© Histoire naturelle des orangers A. Risso et A. Poiteau



Session 1: Trends in the consumption of fresh and processed citrus fruits


Panorama of the world citrus market: the singular evolution of easy peelers

Eric Imbert, Cirad-flhor, France

Analysis of the world fresh citrus trade during the period 1970/2000 reveals strong growth, with the quantities traded increasing from 5.5 million to approximately 9.6 million tonnes.
This apparent dynamism should nevertheless be tempered. Indeed, the growth observed is distinctly below the average for the fruits group and well below that of products such as pip fruits, exotic fruits or bananas. However, there are considerable disparities within the different families making up the citrus group. Although the performance of lemon and orange is disappointing, the rate of increase was particularly strong for the easy peeler family. What is the foundation-intrinsic to the citrus market-for this exemplary dynamism?
On the one hand, there is less competition between fresh and processed fruits than for other citrus fruits such as orange and lemon. The change in consumption patterns benefiting juices and other citrus-based processed products has only had a small effect on clementines, mandarins and hybrids.
On the other hand, real efforts have been made in varietal research, making it possible to improve the quality of the fruits available (no seeds, sugar content, etc.), especially at the beginning of the season, enabling substantial increases in consumption. The development of early clementines at the expense of satsumas is a good example of this quality-based substitution in the EU. Furthermore, these varietal innovations have also made possible a substantial increase in the length of the sales season. The broad range of late hybrids that hardly existed in the 1980s and was developed in the 1990s now accounts for about 15% of winter sales on EU markets.
Finally, exporters have been particularly dynamic in the opening up of new markets. The shipping of easy peelers from the Mediterranean area was developed to eastern Europe and then to North America. Likewise, southern hemisphere exporters have developed a counter-season market, especially in northern Europe.
Will easy peelers continue to play a driving role in the future ? Competition from processed products based on easy peelers should remain limited. Varietal creation is still active and should meet expectations in more coloured, sweeter fruits at the beginning of the season and fruits with fewer seeds at the end of the season. Eastern European markets remain to be developed, especially for late hybrids. Likewise, new prospects are emerging in the large Asian consumer markets and there is room for the development of the counter-season market in the EU.


Evolution of the fresh citrus fruits demand

Frederik van der Monde, Univeg, Belgium


Community policy concerning citrus

Raimondo Serra, European Commission


Fruit and vegetables and preventive nutrition

Catherine Nicolle **, Christian Rémésy *
* Unité des Maladies Métaboliques et Micronutriments - INRA Clermont-Ferrand / Theix , 63122 Saint Genès Champanelle, France
** Vilmorin Clause & Cie, BP 1, 63 720 Chappes, France

The beneficial effect on health of fruit and vegetable consumption is one of the important points that has emerged from epidemiological studies performed in recent years. These plant products have an effect on health through the non-energy fraction-fibres, minerals and micronutrients. They can thus be considered as functional foods but that have a very great diversity of impacts in the digestive sphere, the liver and circulation. They contribute significantly to the supplying of minerals and micronutrients, play a key role in antioxidant protection, in fighting excess weight and also play a major role in the prevention of the plurimetabolic syndrome. They also have other specific effects through their alkali forming capacity and their richness in varied plant micronutrients. For good protection, in particular against cardiovascular diseases and certain cancers, fruit and vegetable consumption must not only be sufficiently varied but must also supply at least 10% of the total energy intake, i.e. about 300 g fruits and 300 g vegetables.


Session 2: Breeding and certification of plant material: towards a new generation of varieties


The new clementine varieties

Francisco Llatser, Viveros Avasa, Spain


Varietal diversification in the mandarin group: the promise of seedless hybrid triploids

P. Ollitrault *, D. Dambier *, F. Luro **, Y. Froelicher **
* Cirad-flhor Montpellier, TA 50/PS4, 34398 Montpellier cedex 5, France
** SRA Inra-Cirad, San Giuliano, 20215 San Nicolao, France

