Introduction. Fruit green-life is a major postharvest attribute on which conservation on commodity chains depends. For climacteric fruits such as banana, green-life must be optimized to fit the transport and market requirements. Calcium was assumed to strengthen cellular tissue and increase the green-life of fruits. Materials and methods. In our study, we tested the effect of preharvest and postharvest calcium applications on attributes of banana fruit for two cultivars (Musa spp., AAA group, cv. Cavendish Grande Naine and Flhorban920 cultivar, AAA group). Results and discussion. Extra calcium in fertilization of Flhorban920 cv. did not significantly affect the green-life of fruits (36 days) or the hardness and thickness of the Flhorban920 cv. skin (63.7 N and 3.94 mm, respectively). The field calcium applications, by fertilization or spraying, did not alter pulp or peel chemical composition. For postharvest treatments, the green-life of Cavendish and Flhorban920 banana was not significantly altered by the presence or absence of calcium, or by the type of application, 45 and 26 days for the Cavendish and Flhorban920 cultivars, respectively.

Introduction. The effects of imidacloprid and fenobucarb insecticides on the dynamics of the psyllid Diaphorina citri and on the incidence of Candidatus Liberibacter asiaticus (Ca. L. a.), the putative causal agent of Huanglongbing disease (HLB), were studied in a field experiment. Materials and methods. The experimental design consisted of three independent 0.5-ha Citrus orchards planted with disease-free HLB-susceptible orange trees, located in a Citrus producing area seriously affected by HLB. Imidacloprid was applied monthly to the trunks in one orchard at a rate of 0.15 g a.i.·tree–1; fenobucarb was sprayed fortnightly in a second orchard at a rate of 250 g a.i.·ha–1. The 3rd orchard was managed as a control without insecticide applications. The total number of adult D. citri specimens and the percentages of trees harbouring psyllid eggs and 5th instar nymphs were monitored at fortnightly intervals in each orchard. Ca. L. a. incidence was assessed in each orchard by PCR at 5 months, 12 months and 24 months after planting. Results. Compared with the control, both the fenobucarb and imidacloprid treatments reduced adult psyllid populations by over 90% and reduced the frequency of trees harbouring eggs and 5th instar nymphs. Only imidacloprid treatments totally prevented development of a new generation of adults from eggs. Two years after planting, the prevalence of Ca. L. a. was 0.939, 0.745 and 0.239 in the control and in the orchards treated with fenobucarb and imidacloprid, respectively. Discussion and conclusion. The results indicated that, although both the insecticides used effectively reduced D. citri populations by killing adults and nymphs and by affecting or preventing psyllid reproduction in orchards, neither of the two insecticide treatments totally prevented transmission of Ca. L. asiaticus. However, due to its long-lasting effect and systemic activity, the imidacloprid treatment provided the best protection against infections, and delayed and slowed down the spread of the pathogen. Furthermore, it reduced the number of pesticide applications needed and left the way open for biological integrated pest management programmes.

Introduction. Mature green vanilla pods accumulate 4-O-(3-methoxy-benzaldehyde)-β-D-glucoside (glucovanillin), which, upon hydrolysis by an endogenous b-glucosidase, liberates vanillin, the major aroma component of vanilla. Little is known on the spatial distribution of aroma-generating phenolics, and the enzymes responsible for their liberation (β-glucosidase) and oxidation (peroxidase). We report here quantitative data with respect to these three components in relation to the anatomy of the pod. Furthermore, the spatial progression of oxidation is shown. Materials and methods. Mature green vanilla pods were analyzed for their contents of phenolics (HPLC), and β-glucosidase and peroxidase activities by spectrophotometric techniques using p-nitrophenyl glucoside and vanillin as substrates, respectively. Lipids were examined under fluorescence microscopy after Nile red staining. Oxidation development was observed on transverse slices of pods. Results and discussion. Phenolics, and β-glucosidase and peroxidase activities showed gradients of increasing-decreasing concentrations from the stem to the blossom end of pods. The β-glucosidaseactivity is distributed in between the placentae, mesocarp, and trichomes in a [7 / 2 / 1] proportion while that of peroxidaseshows a [38 / 1] ratio inthe mesocarp and placentae, and was absent from trichomes. Oxidation begins from the blossom end in the placentae, progressively invading the mesocarp and moving towards the stem end. Conclusion. The green mature vanilla pod is spatially heterogeneous for its phenolics, and β-glucosidase and peroxidase activities, its placentae playing an important role in the liberation of vanillin and its subsequent oxidation.

