Browsing by Author "Tolentino, Georgina Santos"
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- Bioactive compounds and biological properties of oils from three camelia speciesPublication . Salinero, Carmen; Garcia–Santal, Carmen; Tolentino, Georgina Santos; Estevinho, Leticia M.The concentration of polyphenols and antimicrobial and antioxidant properties of oils obtained from seeds of Camellia japonica, Camellia sasanqua and Camellia grijsii, grown in Pontevedra (NW Spain), were studied. Oils were obtained by cold-pressed extraction. Standard methods for moisture, density and acid and iodine values were used to analyse the stability of the fresh oils. Strains of Klebsiella pneumonia, Salmonella sp., Staphylococcus epidermidis and Cryptococcus neoformans, all infectious pathogens in humans, were used to assess the antimicrobial properties of the oils. The concentration of polyphenols ranged from 0.02± 0.006 to 0.04 ± 0.001 mg of gallic acid per g in oils from C. japonica and C. grijsii, respectively. Concerning the antioxidant activity, determined using the DPPH• scavenging activity and the β-carotene bleaching assay. The highest value was found in C. grijsii and the lowest in C. japonica. All the oils showed antimicrobial activity, and exhibited different selectivity and Minimum Inhibitory Concentrations (MIC) for each microorganism under study. The most sensitive was K. pneumonia, followed by Salmonella sp., S. epidermidis and C. neoformans, the highest MIC value being found for C. neoformans. For all the microorganisms, the higher antimicrobial activity was obtained from the oil of C. grijsii, followed by C. sasanqua and C. japonica. Since the highest biological properties were found in the oil containing the highest concentration of polyphenols, it can be hypothesised that these bioactive compounds might play a role in those properties.
- Chemical composition, antioxidante and antimicrobial activity of the leaves of Hancornia Speciosa Gomes (Apocynaceae)Publication . Santos, Uilson Pereira dos; Souza, Kely de Picoli; Tolentino, Georgina Santos; Morais, Jorge Sá; Estevinho, Leticia M.Hancomia species Gomes in a Brazilian tree which fruit is popularly know as mangaba. In this study we aimed (I) to characterize the chemical composition and energy content and to evaluate the antioxidant and antimicrobial activities of the ethanol {EEHS) and methanol (EMHS} extracts from H species leaves.
- Effect of processing conditions on the bioactive compounds and biological properties of bee pollenPublication . Dias, L.G.; Tolentino, Georgina Santos; Pascoal, Ananias; Estevinho, Leticia M.Bee pollen has had a valued place in traditional medicine for centuries, even though its use in modern medicine is still limited by the lack of scientific evidence. In this study, we characterized and compared nine types of bee pollen, submitted to two preservation methods (lyophilization and drying), in relation to the content of phenolic compound and total flavonoids. The biological properties were also evaluated and compared. Pollen analysis allowed us to classify two samples as heterofloral, whilst the remaining were monofloral. The concentrations of flavonoid and phenolic compounds were greater in the lyophilized samples. Even though all samples presented antimicrobial activity, the lyophilized ones induced stronger inhibition against both Gram-negative and Gram-positive bacteria. For the yeasts studied, the difference between the two preservation procedures was not so relevant. The antioxidant activity was also greater in the lyophilized samples. Antimutagenic capacity was observed in all samples, independently of the preservation method, even though some bee pollen types decreased the number of gene conversion and mutant colonies more efficiently. In conclusion, the results suggest that lyophilization is better to preserve the bioactive compounds and biological properties of this natural product.
