for the contract.

Pulses purchased early in the harvest, or after unseasonal rain, can arrive above the moisture level a shipment requires. Where that happens the crop is conditioned — sun drying on tarpaulins or drying floors, or mechanical drying where available — before it enters the cleaning line. Moisture is the single most important factor in whether a pulse arrives sound after four to six weeks in a sealed container, so this step is only skipped when incoming moisture already meets the contract.

Removal of straw, pods, dust, soil and coarse field trash.

The first pass removes bulk contamination that arrives with farm-level threshing: pod fragments, stalk, leaf, string, dust, mud balls and large stones. Pre-cleaning protects the downstream machinery and makes every subsequent separation more effective, because screens and gravity tables work far better on a stream that is already free of coarse trash.

Air separation of dust, chaff, husk and light immature grains.

A controlled air stream lifts material lighter than sound grain out of the flow — dust, husk, chaff, shrivelled and immature grains, and insect-hollowed seed that has lost density. Aspiration is usually integrated into the pre-cleaner and repeated after screening. It is the main tool against light foreign matter, and it also removes a meaningful share of insect-damaged seed because damaged grains weigh less than sound ones.

Vibrating decks separate oversize, undersize and target-size grain.

Stacked vibrating screens split the stream by size. The top deck scalps material larger than the product — clods, stones, pod fragments, foreign seeds — while the lower decks drop out undersize grain, broken pieces, sand and small weed seed. For products sold on a size basis, such as mung beans and Kabuli chickpeas, this is also where the crop is graded into the count or millimetre band the buyer has contracted.

Density separation of stones, mud balls and heavy foreign matter.

A destoner uses a fluidised, inclined deck to separate material of the same size but higher density from the grain flow. This is what removes small stones, soil pellets and metal fragments that pass through screening because they are dimensionally identical to the pulse. Stone content is one of the parameters processors and mills in destination markets check first, so destoning is a routine part of the line rather than an optional extra.

Fine density grading to lift out insect-damaged and hollow seed.

A gravity separator refines what aspiration and destoning start, splitting sound, dense grain from material of similar size but lower specific weight — insect-hollowed seed, partly filled grain, weathered and heat-damaged kernels. On pigeon peas and cowpeas this step does most of the practical work of reducing insect-damaged percentages, because bruchid-attacked seed is dimensionally normal and only density reveals it.

Optical sorting for discoloured, off-colour, mouldy and defective grain.

Optical sorters pass the product in a thin stream past camera arrays and eject grains whose colour falls outside the accepted range — discoloured, stained, mould-marked, heat-damaged, off-variety and remaining foreign seed. Sorting can be run at different intensities: a light pass protects yield while lifting the visual grade, and an aggressive pass produces a very clean sample at the cost of a higher reject fraction and therefore a higher price. "Sortex" is used across the trade as a generic term for this step regardless of machine manufacturer.

Composite sample drawn from the cleaned lot and checked against contract.

Before packing, a composite sample is drawn from the finished lot and checked against the agreed contract parameters — moisture, purity, foreign matter, admixture, damaged and broken grain, discoloured grain and, where applicable, size or count. Retained samples are kept for the lot so that any discussion after shipment can be referred back to what was packed.

Net weighing into the contracted packing, stitched and marked.

Product is weighed to the contracted net weight per bag and closed by machine stitching. Bag type, liner, weight, buyer branding and shipping marks all follow the contract; the packing specification is confirmed in writing before bagging starts, because re-bagging after the fact is expensive and delays loading.

Lot and crop-year marking that ties bags back to intake records.

Packed bags carry the marks agreed with the buyer, which typically include product description, net weight, crop year, country of origin and a lot or batch reference. That reference links the packed consignment back to intake, cleaning and final-check records, which is what makes any later quality query answerable.

Applied where the destination or contract requires it, by licensed operators.

Dry pulses are susceptible to bruchid and weevil activity that can develop in transit, so many contracts and many importing authorities require fumigation before or at the point of stuffing. Fumigation is carried out by licensed operators using approved products and dosage, and the certificate is issued by the operator rather than by the exporter. Requirements differ by destination and change over time, so the applicable treatment is confirmed for each shipment.

Independent inspection where the buyer, bank or destination requires it.

Where the buyer, the letter of credit or the destination requires independent verification, a third-party inspection company is appointed to sample the lot, verify quality against contract, witness weighing and supervise container stuffing. The inspection company is nominated by the buyer or agreed between the parties, and its report is issued directly by that company.

Container inspection, lining where required, stowage and sealing.

Containers are checked for cleanliness, odour, holes and previous cargo residue before loading, and are lined with kraft paper or polythene where the product or destination calls for it. Bags are stowed to distribute weight evenly and to limit movement in transit, desiccant is used where the route and season warrant it, and the container is sealed with a numbered bolt seal recorded on the shipping documents.