Pepper, before being made available for human consumption, have to go through several processing steps. The initial processing (onfarm processing) like removing the fruits from the stalk and sun drying them, etc. are done in a decentralised way in the farms. Although the process is very simple many factors like maturity play an important role in the appearance and colour of the final product. Dipping the despiked fruits in boiling water for a minute prior to drying produces pepper with uniform black colour. During the sun drying operation it is very important to turn over the material periodically for uniform drying. Otherwise a poor product with greyish, unattractive appearance and heavy mould growth could result.
At plantation level, the sun drying operation is being replaced by artificial drying. The specifications for pepper have been made more stringent, incorporating maximum tolerance level for various extraneous matters and this made it essential to go in for machine processing for cleaning and drying of pepper.
In modern spice processing plants, pepper which has been dried at the farm level and graded to different standards, further undergoes processing before being sent for human consumption. The dried pepper is passed through mechanical sifters for removal of pinheads, vegetable seeds, fine dust, sand etc. before winnowing and destoning for removal of dust, stalks, light foreign matter and stones. Now all these operations are being carried out with the help of multiple-sieve-cum-air-classifier type of machines and gravity separators. The separated pepper is then washed in mechanical washers fitted with brushes for the removal of any mould growth, or dust on the surface. The mechanical brushes impart a nice shine to the final product. It is then centrifuged to remove water and then dried in electric or diesel fired indirect dryers. The dried pepper is sent through spirals for final cleaning followed by sterilization either by steam or gamma irradiation before being packed. By using pneumatic conveyer-cum-dryer-cum-grader it is possible to complete the operation of drying and grading quickly in sequential steps.
Grades of Pepper
Pepper is classified into several grades depending on the size and shape of the berries. International Standards Organization (ISO) has classified pepper into non processed (NP), semiprocessed (SP) and processed (P). The ISO have set limits for extraneous matter, light berries, pin heads or broken berries and bulk density for these grades (ISO/DIS 958–1, 1996). Pepper growing countries have their own national standards and the most popular grades in India are Tellichery Garbled Special Extra Bold (TGSEB), Tellichery Garbled Extra Bold (TGEB), Malabar Garbled (MG), Malabar Ungarbled (MUG), Garbled Light (GL), Unspecific and Pinheads(PH)-based on the size, shape and colour.
Other Value Added Products
Microencapsulation is the technique by which the flavour material is entrapped in a solid matrix and is ready for release as and when required. Encapsulation can be achieved by a number of techniques-spray drying, coacervation, polymerization etc. Of this, spray drying appears to be the most popular method employed. The process involves homogenisation of the oil/water mixture in presence of the wall material and removing the water under controlled conditions in a spray drier. The advantage of spray drying over other types of drying is that the product, even though in contact with exiting gas, which is at a higher temperature, will never reach this high temperature within the short residence time. During spray drying the oil/ water emulsion is atomised using an atomiser in the spray drier. The atomisation can be achieved either by the use of a pressure nozzle or a rotary nozzle or by a pneumatic nozzle. The fine droplets of the emulsion come in contact with the hot gas in the spray chamber and a semipermeable membrane is formed which will selectively permit the water molecules to diffuse out where as the flavour imparting essential oil is left behind. The residence time of the emulsion droplets are controlled in such a way that it is separated from the hot stream of gases as soon as the moisture level reaches below the accepted value for the product using a cyclone separator.
The commonly used wall materials for the purpose of encapsulation are selected from among vegetable gums, starches, dextrins, proteins, sugars and cellulose esters. The wall material is selected so as to meet as closely as possible the properties like low viscosity at high solids, ability to disperse or emulsify the active material, non reactivity with the material to be encapsulated both during processing and on prolonged storage, uniform film forming property, ready availability etc.
It has been observed from studies () that the addition of surfactants during the emulsification step prior to spray drying will reduce the volatile oil loss. This has been attributed to the ability of the surfactant to reduce the internal rotation within the droplet during the drying step.
Another process developed for microencapsulation is the CR-100 process () and this overcomes the limitations of the spray drying process like reduction in flavour quality and the yield. Another advantage claimed is that the carrier substance can be tailored to suit the processing conditions. Carriers used in this process include hydrogenated fats and fat based emulsions.
Heat Resistant Pepper
These are double encapsulated products in which the capsules are rendered water insoluble by a suitable coating and the contained flavour is released only at high temperatures such as in baking.
Fat Based Pepper
Spices can be sterilised, ground and encapsulated in a single step by this technique. The process involves a combination effecting pressure changes, temperature shock and shear. This three-in-one process using a twin screw extruder retains the colour and flavour principles in the original form due to the very short processing time involved. The fresh spice when fed into the twin screw extruder, the starchy materials get gelatinised and forms an encapsulated product. This will drastically reduce the bacterial, yeast and mould contamination. The product emerges as a spice “rope” from the extruder which is cut to pellet size. Lucas Ingredients, U.K () are marketing this product under trade name “Master Spice”.
Pepper being the most important spice used by humankind, there is further scope for its product diversification.