- Estudo da segurança alimentar e da qualidade sensorial de pernas curadas de ovinos e caprinosPublication . Tolentino, Georgina Santos; Estevinho, Leticia M.; Rodrigues, SandraO presente trabalho tem como objetivo global estudar o efeito do tempo de cura e da espécie nas características microbiológicas e sensoriais de pernas curadas de ovino e caprino. As pernas de ovino e caprino são produtos provenientes de ovinos da raça Churra Galega Bragançana e caprinos da raça Serrana da região de Bragança, com peso e idade, que já não são valorizados pelos consumidores e fora de marcas de qualidade tipo DOP ou IGP. Para o efeito, foram utilizados dezasseis animais (12 ovelhas e 4 cabras), com peso médio de 20 ± 1,9 kg. Foram selecionadas pernas com peso aproximado de 3kg que sofreram um processo de salga a 20 % (p/v) e um processo de cura em ambientes controlados. As pernas de ovino sofreram diferentes processos de cura, enquanto as da raça caprina foram todos sujeitos ao mesmo processamento. Foram considerados três tratamentos, Ovino 1 (O1), e Caprino 1 (C1) pernas com 8 meses de cura, e Ovino 2 (O2) com 7 meses de cura. Inicialmente avaliaram-se as características microbiológicas para testar a segurança das pernas curadas e posteriormente procedeu-se a sua avaliação sensorial. Os microrganismos estudados foram: aeróbios mesófilos, bolores e leveduras, Staphylococcus aureus, esporos de clostrídios sulfito-redutores, coliformes totais, Escherichia coli, Salmonella spp. e Listeria monocytogenes. A análise sensorial foi efetuada por um painel de provadores treinados, de 9 elementos e foram avaliados parâmetros de aroma, textura, aparência e sabor. Utilizou-se uma escala contínua, não estruturada e ancorada nas extremidades. Os indicadores de qualidade comercial (aeróbios mesófilos e bolores e leveduras), das amostras de O1, C1 e O2 não revelam diferenças significativas entre espécies no entanto verificaram-se diferenças em relação ao tempo de cura, para os aeróbios mesófilos. A média e o desvio-padrão obtidos para os aeróbios mesófilos oscilaram entre 8,59x10^5±2,39x10^6UFCs/g, 3,97x10^5±5,34x10^5UFCs/g e 7,18x10^4±1,42x10^5UFCs/g, respetivamente para O1, C1 e O2. Os valores para os bolores e leveduras oscilaram entre 3,97x10^6±5,45x10^6UFCs/g, 1,81x10^6± 1,73x10^6UFCs/g e 3,73x10^6 ± 5,18x10^6 UFCs/g, respetivamente para O1, C1 e O2. No que diz respeito aos indicadores de qualidade sanitária (Coliformes totais, coliformes fecais e staphylococcus aureus) e segurança (esporos de Clostrídios sulfito-redutores, Salmonella spp. e Listeria monocytogenes), apenas foram detetadas contaminações por coliformes totais, em baixos níveis. Estes resultados sugerem que o produto é seguro para a saúde do consumidor, e que as práticas de higiene na manipulação e transformação foram adequadas, contribuindo para a obtenção de um produto final isento de altos níveis de contaminação. Pelo painel de provadores, as pernas curadas de Caprino foram caracterizadas no geral por uma maior dureza e menor suculência quando comparado com as pernas curadas de Ovino 1 e 2. As pernas curadas de Ovino 1 foram classificadas como tendo maior brilho e as do Ovino 2 maior suculência. A dureza e a persistência do sabor foram os parâmetros que apresentaram maior e menor poder discriminativo, respetivamente. De um modo geral, os provadores conseguiram distinguir os diferentes tratamentos. The present work globally aims to study the effect of species and seasoning time on microbiological and sensory characteristics of cured legs of sheep and goats. Churra Galega Bragançana sheep and Serrana goats’ legs were used. Animals were raised in Bragança region, and they had age and weight not considered by the quality labels DOP and IGP. Sixteen animals (12 ewes and 4 female goats), weighting 20±1.9kg, were used. Legs from the animals’ carcasses after slaughter and cutting, weighting about 3kg were selected, salted (20% salt/weight), and then cured in controlled environment. Three treatments were considered, O1 (ewes legs cured for 8 months), C1 (female goats legs cured for 8 months), and O2 (ewes legs cured for 7 months). Microbiological characteristics were first evaluated to test cured legs safety, and afterwards sensory evaluation was made. The studied microorganisms were: aerobic mesophylic, moulds and yeasts, Staphylococcus aureus, spores from sulfite-reducing clostridia, total coliforms, Escherichia coli, Salmonella spp., and Listeria monocytogenes. Sensory analysis was performed by a trained taste panel, of 9 elements, and aroma, texture, appearance, and