Getting into carob

Carob (Ceratonia siliqua L.), a valuable multipurpose tree that is native to the Eastern Mediterranean, has seeds that are difficult to germinate. Traditional methods of scarification include dropping the seeds into boiling water or sulphuric acid but this is not only hazardous, it also acts as a selection process by killing off seeds with thin coats. However, mechanical methods of scarification, which cause fine cracks on the seedcoats, can be achieved by various hand tools or by motor-driven scarifiers.

credit:Philippe Faucon www.desert-tropicals.com

Carob pods and beans have been used as a food for over 5,000 years. The seeds are also said to be the ancient and original weight used by goldsmiths, and instituted from early times as the carat weight. Carob is now widely used as a chocolate substitute and gum from the seeds is used in cosmetics, textiles, pharmaceuticals and other industrial and food products. As a legume, the pods also make excellent fodder, almost equal to cereal grains in food value, and it is widely used as a forage crop in Asia, Europe and North Africa. Carob has also been introduced to North and South America and to Australia and, as a small to medium (3-15m high) evergreen tree, it is a tough species that survives on steep, stony hillsides where no other crop can grow. The tree itself is used in a variety of ways including: wood production, fuelwood and charcoal; as well as environmentally for watershed protection, windbreaks and shelterbelts, soil erosion control, wildlife habitat and land reclamation.

Annual world yield of dried pods is about 400,000 tons, mostly from Spain, Italy and Portugal but cultivation and preparation of industrial products is rapidly increasing in North Africa, especially in Morocco. Plants bear fruit when 6-8 years old and abundant crops generally occur every second year. Average annual yield of fruit per tree is 90-110kg although yields of 10 tonnes of pods per hectare can be achieved if plants are grown under good conditions and tended well. Carob, or locust bean gum, is obtained from the endosperm of the seed kernels. Careful processing is required to achieve gum of good colour and viscosity but it is commercially valuable because it is especially viscous, low in starch and other impurities, and can be used in place of some expensive gums. The pods and seeds are particularly rich in sugar and contain less fat and more vitamins than cocoa, so carob is often sold as a cocoa substitute in health stores.

Planting stock is usually raised in nurseries from seeds although, if planting carob on land previously used for agriculture, stands can be created by direct sowing. Planting stock can also be propagated by cuttings, suckers, layers and air-layering. For fast growing and high yielding trees, buds from good varieties are grafted to 3-4 year old seedlings in the field. As a dioecious species (separate male and female plants), female trees need to be inter-spaced with 5% well-placed male trees, which provide the necessary pollen. Only the female trees produce brown leathery pods (up to 1 foot long) 11 months after pollination. Density of established trees can range from 25 to 100 plants per hectare.

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