No abstract

This research work was carried out in 2013 and 2014 seasons on "Costata" persimmon trees at Kafr Ashma farm (Menoufeya Governorate),to test the effectiveness of foliar sprays of some stimulants (Ascopin, GA 3 , Glycine, Chitosan, Azolla, Yeast and Kaolin), on tree yield parameters and fruit quality of fruits, especially tannin content. Each treatment was carried out on a separate row of 10 trees. Five monthly sprays were applied starting from 2 weeks after full bloom (mid April), till mid August. Application of these stimulants had good and variable effects, as they caused a significant increase in fruit set %, number of fruits/tree, yield, fruit weight, dimensions, TSS, acidity, TSS/acidity and firmness compared to the control. Samples of fruits at maturity were picked and placed 4 weeks at 4 ºC, and 90 RH and their quality criteria were estimated weekly. Chitosan, Azolla and Yeast achieved the best results in this respect. Yeast treatment resulted in the least content of tannins during fruit growth at harvest and after cold storage, but Ascopin had no positive effect on other quality attributes contrary to the noticeable effects of Chitosan, GA 3 , Azolla and Yeast on increasing T.S.S. % vitamin C, and on decreasing acidity % of fruits and decreasing their weight loss after storage. Fruits from Yeast treatment had the best taste . It is recommended to use any of these stimulants on persimmon orchard, especially Yeast, GA 3 . Azolla and preferably Yeast, because it is highly effective in getting high yield and reducing tannins as well as being a cheap natural material.

ersimmon is an important seasonal fruit which often exhibits rapid softening during postharvest distribution, handling or sometimes on the trees. Storage treatments and packaging types are critical points on degradative pathways of bioactive components reflected to fresh fruits quality properties. The present investigation was conducted during two successive seasons (2015 and 2016) on persimmon (Diospyros kaki L.) fruits c.v. "Costata". Fruits were harvested at maturity orange color and were divided into two groups, the first group was dipped in hot water at 50 o C for 10, 20 and 30 min., while the The second one was dipped in edible coating film consists of (10g maltodextrin, 5g methyl cellulose, 8ml glycerol, 2.5g ascorbic acid, 1g potassium sorbate and 1g calcium chloride/ distilled water liter) for 10, 20 and 30 min., in addition to the untreated fruits (as control). Fruits of all treatments were stored at 4±1 • C and 90% relative humidity (RH) in polyethylene terephthalate (PET) punnets for 8 weeks. The changes in physical and chemical properties of fruits were evaluated as fruits color, weight loss, firmness, total soluble solids (TSS) and titratable acidity percentage also antioxidant components (total phenols, total tannins, flavonoids, ascorbic acid and carotenoids) were studied during storage period every two weeks. The obtained results illustrated that all fruits had storage life eight weeks at cold storage 4±1 • C and 90% relative humidity (RH), fruits treated with edible coated film for 30 mins. have gained best quality in comparison with other treatments its. Since, it's observed delayed in increasing total soluble solids percentage, reduced titratable acidity percentage and fruits firmness. On the other hand, the decrement of antioxidant contents including ascorbic acid, total phenols, flavonoids, were higher in persimmon fruits treated with hot water and control. Therefore, some postharvest treatments such as hot water or edible coating film to improve fruits sensorial quality through reducing the astringency and bitterness components in persimmon.