Caracterização química do mel catarinense: composição, atividade antioxidante e o uso da eletroforese capilar como alternativa na avaliação da qualidade

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Ciência dos AlimentosO objetivo deste trabalho foi caracterizar amostras de mel produzias no Estado de Santa Catarina na safra 2010/2011, e desenvolver e validar métodos para o controle de qualidade de mel empregando a eletroforese capilar. Foram estudadas amostras provenientes de oito regiões do Estado, que apresentaram adequados resultados quanto aos parâmetros de condutividade elétrica, pH, minerais, hidroximetilfurfural, atividade diastásica, frutose, glicose, sacarose e cor. Para apenas uma das regiões os resultados de umidade e acidez livre apresentaram-se fora dos limites legais, provavelmente devido à retirada prematura do mel das colmeias ou sob condições de alta umidade. Além disso, foi possível realizar a discriminação entre amostras de mel de diferentes origens geográficas de acordo com o conteúdo dos principais minerais presentes. As amostras apresentaram apreciável conteúdo de compostos fenólicos totais e carotenoides totais e atividade antioxidante in vitro pelos métodos DPPH e FRAP comprovando o potencial de consumo de mel como alimento funcional. Foram propostos três novos métodos para a determinação de cátions, de açúcares e de hidroximetilfural através de eletroforese capilar. Os três métodos apresentaram adequados resultados quanto à validação analítica, além de serem extremamente rápidos, econômicos e confiáveis, demonstrando o potencial da eletroforese capilar para análises de rotina da determinação da qualidade do melThe objective of this study was to characterize honey samples produced on State of Santa Catarina from the 2010/2011 harvest, and to develop and validate methods for the assessment of honey quality, employing capillary electrophoresis. Samples from eight regions of the State were studied. They showed adequate results for electrical conductivity, pH, minerals, hydroxymethylfurfural, diastase activity, fructose, glucose, sucrose and color. Samples from one of the regions showed moisture content and free acidity over the legal limits, probably due to premature harvest of honey from hives or under conditions of high humidity. Moreover, it was possible to discriminate honey samples from different geographical origins according to the contents of the principal cations present. The samples also showed appreciable contents of total phenolic compounds and total carotenoids, and antioxidant activity by DPPH and FRAP methods, demonstrating the potential of honey as a functional food. Three new methods for the determination of cations, sugars and hydroxymethylfurfural by capillary electrophoresis were developed. The three methods presented appropriate results regarding analytical validation. Furthermore, they were also fast, economical and reliable, demonstrating the potential of capillary electrophoresis for the routine analysis in the assessment of honey qualit

Fast determination of cations in honey by capillary electrophoresis: A possible method for geographic origin discrimination

AbstractThis study reports the development and validation of a fast capillary electrophoresis method for cation determination in honey samples and the classification of honey by geographical origin using Principal Components Analysis (PCA). The background electrolyte (BGE) was optimized using the Peakmaster® software, which evaluates the tendency of the analytes to undergo electromigration dispersion and the BGE buffer capacity and conductivity. The final BGE composition was defined as 30mmolL−1 imidazole, 300mmolL−1 acetic acid and 140mmolL−1 Lactic acid, at pH 3,0, and the separation of K+, Na+, Ca2+, Mg2+ and Mn2+ using Ba2+ as the internal standard was achieved in less than 2min. The method showed satisfactory results in terms of linearity (R2>0.999), the detection limits ranged from 0.27–3.17mgL−1 and the quantification limits ranged from 0.91–10.55mgL−1. Precision measurements within 0.55 and 4.64%RSD were achieved and recovery values for the analytes in the honey samples ranged from 93.6%–108.6%. Forty honey samples were analyzed to test the proposed method. These samples were dissolved in deionized water and filtered before injection. The CE-UV reliability in the cation analysis in the real sample was compared statistically with ICP-MS methodology. No significant differences were found, with a 95% confidence interval between the methodologies. The PCA showed that the cumulative variance for the first two principal components explain more than 85% of the variability of the data. The analytical data suggest a significant influence of the geographical origin on the mineral composition

