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- Author or Editor: Antonios Petridis x
The chemical and biochemical composition of olives relies on some agronomical factors, one of which is the cultivar. In this study, fruits and leaves of 11 Greek olive cultivars were examined concerning their phenol and oleuropein concentrations. Fruit antioxidant activity was determined as well. The obtained results showed that significant differences existed among cultivars regardless of the tissue or the measured parameter. In general, leaves had higher total phenol and oleuropein concentrations than fruits. Finally, the highest oleuropein concentration in fruits was recorded in ‘Pikrolia Kerkiras’ followed by ‘Romeiki’, ‘Megaritiki’, ‘Kothreiki’, and ‘Kalamon’. These cultivars may constitute the raw material in the industrial production of oleuropein.
The antioxidant activities (μmol ascorbic acid equivalent/g fresh weight) of the edible part of fruits grown in northern Greece were determined using the ferric-reducing antioxidant power (FRAP) assay. Differences were observed among species as well as cultivars of the same species. Cornelian cherry had the highest FRAP value followed by jujube. Cherries, black grapes, and blackberry showed high activity followed by pears, persimmons, plums, peaches, white grapes, pomegranates, apples, nectarines, kiwifruits, quinces, figs, and apricots.
The effect of various commercial calcium (Ca) -containing products applied as preharvest foliar sprays on several fruit quality attributes and nutritional status of the kiwifruit cultivar Tsechelidis for a 2-year period is reported. Foliar application of all Ca products plus boron did not affect mean fruit weight compared with the control. During the first year, the highest flesh firmness was measured after application of the Ca-containing products Acid CaLMg and Calfruit plus Qualyfruit. During the second year, the highest flesh firmness was measured after application of the product Acid CaLMg. The highest ascorbic acid content and total antioxidant power were recorded after application of the product Chelan CaP. Foliar application of Power-Ca resulted in an increase of Ca concentration of leaves compared with the control for the first year. During the second year, all Ca-containing products increased Ca concentration of leaves compared with the control. Foliar application of Calfruit plus Qualyfruit, Chelan CaP, Power Ca, and Acid CaLMg resulted in an increase of Ca concentration of fruits compared with the control. The efficacy of the foliar sprays on some of the tested parameters varied from year to year indicating the influence of other parameters on vine nutrition.