The quality of produce is becoming the essential criterion for the fresh fruit market. The definition of organoleptic quality varies in the different European countries. Breeders must therefore attempt to develop a varietal range that can respond to the diversity of these perceptions of organoleptic quality. Seedless fruits, easy peeling, internal and external colour and regular peel contribute to the definition of fruit quality. In addition to seedlessness of new varieties, it is necessary to seek cultivars that are incapable of pollinating self-incompatible varieties, and especially clementine, which now forms most of the easy peeler orchards in production in the Mediterranean area. The spreading of production in time is also a very important objective of easy peeler group breeding programmes. Thus, late varieties are particularly expected by the market.
In the light of these issues, French teams (CIRAD and INRA) have concentrated their efforts on the diversification of the seedless easy peeler range using criteria of high quality in order to extend the production period and prevent the possibility of cross-pollination with clementine. The search for sterility led them to move towards the breeding of triploid cultivars. Plants with three sets of chromosomes rather than two (diploids) are indeed known to display a high level of sterility of both ovules and pollen. It is thus possible to devote efforts on breeding in the field more effectively on other characters. Various biotechnology-based strategies have been developed to obtain triploid hybrids.
The first strategy consists of selecting spontaneous triploidisation events. Numerous triploid mandarin, tangor (mandarin x orange) and tangelo (mandarin x grapefruit) triploid hybrids were obtained after controlled hybridisation, embryo saving and flow cytometry selection. The first fruitings have confirmed the very low fertility of these hybrids and fruits with interesting pomological and organoleptic characteristics have been observed. The second strategy is based on crosses between diploid and tetraploid varieties. The tetraploid varieties are bred by somatic hybridisation or selected from nucellar seed. Several tens of allotetraploid and autotetraploid hybrids were obtained. The first flowering of some of these this year made it possible to start the second stage of the strategy by pollinating diploid varieties. Finally, a method for the fusion of diploid and haploid protoplasts was applied more recently for the direct synthesis of triploid hybrids by conserving the entire genetic make-up of the preselected diploid cultivars. It is thus hoped that the breeding of varieties with predefined characteristics can be guided more effectively.
Following the first selection based on qualitative aspects, the best hybrids resulting from these various strategies will be subjected to varietal trials in order to appraise their agronomic potential. As the juvenile phase lasts for 5 to 6 years, a minimum of 13 to 14 years must elapse between the hybridisation and the extension of a new variety. Beyond the quality aspects, hybridisation is also performed using parents known for their tolerance to African citrus leaf spot in order to develop a varietal range tolerant to this disease that causes considerable damage in sub-Saharan Africa and is threatening the Mediterranean area.


Rootstocks, a key component in sustainable citrus growing

C. Jacquemond *, F. Curk *, R. Zurru **, D. Ezzoubir ***, T. Kabbage ****, F. Luro *, P. Ollitrault *****
* SRA Inra-Cirad, San Giuliano, 20230 San Nicolao, Corse, France
** Consorzio Interprovinciale per la Frutticoltura, Cagliari, Sardinia, Italy
*** Direction des Domaines Agricoles, Casablanca, Morocco
**** Domaines Abbes kabbage, Taroudant, Morocco
***** Cirad-flhor, TA 50/PS4, 34398 Montpellier cedex 5, France

Citrus form the world's leading fruit production, in a zone lying between 40°N and 40°S. The Mediterranean area is the second most important cultivation zone and displays a great diversity of soil and climate conditions. A number of constraints are therefore encountered, such as salinity, limestone and drought, at the same place. With regard to crop health, tristeza is already present in the Mediterranean and is a growing danger because of the massive use of sour orange (Citrus aurantium L.) as rootstock. Finally, the Mediterranean area specialised in the production and marketing of fresh fruits. The fruit quality requirements for this type of market form a considerable constraint and depend to a considerable extent on the choice of rootstock. It allows the adaptation of the varieties cultivated to soil and climate conditions and pest pressure and also plays an important role in yields and the internal and external quality of fruits. The INRA-CIRAD agricultural research station (SRA) at San Giuliano in Corsica set up the first rootstock breeding trials using clementine (Citrus clementina Hort. ex Tan) in 1964. Nearly 160 rootstocks have since been tested and evaluated. These 40 years of experience have made it possible to breed two rootstocks for Corsica that outperform sour orange: Carrizo citrange (Citrus sinensis (L.) Burm. x Poncirus trifoliata (L.) Raf.) and Poncirus trifoliata cv 'Pomeroy'. The rootstocks have faster fruit-setting and higher yields with comparable fruit quality to that induced by sour orange. However, Corsica does not have the same constraints as the rest of the Mediterranean and this is why San Giuliano station is participating today in reflection on the replacement of sour orange in other countries in the Mediterranean zone. The first results of joint trials conducted in Morocco and Italy reveal considerable differences in the behaviour of a rootstock in different locations. These preliminary results show the need to continue multisite experimentation and breeding work in the production zones. Solutions to the Mediterranean abiotic constraints do exist in matters of rootstock but they are not necessarily satisfactory in terms of resistance or tolerance to pests and diseases and fruit yield and quality. The breeding, evaluation and creation of rootstocks is more than ever a topical area. Somatic hybridisation methods seem to be particularly suitable. FLHOR-AG1 (common mandarin Citrus deliciosa Tan. + Poncirus trifoliata (L.) Raf.), bred in such a programme, is already being studied and seems to be promising in the face of the constraints of the Mediterranean area.