Development of a fast MECK method for determination of 5-HMF in honey samples

AbstractIn this study, 5-hydroxymethylfurfural (5-HMF) determination was carried out by a micellar electrokinetic capillary chromatography (MEKC) methodology, using caffeine as the internal standard (IS). The optimisation of the electrolyte composition was approached using a 32 full factorial design with a central point to study the MEKC electrolyte components. Inspection of the response surface indicated that the optimal electrolyte composition was 5mmolL−1 sodium tetraborate (STB, pH 9.3) containing 120mmolL−1 sodium dodecyl sulphate (SDS). Under optimal CE conditions, separation of the investigated substance was achieved in less than 0.7min. Quality parameters, such as linearity (R2>0.99), precision (RSD<5.41%), detection and quantification limits (3.37 and 11.24mgkg−1 for honey samples) and recovery (96.37–99.56%). The proposed methodology was successfully applied to the analysis of 5-HMF in honey samples. The analytical performance of this method makes it suitable for implementation in food laboratories for the routine determination of 5-HMF in honey samples

Caracterização química do mel catarinense

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Ciência dos AlimentosO objetivo deste trabalho foi caracterizar amostras de mel produzias no Estado de Santa Catarina na safra 2010/2011, e desenvolver e validar métodos para o controle de qualidade de mel empregando a eletroforese capilar. Foram estudadas amostras provenientes de oito regiões do Estado, que apresentaram adequados resultados quanto aos parâmetros de condutividade elétrica, pH, minerais, hidroximetilfurfural, atividade diastásica, frutose, glicose, sacarose e cor. Para apenas uma das regiões os resultados de umidade e acidez livre apresentaram-se fora dos limites legais, provavelmente devido à retirada prematura do mel das colmeias ou sob condições de alta umidade. Além disso, foi possível realizar a discriminação entre amostras de mel de diferentes origens geográficas de acordo com o conteúdo dos principais minerais presentes. As amostras apresentaram apreciável conteúdo de compostos fenólicos totais e carotenoides totais e atividade antioxidante in vitro pelos métodos DPPH e FRAP comprovando o potencial de consumo de mel como alimento funcional. Foram propostos três novos métodos para a determinação de cátions, de açúcares e de hidroximetilfural através de eletroforese capilar. Os três métodos apresentaram adequados resultados quanto à validação analítica, além de serem extremamente rápidos, econômicos e confiáveis, demonstrando o potencial da eletroforese capilar para análises de rotina da determinação da qualidade do melThe objective of this study was to characterize honey samples produced on State of Santa Catarina from the 2010/2011 harvest, and to develop and validate methods for the assessment of honey quality, employing capillary electrophoresis. Samples from eight regions of the State were studied. They showed adequate results for electrical conductivity, pH, minerals, hydroxymethylfurfural, diastase activity, fructose, glucose, sucrose and color. Samples from one of the regions showed moisture content and free acidity over the legal limits, probably due to premature harvest of honey from hives or under conditions of high humidity. Moreover, it was possible to discriminate honey samples from different geographical origins according to the contents of the principal cations present. The samples also showed appreciable contents of total phenolic compounds and total carotenoids, and antioxidant activity by DPPH and FRAP methods, demonstrating the potential of honey as a functional food. Three new methods for the determination of cations, sugars and hydroxymethylfurfural by capillary electrophoresis were developed. The three methods presented appropriate results regarding analytical validation. Furthermore, they were also fast, economical and reliable, demonstrating the potential of capillary electrophoresis for the routine analysis in the assessment of honey qualit

Cerebral Venous Thrombosis with Migraine-Like Headache and the Trigeminovascular System

Cerebral venous thrombosis- (CVT-) associated headache is considered a secondary headache, commonly presenting as intracranial hypertension headache in association with seizures and/or neurological signs. However, it can occasionally mimic migraine. We report a patient presenting with a migraine-like, CVT-related headache refractory to several medications but intravenous dihydroergotamine (DHE). The response to DHE, which is considered to be an antimigraine medication, in addition to the neurovascular nature of migraine, points out to a probable similarity between CVT-headache and migraine. Based on experimental studies, we discuss this similarity and hypothesize a trigeminovascular role in the genesis of CVT-associated headache.Peer Reviewe

