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    Leticia Estevinho

    Mead is a traditional alcoholic drink derived from the fermentation of diluted honey in the presence of appropriate yeast. Its modern production, in general terms, involves the addition of nutrients to initial diluted honey,... more
    Mead is a traditional alcoholic drink derived from the fermentation of diluted honey in the presence of appropriate yeast. Its modern production, in general terms, involves the addition of nutrients to initial diluted honey, pasteurization, yeast inoculation, fermentation and removal of impurities. Undesirable events along the process have been reported; among them, we highlight: delayed or arrested fermentations, modified and unpleasant sensory and quality parameters of the final product. These problems have been linked to the inability of yeasts to accomplish their role in extreme growth conditions. Emphasis has also been placed on the long fermentation times required, ranging from weeks to months, particularly when traditional procedures are applied and when the honey concentration is low. A series of alterations to the must and technological changes have been proposed in order to optimize the mead production process. In this context, this review examines the evidence that aims t...
    Pleitrotus ostreatus (P7), P. pulmonarius (P27), and P. mtreaius ?? soyz (P9). Concentrations of eight elements Ca, Cu, fe, Mg, Mn, ??, Na, and P have been determined by short, medium, and long irradiation times with a thermal neutron... more
    Pleitrotus ostreatus (P7), P. pulmonarius (P27), and P. mtreaius ?? soyz (P9). Concentrations of eight elements Ca, Cu, fe, Mg, Mn, ??, Na, and P have been determined by short, medium, and long irradiation times with a thermal neutron flux of 5 x 10" n. cm 2, s* 1. Of these Ca ...
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    Bee pollen is one of the richest and purest natural foods, used in the folk medicine, clinical practices, and food and pharmaceutical industries. This work aims to characterise, for the first time in Portugal, the palynological origin,... more
    Bee pollen is one of the richest and purest natural foods, used in the folk medicine, clinical practices, and food and pharmaceutical industries. This work aims to characterise, for the first time in Portugal, the palynological origin, nutritional value and microbiological safety of this beehive product. It identified ten botanical families, and the more frequent were Boraginaceae and Ericaceae. We have evaluated the water content, aw, pH, reducing sugars, ash, carbohydrate, proteins, lipids, fatty acids and energy. The microorganisms studied were the aerobic mesophiles, moulds and yeasts, faecal coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulphite-reducing clostridia. The studied pollens are nutritionally well balanced, and contain high levels of moisture, proteins, fat, energy, ash, carbohydrates, reducing sugars, essential n-3 fatty acids and good ratios of polyunsaturated fatty acids (PUFA)/saturated fatty acids. In fact, the PUFA represent 66% of the tota...
    Nowadays a great amount of information regarding chemical and biological aspects of bee products is available in the literature, but few data on its therapeutic uses are found. The aim of this study was to evaluate the phenolic profile,... more
    Nowadays a great amount of information regarding chemical and biological aspects of bee products is available in the literature, but few data on its therapeutic uses are found. The aim of this study was to evaluate the phenolic profile, the in vitro antimicrobial activity and effect in the hyaluronidase enzyme (widely related with the inflammation process) of propolis harvested in Portugal. The efficacy of three extracts (hydro-alcoholic, methanolic and aqueous) was also compared. It was chosen the hydro-alcoholic extract, because this was the most effective for extracting phenolic compounds. The antimicrobial activity was accessed in Gram-positive and Gram-negative bacteria and yeasts, isolated from different biological fluids and the results were then compared with the obtained for reference microorganisms. The propolis from Bragança was the one that possessed the highest polyphenols' content. The sample from Beja showed the less significant inhibition of the hyaluronidase enz...
    Organic bee pollen (BP, n = 22) harvested from the Douro International Natural Park (DINP, Portugal) was studied. Nine botanical families were found in the mixture of the samples. The water activity and pH ranged 0.21-0.37 and 4.3-5.2,... more
    Organic bee pollen (BP, n = 22) harvested from the Douro International Natural Park (DINP, Portugal) was studied. Nine botanical families were found in the mixture of the samples. The water activity and pH ranged 0.21-0.37 and 4.3-5.2, respectively. The BP analyses averaged 67.7% carbohydrates, 21.8% crude protein, 5.2% crude fat and 2.9% ash. The energy ranged from 396.4 to 411.1 kcal/100 g. The principal fatty acid found was linolenic, followed by linoleic acid, palmitic acid and oleic acid. The phenolic and flavonoid contents varied from 12.9 to 19.8 mg of gallic acid equivalents/g of extract and from 4.5 to 7.1 mg of catechin equivalents/g of extract, respectively. The scavenger activity and β-carotene bleaching assays values (EC₅₀) were 3.0 ± 0.7 mg/mL and 4.6 mg/mL ± 0.9 mg/mL, respectively. E. coli, sulphite-reducing Clostridia, Salmonella and S. aureus were not found. Since there are studies indicating appreciable differences among BPs from different regions, the full charac...