taste attributes were studied. A continuous, non structured, and anchored in the extremes scale was used. Commercial quality indicators (mesophylic aerobic, moulds and yeasts), from O1, C1, and O2 samples reveal no significant differences between species. However, differences respecting seasoning time, on mesophylic, were found. Mesophylic mean and standard deviation were 8.59x10^5±2.39x10^6UFCs/g, 3.97x10^5±5.34x10^5 UFCs/g, and 7.18x10^4±1.42x10^5 UFCs/g, respectively, for O1, C1 and O2. Moulds and yeasts means and standard deviation were 3.97x10^6±5.45x10^6 UFCs/g, 1.81x10^6± 1.73x10^6 UFCs/g e 3.73x10^6± 5.18x10^6UFCs/g, respectively for O1, C1 e O2. Respecting sanitary (total coliforms, fecal coliforms and Staphylococcus aureus) and safety quality indicators (sulfite-reducing clostridia, Salmonella spp., and Listeria monocytogenes), only low levels of total coliforms contaminations were detected. These results suggests this a safety product to consumers health, and that hygiene practices when manipulating and transforming the legs were adequate, contributing to obtain a final product without contamination. Taste panel characterized ewes cured legs as more tender and juicier compared to goats legs. O1 legs were the brightest, and O2 legs were the juiciest. Hardness and taste persistence were the attributes that presented the higher and the lower discriminator power, respectively. Generally, panelists were able to distinguish the different treatments.
- Estudo da segurança alimentar e da qualidade sensorial de presuntosPublication . Tolentino, Georgina Santos; Estevinho, Leticia M.; Rodrigues, Sandra; Teixeira, AlfredoO presunto é o produto obtido a partir de pernas de suíno curado por salga profunda e seguidamente exposta à secagem e maturação, podendo ser fumada. O desenvolvimento de produtos inovadores como é o caso de presuntos provenientes de pernas de ovino e caprino da raça Churra Galega Bragançano e da raça Serrana da região de Bragança, permite valorizar produtos provenientes de animais com peso e idade, e fora de marcas de qualidade tipo IGP ou DOP que já não são valorizados pelos consumidores.
- Influência do processo de desidratação sobre a atividade antimicrobiana do pólen apícola desidratadoPublication . De-Melo, Adriane A.M.; Tolentino, Georgina Santos; Estevinho, Leticia M.O objetivo deste estudo foi investigar a influência do processo de conservação na ativi-dade antimicrobiana de amostras de pólen apícola do Brasil contra microorganismos isolados de fluidos biológicos e estirpes de referência.Amostras de pólen apícola foram coletadas durante os meses de abril/2012 e setem-bro/2012 em um apiário localizado no Estado de São Paulo, Brasil. Parte das amostras foi subme-tida a desidratação por aquecimento em estufa a 42ºC e parte a desidratação por liofilização. A atividade antimicrobiana foi determinada pelo método de microdiluição em placa [1], na Escola Superior Agrária de Bragança. Como material biológico foram utilizadas bactérias Gram-positi-vas (Streptococcus pyogenes ATCC; Streptococcus pyogenes ESA12; Staphylococcus aureus ATCC 6538™; Staphylococcus aureus ESA54), bactérias Gram-negativas (Escherichia coli ATCC 25922™; Escherichia coli ESA72; Klebsiella pneumoniae ATCC 13883™; Klebsiella spp) e leveduras (Candida albicans ATCC 10231™ e Candida albicans ESA109). Os resultados foram expressos em concentra-ção minima inibitória (CIM; p/v), que é a menor concentração de extrato de pólen apícola capaz de inibir o crescimento microbiano indicado por coloração com cloreto de trifenil tetrazolium (TTC).Todos os extratos apresentaram atividade antimicrobiana. A CIM para bactérias Gram--positivas variou entre 1,4 e 5,3%, enquanto que, para as bactérias Gram-negativas os valores obtidos oscilaram entre 2,5 e 7,0% e para as leveduras entre 16,7 e 25,8%. As amostras liofilizadas exerceram um efeito mais acentuado na inibição de crescimento de todos os microrganismos em estudo comparativamente com as amostras secas em estufa, sugerindo que o aquecimento pode ter alterado os compostos com propriedades antimicrobianas.Grande parte dos produtores de pólen apícola utiliza a desidratação por aquecimento em suas unidades de processamento, no entanto, este estudo indica que a liofilização pode ser uma alternativa ao processo atual que resulte num produto de maior potencial biológico. O consumo de pólen apícola é impulsionado pela demanda por produtos naturais com propriedades tera-pêuticas, portanto, quanto maior o potencial biológico deste produto, maior será a sua procura.