Case Report Cerebral Venous Thrombosis with Migraine-Like Headache and the Trigeminovascular System

Cerebral venous thrombosis-(CVT-) associated headache is considered a secondary headache, commonly presenting as intracranial hypertension headache in association with seizures and/or neurological signs. However, it can occasionally mimic migraine. We report a patient presenting with a migraine-like, CVT-related headache refractory to several medications but intravenous dihydroergotamine (DHE). The response to DHE, which is considered to be an antimigraine medication, in addition to the neurovascular nature of migraine, points out to a probable similarity between CVT-headache and migraine. Based on experimental studies, we discuss this similarity and hypothesize a trigeminovascular role in the genesis of CVT-associated headache

Phenolic compounds and antioxidant activity of seed and skin extracts of red grape (Vitis vinifera and Vitis labrusca) pomace from Brazilian winemaking

The phenolic compounds content and antioxidant activity of seed and skin of pomace from the vinification of grape varieties widely produced in Brazil were investigated with a view to their exploitation as a potential source of natural antioxidants. There was a greater concentration of phenolic compounds in the seeds (2128 to 16,518 mg of catechin equivalents (CE)/100 g) than in the skins (660 to 1839 mg CE/100 g). The highest antioxidant activity values determined as DPPH radical-scavenging ability and ferric reducing-antioxidant power (FRAP) were found for the seeds of the Pinot Noir variety (16,925 mu mol Trolox equivalents (TE)/100 g and 21,492 mu mol Fe(2+)/100 g, respectively) and in the skin extracts of the Isabel variety (3640 mu mol TE/100 g and 4362 mu mol Fe(2+)/100 g, respectively). The skin of Cabernet Sauvignon and Primitivo varieties had the highest contents of anthocyanins (935 and 832 mg/100 g, respectively). The grape seed extracts were rich in oligomeric and polymeric flavanols. The data suggested that grape seed and skin extracts may be exploited as antioxidant agents. (C) 2011 Elsevier Ltd. All rights reserved.CNPq/Cape

Lesion of the subthalamic nucleus reverses motor deficits but not death of nigrostriatal dopaminergic neurons in a rat 6-hydroxydopamine-lesion model of Parkinson's disease

The objective of the present study was to determine whether lesion of the subthalamic nucleus (STN) promoted by N-methyl-D-aspartate (NMDA) would rescue nigrostriatal dopaminergic neurons after unilateral 6-hydroxydopamine (6-OHDA) injection into the medial forebrain bundle (MFB). Initially, 16 mg 6-OHDA (6-OHDA group) or vehicle (artificial cerebrospinal fluid - aCSF; Sham group) was infused into the right MFB of adult male Wistar rats. Fifteen days after surgery, the 6-OHDA and SHAM groups were randomly subdivided and received ipsilateral injection of either 60 mM NMDA or aCSF in the right STN. Additionally, a control group was not submitted to stereotaxic surgery. Five groups of rats were studied: 6-OHDA/NMDA, 6-OHDA/Sham, Sham/NMDA, Sham/Sham, and Control. Fourteen days after injection of 6-OHDA, rats were submitted to the rotational test induced by apomorphine (0.1 mg/kg, ip) and to the open-field test. The same tests were performed again 14 days after NMDA-induced lesion of the STN. The STN lesion reduced the contralateral turns induced by apomorphine and blocked the progression of motor impairment in the open-field test in 6-OHDA-treated rats. However, lesion of the STN did not prevent the reduction of striatal concentrations of dopamine and metabolites or the number of nigrostriatal dopaminergic neurons after 6-OHDA lesion. Therefore, STN lesion is able to reverse motor deficits after severe 6-OHDA-induced lesion of the nigrostriatal pathway, but does not protect or rescue dopaminergic neurons in the substantia nigra pars compacta