The behaviour of traditional rootstocks under abiotic constraints in Morocco

Driss Ezzoubir, Domaines Agricoles, Morocco

The Moroccan citrus sector is of great socio-economic importance. Until very recently, practically all the trees were grafted on sour orange rootstock. The latter is well suited to the various soils and gave good agronomic performance and good fruit quality. However, sour orange gives combinations that are susceptible to tristeza. The latter is a serious threat to Moroccan citrus orchards. It is essential to replace sour orange by other, tolerant rootstocks in order to face up to the threat and conserve the citrus sector.
The lack of information about the behaviour of the new reputedly tolerant rootstocks in the different production regions has meant that a rapid change from sour orange has not been possible. The constraints are numerous: lime soils, salinity, hydromorphic soils and fears that the new rootstocks may not give the same quality of fruits. As a result, growers have displayed reticence with regard to the new rootstocks.
New rootstocks have been introduced accidentally or intentionally in commercial plantations. Trials have also been set up. This means that we have been able to monitor the advantages and disadvantages of the various rootstocks in commercial plantations (vigour, start of production, yield, grade profile, inner and outer quality of the fruits, evolution of maturity, tolerance to lime soils and salinity, susceptibility to Phytophthora, etc.) and to make recommendations for growers.
Monitoring the behaviour of these rootstocks enables us to conclude that sour orange can be replaced by other rootstocks without risks and even advantageously. The importance of sour orange in new plantations is decreasing today.


The Spanish varietal certification system

Luis Navarro, J.A. Pina, J. Juárez, J.F. Ballester-Olmos, N. Duran-Vila, J. Guerri, P. Moreno, C. Ortega, A. Navarro, J.M. Arregui, M. Cambra, S. Zaragoza
Instituto Valenciano de Investigaciones Agrarias (IVIA), 46113-Moncada, Valencia, Spain

The Citrus Variety Improvement Program in Spain (CVIPS) started in 1975. It has the following objectives: a) to recover pathogen-free plants of local cultivars by shoot-tip grafting in vitro (STG); b) to import foreign genotypes through an STG based quarantine procedure; c) maintain healthy genotypes in a Germplasm Bank; and d) to release healthy budwood to citrus nurseries through a certification program. Plants recovered by STG are biologically indexed by inoculation to the following indicator plants: Mexican lime, Pineapple sweet orange, Dweet tangor, Citrus excelsa, Etrog citron, and Parson's Special mandarin. In addition, they are indexed by sPAGE or imprint-hybridization for viroids, by PCR for Citrus leaf blotch virus, by dsRNA analysis for viruses that produce dsRNA during their replication cycle, and by tissue print-ELISA for Citrus tristeza virus. Only healthy genotypes are included in the Germplasm Bank, which has a field collection used for research and horticultural evaluation, a cryostored collection for long-term maintenance, and a screen-house collection that is used to release budwood to nurseries. It contains a total of 475 genotypes, 272 selected in Spain and 203 imported from other countries, representing 43 Citrus species and 33 species from 17 Citrus related genera. Release of healthy budwood from this program to nurseries started in 1979. At that time, there were only 10 registered nurseries, but in the last few years the number has increased to 39. For commercial propagation all nurseries are using budwood from the Germplasm Bank. Since the beginning of the program, about 92 million certified nursery trees from this origin have been planted in the field. This represents more than 75% of the Spanish citrus industry. The CVIPS has produced a very high impact in the citrus industry. Virus and virus-like diseases do not cause any significant damage in the new plantings now and a wide selection of healthy material from the best varieties are available for growers.


