Coconut research at CIRAD

CIRAD, the French Agricultural Research Centre for International Development, is an organization working for the sustainable development of tropical and Mediterranean regions. CIRAD has one main objective: to build sustainable farming systems capable of feeding ten billion human beings by 2050 while preserving the environment. We work with our partners in southern countries to generate and pass on new knowledge to support agricultural development. CIRAD has a network of partners on three continents, and of regional offices, from which it works with more than 100 countries. CIRAD has been working for more than 70 years on the coconut supply chain with our main partners in Africa, Pacific and Asia. Today, a pool of 15 researchers are still working on this plant. The CIRAD strategy is to do collaborative research in order to support the coconut sector in its strategic development. CIRAD is working on collaborative projects in order to: 1. Replant and replace old trees with proper planting material 2. Preserve the biodiversity in genebanks (to address new market trends, climate change…) 3. Decrease the biotic pressure (LYDs and insects) and increase productivity in the field (fertilizers, inter-cropping…) 4. Improve the quality of products (efficient and safe dryers, controlled conditions and duration of storage, innovative process to stabilize coconut water) – (sanitary issue) 5. Encourage diversification of products and participatory certification systems. This will increase farmers' and processors' revenues and create jobs in rural areas. CIRAD recently signed a MoU with ICC (International Coconut Community) in order to facilitate the collaboration between the research organization and the member countries of this international association. The institution did also sign a MoU with the Government of French Polynesia on specific actions to be done to preserve and characterize local coconut varieties. Moreover, some CIRAD projects were described such as the CIDP project in the Pacific, the consultancy for the Government of Ivory Coast to prepare the transfer of the International Coconut Genebank for Africa and Indian Ocean in collaboration with CNRA, COGENT and TIRPAA/FAO and the biological control of biotic stress in Timor Leste. The future of the coconut oil sector is in (i) replanting now with good and certified seedlings, (ii) using available biodiversity to diversify varieties and products commercialized by farmers/processors, (iii) proposing labels in combination with (iv) innovation in production and processing. All these actions, and others to create on social and environmental aspects, can be opportunities to ensure the sustainability of the coconut supply chain

Changes of ultrasound characteristics of mango juice during fruit ripening

Attenuation and propagation velocity of ultrasound signals at 25 MHz were measured on clear mango juice samples using a pulse echo method. Ultrasound characteristics were determined with other physico-chemical characteristics on juice samples extracted from fruits undergoing ripening for three weeks at 23 °C and 80 % RH and periodically removed every two or three days. During fruit ripening, the changes of biochemical composition induced more effect on velocity than attenuation. Velocity were positively correlated to soluble solids content (R = 0.98), to sucrose content (R = 0.80) and negatively correlated to titratable acidity (R = -0.59) and fruit firmness (R = -0.76). A linear model based on soluble solids content and a PLS model based on all the physico-chemical characteristics were built to predict ultrasound velocity. Finally, the results obtained in this study showed that velocity is a relevant parameter linked to the major biochemical changes occurring during controlled fruit ripening. Due to high attenuation of ultrasound waves in mango peel and pulp tissues, confirmation of these results for whole fruit will be a challenge. (Résumé d'auteur

Banana plantain functional properties evaluation during water cooking processes: a NIRS original assay and perspectives

Starch is the major component of edible banana at green stage of maturity, and is well-known to highly contribute to its functional properties. Among others, methods based on near-infrared spectroscopy (NIRS) have already been successfully applied to evaluate various native starch functional properties. In our study, an assay was carried out to try to differentiate the cooking behavior of 6 banana genotypes. Pulp cylinder accessions were cooked in boiling water, and also packed and vacuum sealed in heat-resistant pouches prior to similar cooking. At various time intervals, samples were removed from the water bath and dried at 40°C prior to milling to get stabilized flour samples. The physicochemical properties of the flours were then evaluated by reference methods (DSC, RVA, gravimetry, instrumental firmness).Based on physicochemical properties, a PCA showed that the first 3 components accounted for 84% of the variation. PC1 was positively related to RVA slope (Slope), firmness (F), hot paste viscosity (HPV), and pasting temperature (Ptemp), and negatively correlated to cooking ability (CA). A discussion will be proposed in regards to the wavelengths correlated to the different PCs on the potential structural justification of the phenomenon probably related to starch crystallinity. The factorial map (PCs1 x2) highlighted some crossed-effects of the cooking mode and varietal contribution, making possible to distinguish both processes and genotypes. Results of PLS modeling indicated that NIRS was accurate in predicting Ptemp, HPV, CA, slope, and F with good coefficients of determination (RSQ = 0.70-0.93).Surprisingly, near infrared spectra were able to predict properties measured on the freshly cooked material, although the NIR measurements were carried out on flours. Rapid predictive methods such as NIRS, applied on native or even cooked flour samples can contribute to routinely predict the cooking behavior of the banana starchy resources in breeding programs. (Texte intégral

