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- Propolis volatiles characterisation from acaricide-treated and -untreated beehives maintained at Algarve (Portugal)Publication . Miguel, Maria Graça; Nunes, S.; Cruz, C.; Duarte, J.; Antunes, Maria Dulce; Cavaco, A. M.; Mendes, M. D.; Lima, A. S.; Pedro, L. G.; Barroso, J. G.; Figueiredo, A. C.The variability of the volatile profile of 70 propolis samples from acaricide-treated and -untreated beehives maintained at Algarve (Portugal) was evaluated. Propolis samples were collected in three regions of Algarve at three different periods. Cluster analysis based on the propolis volatiles' chemical composition defined two main clusters, not related to the time of year, collection site, altitude, temperature or humidity ranges, and was based mainly on the relative amounts of viridiflorol, n-tricosane and n-nonadecane for cluster I. Cluster II was mainly characterised by the high thymol content, followed by viridiflorol, n-tricosane and n-nonadecane. The presence of higher thymol levels in propolis samples from cluster II may reflect the long use of an acaricide with thymol as main active ingredient. All samples showed an intense rock-rose aroma supported by the presence of characteristic Cistus and labdanum oil volatile components. Given the nowadays frequent propolis household use, volatiles thorough characterisation may assist in its quality assessment.
- Effect of 1-Methylcyclopropene application prior to storage on fresh-cut kiwifruit qualityPublication . Antunes, Maria Dulce; Miguel, Maria Graça; Metelo, S.; Dandlen, S. A.; Cavaco, A. M.Kiwifruit is commercially important as fresh-cut. The purpose of this work was to study the effect of 1-methylcyclopropene (1-MCP) applied after harvest, before storage, on the posterior behaviour of ripe fruit prepared as fresh-cut. Harvested fruit where treated with 1 mu l L(-1) 1-MCP for 20 hours at room temperature, then stored at 0 C. After 3 months, fruit were removed from storage, peeled and cut longitudinally in quarters, then stored at 2 C for 8 days. Measurements of flesh colour, firmness, soluble solids content (SSC), electrolyte leakage and ascorbic acid were performed after 0, 4 and 8 days. Kiwifruit treated with 1-MCP showed higher firmness and lower a* value, electrolyte leakage and SSC than the control, after 3 months storage. Values of a* and electrolyte leakage increased through fresh-cut storage and after 8 days differences between treatments become almost nil. SSC did not change in fruit treated with 1-MCP, while it increased after 4 days and decreased on 8(th) day in the control. Firmness decreased through fresh-cut storage, being higher in 1-MCP treated fruit than control except on 8(th) day. Ascorbic acid which was higher in control, showed a higher decrease on those fruit and after 8 days was similar in both treatments. Panellists did not find significant differences between treatments, except that 1-MCP treated fruit had better appearance. The application of 1-MCP immediately after harvest showed beneficial effects in keeping kiwifruit quality during 3 months storage, and its effect lasted through shelf-life of those fruit when used as fresh-cut.
- Combined effect of temperature and controlled atmosphere on storage and shelf-life of 'Rocha' pear treated with 1-methylcyclopropenePublication . Gago, Custódia; Miguel, Maria Graça; Cavaco, A. M.; Almeida, Domingos P. F.; Antunes, Maria DulceThe combination of temperature and atmosphere composition for storage of Pyrus communis L. Rocha' treated with 1-methylcyclopropene was investigated. Fruits treated with 312nll(-1) 1-methylcyclopropene were stored at 0? and 2.5? in air and controlled atmosphere (CA) (3.04kPa O-2+ 0.91kPa CO2). Fruits were removed from storage after 14, 26 and 35 weeks, transferred to shelf-life at approximately 22? and assessed for ripening and quality, symptoms of superficial scald and internal browning and the accumulation of biochemical compounds related to scald after 0, 1 and 2 weeks. Superficial scald occurred only in fruits stored for 35 weeks in air at 2.5?. Levels of conjugated trienols and -farnesene increased during the first 26 weeks in storage, remaining constant thereafter. During shelf-life, conjugated trienols were higher in fruits stored in air at 2.5?. Internal browning developed in shelf-life after 26 weeks at 2.5?. Pears in air at 2.5? were not able to stand a 2-week shelf-life after 35 weeks of storage, while fruits stored at 0? under CA ripened slowly after the same storage period. The retention of firmness during shelf-life of 1-methylcyclopropene-treated Rocha' pear can be overcome by elevating the storage temperature from 0? to 2.5?, but CA is a required complement to avoid excessive softening after long-term storage. The ratio carotenoid/chlorophyll increased during storage and shelf-life, as plastids senesced. CA reduced the rate of chlorophyll loss during the first 14 weeks in storage, but its effect was reduced afterwards. Rocha' pear treated with 1-methylcyclopropene had a similar post-harvest behaviour during long-term storage at 0? in air or at 2.5? under CA.