- Microbiological quality and sensory evaluation of new cured products obtained from sheep and goat meatPublication . Tolentino, Georgina Santos; Estevinho, Leticia M.; Pascoal, Ananias; Rodrigues, Sandra; Teixeira, AlfredoThe present work aims to study the effect of species and seasoning time on the physicochemical, microbiological and sensory characteristics of cured legs of sheep and goats. Three cure periods were used: two for sheep and one for goat legs. Legs of lamb were cured for 7 and 8 months whereas legs of goat were cured for 8 months only. Samples were evaluated regarding pH, water activity and indicators of food microbial q uality and safety. A trained panel carried out the sensory analysis, with aroma, texture, appearance and taste being the evaluated parameters. Significant differences were detected between the amount of aerobic mesophiles of the products cured during 7 months and the sheep legs cured during 8 months. Moulds and yeasts were between 1.81 × 106 ± 1.73 × 106 and 3.97 × 106 ± 5.45 × 106 colony-forming units/g, whereas total coliforms varied from 2.80 × 102 ± 4.13 × 102 to 1.31 × 104 ± 2.39 × 104. All samples were negative for toxigenic species. Concerning sensory analysis, hardness and taste persistence were the attributes that presented the highest and the lowest discriminative power, respectively. In general, the panel was able to characterise and distinguish the samples. The cured legs of goats were characterised as harder and as less succulent than those obtained from sheep. Sheep meat with larger time of cure was the brightest, whereas the one with a smaller time of cure was the most succulent. However, goat meat presented higher values of rancid and acid flavour. Sheep meat submitted to longer processing presented the most intense flavour and sheep meat with an inferior cure period presented the lowest intensity in all flavour attributes. This paper describes, for the first time in Portugal, the production and characterisation of cured legs of sheep and goats as a strategy to enhance economic value to good quality products obtained from animals of second category.
