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- Antimicrobial activity of different nanocellulose films embedded with thyme, cinnamon, and oregano essential oils for active packaging application on raspberriesPublication . Casalini, Sara; Baschetti, Marco G.; Cappelletti, Martina; Guerreiro, Adriana; Gago, Custódia; Nici, Silvia; Antunes, Maria DulceThe study focuses on the antimicrobial activity of nanocellulose films (NFC) embedded with thyme, cinnamon, and oregano essential oils for active packaging application. The activity against model pathogenic bacteria was first tested to obtain each oil's minimum inhibitory concentration (MIC). The tests showed that the surface area of the films and the quantity of essential oil strongly influenced the antimicrobial effect. Then, the different active packaging systems were tested directly on packed raspberries to study their actual commercial packaging conditions. Through 12 days of storage at 1 & DEG;C, it was observed that thyme and oregano essential oils were more effective in maintaining the firmness and reducing the weight loss of the fruits compared to cinnamon essential oil or the control; no significant effect was observed on the other quality parameters that were considered. The essential oils independently proved effective in preventing fungal growth. However, the combined impact of thyme+oregano (NAP_TO) demonstrated the best performance.
- Effect of storage time at low temperature on the volatile compound composition of Sevillana and Maravilla raspberriesPublication . Morales, M. L.; Callejon, R. M.; Ubeda, C.; Guerreiro, Adriana; Gago, Custódia; Miguel, Maria Graça; Antunes, Maria DulceIn this study, the effect of storage time at low temperature on volatile compounds in two cultivars of raspberry, Rubus idaeus L. cv. Sevillana and Maravilla, was determined. A total of 28 compounds were identified in both cultivars and showed quantitative differences between the cultivars. The Sevillana cultivar was richer in volatile compounds than the Maravilla cultivar. beta-Ionone had the highest concentration in both cultivars. We observed opposing trends in the volatile compound composition for the cultivars during storage at low temperature, in which 'Sevillana' lost compounds and 'Maravilla' was enriched. Therefore, storage at low temperature causes important changes in the volatile compound profile of raspberry, particularly the Sevillana cultivar, with significant decreases in C-13-norisoprenoids and increases in terpenes. These changes are most likely responsible for the aromatic differences between the cultivars because of the presence of terpenes in 'Sevillana' and C-13-norisoprenoids in 'Maravilla'. (C) 2014 Elsevier B.V. All rights reserved.
- The effect of alginate-based edible coatings enriched with essential oils constituents on Arbutus unedo L. fresh fruit storagePublication . Guerreiro, Adriana; Gago, Custódia; Faleiro, Leonor; Miguel, Maria Graça; Antunes, Maria DulceThe effect of coating Arbutus unedo fresh fruit with alginate-based edible coatings enriched with the essential oils compounds (EOC) eugenol (Eug) and citral (Cit) was studied. The minimum inhibitory concentrations (MIC) against the main postharvest pathogens were determined for Eug and Cit giving values of 0.10 and 0.15 (w/v), respectively. Twelve formulations of edible coatings were used: sodium alginate (AL) was tested at 1 and 2% (w/v) with incorporation of Eug and Cit at MIC and double MIC or their combination at MIC. Arbutus berries were dipped in those solutions for 2 min, and then stored at 0.5 degrees C. Control consisted of uncoated fruit. On days 0, 14 and 28, samples were taken to perform physicochemical and biochemical analysis [color CIE (L*, h degrees), firmness, soluble solids content (SSC), weight Loss, trolox equivalent antioxidant capacity (TEAC), microbial growth and taste panels]. Results showed that edible coatings of 1% AL were the best to maintain most quality attributes of the commodity through storage at 0.5 degrees C. The incorporation of Cit and Eug into the alginate edible coatings improved the coatings in most cases, AL 1% + Eug 0.20% and AL 1% + Cit 0.15% + Eug 0.10% being those that better preserved sensory and nutritional attributes and reduced microbial spoilage. Thus, these coatings may be useful for improving postharvest quality and storage life of fresh arbutus fruit. (C) 2014 Elsevier B.V. All rights reserved.
