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  • Effect of storage time at low temperature on the volatile compound composition of Sevillana and Maravilla raspberries
    Publication . Morales, M. L.; Callejon, R. M.; Ubeda, C.; Guerreiro, Adriana; Gago, Custódia; Miguel, Maria Graça; Antunes, Maria Dulce
    In 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.
  • Pomegranate (Punica granatum L.): A medicinal plant with myriad biological properties - A short review
    Publication . Miguel, Maria Graça; Neves, M. A.; Antunes, Maria Dulce
    The pomegranate, Punica granatum L., which can be found throughout the Mediterranean region, in Southeast Asia, California and Arizona in USA was in ancient times referred as possessing powers of fertility, abundance and good luck (fruit). The biological properties of extracts (antimicrobial, antioxidant, anticancer, anti-inflammatory, among other properties) obtained from several parts of pomegranate is reported in the present work. Due to such properties, the extracts have been used in therapeutics, such as in the prevention of infection, inflammation, cancer, among other applications. However, other aspects are also referred in the present work such as the good practices of culture and fruit preservation, search of new compounds, selection of cultivars through biotechnological techniques for obtaining juice or fruits ready to eat. Such compilation of information was based on the search in the ISI Web of Knowledge (Thomson Reuters) from 2009 up to the beginning of October 2010.
  • Stability of fried olive and sunflower oils enriched with thyrnbra capitata essential oil
    Publication . Miguel, Maria; Antunes, Maria Dulce; Rohaim, Abdulrahman; Figueired, Ana Cristina; Pedro, Luis G.; Barroso, Jose G.
    The stability of olive and sunflower oils for domestic uses after frying cow steak or only heating were evaluated in the presence or absence of the carvacrol-rich essential oil of Thymbra capitata. The treatments consisted of sunflower and olive oils either enriched with 200 mg/l of T capitata oil or without it, heating at 180 degrees C for 20 min, or frying 100 g cow steak at the same temperature and for the same period of time. In all assays, acid, peroxide, and p-anisidine values were followed over time. The fatty acid profile was estimated before heating or frying as well as at the end of the experiment. The results showed that the type of fat as well as the type of treatment (frying or heating) was determinant for the acid, peroxide, and p-anisidine values found. The presence of the essential oil also demonstrated to affect those values depending on the type of the oil as well as on the type of the treatment (frying or heating). In contrast, the fatty acid profile did not change greatly.
  • 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.
  • A possibility for non-invasive diagnosis of superficial scald in 'Rocha' pear based on chlorophyll a fluorescence, colorimetry, and the relation between alpha-farnesene and conjugated trienols
    Publication . Guerra, Rui Manuel Farinha das Neves; Garde, I. V.; Antunes, Maria Dulce; da Silva, J. M.; Antunes, Rosário; Cavaco, A. M.
    This study aimed to identify physiological markers in superficially scalded 'Rocha' pear (Pyrus communis L 'Rocha') that would relate to chlorophyll a fluorescence (CF), allowing a non-invasive diagnosis of the disorder. Conditions chosen before shelf life provided two fruit groups with different developing patterns and severity of superficial scald: T fruit fully developed the disorder in storage, while C fruit developed it progressively throughout shelf life. Principal component analysis (PCA) of all the measured variables, and simple linear correlations among several major parameters and scald index (SI)/shelf life showed that scald and ripening/aging were concurring processes, and that it was not possible to isolate a particular variable that could deliver a direct non-invasive diagnosis of the disorder. For both fruit groups the SI resulted from the balance between the reducing power (OD200) and the content of conjugated trienols (CTos) and alpha-farnesene (alpha-Farn) in the fruit peel. At OD200 > 150 there was a linear relationship between CTos and OD200, suggesting that the level of antioxidants was self-adjusted in order to compensate the CTos level. However, at OD200 < 150 this relationship disappeared. A consistent linear relationship between dos and alpha-Farn existed throughout shelf life in both fruit groups, contrarily to the early storage stage, when those compounds do not relate linearly. The CF variables F-0, F-v/F-m, and the colorimetric variables, L* and h degrees were used in multi-linear regressions with other physiological variables. The regressions were made on one of the fruit groups and validated through the other. Reliable regressions to alpha-Farn and CTos were obtained (R approximate to 0.6; rmsec approximate to rmsep). Our results suggest that a model based on CF and colorimetric parameters could be used to diagnose non-invasively both the contents and the relationship between alpha-Farn and CTos and hence the stage of scald development. (C) 2011 Elsevier By. All rights reserved.
  • Chlorophyll a Fluorescence: a Fast and Low-Cost Tool to Detect Superficial Scald in 'Rocha' Pear (Pyrus communis L. 'Rocha')?
    Publication . Garde, I.; Antunes, Maria Dulce; da Silva, J. M.; Guerra, Rui Manuel Farinha das Neves; Cavaco, A. M.