- Physicochemical characterization, microbiological quality and safety, and pharmacological potential of Hancornia speciosa GomesPublication . Santos, Uilson Pereira dos; Tolentino, Georgina Santos; Morais, Jorge Sá; Souza, Kely de Picoli; Estevinho, Leticia M.; Santos, Edson Lucas dosHancornia speciosa Gomes is a fruit tree, commonly known as the mangaba tree, which is widespread throughout Brazil. The leaves of this plant are used in traditional medicine for medicinal purposes. Thus, the objective of this study was to perform a physicochemical characterization, identify the lipophilic antioxidants and fatty acids, and determine the microbiological quality and safety of H. speciosa leaves. In addition, the antioxidant, antimutagenic, and inhibitory activities of the ethanolic extract of H. speciosa leaves (EEHS) against enzymes related to neurodegenerative diseases, inflammation, obesity, and diabetes were investigated. Furthermore, this study aimed at assessing the in vivo effects of the EEHS on the glycemia of normoglycemic and diabetic Wistar rats. Physicochemical characterization was performed by colorimetry and gas-liquid chromatography with flame ionization detection (GC-FID). The total number of colonies of aerobic mesophiles, molds, and yeasts was determined. The total coliforms and Escherichia coli were counted using the SimPlates kit, and sulphite-reducing Clostridium spores were quantified using the sulphite-polymyxin-sulfadiazine agar method. Salmonella spp. were detected using the 1-2 Test. The antioxidant activity of the EEHS was measured by its inhibition of 2,2′-azobis(2-amidinopropane) dihydrochloride- (AAPH-) induced oxidative hemolysis of human erythrocytes. The antimutagenic activity was determined using the Ames test. The acetylcholinesterase, butyrylcholinesterase, tyrosinase, hyaluronidase, lipase, α-amylase, and α-glycosidase enzyme-inhibiting activities were assessed and compared with commercial controls. The in vivo effects of the EEHS were assessed using the oral glucose tolerance test in normoglycemic Wistar rats and measuring the blood glucose levels in diabetic rats. The results demonstrated physical-chemical parameters of microbiological quality and safety in the leaves of H. speciosa, as well as antioxidant and antimutagenic activities and inhibition of enzymes related to neurodegenerative diseases, inflammation, obesity, and diabetes. In in vivo assays, it was shown that the normoglycemic rats challenged with glucose overload show significantly decreased blood glucose levels when treated with the EEHS. Taken together, the results ensure the microbiological quality and safety as well as showing the contents of carotenoids and polyunsaturated fatty acids of H. speciosa leaves. Additionally, the antioxidant, antimutagenic, anti-inflammatory, anti-Alzheimer’s disease, anti-Parkinson’s disease, antiobesity, and antihyperglycemic activities of the EEHS were demonstrated.
- Quality and microbiological safety and antifungal activity of Hancornia Speciosa Gomes (Apocynaceae).Publication . Santos, Uilson Pereira dos; Souza, Kely de Picoli; Tolentino, Georgina Santos; Carollo, Carlos Alexandre; Estevinho, Leticia M.; Santos, Edson Lucas dosThe aim of this study was to evaluate the quality and microbiological safety and antifungal activity of the ethanolic extract of the leaves of Hancomia Gomes (EEHS), a Brazilian fruit tree popularly known mangabeira .
- Studio de la seguridad alimentar y de la calidad sensorial de piernas curadas de ovinos y caprinosPublication . Tolentino, Georgina Santos; Estevinho, Leticia M.; Rodrigues, Sandra; Teixeira, AlfredoEste trabajo tiene como objetivo evaluar el efecto del tiempo de cura y de la especie sobre las características microbiológicas y sensoriales de piernas curadas de ovino y caprino. Se han utilizado dieciséis animales, con peso medio de 20±1,9 kg. Las piernas seleccionadas, con aproximadamente 3 kg, han sido sometidas a un proceso de salazón y un proceso de cura en ambiente controlado. A las piernas de ovino se les han aplicado diferentes tiempos de cura (8 y 7 meses), y a las piernas de caprinos un único tiempo de cura de 8 meses. Se evaluaron las características microbiológicas para probar la seguridad alimentaria y se procedió a su evaluación sensorial. Los microrganismos estudiados fueron: aerobios-mesófilos, hongos, S. aureus, esporas de Clostridium sulfito-reductores, coliformes totales, E. coli, Salmonella spp, Listeria monocytogenes. El análisis sensorial ha sido llevado a cabo por un panel de catadores entrenados, que han evaluado parámetros de aroma, textura, apariencia y sabor. Se ha utilizado una escala continúa, no estructurada y anclada en las extremidades. Los resultados obtenidos sugieren que el producto es seguro y que las prácticas de higiene durante la manipulación y transformación son adecuadas. En general, los catadores han conseguido distinguir los diferentes tratamientos.