The implications of varietal protection for operators

Françoise Dosba
UMR 1098, Biologie du développement des plantes pérennes cultivées, ENSA.M - INRA, 2 place viala, 34060 Montpellier cedex 1

The aim of the International Union for the Protection of New Varieties of Plants (UPOV) is the protection of new plant varieties, and especially Citrus. Any new variety for which an application has been made by the breeder or his successor in title can be the subject of DUS testing (for Distinctness Uniformity and Stability).The aim is to demonstrate that the variety deposited is distinct from any other variety, that it is sufficiently uniform and remains unchanged after successive reproduction or multiplication operations. This examination with a view to awarding a breeder's right is performed by bodies competent in comparative growing tests and leads to the description of a variety on the basis of pertinent, essential characters. The material supplied for examination must be representative of the variety and free of important pests or diseases that might affect the expression of characters. Qualitative, quantitative or pseudo-quantitative pomological characters are used to distinguish between varieties and must be the subject of at least two observation seasons. New types of character such as molecular characters are envisaged but are not yet accepted by UPOV regulations. An international organisation is being set up for DUS testing. Variety protection can be effective at the national or international level. In France, the CPOV (Comité pour la protection des obtentions végétales) handles all applications for national protection, while the OCVV (Office communautaire des variétés végétales) in Angers records applications for protection throughout the European Union. Discussion of the advantages of protection for operators.


Session 3: Quality from the orchard onwards: the impact of pests and diseases


The present status of citrus pathogens in the Mediterranean basin

Christian Vernière *, Luis Navarro **, Joseph Marie Bové ***
* Cirad-flhor, TA 50/PS4, 34398 Montpellier cedex 5, France
** IVIA, Moncada, Valencia, Spain
*** INRA et Université Victor Segalen Bordeaux 2, BP 81, 33883 Villenave d'Ornon, France

Mediterranean citrus production is mainly dedicated to the fresh market. The sanitary aspect of fruits may therefore greatly impact the benefit of the producers. The Mediterranean Basin is still free of the most important citrus diseases, but citrus must face endemic and newly emerging pathogens.
Some existing pathogens may induce dramatic consequences and their transmission by insects makes their control difficult. Two viruses are responsible for citrus Tristeza and Vein Enation Woody Gall diseases and the mollicute Spiroplasma citri causes Stubborn. They are classified as quarantine organisms in the EC where they are found in some countries. Other pathogens can induce symptoms on citrus and their effects are noticeable under certain conditions. They are only mechanically or graft transmissible agents. They include the viroids responsible for exocortis and cachexia, the psorosis virus and the virus-like agents inducing oak leaf patterns. The propagation of material tested free from all these graft-transmissible diseases makes it possible to decrease the inoculum and sometimes eradicate some of these pathogens from the orchards. However, additional strategies are necessary to lessen the impact of insect transmitted agents.
Fungal diseases can lead to important fruit losses and tree decline. Mal Secco, which is caused by Phoma tracheiphila, is a major problem on lemons and citrons in certain areas of the Mediterranean Basin. Phytophthora species, which cause gummosis and root rot, are endemic in all the citrus producing countries. Appropriate cultural practices and the use of tolerant rootstocks should control Phytophthora-induced diseases.
Two viral diseases were recently described in the Mediterranean Basin. Citrus Chlorotic Dwarf CCD appeared in the mid-1980s in Turkey and mainly affects lemons, grapefruit and some mandarins. The CCD virus is transmitted by a whitefly and induces chlorotic and variegation patterns on leaves and stunting on early infected trees. The Citrus Leaf Blotch Virus was detected during indexing of the Spanish citrus quarantine programme from a kumquat cultivar inducing bud union crease on Troyer citrange. It was later detected in other citrus cultivars.
The quarantine, sanitation and certification programmes in some Mediterranean countries have contributed to improving the sanitary status of citriculture and to revealing new biotic constraints. They will help to prevent the introduction of economically damageable pathogens that cause serious epidemics in other citrus producing regions: severe strains of CTV, Huanglongbing, variegated chlorosis, citrus bacterial canker and Phaeoramularia fruit and leaf spot disease.


