ITDG 
Interdev Agroalimentaire  

Small-scale processing of pepper (Piper nigrum)

	Type de fiche	Techniques/Technologies
	Mise en œuvre	ITDG(Royaume Uni)
	
	Zone géographique	Global; 
	Mots clés	POIVRE; EPICE; SECHAGE

	Echelle d’action	Village; Groupe
	Public(s) cible(s)	Small- and medium-scale food processors

Contexte
Black pepper is the dried berry of the vine Piper nigrum.  It accounts for a quarter of the total world trade in spices.  The pepper is black in colour and has a strong aroma and hot taste.  It is used for seasoning foods. The berry is 0.25cm in diameter and has a wrinkled skin.  The product can either be sold whole or ground.

The pepper berries are preserved by drying. The low moisture content prevents the growth of micro-organisms.  When the product is carefully dried and packed in moisture- and air-proof containers, it has a shelf life of several months.

Problématique / Objectifs
  Only mature pepper spikes should be harvested.  Immediately after harvesting the pepper spikes should be laid out in the sun to ensure that the final product has a deep black colour.
  The pepper berries should be dried as quickly as possible after harvest to prevent mould growth.  A small trace of mould can reduce the value of the pepper by half.
  The final product should have a moisture content of less that 12%.  Determining the point of adequate drying is critical.  Over-drying results in a loss of flavour and a reduced weight or yield, which in turn reduces the return on the crop. Under-drying leads to problems with mould growth and reduced storage capacity.  In Sri Lanka, a simple method is used to determine if the crop is dry enough - the processor places his hands into a heap of pepper and if the pepper sticks to the hairs on the hand it is sufficiently dry.
  The drying temperature should not exceed 60 C or flavour components will be lost.
  When blanching the berries it is important that the pepper is not left in he water for more than 10 minutes as volatile flavour components can be lost and the enzymes responsible for the colour changes may be de-activated.

Description/Mise en oeuvre
The processing of black pepper follows these basic steps:

  Harvest
  Fermentation
  Threshing
  Sorting
  Washing
  Blanching (optional)
  Drying
  Winnowing
  Grading
  Packaging and storage

A process flow sheet is available (ref link)
Harvest
Only mature pepper spikes should be harvested.  The flavour and heat intensity are not fully developed in unripe pepper berries.  The pepper berries grow in clusters as 'spikes'.  The spikes should be cut from the pepper vines, rather than cutting the individual berries.

Fermentation
Immediately after harvesting the pepper spikes are laid out in the sun to ferment and to allow the deep black colour to develop.

Threshing
After fermentation, the berries are detached from the spikes.  This can be achieved by hand, by trampling the spikes under foot or beating them with sticks. In some countries threshing and sorting does not take place until after drying.

Sorting
The pieces of stem are removed from the berries.  Large pieces of stem can be picked out by hand, while smaller pieces are removed by winnowing. 

Washing
The pepper berries are washed in clean cold water.  Light berries, which are not suitable for culinary use, will float on top of the water.  These should be removed and dried separately and can be used for oil distillation.

Blanching (optional)
Blanching increases the rate of drying and speeds up the enzymatic reaction that produces the final desired black colour.  It is carried out by immersing the berries in hot, but not boiling, water for up to 10 minutes until the colour changes to a dark green.  A simple method of blanching involves placing the berries in a clean cloth sack that is attached to a stick. The sack can then be immersed and removed from the hot water with relative ease.  After blanching, the raw material should be dipped immediately in cold water to prevent over-blanching or cooking.  Blanching is not essential, but is commonly practised in Indonesia and Sri Lanka.

Drying
The pepper should be dried to a final moisture content of 12%.  Pepper berries are placed on mats that are placed in the sun, away from dirt and dust, and protected from animals and birds. Drying can take up to 12 days in the sun.  Mechanical driers can also be used, which reduces the time needed to dry the produce.  The drying temperature should not exceed 60 C as this spoils the flavour of the pepper.  A range of mechanical driers is available. The choice will depend on local availability, cost and scale of operation.

Winnowing
Dust, dirt and other foreign matter is removed by winnowing the dried seed.

Grading
Pepper berries are graded by size and weight.  This can also be done using a winnowing basket.

Packaging and storage
The pepper berries are packaged in polypropylene as this protects the product from air and moisture.  Polythene is not suitable as it allows the volatile components to pass through. The packets should be stored in a cool, dry place.

Résultats/Eléments chiffrés
The following equipment is required:

Mats for drying or drier
Winnower 
Packaging material
Heat sealer
Grinder/mill (if secondary processing into ground pepper)
Weighing scale

Enseignements
  Processors should pay strict attention to hygiene.  Clean, potable water should be used for washing the berries.  During drying (if sun-dried) the berries should be protected from dust and dirt. Animals, rodents and birds should be kept away from the berries during drying as they are a potential source of contamination. 
  Secondary processing by grinding can add value to the product.  However, this process is fraught with difficulties.  With a whole product it is easy to assess the quality, whereas with a ground product it is very difficult.  Because of this, there is consumer resistance to ground pepper, which can only be overcome by consistently producing high quality ground pepper and gaining the consumers loyalty and trust.  Also, ground pepper loses its flavour more rapidly than the whole berries and has a shorter shelf life.
  Light berries, that are unsuitable for culinary use and are separated out during processing, can be used for oil distillation.  Processors should only carry out oil distillation if they are familiar with the process and they have determined the market demand for the product.  Essential oil distillation is described in a separate fiche (link).

Auteur : Sue Azam Ali
Saisie le : 03/12/2001
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