Percorrer por autor "Freitas, Alex da Silva"
A mostrar 1 - 7 de 7
Resultados por página
Opções de ordenação
- Brazilian samples of bee samples pollen: palynological origin, phenolic content, antioxidant properties and antimicrobial activityPublication . Arruda, Vanilda Aparecida Soares de; Santos, Alexandre Vieria; Figueiredo, Davi; Meira, Sampaio; Estevinho, Leticia M.; Barth, Ortrud M.; Freitas, Alex da Silva; Almeida-Muradian, Ligia BicudoTotal phenolic and flavonoids phytochemical concentration was measured in bee pollen samples, Appis Mellifera , as well as their botanical origin, antioxidant activity and antimicrobial activity. Pollen loads were washed with 70% ethanol and identified using a 400x magnification. The content of total polyphenols and flavonoids was measured spectrophotometrically with gallic acid and quercetin as standard. The antioxidant activity was evaluated by the linking capacity of (i)the free radical DPPH (2,2-Diphenyl-1-picrylhydrazyl), (ii)ORAC and (iii)system β-carotene/linoleic acid. The experiments were performed in triplicate and the results expressed as mean ± standard deviation. All statistical analysis were performed using the program STATISTICA 8.0 and adopting the significance level of 5% (p<0.05). Were using six samples of dehydrated bee pollen collected in Ribeirao Preto, SP, Brazil during the years of 2010 and 2011. Five families were found in the mixture of bee pollen: Mimosa caesalpiniaefolia , Mimosa scabrella, Asteraceae, Poaceae, Zea mays. Each dried bee pollen sample was composed mainly of Mimosa caesalpiniaefolia (Fabaceae-Mimosoideae). The variations were (dry basis): 17.64±1.57 to 32.14±2,88 mg GAE/g of bee pollen for phenolic compounds; 2.51±0.28 to 3.71±0.25 mg quercetin/g of pollen for flavonoids concentration; 77.15±0.72 to 90.56% for antioxidant activity (DPPH) and 3.19±0.25 to 4.61±0.33 mg/mL for EC50; 183.42±16.26 to 338.32± 33.38 μmols eq. Trolox/g for ORAC and 68.96±2.75 to 85.90±2.27% for β -carotene/linoleic acid. Samples of pollen, phenolics and flavonoids have the potential biological, showing high antioxidant activity by the three methods used. It was verified that the presence of pollen differentially affected the growth of bacteria Gram-positive, Gram-negative and yeasts under study, depending this on the microorganism and the pollen used in fact, only one after sample was monofloral Mimosa caesalpiniaefolia. This is an important study since; their characterization can increase their economic value. The opinions, hypothesis and conclusions or recommendations expressed in the article are those of the authors and do not necessarily coincide with those of FAPESP.
- Comparative study of the physicochemical and palynological characteristics of honey from Melipona subnitida and Apis melliferaPublication . Almeida-Muradian, Ligia Bicudo; Stramm, Klaus Martin; Horita, Andreia; Barth, Ortrud M.; Freitas, Alex da Silva; Estevinho, Leticia M.Twenty-four samples of Apis mellifera honey and twenty-four samples of Melipona subnitida (Jandaira) honey were collected in the northeast of Brazil. Moisture, hydroxymethylfurfural, free acidity, insoluble solids in water, diastase activity, ashes, electrical conductivity, proteins, lipids, total carbohydrates, energy and sugars were the parameters analysed. The efficiency of the qualitative tests (Fiehe’s test, Lugol’s reaction, Lund’s reaction) was tested. Pollen types and the corresponding plant species were identified in all samples (3 in Apis and 1 in Melipona). Apis mellifera honey samples demonstrated parameters in accordance with the Brazilian Legislation, while the Melipona subnitida honey samples displayed moisture (24.80%) and diastase activity (null) in discordance with the established by the regulation for Apis mellifera honeys. Apis honey samples presented higher values of electric conductivity (284.00 lS cm 1) than the obtained from the Jandaira honey samples (102.77 lS cm 1) as well as a darker colour (26.67 mmPfund) when compared with Jandaira honey (7.00 mmPfund). The concentration of the glucose, fructose and sucrose was higher in the Apis honeys than in the Jandaira honey. The characteristics of the two types of honey were very different, highlighting the need of developing specific legislation for stingless bees’ honey.
- Effect of processing conditions on characteristics of dehydrated bee-pollen and correlation between quality parametersPublication . De-Melo, Adriane A.M.; Estevinho, Leticia M.; Sattler, José Augusto Gasparotto; Souza, Bianca Rodrigues; Freitas, Alex da Silva; Barth, Ortrud M.; Almeida-Muradian, Ligia BicudoThe aim of the present study was to compare the physical, chemical and biological parameters and the microbiological quality of bee-pollen samples treated with different dehydration processes and to correlate the results. The samples came mainly from Eucalyptus (Myrtaceae) and Eupatorium (Asteraceae) plants. The dehydration conditions of the samples influenced the L*a*b* colour parameters and the biological value. Unlike the protein and lipid content, the glucose and fructose content were unaffected. The vitamin E content (27.2 ± 0.3 μg/g, 27.5 ± 0.4 μg/g) in oven-dehydrated samples with forced air circulation was significantly lower (P < 0.05) compared with lyophilized samples (37.5 ± 0.2 g/100 g, 53.7 ± 3.9 g/100 g). Overall, the results were inconclusive for vitamin B complex, minerals and microbiological indicators. There was a positive correlation between the colour parameters L* and b* and the total phenolic content, as well as between phenolic content and the antioxidant and antimicrobial capacity. The data indicate that lyophilization might be a viable alternative to the current process, resulting in dehydrated bee-pollen with higher biological activity.