Mediterranean citrus pests

Serge Quilici
Cirad-flhor, Pôle de Protection des Plantes (3P), 7 Chemin de l'IRAT, 97410, Saint-Pierre, La Réunion, France

Although the citrus crops in the Mediterranean area are subject to attacks by fairly numerous pest species, only a small number of these are likely to be key pests.
Among fruit flies, the Mediterranean fruit fly or Medfly, Ceratitis capitata, is generally a cause of direct damage to numerous citrus species and varieties. For many years, the methods used to control this pest have been based on the placing of a combination of bait and insecticide or, more recently, mass trapping using attractants that are specific for females. The peach fruit fly, Bactrocera zonata, which appeared a few years ago in Egypt, is also a major risk for all the countries in the region.
Several aphid species can cause direct damage to citrus crops, but the main risk in certain countries results from the ability of certain species (in particular Aphis gossypii) to spread tristeza virus. Scales are serious pests in numerous countries in the region, and in particular a number of diaspine species and also certain Lecaniidae and Pseudoccidae. They are generally controlled by mineral oil spraying and sometimes insecticides. The citrus flower moth, Prays citri, causes varying degrees of damage according to the country, sometimes strongly affecting production and necessitating specific treatment. The appearance of the citrus leafminer, Phyllocnistis citrella, in numerous Mediterranean countries in the first half of the 1990s resulted in much work on chemical and biological control methods in order to adapt the integrated control programmes previously set up. These generally contributed to a distinct improvement of the situation. The impressive damage caused by the leafminer in the years following its arrival is now considered to be limited in adult orchards. Furthermore, various mites belonging to the Tetranychidae (Tetranychus urticae, Panonychus citri) or Eriophyiidae (Phyllocoptruta oleivora, Aceria sheldoni) families are regular pests whose control often requires the one-off application of mineral oils or specific acaricides.


Citrus leaf spot in tropical and subtropical Africa: a threat for neighbouring regions?

Christian Vernière *, Jean Kuaté **
* Cirad-flhor, TA 50/PS4, 34398 Montpellier cedex 5, France
** IRAD, Yaoundé, Cameroun

Citrus leaf spot, a fungal disease caused by Phaeoramularia angolensis, is spreading rapidly in Africa. It was described in 1952 in Angola and Mozambique and is now present in 19 countries in tropical and subtropical Africa, reaching the Republic of Guinea in the west and going northward in the east as far as Ethiopia and even the Yemen. Citrus production in tropical and subtropical Africa (excepting South Africa) totals some 4.9 million tonnes (FAO 1999-2000). In tropical Africa, citrus fruits are a diversification crop in comparison with cash crops and are generally grown in smallholding orchards. They are a source of income through outlets on growing urban markets and export sales. Furthermore, the European Union classifies Phaeoramularia angolensis as a quarantine organism and prohibits all citrus imports from contaminated regions.
Attacks cause 20 to 100% crop loss through deterioration or the fall of early infected fruits. They can also lead to the depreciation of the orchard as leaf fall causes the slow decline of the trees. Expression of the disease can occur in zones whose altitude ranges from sea level to 2,000 metres, but the most serious attacks occur at between 600 and 1,000 m, which are also the zones that are favourable for the production of high-quality fruits. Furthermore, chemical control is the only strategy applied to attempt to reduce the impact of the disease, but it pollutes and is expensive and hence poorly suited to these developing countries.
Little work has been performed on citrus leaf spot. Research has been conducted above all in Cameroon and also in Kenya. It has shown that no resistance to the fungus exists; only satsuma, grapefruit, lemon and kumquats display tolerance or low susceptibility. The main commercial varieties (orange, grapefruit, mandarin) are susceptible. Temperature and rainfall appear to affect expression of the disease. However, very few data exist on the sources of inoculum, population variability and the spread of the disease in time and space. This poor knowledge of the fungus and epidemic factors means that citrus leaf spot is a threat to neighbouring producer countries like South Africa and those of the Mediterranean area.


