Introduction. Red-purple pitahaya (Hylocereus sp.) is a promising crop grown commercially in dry regions of Central America. Both its skin and flesh are characterized by being a glowing, deeply red-purple color. Materials and methods. The main physicochemical characteristics of three commercial cultivars of red pitahaya were assessed, including total phenolic compounds contents, total betacyanins, vitamin C and oxygen radical absorbance capacity (ORAC). Thermal stability of betacyanins at different temperature and pH was also assessed. Results and discussion. Pitahaya fruit has a low vitamin C content ranging from (116 to 171) µg·g–1 of fresh pulp without seeds, but it is rich in betacyanins [(0.32 to 0.41) mg·g–1] and phenolic compounds [(5.6 to 6.8) µmol Eq gallic acid·g–1]; it has a high antioxidant ORAC value of (8.8 to 11.3) µmol Eq Trolox·g–1. Visible spectra of aqueous fruit extracts were very similar to that of pure betacyanin. Indeed, the characteristic color of juice diluted to 1% presents a high hue angle (H° = 350º ± 3) and high chroma values (C* = 79 ± 2). Thermal stability of pitahaya betacyanin decreases with pH, but it remains compatible with industrial utilization as a colorant (half-time = 22.6 min at 90 °C at pH = 5 of the fruit) and was found to be very similar to that previously reported for beetroot. Conclusions. Pitahaya juice combines the functional properties of a natural food colorant with high antioxidant potency.

Introduction. Noni (Morinda citrifolia) has a long history related to medical uses in Southeast Asian countries. Today, noni grows in the majority of the southern Pacific areas, in India, the Caribbean, South America and the West Indies. One of the challenges of recent years was to process Morinda citrifolia fruit juice, to make a more modern drug from a traditional product. In order to obtain better understanding of the medicinal characteristics of the noni fruit cultivated in Cambodia, the biochemical and mineral compositions of the raw juice extracted from M. citrifolia fruits were determined. Materials and methods. Whole fresh fruits of M. citrifolia which came to France from Cambodia were preserved at –20 °C during the duration of the experimentation. Commercial Tahitian noni juice was bought pasteurized to be used as a reference. The extraction was carried out on two batches of Cambodian fruits using a hydraulic press. Contents in oil, fatty acids, proteins, amino-acids, sugars and minerals of juices were analyzed. Results. Composition of noni juice of different origin was determined, compared, and discussed in relation to the biochemical and mineral composition of other vegetable oils. Conclusion. The biochemical composition of the noni juice, which showed a high content of antioxidant molecules, is not sufficient to explain the famous medicinal effects of noni juice. Certain molecules, in particular alkaloids, still have to be studied.

Introduction. Chlorophyll fluorescence (chl-fluorescence) has been used in postharvest studies as a non-destructive technique for evaluating fruit ripening. Since there are no available studies using chl-fluorescence in guava fruit, the aim of this work was to verify the relations between chl-fluorescence parameters and fruit quality attributes, such as skin color and fruit firmness, and to measure the chl-fluorescence during ripening of guava fruit. Materials and methods. Firstly, maximal (Fm), minimal (Fo), variable (Fv), and variable to maximal [Fv/Fm] fluorescence yields, skin color (Hº) and fruit firmness were evaluated in guava fruit harvested at three ripeness stages: dark-green (I), light-green (II) and yellowish-green (III). Secondly, changes in the above chl-fluorescence parameters and Hº were measured during 7 days of ripening. Relations between the evaluated parameters were also studied. Results and discussion. The three ripeness stages were well segregated using the Hº, Fm and fruit firmness parameters. Fo was insensible to early changes in fruit ripening, maintaining relatively stable values until fruit firmness of 20 N. When considering changes in chl-fluorescence and Hº during ripening, there were no significant differences between guava fruit harvested at stages II or III. The [Fv/Fm] value decline was only evident on the fifth day of ripening, whereas Fv, Fm and Hº began to decrease on the first day. Regardless of [Fv/Fm], the relations between chl-fluorescence parameters and Hº tended to increase from ripeness stages I to III, with Fm having the highest correlation with Hº. The results show that chl-fluorescence can be used to evaluate the ripening and senescence of guava fruit, with Fm being a good ripening indicator.

Introduction. La pomme de cajou, souvent considérée comme un sous-produit de l’industrie de la noix de cajou, reste très peu valorisée. Parmi les diverses options technologiques possibles pour la clarification des jus de fruits pulpeux, la microfiltration tangentielle sur membrane minérale est un procédé particulièrement prometteur. L’objectif de notre travail a donc été d’évaluer l’intérêt de ce procédé pour la production de jus de pomme de cajou clarifié. Matériel et méthodes. Des essais de filtration ont été réalisés à 30 °C sur une installation pilote de laboratoire munie de diverses membranes tubulaires en alumine. Quatre membranes ont été testées, différenciées par le diamètre moyen de leurs pores [(0,1 ; 0,2 ; 0,8 et 1,4) µm]. Les performances (densité de flux de perméat) et la composition du jus clarifié obtenu (tannins condensés, acidité titrable, acide ascorbique, pH, turbidité, couleur et extrait sec soluble) ont été comparées pour chacune de ces membranes. L’utilisation d’un prétraitement enzymatique de liquéfaction couplé à la microfiltration a également été abordée. Résultats et discussion. Les densités de flux de perméat obtenues ont été comprises entre (36 et 79) L·h–1·m–2. Dans les conditions testées, les membranes de diamètre de pores de (0,1 et 0,2) µm ont conduit aux meilleurs résultats. Le couplage de la microfiltration avec un prétraitement enzymatique de liquéfaction a amélioré les performances de la filtration de (30 à 60) %. Toutes les membranes ont permis d’obtenir un jus parfaitement limpide dont la teneur en acide ascorbique a été très voisine de celle du jus frais. En revanche, les composés phénoliques présents en grande quantité dans le jus de pomme de cajou brut ont été presque totalement éliminés au cours de l’opération permettant ainsi de diminuer considérablement l’astringeance du jus. Conclusion. Nos travaux ont vérifié le potentiel du procédé de microfiltration tangentielle sur la production de jus clarifié de pomme de cajou. Néanmoins, avant d’envisager une future application industrielle, les conditions de traitement devront être optimisées et les qualités nutritionnelle et sensorielle du jus clarifié devront être mieux caractérisées.