- Nutritional quality changes of fresh-cut tomato during shelf lifePublication . Antunes, Maria Dulce; Rodrigues, Daniela; Pantazis, V.; Cavaco, A. M.; Siomos, A.; Miguel, Maria GraçaEffects of dip treatments on nutritional quality preservation during the shelf life of fresh-cut tomato (Licopersicum esculentum Mill.) cv. Eufrates were investigated. Fresh-cut tomatoes were dipped in solutions of 2% ascorbic acid, citric acid, and calcium lactate for 2 min, then stored at 4°C for 20 days. Color (L*, a*, and b*), firmness, °Brix, phenolics, ascorbic acid content, antioxidant activity (DPPH), and sugars were measured during storage. Pathogen development was monitored, and a sensory evaluation was performed. Ascorbic acid was better in maintaining firmness. No treatments significantly affected °Brix, color, or sugars. Ascorbic acid maintained a higher antioxidant capacity, phenolics, and ascorbic acid content, and was better at reducing bacterial growth, while citric acid treatment was better at prevention of yeast and molds proliferation. Fresh-cut tomatoes showed good quality after 10 days of shelf life, except for flavor with the calcium lactate treatment. Ascorbic acid treatment better preserved the general and nutritional quality parameters. © 2013 The Korean Society of Food Science and Technology and Springer Science+Business Media Dordrecht.
- Edible coatings enriched with essential oils and their compounds for fresh and fresh-cut fruitPublication . Gago, Custódia; Cavaco, A. M.; Miguel, Maria Graça; Antunes, Maria DulceFresh fruit and vegetables consumption has increased in the past few years due to the enhanced awareness of consumers for healthy food. However, these products are highly perishable, and losses can be of great significance if postharvest correct management is not provided. Fresh-cut products are of increasing importance, since they are presented to the consumer in a state that allows for direct and immediate consumption. However, those products are even more perishable since cutting can induce a series of senescence associated responses to wounding, and are more susceptible to microbial spoilage. Edible coatings, which intend to reduce ripening processes and protect the fruit from water loss and spoilage may be a good way to enhance the shelf life of these products. More recently, the inclusion of additives into these edible coatings to increase their effectiveness, such as essential oils and their constituents with antimicrobial and antioxidant activities, has been reported and patented. © 2012 Bentham Science Publishers.
- Phenols, flavonoids and antioxidant activity of aqueous and methanolic extracts of propolis (Apis mellifera L.) from Algarve, South PortugalPublication . Miguel, Maria Graça; Nunes, S.; Dandlen, S. A; Cavaco, A. M.; Antunes, Maria DulcePropolis is a resinous substance collected by honeybees to seal honeycomb, which has been used in folk medicine due to its antimicrobial and antioxidant properties. In the present study, water and methanol were used to extract phenols and flavonoids from propolis collected in thirteen different areas in the Algarve region during the winter and spring. The ABTS(center dot+), DPPH center dot, and O-2(center dot-) scavenging capacity, and metal chelating activity were also evaluated in the propolis samples. Methanol was more effective than water in extracting total phenols (2.93-8.76 mg/mL) (0.93-2.81 mg/mL). Flavones and flavonols were also better extracted with methanol (1.28-2.76 mg/mL) than with water (0.031-0.019 mg/mL). The free radical scavenging activity, ABTS (IC50 = 0.006-0.036 mg/mL), DPPH (IC50 = 0.007-0.069 mg/mL) and superoxide (IC50 = 0.001-0.053 mg/mL), of the samples was also higher in methanolic extracts. The capacity for chelating metal ions was higher in aqueous extracts (41.11-82.35%) than in the methanolic ones (4.33-29.68%). Propolis from three locations of Algarve region were richer in phenols and had better capacity for scavenging free ABTS and DPPH radicals than the remaining samples. These places are part of a specific zone of Algarve known as Barrocal.
- Quality changes during storage of apricot (prunus armeniaca l.) cv. ‘beliana’ and ‘lindo’ trated with calciumPublication . Antunes, Maria Dulce; Miguel, Maria Graça; Neves, M. A.; Cavaco, A. M.; Nunes, CarlaCalcium salts have been successfully used to maintain firmness and to slow down ripening processes in some fruit. This work studies the effect of postharvest calcium chloride applications on the quality preservation of apricot (Prunus armeniaca L.) cv. ‘Beliana’ and cv. ‘Lindo’ during storage. Harvested apricots were dipped in 0, 1, 3 or 5% CaCl2 solutions for 2 min. Fruit were left to dry for 1 h at ambient temperatures and then stored at 3 ºC. Fruit were analysed after 0, 6, 14, 21 and 28 d storage for weight loss, firmness and soluble solids content (SSC). A taste panel was performed at the beginning and at the end of the experiment. Weight loss increased through storage in both cultivars. ‘Lindo’ did not show differences among treatments in weight loss, but ‘Beliana’ had higher weight loss in fruit treated with 3% CaCl2 followed by 5%. Firmness decreased through storage without differences among treatments in ‘Beliana’, except after 5 d where all treatments where firmer than control. The ‘Lindo’ apricots treated with 3 and 5% CaCl2 showed higher firmness values than the other treatments through storage, except at 28 d where only the 5% CaCl2 had significantly higher firmness. ‘Beliana’ did not show differences in SSC among treatments. However, ‘Lindo’ had lower SSC when treated with 1% CaCl2. When tested after 27 d storage, panellists preferred fruit from the 1% CaCl2 treatment followed by the control for both cultivars. It seems that CaCl2 treatments with concentrations over 3% are prejudicial for apricots. Concentrations between 1 and 3% should be assayed, since 1 and 3% look to be beneficial for the different quality parameters.