Tephritid fruit flies (Diptera, Tephritidae): pests of economic significance for citrus production

J.P. Cayol, W. Enkerlin, A. Bakri, J. Hendrichs
Insect Pest Control Section, Joint FAO/IAEA Division for Food and Agriculture, International Atomic Energy Agency, Vienna, Austria

The Tephritid fruit flies (Diptera, Tephritidae) of economic significance are, for a large part, polyphagous species. The number of host plants can vary from about ten to several hundred fruit varieties, as in the case of the Mediterranean fruit fly or medfly, Ceratitis capitata Wiedemann. Citrus species are often among the preferred hosts of these tephritid fruit fly species. In many temperate, sub-tropical and tropical countries, tephritid fruit flies are the major pests of citrus, causing up to 80% losses when no effective control measure is applied.
Medfly is the most important tephritid pest of citrus in the Mediterranean Basin, but also in some Sub-Saharan countries, in the United States of America (California and Florida), where it is a pest of quarantine importance and is permanently monitored, and in some Latin-American countries. In Central America, apart from the exotic medfly, the major endemic tephritid pest of citrus is the Mexican fruit fly, Anastrepha ludens (Loew), while in most of South America it is the South-American fruit fly, Anastrepha fraterculus (Wiedemann). While medfly is present on the Western coast of Australia, the Queensland fruit fly, or Qfly, Bactrocera tryoni (Frogatt), is present on the Eastern coast. In South-East Asia, the major tephritid pests of citrus belong to the Oriental fruit fly, Bactrocera dorsalis (Hendel), complex.
Several specific control methods have been developed and applied successfully against tephritid fruit fly species. The Sterile Insect Technique (SIT), developed in the 1950s, has been successfully used against the medfly, the Oriental fruit fly, the Qfly, and the Mexican fruit fly. The Male Annihilation Technique (MAT), based on the attractiveness of methyl-eugenol or cue-lure for the males of several Bactrocera species, was developed in the 1940s. The MAT has then been used successfully, among others, against B. dorsalis in Hawaii and in California. The Bait Application Technique (BAT), developed in the 1950s, though not as species-specific as the SIT and the MAT, has been used against B. dorsalis in Hawaii. In Israel, the BAT, first used in 1958, is until today the major control method used in commercial citrus orchards throughout the country. In spite of the development of these specific techniques, conventional control using cover sprays of broad-spectrum insecticides is still used in some countries, inducing resistance and major problems due to secondary pests such as the citrus leafminer, Phyllocnistis citrella (Stainton).
In recent decades, the SIT and MAT were mainly used for the eradication of the target tephritid species from a given area or country after an outbreak of an exotic species of major economic importance had occurred or from islands as in the case of Japan. Since the 1990s, the constant efforts in the optimisation of the techniques, most notably of the SIT, has paid off resulting in a cost-effective use of such techniques for suppression, rather than only for eradication of the target species. Consequently, the SIT is now often used as a biological insecticide replacing the conventional control methods for the areawide suppression of the target species, in combination with other techniques, within an integrated pest management approach. In some cases, these methods are even used on a preventive basis, as is the case for the Preventive Medfly Release Programme in California, or with the use of MAT against the peach fruit fly, Bactrocera zonata (Saunders), in Israel.
The various aspects of tephritid fruit fly as major citrus pests worldwide and the various control methods and strategies are reviewed and discussed.


Session 4: The labelling policy in Corsica and Spain


Promotion policies in the citrus sector

Octavio Ramon, President of CLAM, President of CGC, Vice-President of Intercitrus, Spain


An example of segmentation by origin: the PGI for Corsican clementine

Dominique Agostini* , JA. Prost**, F. Casabianca**, J. Bouffin*
* Station de Recherches Agronomiques (SRA) INRA-CIRAD - San Giuliano - Corsica
** Laboratoire de Recherche sur le Développement et l'Elevage (LRDE) INRA - Corte - Corsica