Introduction. En Tunisie, les dattes de type Deglet Nour sont réputées pour leur couleur jaune doré et elles présentent une valeur marchande élevée ; elles constituent la majorité des dattes exportées vers l’Europe. L’objectif de nos travaux a été d’étudier l’effet de l’oxygène et de la température sur la dégradation de la couleur de ce type de dattes durant la période d’entreposage. Matériel et méthodes. L’évolution de la couleur de dattes du type Deglet Nour stockées sous humidité relative constante (75 %), à trois températures différentes [(10, 25 et 37) °C] et en présence de trois concentrations d’oxygène [(0, 20 et 40) %] a été suivie chaque semaine durant 35 jours à l’aide de la mesure des paramètres L* et b* de l’échelle Hunter Lab. Résultats. La température a joué un rôle déterminant dans la dégradation de la couleur des dattes durant l’entreposage et l’effet de l’oxygène a été important quoique secondaire. Conclusion. La couleur des dattes au cours de leur stockage se révèle pouvoir être prédite à partir du seul paramètre b* de l’échelle Hunter Lab. Dans le cas des dattes conditionnées sous différentes concentrations en oxygène et à différentes températures, la perte de la couleur initiale du fruit a été davantage expliquée par une augmentation de la température ambiante que par la variation de la concentration en oxygène du milieu de conservation. La dégradation de la couleur serait causée par des brunissements non enzymatiques et enzymatiques oxydatifs.

Introduction. Les variations phénotypiques et la multiplicité des dénominations des variétés marocaines de figuiers rendent confuse l’identification variétale des accessions de Ficus carica L. Matériels et méthodes. Quinze accessions présentes en collection dans la région de Meknès correspondant à cinq dénominations différentes ont été caractérisées en combinant deux approches : pomologique et moléculaire (SSR et ISSR). Résultats. Les résultats obtenus ont permis d’identifier des accessions distinctes et des redondances au sein de chacune des cinq dénominations. Conclusion. La complémentarité des deux approches se révèle utile pour l’établissement d’une collection de référence.

Introduction. Vegetative and fruit growth in fruit trees are differentially sensitive to water deficit during the season depending on the stage of fruit growth. Attempts have been made to evaluate the possibilities of using regulated deficit irrigation to control vegetative growth and save water in the fruit industry. Materials and methods. Effects of water stress (WS) and crop load (CL) on fruit growth and carbon assimilation rates were evaluated in a 7-year-old ‘Elegant Lady’ peach orchard. A completely randomized block design with 2 × 3 factors [irrigation with two levels (control and WS) and CL with three levels (light, commercial and heavy)] was used. Results and discussion. Both WS and CL affected fruit growth during the last stages but not early on. CL did not affect trunk water potential which was, however, significantly reduced by WS throughout the day and the season. Trunk water potential of water-stressed trees was lower than that of control trees throughout the day and the season regardless of CL. The magnitude of WS increased as the season progressed. Stomatal conductance, transpiration rate and CO2 assimilation rate were not affected by CL but were reduced by WS. The trees responded (acclimated) to stress by progressively reducing their transpiration rate as the severity of stress increased. For each irrigation regime, assimilation rates were similar for all three crop levels. This indicated the existence of alternate sinks for assimilates when CL was low, which compensate for the reduction of fruit sink activity resulting from fruit thinning. Conclusion. Water deficit reduced trunk water potential, stomatal conductance, transpiration and photosynthesis in ‘Elegant Lady’ peach trees. However, CL had a limited effect on these functions. There were good correlations between trunk water potential and either stomatal conductance or assimilation rate in water-stressed trees but not in control trees. This indicates a poor coordination between leaf functions in peach trees under optimal conditions. However, these relationships were stronger under WS conditions. Thus, water use efficiency appeared to increase under water deficit conditions.

Introduction. Non-destructive estimation of leaf area saves time as compared with geometric measurements. For this reason, several leaf area prediction models were produced for some plant species such as grape, avocado and kiwifruit in previous studies. In this research, we attempted to offer a reliable equation that predicts strawberry leaf area non-destructively by linear measurements of leaf geometry. Materials and methods. An equation was developed by using Sweet Charlie and Camarosa strawberry cultivars and by measuring lamina width, length and leaf area. Results and discussion. It was found that the relationships between the actual leaf area and the predicted leaf area given by the equation developed were significant at a level of 0.1% and that r2 was 0.993. In addition, the model was validated by measurements of new leaf areas of seven other strawberry cultivars. Conclusions. The model developed could be used for strawberries in relevant studies.