Effect of delaying pre cooling treatment on fruit quality and storability of "thompson seedless" and "flame seedless" grapes.

Includes reference.

Thompson Seedless and Flame Seedless grapes were harvested at maturity stage from a private farm at Cairo-Alex. desert road. Fruits were cooled using ice inside polyethylene bags to protect them from directly touch with ice. Fruits were cooled after O. 1, 2, 3 hours after harvest or non-cooled (control). Fruits were left under the shadow of vines until cooled and were transported to the laboratory to be packed inside perforated polyethylene bags (40 mm and 400 hails per m3 ). and stored at O! C and 90:95 % RH for 35 days. Weekly intervals samples were taken to determined .decay, weight loss, and shatter incidence, berry firmness, bunch freshness (stem color and dryness. berry appearance), lotal soluble solids and total acidity contents were measured and tabulated. Post harvest pre cooling treatments significantly reduced decay, weight loss, shatter, total spoilage incidence of grapes during storage. Also, pre cooling treatments had a significant effect on reducing the softening rate in berry firmness of grapes during storage. Moreover, post harvest pre cooling treatments had a good effect on total soluble solids and total acidity conlents of grapes during storage. Moreover, in the most studied parameters were not affected significantly differences among the first three treatments (post harvest pre cooling after 0, 1. 2 hours from harvest). These results confirmed that , post harvest pre cooling treatments have to be done within 2 hours at the maximum delaying period in order to maintain grapes at a good quality for long distance transportation or long storage period.

Summary in Arabic.

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