Fruit flies : disinfestation, techniques used, possible application to mango

Introduction. The methods of fruit disinfestation against fruit flies use processes (physical methods) which differ according to the export country and fruit which must be disinfested. The term definitions are made clear and the various treatments are presented. Heat treatments. For mango, treatments usable for disinfestation can only utilize heat, because of the strong sensitivity of this fruit to cold temperatures. The heat treatments in general consist of using an immersion in hot water by a system of batches or an uninterrupted bath. These treatments are then followed or not by a fruit fast cooling which can be carried out by ventilation (cold air) or hydrocooling (water). Heat can also be obtained by use of forced hot air or hot vapor, because a higher temperature than 45 °C kills fly eggs and larvae. Microwave treatments. The use of microwaves is also a technique which makes it possible to increase the temperature in the fruit heart. Irradiation. The last possible solution is the use of irradiation, which uses a principle different from the preceding treatments. Conclusion. In comparison with the most current treatments (vapor heat treatment and forced hot-air treatment), the hot water treatment has many advantages: it is easy to implement, it is quick, it kills surface parasitic organisms, it makes it possible to clean the fruit surface and its cost only corresponds to approximately 10%of the cost of one vapor heat treatment. It would thus be recommended for mango disinfestation

Some properties of starch and starch edible films from under-utilized roots and tubers from the Venezuelan Amazons

International audienceBiopolymers from agricultural starchy commodities can be raw materials for edible, biologically degradable plastics. They have promising uses, having been proposed for replacing synthetic films. There are several starchy sources not yet quite exploited such as tropical roots and tubers that could be excellent starch sources to produce edible films with distinctive functional properties. The objective of this study was to formulate edible films from six tropical starchy crops. Starches were extracted and purified to 97-99% purity from Ipomoea batatas, Arracacia xanthorriza roots, Colocasia esculenta, Xanthosoma sagittifolium corms, and Dioscorea trifida tubers (white and purple) cultivated in the Venezuelan Amazons. The non-conventional starches were characterized for purity, amylose content and gelatinization profile by differential scanning calorimetry, starch granular morphometry and rheological properties. Starch-based films were processed by casting solutions prepared with each starch, glycerol, and distilled water. Starch suspensions were gelatinized by heat, degassed, poured in plates and dried. In the films, studies performed were water vapor, oxygen and carbon dioxide permeability, and mechanical properties in terms of tensile strength. Crystallinity patterns of native starches and films were also obtained. Ipomoea batatas and Colocasia esculenta exhibited polymorphism A+B type X-ray pattern, Xanthosomasagittifolium, an A-type X-ray pattern, and Arracacia xanthorriza and both Diosocrea trifida, B-type patterns; while starch-based films had all a B-type X-ray pattern. As expected, the potential for these types of films are more in the area of decreasing gas exchange rather than retardation of water loss due to their hydrophilic nature. Films from these non-conventional starch sources with barrier and mechanical characteristics tailored for specific uses can be of interest as plastics for the food industry and results may be of significance also, for starch-based foams