Aplicações da tomografia de ressonância magnética nuclear como método não-destrutivo para avaliar os efeitos de injúrias mecânicas em goiabas 'Paluma' e 'Pedro Sato'
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Data
2002-12-01
Autores
Mattiuz, Ben-Hur [UNESP]
Biscegli, Clovis Isberto
Durigan, José Fernando [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Fruticultura
Resumo
Objetivou-se determinar o potencial do uso da tomografia de ressonância magnética, como método não-destrutivo, para avaliar os efeitos das injúrias mecânicas em goiabas. Foram utilizados frutos no estádio de maturação de vez das cultivares Paluma e Pedro Sato. Na injúria por impacto, os frutos foram deixados cair, em queda livre, de uma altura de 1,20 m, sofrendo dois impactos, em lados opostos de sua porção equatorial. Na injúria por compressão, os frutos foram submetidos a um peso de 29,4 N, por 15 minutos. Para a injúria por corte, foram efetuados dois cortes, no sentido longitudinal dos frutos, de exatamente 30 mm de comprimento por 2 mm de profundidade. Os frutos injuriados foram armazenados sob condições de ambiente (22 ± 2 °C e 40 %UR). Foram realizadas análises com tomógrafo de ressonância magnética Varian Inova de 2 Tesla. As imagens foram obtidas a partir da detecção dos prótons de hidrogênio (¹H). Para cada fruto, foram obtidos tomogramas simétricos a partir do centro do fruto. A tomografia de ressonância magnética nuclear mostrou-se uma ferramenta eficaz na detecção de injúrias internas de frutos. O estresse físico causado pelo impacto produziu um colapso interno nos lóculos desses frutos (internal bruising), levando à perda da integridade celular e a conseqüente liquefação dos tecidos placentários. A cultivar Pedro Sato mostrou uma suscetibilidade maior à injúria por impacto que a 'Paluma'. A injúria por compressão tornou-se mais evidente no pericarpo externo do fruto, de ambas as cultivares. A injúria por corte levou a lignificação dos tecidos no local injuriado e deformações superficiais devido à perda acentuada de matéria fresca no local da lesão, evidentes no sexto dia de avaliação.
The present study reports on the potential of the use of the tomography of magnetic resonance, as a non-destructive method, to evaluate the effects of the mechanical injuries in guava fruits. Fruits were harvested at mature stage of Paluma and Pedro Sato cultivars. In impact injury, fruits were allowed to fall freely from a height of 1.2 m, subjecting them to two impacts on opposites sides of the equatorial portion of the fruit. In compression injury, fruits were submitted to a weight of 29.4 N for 15 min. For the cut injury, two longitudinal cuts were made, 30 mm in length and 2 mm deep. Fruits were stored under ambient conditions (22±2 °C, 40 % RH). Magnetic resonance images (MRI) of intact guava were acquired using the Varian 2 Tesla tomography. Images were obtained from the hydrogen (H¹) of the water content and in each fruit was obtained symmetrical image from the center of the fruit. The magnetic resonance image ( MRI) technique was shown to be an effective tool in the detection of internal injuries of fruits. The physical stress caused by the impact produced an internal collapse of fruit locules (internal bruising), taking to the loss of the cellular integrity and the consequent liquefaction of the placentary tissues. The Pedro Sato cultivar showed a larger susceptibility to impact injury that the 'Paluma'. The compression injury became more evident in the external pericarpo of the fruit, for both cultivars. The cut injury took the lignification of the tissues in the injured place and superficial deformations due to the accentuated loss of fresh matter in the place of the lesion, evident in the sixth day of evaluation.
The present study reports on the potential of the use of the tomography of magnetic resonance, as a non-destructive method, to evaluate the effects of the mechanical injuries in guava fruits. Fruits were harvested at mature stage of Paluma and Pedro Sato cultivars. In impact injury, fruits were allowed to fall freely from a height of 1.2 m, subjecting them to two impacts on opposites sides of the equatorial portion of the fruit. In compression injury, fruits were submitted to a weight of 29.4 N for 15 min. For the cut injury, two longitudinal cuts were made, 30 mm in length and 2 mm deep. Fruits were stored under ambient conditions (22±2 °C, 40 % RH). Magnetic resonance images (MRI) of intact guava were acquired using the Varian 2 Tesla tomography. Images were obtained from the hydrogen (H¹) of the water content and in each fruit was obtained symmetrical image from the center of the fruit. The magnetic resonance image ( MRI) technique was shown to be an effective tool in the detection of internal injuries of fruits. The physical stress caused by the impact produced an internal collapse of fruit locules (internal bruising), taking to the loss of the cellular integrity and the consequent liquefaction of the placentary tissues. The Pedro Sato cultivar showed a larger susceptibility to impact injury that the 'Paluma'. The compression injury became more evident in the external pericarpo of the fruit, for both cultivars. The cut injury took the lignification of the tissues in the injured place and superficial deformations due to the accentuated loss of fresh matter in the place of the lesion, evident in the sixth day of evaluation.
Descrição
Palavras-chave
Psidium guajava, Postharvest, mechanical injuries, NMR tomograph, internal bruising, Magnetic resonance image, Psidium guajava, Pós-colheita, injúrias mecânicas, Tomografia, ressonância magnética nuclear, injúria interna
Como citar
Revista Brasileira de Fruticultura. Sociedade Brasileira de Fruticultura, v. 24, n. 3, p. 641-643, 2002.