Changes in L-phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity and total phenolic, ortho-diphenolic and fat contents of olive¯esh in response to different irrigation treatments applied to olive tree cv Arbequina were studied during fruit ripening. Results indicate that the fat content of olivē esh at harvest was not affected by irrigation, although olives from the most heavily irrigated treatment reached their ®nal fat content (dry weight) earlier than those from other irrigation treatments. PAL activity and phenolic content, expressed on a dry weight basis, decreased during fruit development and were affected by irrigation, being lowered as the water supplied increased. Good correlations were established between PAL enzymatic activity and the polyphenol and ortho-diphenol contents of olive¯esh, indicating that PAL is involved in the phenolic metabolism of olive fruit. The phenolic content of the oil depends on the PAL activity in the fruit, which varies with changes in water status.

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This study is an exhaustive chemical characterization of the phenolic compounds, triterpenes, and organic and ascorbic acids in red-fleshed apple varieties obtained by different breeding programs and using five traditional and new white-fleshed apple cultivars as reference. To carry out these analyses, solid-liquid extraction (SLE) and ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) were used. The results showed that the red-fleshed apples contained, in either the flesh or peel, higher amounts of phenolic acids (chlorogenic acid), anthocyanins (cyanidin-3-O-galactoside), dihydrochalcones (phloretin xylosyl glucoside), and organic acids (malic acid) but a lower amount of flavan-3-ols than the white-fleshed apples. These quantitative differences could be related to an up-regulation of anthocyanins, dihydrochalcones, and malic acid and a down-regulation of flavan-3-ols (anthocyanin precursors) in both the flesh and peel of the red-fleshed apple varieties. The reported results should be considered preliminary because the complete phytochemical characterization of the red-fleshed apple cultivars will be extended to consecutive harvest seasons.

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The study of the antioxidant effects of biophenolic compounds is supported by the current interest in natural products and the ongoing replacement of synthetic antioxidants by natural antioxidants from plant sources. Olives and olive oil, especially extra virgin olive oil, contain a variety of bioactive compounds (phytochemicals) widely considered to be potentially beneficial for health. This research was focused on evaluating the antioxidant activity of the enriched refined olive oil to discover a possible functional food application. Different concentrations of individual and combined phenolic compounds were added to the refined olive oil as lipid matrix, and the antioxidant activity expressed as oxidative stability in hours was determined by using the Rancimat method. Additionally, the bitter index was evaluated to assess the effect of the enrichment in relation to the organoleptic quality. The results showed that the antioxidant activity depends on the concentration of the phenol used for the assay and the chemical structure. In general, the most positive effects were observed in 3,4-dihydroxy and 3,4,5-trihydroxy structures linked to an aromatic ring that conferred to the moiety a higher proton dislocation, thus facilitating the scavenging activity.