- A multivariate approach based on physicochemical parameters and biological potential for the botanical and geographical discrimination of Brazilian bee pollenPublication . De-Melo, Adriane A.M.; Estevinho, Leticia M.; Moreira, Manuela M.; Delerue-Matos, Cristina; Freitas, Alex da Silva; Barth, Ortrud M.; Almeida-Muradian, Ligia BicudoFifty six Brazilian bee pollen samples were characterised, and their botanical and geographical origins were studied. The samples were also classified based on physicochemical and biological properties. The characterisation was done using Soxhlet extraction and micro-Kjeldahl methods, ashing at 550°C, transmittance, microscopy, spectrophotometry, inductively coupled plasma optical emission spectrometry and high-performance liquid chromatography. As expected, the values of proteins (7.9–32.2g/100g), lipids (3.2–13.5g/100g), ash (1.9–3.6g/100g), carbohydrates (54.9–82.8g/100g), K (3.4–9.8g/kg), Ca (0.9–4.1g/kg), Mg (0.6–2.4g/kg), Fe (46–1180mg/kg), Na (20–374mg/kg), Mn (25–215mg/kg), Zn (30–101mg/kg), Cu (7.4–19.7mg/kg), total phenolics (6.5–29.2mgGAE/g)and flavonoids(0.3–17.5mgQE/g)as well as the phenolic profiles varied among the samples. In general, the products had high antioxidant capacity (ORAC: 133–563 μmol TE/g; DPPH: 9.4–155μmolTE/g) and the antimicrobial capacity varied according to the sample and microorganism tested. The instrumental colour parameters could be used as indicators of some minerals. Based on multivariate approaches, bee pollen from Southern Brazil seemed to have a higher biological potential, whereas products from the Northeast region had higher calcium and magnesium levels. Similarities were identified in bee pollen containing C. nucifera or Brassica, and monofloral bee pollen seemed to have higher mineral content than heterofloral bee pollen.
- Phenolic profile by HPLC-MS, biological potential, and nutritional value of a promising food: Monofloral bee pollenPublication . De-Melo, Adriane A.M.; Estevinho, Leticia M.; Moreira, Manuela M.; Delerue-Matos, Cristina; Freitas, Alex da Silva; Barth, Ortrud M.; Almeida-Muradian, Ligia BicudoThe objective of this study was to determine physicochemical and phenolic profiles as well the antioxidant and antimicrobial capacities of monofloral bee pollen samples from Brazil. Traditional methods were used. The phenolic profile was determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS). The protein (10.6–33.9 g/100g), lipids (3.2–8.3 g/ 100g), ashes (2.6–3.8 g/100g), total phenolic (5.6–29.7 mg GAE/g), and total flavonoid (0.3– 19.0 mg QE/g) values were variable, even between products with the same botanical origin. The minerals analyzed were found in amounts varying between 10 mg/kg and 9.1 g/kg. Each product presented specific color parameters. Myrcia bee pollen presented the greater antioxidant capacity, and Mimosa scabrella bee pollen from Santa Catarina state was the most efficient in inhibiting bacteria and yeasts. Among the compounds identified by HPLC-MS, flavonoid 3-O-glycosides predominated. The physicochemical and phenolic profiles of each sample were distinct, and there was no pattern between monofloral products of the same pollen type.
- Pólen apícola desidratado: compostos fenólicos, flavonoides, atividade antioxidante e origem botânicaPublication . Arruda, Vanilda Aparecida Soares de; Meira, Santos; Estevinho, Leticia M.; Barth, Mónica; Freitas, Alex da Silva; Almeida-Muradian, Ligia BicudoO pólen apícola, produto da aglutinação do pólen das flores com néctar e substâncias salivares da abelhas, tem sido promovido como suplemento da dieta humana por apresentar propriedades nutricionais e bioativas.
- Propriedades biológicas do pólen apícola de coqueiro, coletado na Região Nordeste do BrasilPublication . Arruda, Vanilda Aparecida Soares de; Freitas, Alex da Silva; Barth, Ortrud M.; Estevinho, Leticia M.; Almeida-Muradian, Ligia BicudoO pólen apícola, com vastas aplicações na alimentação humana, resulta da aglutinação de grãos de pólen de várias fontes vegetais efetuada pelas abelhas, mediante acréscimo de substâncias salivares e pequenas quantidades de néctar ou mel. O presente trabalho objetivou avaliar o conteúdo de compostos fenólicos, flavonoides totais e o potencial antioxidante dos extratos etanólicos de pólen apícola desidratado, assim como sua atividade antimicrobiana. Todas as amostras, coletadas na região nordeste, apresentaram mais de 45 % do pólen de coqueiro (Cocus nucifera). Os valores obtidos para compostos fenólicos e flavonoides totais variaram de 13,76 a 24,60 mg GAE/g de pólen apícola (GAE: equivalentes em ácido gálico) e 2,52 a 6,90 mg de quercetina/g de pólen apícola respectivamente. O EC50 variou de 1,30 a 8,08 mg pólen apícola /mL de extrato. Os extratos de pólen apícola apresentaram valores entre 61,63 e 83,90 % utilizando-se o método do β-caroteno. Quando quantificada por ORAC, a atividade antioxidante medida ficou entre 195,15 e 294,69 μmols eq. trolox/g pólen apícola. Relativamente à atividade antimicrobiana quantificada pelo método da microdiluição em placa, verificou-se que o produto inibiu o crescimento de todos os microrganismos em estudo, sendo o efeito dependente do gênero. Candida albicans foi mais resistente e Staphylococcus epidermides mais sensível. Os resultados indicaram que o pólen apícola possui atividade biológica e o crescente interesse pelo produto enfatiza a necessidade de novas pesquisas para investigar as suas propriedades, agregando deste modo valor ao produto.