Coffee Science - v.06, n.3, 2011

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/7817

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    Evaluation of coffee drying costs: pre-drying on concrete terrace and complementary drying in co-current and counter-current flow dryer
    (Editora UFLA, 2011-09) Martin, Samuel; Silva, Jadir Nogueira da; Zanatta, Fabio Luiz; Galvarro, Svetlana Fialho Soria; Volk, Marcus Bochi da Silva
    The study of drying costs is an important tool to be considered when deciding on an adequate drying system. One needs to consider the energy needed for air heating, electrical energy needed to run the fans, energy to transport the product, labor costs, maintenance costs, depreciation, interest rates and breakdown costs. The objective of this study was to determine the total drying cost per bag of dry coffee beans (Coffea arabica L.), by drying processed coffee in the form of pulped cherries, with pre-drying on a concrete yard followed by complementary drying in a developed prototype dryer with concurrent and countercurrent flows. The dryer was constructed of a metallic frame and plates, with a static capacity of 1.55 m 3 . An initial concurrent drying stage was separated from a second counter-current flow drying stage by a repose chamber. Two treatments were applied: a) Treatment 01: 12 hours of intermittent drying with intermittent rotation and 12 hours of rest, with air temperature of 45 °C and rotation of the beans every 90 minutes for drying (for a period of 10 minutes each); b) Treatment 2: 12 hours of intermittent drying with continuous rotation and 12 hours of rest, with air temperature of 70 °C. Coffee quality was determined via a sensorial analysis (cup-test). It was concluded that: The fixed cost of the multiple flow dryer was the principal component in the total cost of drying, principally since it was treated as a prototype; Increase in the drying capacity of the system with application of treatment 02 (with continuous rotation), in relation to treatment 01 (with intermittent rotation), drastically reduced total drying costs; The results obtained from treatment 01 demonstrate its economic infeasibility, due to the elevated drying costs encountered for the proposed system under the conditions in which this study was performed.
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    Selectivity of rynaxypyr for three species of phytoseiid mites relevant to coffee in Brazil
    (Editora UFLA, 2011-09) Reis, Paulo Rebelles; Franco, Renato André; Silva, Fábio M. Andrade
    Among the predaceous mites, those of the Phytoseiidae family are the most important and studied. The phytophagous mites Brevipalpus phoenicis (Geijskes, 1939) (Tenuipalpidae) and Oligonychus ilicis (McGregor, 1917) (Tetranychidae), on coffee trees (Coffea spp.), are frequently found in combination with the predaceous mites Iphiseiodes zuluagai Denmark & Muma, 1972, Amblyseius herbicolus (Chant, 1959) and Euseius citrifolius Denmark & Muma, 1970, among others. The purpose of this research was to study the effects of the insecticide rynaxypyr (chlorantraniliprole 200 SC) on these three species of Phytoseiidae, relevant to coffee and citrus, following standard laboratory procedures. Mated female mites were exposed to fresh-dried residues on a glass surface, with 7 treatments, 5 mites per glass plate and 6 replicates, in a completely randomized experimental design. Each test lasted 8 days, with a daily count of the surviving females and of eggs laid. Rynaxypyr, in all tested concentrations (15, 30, 50, 100 and 500 mg a.i./liter of water), was selective for the studied species, A. herbicolus, I. zuluagai, and E. citrifolius. Overall the treatments resulted in low mortality rates and negligible impact on the reproduction. Therefore, based on IOBC standards, rynaxypyr can be classified as not harmful (Class 1), comparable to the agrochemical hexythiazox equivalent to a harmless standard of selectivity in the laboratory. Rynaxypyr is therefore a complement to programs of integrated pest management, to preserve the populations of predatory mites in crops of coffee and citrus, among others, in Brazil.