Resumo

BALOIS-MORALES, R. et al. Antisenesence anzymatic system, catalase-superoxide dismutase, in pitahaya (Hylocereus undatus) fruits stored at low temparatures. Rev. Chapingo Ser.Hortic [online]. 2008, vol.14, n.3, pp.295-299. ISSN 2007-4034.

The objective of this investigation was to evaluate the effect of low temperatures on the anti-senescence catalase (EC. 1.11.1.6; CAT)-superoxide dismutase (EC. 1.15.1.1; SOD) enzymatic system of pitahaya (Hylocereus undatus) fruit during storage. Groups of fruits from Tehuacan, Puebla, were stored four days at room temperature (22±1 °C), and at 3, 7 and 11±1 °C for 7, 14 and 21 days, and after each cold-storage period they were kept for four days at 22±1 °C. Catalase and SOD activity was evaluated in fruit pulp from 20 treatments, including a control without storage. Four days at 22±1 °C did not modify CAT nor SOD activity (18.75 y 3.25 U·g^-1, respectively) compared with the control. Cold storage significantly diminished CAT activity, relative to the control. Inhibition of CAT activity was not dependent on cold storage temperature or time, but mean inhibition in fruits stored at 11±1 °C (13.07 U·g^-1) was slightly lower than at 3 and 7±1 °C (12.39 U·g^-1). After cold storage, CAT inhibition was partially or totally reverted after four days of storage at 22±1 °C. SOD activity was not significantly affected by low temperatures, and in general, after cold storage, it was activated with complementary storage at 22±1 °C. CAT activity is inhibited by cold storage, but SOD activity, which diminishes the process of senescence generated by oxidative stress, is activated in the pitahaya fruits.

Palavras-chave : stress; cold-storage; senescence.