- Indicadores precoces de longevidade em buganvília envasadaPublication . Gago, Custódia; Monteiro, José A.The aims of this work were to study bract and flower abscission in Bougainvillea spectabilis ?Killie Campbell? plants, under post-production conditions. The effect of spraying with Silver Thiosulphate (STS) and with Naphtalene Acetic Acid (NAA, at high concentration: 500 mg.l-1), separately or together, was tested on plants exposed or not to exogenous ethylene. Quantification of non-structural carbohydrates in the bracts, leaves and stems, as well as the respiratory rates of these plant organs were assessed. In another stage, the photosynthetic rates of leaves and bracts were determined and the anthesis of the flowers, existing in the interior of each group of bracts, was monitored. In the absence of exogenous ethylene, NAA was enough to reduce CD bract abscission during post-production. If plants were exposed to exogenous ethylene, then the treatment STS+NAA was needed to reduce bract abscission. Pooling together the four post-production treatments, bract abscission was positively correlated with bract+flower dark respiration, and with bract+flower total non-structural carbohydrates. Similary to what was previous found for other plant organs bract+flower respiration seems to be a good early indicator of bract longevity. Plants that presented greater bract longevity (i. e., NAA and STS+NAA treatments) were the ones that had a reduced percentage of opening flowers and whose flowers had shorter period of anthesis. Flower and bract longevity in potted bougainvillea are distinct events although they abscise together.
- Antioxidant activities of eight Algerian plant extracts and two essential oilsPublication . Boulanouar, B.; Abdelaziz, G.; S, Azza; Gago, Custódia; Miguel, Maria GraçaTotal phenol, hydroxycinnamic acid derivatives, flavone/flavonol and flavanones/dihydroflavonol contents of hydro-alcoholic extracts, obtained by sonication, from the aerial parts of Artemisia campestris L., Anthemis arvensis L., Haloxylon scoparium Pomel, Juniperus phoenicea L., Arbutus unedo L., Cytisus monspessulanus L., Thymus algeriensis Boiss et Reut, Zizyphus lotus L (Desf.) collected in Djebel Amour (Sahara Atlas, Algeria) were quantified by spectrophotometric methods. The chemical composition of the essential oils obtained by hydrodistillation from Artemisia campestris L. and Juniperus phoenicea I aerial parts were also evaluated by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). The antioxidant activity of the extracts and essential oils was assessed measuring the capacity for preventing lipid peroxidation using two lipidic substrates (egg yolk and liposomes), the capacity for scavenging DPPH, ABTS, superoxide anion radicals, hydroxyl radicals and peroxyl radicals. Anti-inflammatory activity was assessed by measuring the capacity for inhibiting lipoxygenase. Reducing power and chelating capacity were also assayed. The results showed different amounts of total phenols depending on the method used: A. campestris extract had the highest levels of total phenols when the measurement was made at lambda = 280 nm, whereas H. scoparium and A. unedo extracts showed the highest levels of total phenols with Folin-Ciocalteau. C. monspessulanus had the highest levels of flavones/flavonols and flavanones/dihydroflavonols. The essential oils of A. campestris and J. phoenicea were mainly constituted by alpha-pinene, beta-pinene and sabinene; and a-pinene, respectively. The methods used for assaying the capacity for preventing lipid peroxidation revealed to be inadequate for extracts due to the great interferences detected. The essential oils were more active than the generality of extracts for scavenging peroxyl radicals and for inhibiting lipoxygenase, whereas A. unedo extract was the most active for scavenging ABTS, DPPH, superoxide anion radicals and it also had the best reducing capacity. In a general way, the great majority of the antioxidant activities correlated well with the phenol content although such correlation was not so clear with the flavonoid content. (c) 2013 Elsevier B.V. All rights reserved.
- 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.