    This study aimed to test whether the chlorophyll a (Chla) fluorescence determined by a low-cost non-modulated fluorometer could provide fast, reliable and non-invasive estimators of superficial scald in 'Rocha' pear (Pyrus communis L. 'Rocha'). Fruit were harvested before the optimal maturation stage and cold stored under normal atmosphere for 7 months (NA: 0 degrees C, 90-95% RH) and 2 in controlled atmosphere (CA: 0 degrees C, 90-95% RH, 1.5 kPaO(2) + 0.5 kPa CO2) (T), or harvested at the optimal maturation stage and cold stored for 9 months under CA (C). Then, they were transferred to shelf-life conditions (22+/-2 degrees C, 70% RH) and followed for 7 d. Chla fluorescence, scald index (SI), ripening attributes, alpha-farnesene, conjugated trienols, and photosynthetic pigments were determined for each pear in both groups. Conditions chosen before shelf-life did not prevent the subsequent ripening of any fruit, but changed dramatically the superficial scald development pattern: in C fruit, the disorder developed progressively during shelf-life, whereas in T fruit, it peaked during storage. C fruit exhibited a significant negative correlation (R=-0.65; p<0.05) between Fv/Fm and scald development, but not with ripening (R=-0.15; p<0.05). As expected, the opposite was observed in T fruit, in which only a low, positive, yet significant correlation was found between Fv/Fm and ripening (R=0.44; p<0.05). The multiple regression approach using Fv/Fm and other Chla fluorescence parameters produced an equation from which we calculated the 'predicted' scald index in C fruit. This correlated clearly (R=0.73; p<0.05) with the real values visually assessed. If color values a*, b* and Hue were included in this multiple regression, the correlation was significantly enhanced (0.91; p<0.05). Although preliminary, this study has shown that basic Chla fluorescence parameters are valuable estimators of superficial scald in 'Rocha' pear and might be used in the early detection of the disorder.
  • Physicochemical Characterization and Antioxidant Activity of Commercial Portuguese Honeys
    Publication . AAZZA, Smail; Lyoussi, B.; Antunes, Maria Dulce; Miguel, Maria Graça
    The present study evaluated the physicochemical characteristics and antioxidant activity of 13 commercial honeys from diverse floral origin, produced in Portugal. The values of electrical conductivity of cardoon and pennyroyal honeys were superior to the maximum limits defined by European legislation. Citrus, strawberry tree, and 1 sample of lavender honeys had values of diastase activity below those determined by European legislation. Strawberry tree, pennyroyal, and cardoon honeys had the highest amounts of potassium that coincided with the highest electrical conductivity. Strawberry tree honey was the most effective as antioxidant along with cardoon and heather honeys. This ability was strongly correlated with the amounts of phenols and flavonoids and not with the levels of vitamin C or proline.
  • Physicochemical characterization and antioxidant activity of honey with Eragrostis spp. pollen predominance
    Publication . AAZZA, Smail; Elamine, Youssef; EL-GEUNDOUZ, Soukaina; Lyoussi, Badiaa; Antunes, Maria Dulce; Estevinho, Leticia M.; Anjos, Ofélia; Carlier, Jorge; Costa, Maria C.; Miguel, Maria
    This study aimed to characterize the pollen and physicochemical profiles, and to evaluate the antioxidant capacity of six samples of Moroccan honey. The pollen grains of Eragrostis spp. were predominant in all samples (from a minimum of 46.581.59% to 72.72 +/- 2.43% as a maximum), exceeding the minimum (generally 45%) required for the monoflorality nomination of a honey sample, and suggestion a case of newly reported honey. The analyzed samples had low diastase activity and hydroxymethylfurfural (HMF) content. Potassium was the dominant element in practically all samples, except the sample with the highest Eragrostis spp. pollen percentage, which showed sodium predominance. The honey color ranged from water white to light amber, and positively correlated the concentrations of phenols, proline and the capacity for scavenging free radicals. However, great variability observed in all the analyzed parameters, and could not be explained by the variability of the Eragrostis spp. pollen percentage, which suggests a hypothesis of low concentrated nectar. Practical applicationsThe melissopalynological profile of honey is an important parameter for determining the type of honey (multifloral, monofloral, blossom, honeydew) and its relationship to the botanical and geographical provenance. There is generally a relationship between the pollen profile of honey and the biological properties. The physicochemical characterization, antioxidant activity and melissopalynological profile of Eragrostis honey was reported for the first time in this study. These data intend to contribute for the introduction of a new type of honey labeled as Eragrostis honey. At the same time, the evaluation of the antioxidant activity may also trigger the search of other biological properties with medicinal attributes for the new Eragrostis ssp. honey.
  • Is propolis safe as an alternative medicine
    Publication . Miguel, Maria Graça; Antunes, Maria Dulce
    Propolis is a resinous substance produced by honeybees as defense against intruders. It has relevant therapeutic properties that have been used since ancient times. Nowadays, propolis is of increasing importance as a therapeutic, alone or included in many medicines and homeopathic products or in cosmetics. Propolis is produced worldwide and honeybees use the flora surrounding their beehives for its production. Therefore its chemical composition may change according to the flora. The phenolic and volatile fractions of propolis have been revised in the present study, as well as some of the biological properties attributed to this natural product. An alert is given about the need to standardize this product, with quality control. This has already been initiated by some authors, mainly in the propolis from the poplar-type. Only this product can constitute a good complementary and alternative medicine under internationally acceptable quality control.
  • The effect of alginate-based edible coatings enriched with essential oils constituents on Arbutus unedo L. fresh fruit storage
    Publication . Guerreiro, Adriana; Gago, Custódia; Faleiro, Leonor; Miguel, Maria Graça; Antunes, Maria Dulce
    The 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.