Antifungal efficacy of botanicals against major postharvest pathogens of Kinnow mandarin and their use to maintain postharvest quality

Introduction. Kinnow is an important citrus crop grown in India, which suffers from several postharvest diseases during storage. Hence, an attempt was made to combat such diseases with the botanicals Aloe vera, Eucalyptus and Ocimum on Kinnow mandarin to prolong its availability for a longer time. Materials and methods. For this, in vitro and in vivo studies were conducted. The poisoned food technique was used for in vitro studies, and, for in vivo studies, Kinnow fruit were pre-inoculated with pathogens (Penicillium digitatum and P. italicum), treated with different botanicals, then stored at (5 ± 1) °C temperature and 85–90% RH. Results and discussion. Our results indicated that all botanicals inhibited the growth (colony diameter) of both pathogens over untreated PDA plates, but the inhibition was the strongest by Aloe vera extracts. Similarly, under in vivo conditions, all botanicals influenced the decay incidence, decay loss, lesion diameter, respiration rate, ethylene evolution and physiological loss in weight, but Aloe vera was the most effective. All the botanicals were able to retain postharvest quality of Kinnow fruits without any adverse effect on quality parameters such as TSS, TA and ascorbic acid. Under in vivo conditions, the incidence of Penicillium italicum was higher than P. digitatum; however, it was the reverse under in vitro conditions. Conclusion. Thus, it is evident from our studies that botanicals have the potential to control green and blue mold without causing any injury or harmful effects on Kinnow mandarin; botanicals can be recommended as a safe method for extending its storage life while maintaining fruit quality at the same time

Effect of postharvest treatments with polyamines on physiological and biochemical attributes of kiwifruit (

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

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), KMnO4-impregnated chalks, KMnO4-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 ethylene-absorbent sachets or with KMnO4-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