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Advice on Publications Available.This article on carob bean has been prepared by Andrew Gebhardt, an innovative farmer who has pioneered carob bean production in South Australia. The article is of interest for two reasons. Firstly, the information on carob bean and its uses and potential is valuable as it is a crop with very real potential for Australia. Secondly, the efforts by Mr Gebhardt to establish the crop is one of perseverance, initiative and hard work. The difficulties that he experienced are typical of those involved in establishing many new crops in a new environment. We appreciate his willingness to share his knowledge and experiences.
Andrew GebhardtI was seeking a sustainable crop and was attracted by tree crops which I saw as having a number of advantages. These included a deep rooting habit which I saw as ensuring a cycling of nutrients from deep in the soil to the foliage and thence to the soil via litter, in much the same way as in the forest cycle. Another advantage was that trees would be long-lasting. I was also seeking a tree species which would be subject to few pest and disease problems, would involve little work once they were established, could be readily harvested mechanically and which produced a valuable product that could be readily marketed. Carob trees appeared to meet all these criteria.
The carob bean is a leguminous tree crop of the Mediterranean region with Spain producing almost 50% of world production and Italy and Portugal a further 25%. Total world production exceeds 300 000 tonnes.
The pods contain about 90% fruit (known as kibble) and 10% seed. The kibble has a high sugar content of 35 to 50% and can be used as stock food or as a feed additive. It can also be used for human consumption in the form of ground powder or syrup. Both the powder and syrup can be used as a flavouring in drinks, confectionery, cakes and biscuits. Carob seed is used for the production of carob gum, a galactomannan, which is used as a high quality thickener in food products such as ice cream, desserts and soups.
We have now been growing carob trees for 14 years and harvested our first crop in March 1996. It has been very much a learning experience and we made some expensive and time-consuming mistakes. Our first planting was made in 1981 using seedlings and the early field establishment was good. Unfortunately, a severe frost late in the spring of 1982 killed all the 1982 plants and most of the 1981 plants. We replanted in 1983 but again experienced serious losses due to frosts. We subsequently replanted and in 1985 direct seeded a further area. We protected the young seedlings with old tyres and this, along with the direct seeding, helped us establish a good stand. On the basis of our experience we can now recommend the following cultural operations.
Propagation can be done from seed established in pots prior to planting out or from pre-germinated seed sown directly into the field. The suggested plant spacing is about 10m by 7 m which gives 110 trees/ha. Established seedlings must be grafted as carobs are dioecious and seed usually produces about 70% male plants. For commercial production, an orchard should contain about 95% female plants of a superior variety. Top grafting is most effective and is most successful when it is done to plants growing strongly. It is recommended that about 300 g of nitrogen be applied to each tree about 3 weeks prior to grafting to stimulate growth and sap flow and improve the success of the grafting. Trees take about 10 years before they commence bearing and then take a further 10 years before they come to full bearing.
To facilitate mechanical harvesting the lower branches of young trees should be removed to give a clear 1 to 1.2 m of stem above ground level. From time to time the centre of the tree and any cross-over branches should be removed to let light into the tree. Flowers form on wood which is at least 3 years old so some space is required in the canopy.
Young carob trees are sensitive to wind and it is advisable to plant windbreaks prior to establishing an orchard. Wind breaks are also of benefit to mature trees as they reduce damage to flowers and young pods. To date, we have experienced no diseases or pest problems of any consequence. However, galahs have caused some problems by attacking new grafts.
Carobs are well suited to mechanical harvesting, which is seen as a pre-requisite for production in Australia. The pods ripen fairly evenly and by growing varieties in which the pods abscise fairly easily harvesting can be done in a single pass. The transport of pods from the harvester to the shed requires special equipment as the harvester can pick about 15 tonnes per hour.
The process of breaking up the pod and separating the seed and kibble requires a regional processing facility. The pods are passed through a slow revving hammer mill with the output going to shaker/blower screens to separate out the seed and the kibble. Production must currently be exported as there is no local processing facility. It is estimated that a throughput of at least several hundred tonnes would be required for a viable processing operation for gum production.
Carob powder is made by gentle roasting and grinding. Carob syrup is made by dissolving the sugars and flavour and then concentrating the mixture to a syrup.
Australia currently imports about 1000 tonnes of carob gum per year at about A$5.00 / kg. However, the price fluctuates widely and in 1995 the price rose to A$32.00 /kg. Australia also imports about 60 tonnes of carob powder with a wholesale value of about $2.00 /kg. The cost of establishing a carob orchard is estimated at about $7500 per hectare with no return for at least 10 years. However, once the trees reach full bearing, returns should be about $10 000 per hectare.
Carob has a delicious flavour and is seen as a healthy and tasty alternative to coffee or chocolate. It has the advantage of not containing the caffeine stimulant contained in coffee or the theobromine stimulant found in chocolate. The orchard at Burra has now established the carob industry in Australia but increased production will be required to warrant construction of a local gum extraction plant. Once production has reached a suitable level a marketing program will be required to exploit its undoubted potential as a food and drink flavouring.
More complete information on growing carobs in Australia is given in the publication 'Growing Carobs in Australia' by H. Ebenshade and G. Wilson (Goodland and Dobson, Box Hill, Victoria ).
Any claims made by authors in the Australian New Crops Newsletter are presented by the Editors in good faith. Readers would be wise to critically examine the circumstances associated with any claims to determine the applicability of such claims to their specific set of circumstances. This material can be reproduced, with the provision that the source and the author (or editors, if applicable) are acknowledged and the use is for information or educational purposes. Contact with the original author is probably wise since the material may require updating or amendment if used in other publications. Material sourced from the Australian New Crops Newsletter cannot be used out of context or for commercial purposes not related to its original purpose in the newsletter
Contact: Dr Rob Fletcher, School of Land and Food, The University of Queensland Gatton College, 4345; Telephone: 07 5460 1311 or 07 5460 1301; Facsimile: 07 5460 1112; International facsimile: 61 7 5460 1112; Email:
r.fletcher@mailbox.uq.edu.au[
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