Clementine forms an important proportion of the economy of Corsica. For many years, marketing fruits with leaves-forbidden for the other origins-enabled it to be very profitable. The leaf became the symbol of Corsican clementine. Furthermore, as Corsica is the only citrus-producing region of metropolitan France, national regulations were decentralised.
A change in European phytosanitary regulations in 1993 meant that Corsican growers lost their exclusive right to sell clementines 'with leaves'. Meanwhile, certain producers' groups had encouraged the planting of Spanish cultivars reputed to be more productive. This strategy of imitation exposed them to fierce competition with the countries with low production costs (Spain and Morocco). From 1994 to 1998, a research programme that included a study of the sector aimed at identifying the reasons for the very poor sales of the product that had led to a real danger for the Corsican production system (Agostini et al., 1996; de Sainte Marie et al., 1999). The decreased confidence of consumers and traders (at various levels) in the product expected had become the main reason for lack of interest to the advantage of other origins. The causes of the extreme variability of the quality of commercial batches that tarnished the traditional image of clementines grown in Corsica lay as much in cultural practices and the modes of organisation formed by local packing and marketing structures as in the different forms of relations between the stakeholders.
The presentation of these results in a technical meeting in June 1999 triggered brutal awareness. Guaranteeing the identification of a specific product with a production zone requires the mobilisation of the appropriate legal and institutional measures. The Corsican citrus growing profession therefore undertook a certification process with a request for a PGI for 'Clémentine de Corse'. In fact, the setting up of such a sign of recognition does lead to identifying a clementine market segment, making it possible to avoid a situation of potential competition and achieving better product sales.


Session 5: Innovative juice production techniques and the bioavailability of micronutrients


Constraints and prospects for citrus juice treatments

Max Reynes
Cirad-flhor, TA 50/PS4, 34398 Montpellier cedex 5, France

Consumer demand for processed products whose qualities are close to those of fresh fruits is increasingly strongly in fruit juices. Pure juices are gaining the edge on nectars, for example. Indeed, the organoleptic and nutritional aspects are becoming determinant criteria in the choice of extraction, stabilisation and concentration technologies and also in packaging so that high quality products can be ensured for consumers.
Citrus juices are very rich in micronutrients and vitamins and are used as an example to show the different possible stabilisation pathways for guaranteeing product quality-both nutritional and organoleptic-for consumers who are usually far from the production zone.
The prospects of new processes will be mentioned in order to glimpse the lines of co-operation and research that could develop between the main stakeholders in the citrus sector.


Application of the vacuum flash-release process to citrus for the preparation of purées, nectars and essential oils

Pierre Brat
Cirad-flhor, TA 50/PS4, 34398 Montpellier cedex 5, France

Vacuum Flash-Détente®(flash release), a new alternative to traditional blanching/crushing, is a process consisting of heating the material (fruit, vegetables) to 60-90°C and then placing it under a vacuum chamber (30-50 mbar). On release, the instantaneous evaporation of a proportion of the water content (approximately 10 %) causes a break-down of the material as a result of expansion, with the formation of intercellular micro-channels.
This adiabatic process applied to lemons has given, after refining, purées with specific characteristics in comparison with juices and purées prepared using a traditional process. The consistency and viscosity of Flash-Détente® purées are distinctly better than those of reference products as part of the outer coating of the fruits is incorporated, giving higher cell wall contents, and also because of the increase of intercellular space in the middle lamella. The colour of Flash-Détente® purées is also paler and more intense because of the incorporation of whitish tissues (albedo) from the outer envelope of the fruits; however, bitterness must be removed from Flash-Détente® purée.
Finally, essential oils have been recovered from citrus peel (lemon, sweet orange, mandarin and grapefruit) by the Flash-Détente® process with comparable yields to those of traditional extraction processes. Their terpene contents are higher and oxygen compound contents are lower in comparison with cold-pressed oils.


Membrane technique application in the processing of tropical fruit juices

Manuel Dornier
Cirad-flhor / Ensia-Siarc, TA 50/PS4, 34398 Montpellier cedex 5, France

