บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Effect of harvest date and storage on antioxidant systems in pears.

Spinardi A., Visai C.

5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004. page 8

2004

บทคัดย่อ

Effect of harvest date and storage on antioxidant systems in pears.   In many fruits the ripening process is characterised by an increase in oxygen consumption related to the climateric rise.The enhanced oxidative metabolism could generate an excess in active oxygen species (AOS) that, if not effectively detoxified by the cell defence systems, leads to a peroxidation of biomembranes, to a damage of cell compartmentation and, ultimately, to tissue senescence and general disorders.Studies o­n some components of the system of enzymatic and non enzymatic antioxidants involved in the protection of cells from oxidative damage, are reported.

Pears (Pyrus communis cm. Passa Crassana) were picked at 3 different stages of ripening : immature, commercial ripe and fully ripe.Commercially ripe fruits were stored for 3 and 4 months at normal atmosphere (T:1.5 °C ; RH 95%).Ethylene production rates were measured and the activity of the scavenging enzymes as superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) were evaluated.The levels of the antioxidant ascorbic acid (AA) and of malondialdehyde (MDA), a marker of lipid peroxidation, were also determined.

Ethylene levels were barely detectable at all 3 harvest dates and increase progressively during storage.The ripening stage did not affect SOD activity, whereas first APX and then GR activities increased during the harvesting period.The activities of SOD andAPX decreased significantly during storage and that of GR was enhanced.AA reached the highest level in commercial ripe fruits.Furthermore, Storage had a negative effect o­n AA content and caused a gradual, marked decrease.MDA did not change in fruits of different ripening stages, while in pears after storage the levels were significantly higher.

These results suggest that principally during storage defence mechanisms against AOS fail to provide adequate protection and oxidative stresses occur.