Nouvelle orientation de la filière cocotier : mieux valoriser le potentiel alimentaire de la noix

Le déclin de l'ère industrielle du cocotier axée principalement sur la production d'huile de coprah est amorcé. Ceci ne signifie pas la disparition des industries utilisant le cocotier, mais leur orientation progressive vers des produits alternatifs, plus spécifiques de la plante et adaptés aux exigences modernes de consommation. Le cocotier revient a ce qu'il a été durant des millénaires, une culture vivrière villageoise ou un arbre fruitier des villages et des villes, une plante de civilisation au fort impact environnemental et culturel. Des recherches sont en cours pour que cette reconversion soit accompagnée d'une forte valeur ajoutée. (Résumé d'auteur

Impact of Ohmic Heating on Coconut Water Volatile Compounds

Immature coconut water (CW) is a low acid fruit juice mainly composed of sugars and minerals. Beside its healthy feature, it can also be a pleasant refreshing drink especially when coming from aromatic coconut varieties. Unlike conventional thermal processes, ohmic heating is an innovative technology using volumetric heating technique to pasteurize or sterilize food products. As such, it is known to overcome the overheating problem in fruit juices and to improve aroma preservation. This work aimed at obtaining a commercially safe CW beverage by ohmic heating while looking at the volatile compounds kinetic evolution. Coconut water from an aromatic Thailand Green Dwarf variety was submitted to different ohmic heating time-temperature treatments ranging from 100°C to 140°C and from 0 to 600 seconds. Volatile compounds from the fresh and heated samples were extracted by headspace-solid phase microextraction before being identified by gas chromatography coupled to mass spectrum analysis. Volatile compounds variations were described thanks to principal component analysis and chemical kinetics. Sixty volatile compounds were identified. Even after high temperature ohmic heating treatment, flavor compounds responsible for the typical CW aroma remained in samples headspace. None of the Strecker degradation molecules was detected in the GC analysis of CW after a 5s or 10s treatment at 140°C. The variations of the volatile compounds composition and levels during ohmic treatment confirmed that the higher the temperature is, the less the impact on the chemical reactions thus on flavor quality. At least two volatile molecules were apparently good indicators of the heating treatment level: 3-penten-2-one and ethyloctanoate. During the isothermal stage, the kinetic approach lead to Ea=67.7 kJ.mol-1 for the 3-penten-2-one increase. These results proved that ohmic HT-ST treatments could ensure a commercially safe high quality beverage thanks to a better retention of the original volatile compounds of immature coconut water. (Résumé d'auteur

Détermination de la qualité de l'eau de coco en fonction du stade de maturation des noix et lors de sa stabilisation par chauffage ohmique et filtration membranaire

L'eau de coco, liquide transparent situé dans la noix de coco (Cocos nucifera L.), est une boisson tropicale rafraîchissante dont le marché est en pleine expansion. Ce jus de fruit possède des propriétés originales dues à sa composition en sels minéraux, sa faible teneur en sucres solubles et son arôme. Cependant, ses propriétés physico-chimiques ont été peu étudiées et sa stabilisation reste un défi technologique, notamment en raison de la présence de deux enzymes PPO et POD et de la thermosensibilité des composés aromatiques. Aussi ce travail s'attache, premièrement, à décrire les caractéristiques physicochimiques et le profil aromatique de l'eau de coco de cinq variétés récoltées à trois stades de maturité. A partir de ces données, un indice global de qualité a été construit. Il permet de prédire le potentiel de transformation en boisson de différentes variétés de cocotier. Deuxièmement, une étude de la dégradation de l'eau de coco à température ambiante tropicale (30°C) a permis de détecter les phases critiques du phénomène. Enfin, des essais de stérilisation de l'eau de coco ont été réalisés dans un réacteur batch de traitement ohmique et dans un pilote d'ultrafiltration avec des membranes de diamètres de pores 10, 20, 50 et 100 nm. Le chauffage ohmique a démontré sa capacité à inactiver les enzymes (barème de traitement optimal de 5 s à 140°C) mais il provoque des modifications du profil aromatique. L'ultrafiltration avec une membrane de diamètre de pores 20 nm permet d'obtenir des densités de flux intéressantes d'un point de vue économique, de retenir la totalité des enzymes mais il semble qu'une partie non négligeable des molécules de type ester, soit retenue. (Résumé d'auteur