    ... Hazelnut (Corylus avellana L.) belongs to the Betulaceae family. The hazel is a tree or shrub that may grow to 6 m high, exhibiting deciduous leaves. ... (2007). Hazel (Corylus avellana L.) leaves as source of antimicrobial and... more
    ... Hazelnut (Corylus avellana L.) belongs to the Betulaceae family. The hazel is a tree or shrub that may grow to 6 m high, exhibiting deciduous leaves. ... (2007). Hazel (Corylus avellana L.) leaves as source of antimicrobial and antioxidative compounds. ...
    Honey is a natural product with recognized physical and chemical properties, which contribute to its biological activity. However, honey is currently being sold at low prices, making it imperative to find alternatives to make apiculture a... more
    Honey is a natural product with recognized physical and chemical properties, which contribute to its biological activity. However, honey is currently being sold at low prices, making it imperative to find alternatives to make apiculture a viable national enterprise. One of these alternatives could be mead production. Despite the excellent properties of honey, mead production faces several problems, namely, delays and "pouts" fermentations, lack of product uniformity, and production of yeast off-flavors. Many factors might be related with these problems, such as honey variety, temperature, medium composition (vitamin and nitrogen content), fermentative yeast, and pH. Due to all these factors, mead production has decreased over the years. To overcome this situation, more research is needed to optimize the production of this beverage. This chapter presents a comprehensive review of previous research on mead production. It will focus on honey characterization and mead producti...
    Mead is a traditional alcoholic drink derived from the fermentation of diluted honey in the presence of appropriate yeast. Its modern production, in general terms, involves the addition of nutrients to initial diluted honey,... more
    Mead is a traditional alcoholic drink derived from the fermentation of diluted honey in the presence of appropriate yeast. Its modern production, in general terms, involves the addition of nutrients to initial diluted honey, pasteurization, yeast inoculation, fermentation and removal of impurities. Undesirable events along the process have been reported; among them, we highlight: delayed or arrested fermentations, modified and unpleasant sensory and quality parameters of the final product. These problems have been linked to the inability of yeasts to accomplish their role in extreme growth conditions. Emphasis has also been placed on the long fermentation times required, ranging from weeks to months, particularly when traditional procedures are applied and when the honey concentration is low. A series of alterations to the must and technological changes have been proposed in order to optimize the mead production process. In this context, this review examines the evidence that aims t...
    Propolis from stingless bees Tetragonisca fiebrigi found in Brazil is used in folk medicine by their nutritional and therapeutic properties. However, there are no scientific records evidencing such properties. The present study was... more
    Propolis from stingless bees Tetragonisca fiebrigi found in Brazil is used in folk medicine by their nutritional and therapeutic properties. However, there are no scientific records evidencing such properties. The present study was designed to investigate the chemical composition and the biological properties of propolis from T. fiebrigi. For this, the chemical composition of the ethanol extract of propolis (EEP) was determined by GC-MS and presented phenolic compounds, alcohol, and terpenes as its major class compounds. The antimicrobial activity was accessed in gram-positive and gram-negative bacteria and in fungi, isolated from different biological fluids and reference strains. The EEP was active against all microorganisms and showed antioxidant activity by scavenging free radicals, inhibiting hemolysis and lipid peroxidation in human erythrocytes incubated with an oxidizing agent. The anti-inflammatory potential of the EEP was confirmed by inhibition of the hyaluronidase enzyme. The cytotoxic activity was concentration-dependent against K562 cells, with a predominance of death by necrosis. Taken together, these results show that propolis from T. fiebrigi has important therapeutic activities, which suggest its potential application in the pharmaceutical industry, as well as in health foods, beverages, and nutritional supplements.
    Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata (CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition, antioxidant and antimicrobial activities. Levels of fatty acids determined... more
    Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata (CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition, antioxidant and antimicrobial activities. Levels of fatty acids determined by ¹H-nuclear magnetic resonance analysis were similar to those reported for olive oils (82.30%-84.47%; 5.69%-7.78%; 0.26%-0.41% and 8.04%-11.2%, for oleic, linoleic, linolenic and saturated acids, respectively). The CR oil showed the best antioxidant potential in the three in vitro models tested. With regard to EC₅₀ values (µg/mL), the order in DPPH radical-scavenging was CR (33.48) < CO (35.20) < CS (54.87). Effectiveness in reducing power was CR (2.81) < CO (3.09) < CS (5.32). IC₅₀ for LPO inhibition were 0.37, 0.52 and 0.75 µg/mL for CR, CO and CS, respectively. All the oils showed antimicrobial activity, and exhibited different selectivity and MICs for each microorganism tested (E. coli, B. cereus and C. albicans). B. cereus was the less sensitive species (MIC: 52.083 ± 18.042 for CO; 41.667 ± 18.042 for CR; 104.167 ± 36.084 for CS mg/mL) and the E. coli was the most sensitive to camellia oil's effect. The standard gentamicin presented higher MIC for E. coli (4.2) than the CR (MIC= 2.6) and CO (MIC = 3.9) oils.
    Meat species identification in food has gained increasing interest in recent years due to public health, economic and legal concerns. Following the consumer trend towards high quality products, game meat has earned much attention. The aim... more
    Meat species identification in food has gained increasing interest in recent years due to public health, economic and legal concerns. Following the consumer trend towards high quality products, game meat has earned much attention. The aim of the present work was to develop a DNA-based technique able to identify hare meat. Mitochondrial cytochrome b gene was used to design species-specific primers for hare detection. The new primers proved to be highly specific to Lepus species, allowing the detection of 0.01% of hare meat in pork meat by polymerase chain reaction (PCR). A real-time PCR assay with the new intercalating EvaGreen dye was further proposed as a specific and fast tool for hare identification with increased sensitivity (1pg) compared to end-point PCR (10pg). It can be concluded that the proposed new primers can be used by both species-specific end-point PCR or real-time PCR to accurately authenticate hare meat.
    The phenolic compounds composition, antioxidant potential, and antimicrobial activity of different table olives from Portugal, namely, natural black olives... more
    The phenolic compounds composition, antioxidant potential, and antimicrobial activity of different table olives from Portugal, namely, natural black olives "Galega", black ripe olive…
    The chemical composition and biological properties of Portuguese wild mushrooms ( Cantharellus cibarius, Hypholoma fasciculare, Lepista nuda, Lycoperdon molle, Lycoperdon perlatum, Ramaria botrytis, Tricholoma acerbum) were evaluated in... more
    The chemical composition and biological properties of Portuguese wild mushrooms ( Cantharellus cibarius, Hypholoma fasciculare, Lepista nuda, Lycoperdon molle, Lycoperdon perlatum, Ramaria botrytis, Tricholoma acerbum) were evaluated in order to assess these products as sources of nutrients and nutraceuticals. The analyzed mushrooms contain very useful phytochemicals such as phenolics, tocopherols, ascorbic acid, and carotenoids. All of the species proved to have antioxidant activity (measured by four different methods), being more significant for R. botrytis (EC 50 values < 1 mg/mL). Lycoperdon species were resistant to all of the tested microorganisms, and the other samples revealed antimicrobial activity selectively against Gram-positive bacteria, with very low minimal inhibitory concentration, in some cases, even lower than the standard. The combination of bioactive compounds and rich nutritional composition (high contents in protein and carbohydrates, low content in fat with the precious contribution of unsaturated fatty acids and the absence of trans fatty acids) in the mushroom makes it a very special food.
    The effects of fruiting body maturity on chemical composition and antimicrobial activity of the wild mushrooms, Lactarius deliciosus and Lactarius piperatus, were evaluated. Immature and mature samples were analyzed for proximate... more
    The effects of fruiting body maturity on chemical composition and antimicrobial activity of the wild mushrooms, Lactarius deliciosus and Lactarius piperatus, were evaluated. Immature and mature samples were analyzed for proximate constituents (moisture, fat, crude protein, ash, carbohydrates), nutritional value, and individual composition in fatty acids and sugars. Protein content, MUFA (monounsaturated fatty acids), and PUFA (polyunsaturated fatty acids) percentages increased with the fruiting body maturity stage, while carbohydrate and SFA (saturated fatty acids) content decreased. The maturity stage did not significantly affect the individual sugar profile. The antimicrobial activity of the mushrooms was screened against Gram positive and Gram negative bacteria and fungi, and correlated to the amounts of phenols, flavonoids, ascorbic acid, beta-carotene, and lycopene present in the immature and mature fruiting bodies. Mature fruiting bodies with mature spores presented lower antimicrobial activity, which was in agreement with the bioactive compound content found in those samples.

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