Tropical fruit juices are an important economic issue for numerous producer countries. Indeed, local and export markets have grown continuously for several years. However, demand is focusing on fruit juices with good sensorial and nutritional qualities and an increasingly diversified range of products. Membrane techniques have considerable potential in this context. They are often more respectful of the fruit juice quality than conventional processes. Furthermore, some are of great interest for the development of new products. The work conducted since 1995 is aimed mainly at evaluating three membrane techniques with the prospect of industrial use: tangential microfiltration over ceramic membranes for the clarification or cold stabilisation of pulpy tropical fruit juices, osmotic evaporation for low temperature juice concentration and, more recently, electrodialysis for the deacidification of particularly acid juices.
For the production of clarified fruit juices, tangential microfiltration has the advantage of being a continuous operation. The use of an appropriate membrane also makes possible the total retention of microorganisms and hence the stabilisation of the product without heating. Most tropical fruit juices are very rich in pulp. Combination with an appropriate enzymatic treatment (free enzymes or enzymes fixed in a bioreactor) is proposed to reduce viscosity and membrane fouling. We have shown that it is possible after the optimisation of treatment conditions to obtain clarified juices of interesting quality using numerous fruits such as passion fruit, mango, banana, citrus fruits and pineapple.
Concentration is an operation of prime importance in the tropical fruit juice industry as it makes it possible to limit transport and storage costs. Heat evaporation is the concentration technique most commonly used today. Although it is performed under vacuum, the technique always results in a deterioration of product quality. Osmotic evaporation, a new cold concentration process, is being studied for better conservation of the qualities of fresh fruits. The technique consists of placing a hydrophobic porous membrane between the fruit juice to be processed and a concentrated saline solution. The difference in the activity of the water in the two solutions creates a vapour pressure gradient in the membrane pores, which remain filled with water. This
spontaneous phenomenon causes a transfer of water from the fruit juice to the brine without heating being required. Tests performed at from 25 to 30°C on various fruit juices show that this technique can be used to produce a soluble dry extract of at least 60%. The evaporation flows obtained are close to 0.6 kg.h-1.m-2 under industrial conditions and some 10 kg.h-1.m-2 in the laboratory. Sensorial analyses show improvement of the colour, taste and aroma of the fruit juice in comparison with heat concentration. Product vitamin C is conserved as the process temperature is low.
The very high acidity of certain fruits such as passion fruits limits use of the juice for adding aroma to beverages, for example. The development of deacidification techniques that conserve the aromatic characteristics of the initial juice should make it possible to develop products that are better suited to this type of use. Ongoing studies show that electrodialysis has strong potential in this field. The technique is being evaluated using different configurations (homopolar and bipolar membranes) and makes it possible to deacidify products without significantly changing the aromatic profile.


Innovations in citrus peeling technology: commercial development of fresh cut citrus

Mohamed A. Ismail, FDOC, USA

Fresh cut fruits and vegetables are among the fastest growing categories in the food industry. In the U.S., sales of fresh-cut produce reached $12 billion in 2000 (Produce Marketing Association, 2000), and more than doubled from $5 billion in 1995 to $10.5 billion in 1999. Fresh-Cut fruits and vegetables are increasingly more visible in the produce department of most supermarkets. Attractively packaged watermelon, cantaloupe, pineapple and honeydew melons are at the top of fresh-cut fruit category. Consumer demand for convenience is the driving force behind this phenomenal growth. Citrus fruit, however, did not participate or contribute to the growth of the fresh-cut fruit category.
The decline in consumption of fresh citrus, particularly grapefruit in the U.S. prompted the Florida Department of Citrus to initiate a project aimed at developing a citrus peeling machine to enhance convenience and increase consumption. In 1998, a single tabletop peeling unit/head was built and tested on water infused fruit with limited success. Heinzen Manufacturing International of Gilroy, California constructed a two-head peeling system consisting of a hopper, a two-lane singulating conveyor and a PLC indexing mechanism. The two-head system was tested on enzyme-softened 'Valencia' oranges and grapefruit, and was successful in peeling 50 fruit per minute. The new peeling unit is relatively small with a footprint of approximately 1ft2 (0.09m2). It consists of a set of six blades mounted on spring-loaded stainless steel members. The blades score the peel to a depth of 1-2mm. As the fruit clears the blade mechanism, it is impaled with a six-member barb mechanism, which removes the peel from the majority of the fruit. A special roller conveyor separates the peel from partially peeled fruit.
The peeling machine is patented by the Florida Department of Citrus and its domestic usage was granted to two United States companies, Del Monte Fresh Produce of Coral Gables and Golden Groves of Fort Pierce, Florida. Del Monte will soon be installing a citrus peeling system in Florida with a projected capacity of approximately 2700kg. peeled fruit per hour. Licensing of the peeling machine for use overseas is still open.




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