Postharvest of irradiated Tahiti lime fruits/Pos-colheita de frutos de lima acida 'Tahiti' irradiados

This study aimed to evaluate the postharvest quality evolution of gamma-irradiated 'Tahiti' limes. Shiny, olivegreen fruits with coarse skin (56 cm equatorial diameter) harvested in commercial orchars and processed in commercial packing house line were used. In a preliminary assay, fruits harvested in April 2011 were exposed to a gamma radiation range from 0 to 750 Gy. The 250 and 750 Gy doses negatively affected skin quality and pulp of exposed fruits. For this reason, new assays were carried out using lower doses to irradiate fruits harvested in July 2011 (off-season) and January 2012 (regular harvest period). Fruit harvested in both periods were selected and exposed to radiation doses of 0, 50, 100, 150, and 200 Gy. All irradiations occurred at a rate of 0.46 Gy/h. After fruit irradiation, physical and chemical analyses were performed along a 20-day storage period at room temperature (24 [+ or -] 1[degrees]C and 80 [+ or -] 5% RH). Irradiation of fruits harvested in July 2011 and January 2012 and treated with doses of up to 200 Gy did not affect the ascorbic acid content, but doses > 100 Gy caused skin yellowing of fruits harvested on both periods. Gamma radiation at doses [greater than or equal to] 50 Gy reduced the total soluble solids content in off-season fruits. Exposure of fruits harvested in the main harvest period to radiation doses [greater than or equal to] 150 Gy increased weight loss. Irradiation of 'Tahiti' limes at doses between 50 Gy and 700 Gy did not preserve postharvest quality during storage at room temperature. Index terms: Citrus latifolia, conservation, gamma radiation, fruit quality. O presente trabalho objetivou avaliar a qualidade pos-colheita de frutos de lima acida 'Tahiti' irradiados. Frutos colhidos de pomares comerciais com casca rugosa, de cor verde oliva brilhante e diametro equatorial medio de 56 mm foram beneficiados em casa de embalagem comercial. Em ensaio preliminar foram irradiados frutos colhidos em abril de 2011 com doses de irradiacao entre 0 e 750 Gy. As doses de 250 a 750 Gy afetaram negativamente a qualidade interna e externa dos frutos. Consequentemente foram realizadas novas avaliacoes com doses menores de radiacao para frutos colhidos em julho de 2011 (entressafra) e janeiro de 2012 (safra). Em ambas as datas, os frutos foram selecionados e submetidos as doses de 0, 50, 100, 150 e 200 Gy. Em todas as datas, foi usada taxa de irradiacao de 0,46 Gy/hora. Apos a irradiacao, os frutos foram submetidos a analise