- The effect of temperature and film covers on the storage ability of Arbutus unedo L. fresh fruitPublication . Guerreiro, Adriana; Gago, Custódia; Miguel, Maria Graça; Antunes, Maria DulceThe strawberry tree (Arbutus unedo L) fruits are used in small quantities for fresh consumption despite their excellent flavor. The aim of this work was to evaluate the storage ability of strawberry tree fruits for fresh consumption. Harvested fruits were stored in polystyrene foam trays covered with two film types: linear low density polyethylene of 10 mu m thickness (PPL) or polyethylene film perforated with holes of 10 mm diameter spaced 50 mm (PP). Through 15 days storage at 0,3 and 6 degrees C, fruits were analyzed for quality parameters. The strawberry tree fruits presented relevant qualitative properties and were appreciated by panelists. Color parameters (L*, h degrees, C*) had higher decrease at 3 and 6 degrees C than at 0 degrees C. The degrees Brix almost did not change and firmness decreased mainly in the first 4 days storage. Ethanol and weight loss increased with temperature mostly from 3 to 6 degrees C. Strawberry tree fruits are a good source of ascorbic acid, glucose, fructose, anthocyanins and antioxidant activity. Those properties are maintained through 15 days storage at 0 degrees C followed by 3 degrees C. Film covers showed no significant differences between them. The temperature of 0 degrees C was the best for preservation of fruit quality through 15 days shelf-life. (C) 2013 Elsevier B.V. All rights reserved.
- Bougainvillea post-production: NAA and STS control of bract abscission is subject to exogenous ethylenePublication . Gago, Custódia; Monteiro, José; Rodrigues, M. H.The effect of NAA (500 mg.L-1 sprayed once at end-of-production), STS (0.4 mM sprayed every 15 days after bracts started to be apparent) and STS+NAA on plants exposed or not to exogenous ethylene (from ethephon), were tested using two completely randomized experiments. At the end-of-production plants were placed for three days under simulated transport conditions (17 +/-1 degreesC, no light) and then, placed under interior conditions (21 +/-1 degreesC and 11 mu mol.m(-2)s(-1) of cool white fluorescent light 12 hr a day). Twice a week, during postproduction (PP) the number of developing (D) bracts as well as the number of completely developed (CD) bracts remaining in the plants were assessed. Among the treatments tested, NAA was enough to reduce CD bract abscission during post-production, abscising at day 32 PP, a maximum of 50% of the bracts, provided that no exogenous ethylene was present. If plants were exposed to exogenous ethylene, then the treatment STS + NAA was needed to reduce bract abscission, abscising at 32 PP a maximum of 58% of CD bracts. At this time, plants treated only with STS had abscised all CD bracts if exposed to ethylene or at least 97% of CD bracts if not exposed to ethylene.
- 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.
- Effect of calcium chloride and 1-MCP (Smartfresh (TM)) postharvest treatment on 'Golden Delicious' apple cold storage physiological disordersPublication . Gago, Custódia; Guerreiro, Adriana; Miguel, Maria; Panagopoulos, Thomas; Silva, Manuela; Antunes, Maria DulceCalcium (Ca2+) and 1-methylcyclopropene (1-MCP) appear to have opposite effects on the development of bitter pit. However, both post-harvest treatments seem capable of influencing fruit ripening, reducing superficial scald and improving post-storage quality. The objective of this work was to investigate the effect of calcium chloride and 1-MCP alone or combined on the incidence and development of physiological disorders and the delay of ripening of apples during storage (at 0.5 degrees C in air) and subsequent shelf-life at room temperature approximate to 22 degrees C. 'Golden Delicious' apples were harvested in 10 orchards and treated with calcium chloride (1.5%, w/v), 1-MCP (625 nL L-1), calcium chloride plus 1-MCP, and without any treatment (control). Physiological disorders and quality parameters were evaluated at harvest and after 6 months storage as well as after 7 d shelf-life. The 1-MCP treatment was effective to prevent superficial scald, slow softening, increase soluble solids content and reduce electrolyte leakage and color changes associated with ripening, during storage and shelf-life. However, this treatment also enhanced the development of bitter pit, especially the moderate and severe symptoms in some orchards, which may be attributable to orchard cultivation techniques. CaCl2 alone and CaCl2 plus 1-MCP reduced bitter pit intensity by reducing moderate and severe incidence, maintained higher lightness and had firmer fruit than control.Postharvest dips of 'Golden Delicious' apples in CaCl2 before 1-MCP application (CA + MCP), may be a good solution to prevent scald, and reducing the bitter pit which is enhanced by 1-MCP alone. (C) 2016 Elsevier B.V. All rights reserved.
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