2.9 Processing
Grinding a herb or spice to a specified particle size using standardised sieve apertures is a normal processing activity . Grinding gives easier mixing in the final food product and aids the dispersion of flavour throughout the food . A food manufacturer will have specific parti cle size requirements and the processor will have to mill the herb or spice through sieves that will ob tain the fineness required. There are specific examples. White pepper is produced by removing the pericarp (fruit wall) from ripe pepper fruits, and then grinding. White pepper is traditionally prepared by steeping ripe fruits in water for a few days, rubbing to remove the pericarp, washing and drying. The berries that are beginning to ripen are put into bags and soaked in water to soften the pericarp, which is then washed off and the seeds dried in the sun. The quality of the water used for soaking the berries is important, as pepper soaked in muddy or dirty water may be discoloured or have foreign odours. Soaking tanks and clean water produces pepper of higher quality. For black pepper, berries are harvested when mature green, de-spiked and dried in the sun. For both black and white pepper, the quality of the product is dependent on the weather, as almost all the pepper is sun-dried. Efforts to improve quality by cleaning out foreign matter, stalks, and light berries by simple sieves and blowers reduce the amounts transported and increase the value. Ground pepper is obtained by grinding pepper with equipment like a hammer-mill. The pepper is first fluidised for the removal of extraneous matter and then passed through screens. Specifications for a mill and grinder are available at:
http://www.fao.org/inpho/isma?m=equipment&txt=spice&i=INPhO&p=SimpleSearchDetail&lang=en&op=or&n=2
Cardamom capsules should be sorted into size classes and different size sieves will allow different grades to be separated as well as the separation of split and insect infested capsules. In addition to the green cardamom capsules, there is a bleached cardamom product that is creamy white or golden yellow in colour. Bleaching can be undertaken with dried capsules or freshly harvested capsules. The bleaching of fresh capsules is undertaken by soaking for one hour in 20% potassium metabisulphite solution containing 1% hydrogen peroxide solution to degrade the chlorophyll. On drying these capsules yield a golden yellow colour. The bleaching of dry capsules can be undertaken by a number of methods viz sulphur bleaching, potassium metabisulphite with hydrochloric acid and hydrogen peroxide, hydrogen peroxide, or the traditional method by steeping in soap-nut water. The quality requirements vary depending on the end use and are related to moisture level, cleanliness, content of sub-standard product, extraneous matter, appearance and colour, for example if the processor values the extractives, volatile oil and specific ingredients. There are specific quality standards for India and Sri Lanka . Although cardamom is usually sold in the form of dried capsules, cardamom is also processed into various products such as seeds, powder, oil, oleoresin, and encapsulated flavour. Cardamom seeds are obtained by decorticating the capsules by use of a plate mill. The ratio of seeds to husk is 30:70. The storage of cardamom seed needs care to maintain the essential oil and boxes lined with aluminum foil are favoured. Cardamom as a powder gives the maximum flavour to the food products but the disadvantage is that it loses aroma quality by the loss of the volatiles. Whole nutmegs are grouped under three broad quality classes. Sound: nutmegs that are mainly used for grinding and for oleoresin extraction. Substandard: nutmegs that are used for grinding, oleoresin extraction and essential oil distillation; and poor quality nutmegs for essential oil distillation. The shelling of nutmegs can be undertaken by hand or machine, and care is necessary to prevent bruising of the kernels. Cracking the shell is often undertaken by machine that can be a centrifugal type in which the rotary motion of the machine forces the nut to be thrown at high speed against the inside of the drum. Once the cracking is complete, the nuts are sorted when whole kernels are separated from broken pieces. Floatation in water is used to remove unsound kernels, as these kernels are lighter than water and float. Sound kernels can be sorted on their quality and size and separated from broken kernels. Sizing can be carried out using different mesh sized sieves. Sorted kernels are bagged and labeled and fumigated when for export.
Application of fat–soluble anti-oxidants has been found to improve colour retention in Capsicums, Chilli peppers and Paprika, and the addition of these antioxidants is more effective after curing than before and in the ground spice rather than whole pods.Cayenne pepper is prepared by grinding chillis through a 40-mesh sieve. The spice should be a uniform fine powder, orange to dark red with a hot biting taste. Paprika pepper is a relatively coarse bright to brilliant red powder with a spicy and only mildly pungent flavour.
Saffron stigmas are graded on colour, bitterness and aroma, and the ISO 3632-1 classification divides the filaments into four categories depending on % floral waste and % extraneous matter and on the assay results for colour, bitterness and aroma. The processor will sell different categories based on grading.
Dried turmeric rhizome has a rough dull outer surface with scales and root bits. Smoothing and polishing the outer surface by manual or mechanical rubbing improve the appearance. Manual polishing consists of rubbing the dried turmeric on a dried surface. The mechanical methods can be a hand-operated barrel drum or power-operated drums. The turmeric rhizomes are rotated and the polishing occurs with abrasion against the metal mesh of the drum and mutual rubbing of the rolling rhizomes. In India the yield of polished turmeric from the untreated rhizome varies from 15-25%.