Introduction. Vietnam is among the world's top 20 mango producing countries. In this country, the ‘cat Hoa loc’ variety is predominant, with 17 692 ha under cultivation with an annual production of 58 471 t; it is considered to be the best mango variety in the Mekong delta. Ripening of the fruit is typically expressed by a skin colour change from green to bright yellow. This variety is highly prized by local and foreign consumers, but subject to different disorders, especially fruit fly infestations. Heat treatment is a safe alternative to chemical treatments. It can impair mould development and control fruit infestation by destroying fruit fly eggs and larvae. It may have a greater or lesser effect on fruit physiology. If the treatment temperature and duration are incorrectly handled, skin burns may result and the internal quality of the fruit may be affected. Materials and methods. ’Cat Hoa loc’ mangoes at the commercially mature stage were subjected to hot air treatment (47 °C and 90% RH) of different durations [(0, 20, 40, 60, 90, 120 and 180) min from the fruit core attaining the temperature]. After treatment, the fruits were stored at 25 °C and quality parameters evaluated (weight loss, peel and flesh colour, percentages of fruit with burns and rots, burn index, ripening percentage, firmness, TSS, TA, vitamin C content, pH, reducing and total sugars, and taste test). Results and discussion. For the ‘cat Hoa loc’ variety, heat treatment accelerated ripening of the fruit in the initial storage period and colour changes occurred more quickly. However, after 7 days' storage, the difference in Hue value between the treated and control fruits disappeared. Hot air treatment at 47 °C of different durations [(20 to180) min] did not affect the internal coloration changes of ‘cat Hoa loc’ mangoes, but did affect the flesh firmness. We found that, after 3 d, hot air treatment at 47 °C led to significantly faster weight loss than control fruits but this difference disappeared after 7 d. Total sugar content was not affected by the treatment, but titratable acidity decreased more quickly in treated fruits.

Introduction. Rhizopus stolonifer is the causal agent of Rhizopus rot disease in various fruit and vegetables. Materials and methods. The effect of chitosan was evaluated in vitro on mycelial growth, sporulation, morphological characteristics and germination of spores of three isolates of R. stolonifer (from peach, papaya and tomato). The effect of chitosan on controlling Rhizopus decay in peach, papaya and tomato fruit in situ in comparison with the synthetic fungicide dichloran was also studied. Results and discussion. Our results showed that the mycelial growth and sporulation of the three isolates were markedly inhibited at all tested chitosan concentrations. The highest antifungal indexes and sporulation reduction were observed with chitosan at 2 mg·mL–1. In our study, the morphological characteristics of the spores of R. stolonifer showed different behavior depending on the evaluated isolates. In general, the highest effect on germination was observed at the chitosan concentration of 2 mg·mL–1. Our results demonstrated that chitosan was effective in reducing the percentage of infection and the severity index on peach, papaya and tomato fruit compared with those of non-treated control. The chitosan was not more effective than dichloran in reducing the percentage of infection. The results of the study suggest that chitosan (2 mg·mL–1) is a good alternative for the control of Rhizopus decay on peach, papaya and tomato fruit; it could be considered as a potential agent in natural alternatives to control postharvest diseases.

Introduction. Physalis has been known for a long time in Egypt. Among unexploited tropical fruits, Physalis is a very promising fruit. Recently, the economic importance of Physalis has risen, due to its high acceptance for local consumption, achieving great success in the African, Latin American and European markets. One of the challenges of recent years has been to participate in the development of Physalis as a commercial crop of economic utility. In order to understand the nutraceutical and medicinal characteristics of Physalis fruits cultivated in Egypt, the biochemical composition of the raw Physalis pubescens juice was determined. Materials and methods. Whole fresh fruits of Physalis pubescens from Egypt were preserved at –20 °C for the duration of the experiment. The juice was extracted from Physalis fruits by using a fruit pulper then filtered on cheesecloth to separate seeds and skins. Contents of oil, fatty acids, proteins, amino acids, sugars and minerals of the juice were analyzed, and were compared and discussed in relation to the biochemical composition of other fruits and vegetable oils. Results. Yield of the juice was high (64%) and it is a rich source of minerals such as potassium (11.32 g·100 g–1 dm), phosphorus (5.55 g·100 g–1 dm), zinc (0.02 g·100 g–1 dm) and boron (0.01 g·100 g–1 dm), polyphenols (76.6 mg·100 mL–1) and carotenoids (70 µg·mL–1). It contained good amounts of vitamin C (38.77 mg·100 mL–1) and it could be a good potential source of essential amino acids such as isoleucine, valine and tryptophan [(4.2, 3.9 and 3.9) g·100 g–1 protein], whose amounts were higher than those recommended by the FAO / WHO / UNU. Additionally, it contains a low amount of oil (1.1 g·100 g–1 dm). Conclusion. Physalis juice should attract great interest because of its composition. Its potential nutraceutical quality could participate in the development of Physalis as a commercial crop. Certain molecules such as antimicrobial molecules and bioactive withanolides, which have the famous ethnomedical and medical effects of Physalis juice, still have to be studied.