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Propolis is a natural honeybee product known to be beneficial for human health, with a complex chemical composition, highly dependent on the collection site. The objective of the present research was to evaluate phenols and antioxidant activity of propolis samples collected in three main areas of Algarve, South of Portugal. Water revealed to be less effective for extracting phenolic compounds from propolis than the methanol and water/ethanol. The last two were good extraction solvents of phenols. Nevertheless water/ethanol was the solvent chosen because it was able to extract phenols in considerable amounts being less toxic than methanol. In spring, higher amounts of phenols (total phenols, flavones, flavonols, flavanones and dihydroflavonols) were detected in hydro-alcoholic extracts of propolis than in winter. Among the three main areas of Algarve where samples were collected, those from Barrocal had the highest levels of polyphenols, independent on the season (winter or spring). Within each area, the levels of phenols changed according to the zone. Concerning antioxidant activity, samples from Barrocal presented better radical scavenging abilities than those from the remaining areas, independent on the antioxidant method and collection season. Such results correlated closely with the levels of total phenols, flavones and flavonols in samples. (C) 2010 Elsevier Ltd. All rights reserved.

The market share of minimally processed fruits and vegetables has continuously increased in the past years due to consumer life style. These products have high expectations regarding quality and shelf-life. The objective of the present work was to evaluate the effect of additives applied externally after cutting in fresh-cut kiwifruit, pears, strawberries, tomatoes, and peppers. Fruit were washed in water, cut longitudinally in quarters and dipped in solutions of 2% citric acid, 2% ascorbic acid or 2% calcium lactate. Subsequently, fruit were packed in plastic trays, covered with 15 mu m thick polyethylene film and stored at 4 degrees C for 9 d. At intervals of 0, 3, 6 and 9 d, measurements of firmness and total phenolics content were performed. Calcium lactate was efficient in maintaining firmness in most fresh-cut fruit. Total phenolics content were higher in kiwifruit, strawberries and peppers than in pears and tomatoes. Ascorbic acid was the most efficient dip to maintain or increase the total phenolics content of the fresh-cut fruit studied.

The effects of Fe deficiency on the antioxidant properties of strawberry juice was carried out with a day-neutral cultivar 'Selva'. Bare root transplants (without leaves) with approximately 18 cm, were transferred to Hoagland's nutrient solution with (Fe2.5) and without Fe (Fe0), using Fe-EDDHMA as the Fe source: 0 and 2.5 5 μM Fe. Plants were grown in 20 L containers in a glasshouse for 6 weeks (from April 27 to June 5) under natural light and air temperature ≤ 25°C. Twelve transplants were used per treatment, distributed in a complete randomized design. Plants grown in absence of Fe revealed chlorotic symptoms approximately after three weeks, based on SPAD values measured in young leaves (

The essential oils, isolated by hydrodistillation, from the flowers of different cultivars of Citrus sinensis (L.) Osbeck (Cs) and Citrus clementina Hort. Ex Tan. (Cc) collected at different harvesting times, were analyzed by GC and GC-MS. All the samples studied afforded yellowish oil which yields ranged from 0.05 to 0.08 % (v/w). The monoterpene fraction dominated both oils (66-91%), being the monoterpene hydrocarbons the main components of this fraction (45-69%). Sabinene (31-48%), linalool (15-32%) and limonene (4-10%) dominated both Cs and Cc oils. trans-Nerolidol was the major sesquiterpene component, attaining 3-10%. Cluster analysis of the essential oil composition from the twelve samples studied, confirmed a major chemical homogeneity (Scorr>0.95) despite the fact of having used different periods of hydrodistillation, different harvesting times and being flowers of two different Citrus species.

The effects of cultivar and orchard on the content of ascorbic acid and flavanone glycosides as well as on the antioxidant activity of citrus juices were studied. Ascorbic acid and flavanone glycosides were determined using HPLC method. For antiradicalar activity evaluation, TAEC and ORAC methods were used. Citrus of 'Valencia late' from Faro and 'D. Joao' presented the highest levels of hesperidin in contrast to the citrus of 'Valencia late' from Silves with 0.4 mg/ml, a value closer to those of Navel oranges 'Navelate' and 'Lanelate'. Citrus of 'Valencia late' from Silves and 'D. Joao' presented the lowest levels of narirutin. 'Ortanique' and 'Encore' cultivars were poorer in ascorbic acid compared with the oranges. When the TEAC method was used for the determination of antioxidant activity, 'Valencia late' from Faro presented the best activity. A good relation was observed between antiradical activity measured through the TEAC method and the amount of ascorbic acids in samples. None relation was found between the levels of flavanones and antiradical activity. When the ORAC method was applied, the best activity was found for 'Navelate' and 'Encore' samples and practically none relation between this method and the amounts of ascorbic acid and flavanones was found.