NOTICE: Hard copies of the Australian New Crops Newsletter are available from the publisher, Dr Rob Fletcher. Details of availability are included in the
Advice on Publications Available.A project to investigate the feasibility of carob (Ceratonia siliqua L.) for low rainfall areas of the Murray Valley region in South-eastern Australia has been commenced by Mr Digby Race, Research Officer - Farm Forestry, The Johnstone Centre, Charles Sturt University, PO Box 789, Albury, NSW 2640.
Digby attended the Third International Carob Symposium, held at Tavira, Portugal on 19-23 May, 1996 and reports on the outcomes of the conference, as they may relate to the development of the carob industry in Australia.
Previous International Carob Symposia were held in Algarve, Portugal (1978) and Valencia, Spain (1987). Portugal and Spain have approximately 100,000 ha of carob trees and process approximately half of the world's commercial carob supply. World carob p od production is approximately 315,000t per year and the main carob bean producers and exporters are Spain (42%), Italy (16%), Portugal (10%), Morocco (8%), Greece (6.5%), Cyprus (5.5%) and Turkey (4.8%).
The Symposium consisted of formal presentations over three days, followed by field trips to carob variety trials conducted by the Regional Office of the Department of Agriculture, a farming property with 100 ha of carob trees (9,000 trees) and sites to inspect the role of the carob and other native plants within the natural ecology.
Carob is a perennial leguminous tree, native to the Mediterranean basin and South-west Asia. It has been cultivated throughout the Mediterranean region for 4,000 years. It "... is currently being reemphasised as an alternative in dryland areas with Med iterranean climates for diversification and revitalisation of coastal agriculture" (Tous et al., 1996, Proceedings of the Third International Carob Symposium, to be published by the University of Lisbon, Portugal, shortly).
Carob has drought resistance, requires little maintenance and produces a range of products from the seed and the pod. From the seed, the endosperm is extracted to produce a galactomannan, which forms locust bean gum (LBG), a valuable natural food addit ive. The pod is useful for high-energy stock feed (although high tannin content can limit its consumption) and the human food industry, as cocoa products and syrups.
The current trend is to establish mechanically harvestable carob orchards with dual-purpose carob varieties having acceptable seed and pod yield and high gum quality. Preliminary breeding in Spain aims to improve agronomic characters, including the bea ring age, yield, regularity of yield, growth habit, harvesting ease and disease resistance and the processing qualities, such as kernel/endosperm yield, gum quality, pod size and sugar content.
Most current carob orchards in Portugal and Spain are located on steep, rocky sites, requiring hand harvesting; harvesting represents 30-35% of the total production costs. Future varieties will be developed for mechanical harvesting. Such varieties wil l require relatively small canopies, an erect growth habit, rigid fruit-bearing branches, and would be planted on regular spacings at an orchard density of about 150-200 trees per ha (for example, at 6m x 1lm - 6m x 8m tree spacings).
There are few robust genetic pools of native carob available for crop improvement, however the native carob populations in Spain, Italy and Portugal are being surveyed and a comprehensive arboretum of the many native and cultivated carob varieties is b eing established. Techniques for cultivar identification are also being developed.
Carob is a trioecious tree, with male, female and hermaphrodite inflorescences (usually on different trees). Female trees tend to have higher yields than hermaphrodite trees and the optimum proportion of male trees in an orchard ranges from 5 to 20%, w ith most having 12% pollinator trees. Techniques are not yet available to determine the gender of seedlings prior to flowering.
Carob has highly variable flower and fruit production within orchards and between years and this undermines the market for farmers and industrialists, alike.
The presence of fruit has been found to have an inhibiting effect on the formation of the current season's flowers, therefore inhibiting fruit production the following year. Unspecified endogenous (internal) factors are believed to play an important ro le in flower and fruit variability (Von Haselberg, 1996, Proceedings). As well, the lack of suitable pollen may contribute to low fruit production (Martins-Loucao et al. 1996, Proceedings). Despite having a pollen period of several months, t he quantity of airborne pollen is low, suggesting that more male trees are required. Both wind and insects act as pollinating agents.
