No abstract

No abstract

Effect of postharvest treatments with polyamines on physiological and biochemical attributes of kiwifruit (Actinidia deliciosa). Abstract-Introduction. Kiwifruit is a typical climacteric fruit, which grows profitably well in sub-temperate climatic conditions. The major problem with kiwifruit is that it does not ripen for about a week at room temperature but after this period there is a sudden rise in the respiration rate and fruits remain in edible condition for only a few days, giving it a very short shelf life in ambient conditions. Materials and methods. Kiwifruits were treated with different concentrations of spermine [(0.5, 1.0 and 1.5) mM] and spermidine [(1.0, 1.5 and 2.0) mM] by the immersion method; biochemical and physiological analyses were carried out, then fruit were stored in ambient conditions for 15 days. Results and discussion. Polyamine-treated fruits did not show any amount of ethylene evolution up to the 6th day of storage as compared with those of control, in which it started after the 3rd day of storage. The respiration rate was also the lowest in treated fruit. Similarly, polygalacturonase and lipoxygenase activities rose rapidly in control fruits in comparison with polyamine-treated fruits. Conclusion. The doses of spermine at 1.5 mM and spermidine at 2.0 mM showed the best results in extending the shelf life of kiwifruits when stored in ambient conditions [(22 ± 4)°C, RH: (65 ± 5)%].

Ethylene absorbents influence fruit firmness and activity of enzymes involved in fruit softening of Japanese plum (Prunus salicina Lindell) cv. Santa Rosa.Abstract -Introduction. Plum cv. Santa Rosa shows climacteric behaviour and grows profitably under sub-temperate conditions in India. After ripening, it has a very limited shelf life (3-4 days) in ambient conditions [(38 ± 2)°C and at (68 ± 4)% RH]. Hence, there is an urgent need to extend its marketability using recent techniques. Materials and methods. Plums were harvested at the pre-climacteric and climacteric stages of maturity and packed with newspaper shreds (control), KMnO 4 -impregnated chalks, KMnO 4 -impregnated newspaper shreds or ethylene-absorbent sachets; then they were transported by road to New Delhi. The biochemical and physiological analyses were carried out at 3-day intervals on plums stored in supermarket conditions [(20 ± 1)°C and at (90 ± 2)% RH] for 15 days. Results and discussion. Untreated fruits had less firmness than those which were packed with ethylene absorbents. The activities of fruit-softening enzymes such as lipoxygenase (LOX), polygalacturonase (PG) and pectin methylesterase (PME) increased rapidly in the control treatment in comparison with plums packed with various ethylene absorbents, the least being either with ethyleneabsorbent sachets or with KMnO 4 -impregnated newspaper shreds. Plums of pre-climacteric and climacteric maturity attained respiration and ethylene evolution peaks on the 9th day and 6th day, respectively. Conclusions. The plums of pre-climacteric and climacteric stages of maturity packed with ethylene-absorbent sachets showed the best results in supermarket conditions in maintaining the firmness, quality and shelf life of plum up to the 12th day and 9th day of storage, respectively. Les activités des enzymes de ramollissement des fruits comme la lipoxygénase (LOX), la polygalacturonase (PG) et la pectine méthylestérase (PME) ont augmenté rapidement dans les fruits témoins par rapport à ceux qui avaient été emballés avec les différents matériaux absorbeurs d'éthylène, ces activités étant moindres pour les prunes emballées soit avec les sachets d'absorbeurs d'éthylène, soit avec des lanières de journaux imprégnées de KMnO 4 . Les prunes aux stades de maturité pré-climatérique et climatérique ont atteint leurs pics de respiration et d'évolution de l'éthylène le 9e jour et 6e jour, respectivement. Conclusion. Les prunes japonaises récoltées à des stades de maturité pré-climatérique et climatérique, emballées en présence de sachets absorbeurs d'éthylène et stockées en conditions de supermarchés, ont donné les meilleurs résultats pour le maintien de la fermeté, de la qualité et de la durée de vie des fruits jusqu'au 12 e jour et 9 e jour de stockage, respectivement. India /

No abstract