The most common practice for establishing carob orchards is to graft selected varieties grafted onto seedling rootstocks; grafting represents about 10% of total production costs in carob. Some progress has been reported towards cloning carob (Alord a and Medrano, 1996, Proceedings).
Some carob varieties bear after four to five years and this depends on cultural practices and rainfall. Carob has a deep tap root and is adapted to very dry conditions, such as 200mm rainfall/year. To optimise the benefit of any irrigation, local monit oring is recommended.
Harvested carob pods are firstly kibbled, a coarse grinding process following by screening. This separates the pod from the unbroken seed. The carob pod is used as animal feed or carob powder is extracted for human consumption. The largest kibbler in S pain processes 20 million kg of pods (2 million kg of seed) per year. Kibblers buy carob pods at about A$0.50 per kg from farmers.
The endosperm is extracted from the seed by grinding to produce LBG. There are about 13 processors worldwide who produce LBG, and half of them operate in Spain. The world demand for LBG requires 35,000t of carob seed per year. LBG is used in the food i ndustry for its strong gel characteristics, which are useful in products such as canned pet food, since they are maintained after heating.
A reasonably strong future is predicted for LBG production, provided the price of carob seed remains steady at A$2.00 to 2.50 per kg and supplies remain stable. The different grades of LBG depend upon the amount of seed coat present.
Potential for Australia
Carob has been intermittently explored over the last 20 years as a potential tree crop industry in areas of Australia with less than 700mm rainfall per year. Carob pod/seed mix has considerable commercial value as a livestock fodder supplement (A$1 40 per mt), as a thickener, in canned products such as pet food (A$1,200 per mt) and as an ingredient in confectionery (A$3,000 per mt) (Hogan, 1995, Uncle Bens of Australia, Wodonga, Victoria).
A viable carob industry could contribute to LBG import replacement (A$ 4-5 million per year for a major importer; A$10 million per year, Australia-wide) and have the potential to compete in a world LBG market worth A$100 million per year (Hogan 1995). /P
Farm experience indicates carob trees are suited to the marginally productive agricultural land in the Murray Valley and begin to produce a commercial harvest after approximately 10 years (Gebhardt, 1996, Australian New Crops Newsletter 6: 5-6).
Carob has a deep root system enabling production with just 250mm rainfall/year, although ideal conditions are about 500mm (Esbenshade and Wilson, 1986, Growing Carobs in Australia. Goddard and Dobson Publishers, Box Hill, Victoria).
There is a lack of crop options for low rainfall agroforestry and a current need to improve natural resource management of 250,000ha in the 400-700mm rainfall zone within the Murray-Darling Basin. Carob appears to offer considerable potential as an opt ion.
There is sufficient Australian and overseas experience to establish "best bet" commercial plantings of carob. Recent trials in South Australia also suggest that carob can be mechanically harvested using standard nut and fruit harvesters.
There is considerable demand for LBG in Australia (A$10 million per year) and this is currently imported from Mediterranean processors. Small-scale processing of carob pulp for human use already occurs in Australia.
If a critical mass of carob production was established in one region, kibbling may become viable, since it would not require a large capital investment. However, processing for technical grade LBG or above, would require a more substantial capital inve stment.
Acknowledgments
The author wishes to thank Mark Hogan and his employer, Uncle Bens of Australia, Wodonga, Victoria for their continuing support. He would also like to thank Andrew Gebhardt (Burra, South Australia) for his continuing practical advice; Dr Juan Tous I and Ignacio Batlle (Institut de Recerca i Tecnologia Agroalimentaries, Reus, Spain) for their expertise; Mario Reis, Jose Sr. and Jose Jr. Cincenetti (Alimentaria Adin) for their willingness to share their processing expertise; and Pr of. Dr Maria Amelia Martins-Loucao, Dr Graca Oliveira and their team for organising the conference.
The Joint Venture Agroforestry Program (RIRDC/L WRRDC/FWPRDC) is funding the investigation of the requirements of a viable carob industry.
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[
New Crops Home Page] [New Crops Program] [Australian New Crops Newsletter] [New Crops Publications] [Order Form] [People] [Crop Profiles] [Other Resources]originally created by:
GK; latest update 6 June 1999 by: RF