Maria Lucia Masson

Study of preparations of bee pollen extracts, antioxidant and antibacterial activity

Objetivou-se, neste estudo determinar compostos fenolicos, a atividade antioxidante a antibacteriana dos extratos etanolicos de polen, obtidos com diferentes concentracoes de etanol. As diferentes condicoes de extracao (etanol de 40 a 90%) apresentaram diferentes efeitos no conteudo dos compostos fenolicos extraidos. Os extratos de polen obtidos com etanol a 60, 70 e 80% apresentaram maiores niveis de compostos fenolicos (>10 mg/g) e nao apresentaram diferencas estatisticas entre essas condicoes de extracao. A quantidade de compostos fenolicos nos extratos de polen variou de 3.6 a 8.1 e 6.6 a 11 mg de equivalente em acido galico por g de polen (GAE), para os estados de Alagoas e Parana, respectivamente. Os maiores indices de atividade antioxidante para o polen do estado de Alagoas foi de 83.30% e 81.15 % para o polen do estado do Parana. O polen do estado do Parana extraido com etanol a 60%, apresentou o maior indice de atividade antioxidante e tambem a maior concentracao de compostos fenolicos. A bacteria Staphylococcus aureus foi inibida pelo extrato etanolico do polen de Alagoas, em todas as concentracoes, exceto no extrato etanolico a 90%. O extrato etanolico a 60%, no polen do Parana, inibiu Bacillus subtilis, Pseudomonas aeruginosa e Klebsiella sp.

Levantamento de dados epidemiológicos relativos à ocorrências/ surtos de doenças transmitidas por alimentos (DTAs) no estado do Paraná Brasil, no período de 1978 a 2000

As doencas transmitidas por alimentos (DTAs) sao causadas por agentes biologicos, quimicos ou fisicos, os quais penetram no organismo humano pela ingestao de agua ou alimentos contaminados. Este trabalho tem como objetivo a realizacao de um levantamento dos dados disponiveis sobre surtos de origem alimentar ocorridos no Parana, no periodo de 1978 a 2000. O perfil epidemiologico das doencas transmitidas por alimentos no Brasil ainda e pouco conhecido, somente alguns estados e/ou municipios dispoem de estatisticas e levantamentos reais sobre os agentes etiologicos mais comuns, alimentos mais frequentemente envolvidos e fatores contribuintes. Alem disso, doencas transmitidas por alimentos nem sempre sao oficialmente notificadas. No Parana, dados obtidos oficialmente e disponiveis de surtos de DTAs apontam como agentes etiologicos mais frequentes os de origem bacteriana, destacando-se Staphylococcus aureus e Salmonella sp. Verifica-se que os alimentos mais frequentemente associados aos surtos sao de origem animal, sendo os domicilios os locais de ocorrencia de maior incidencia. O numero de surtos de DTAs cresce a cada ano e grande parte dos consumidores desconhece os requisitos necessarios para uma correta manipulacao de alimentos, incluindo o armazenamento (locais, temperatura, tempo de armazenamento) e, principalmente os perigos que podem estar associados aos alimentos contaminados. Os gastos destinados ao tratamento das DTAs foram quantificados a partir de dados do Sistema Unico de Saude (SUS) e do Hospital de Clinicas/UFPR de Curitiba, mostrando-se elevados e reafirmando que a area de seguranca alimentar necessita maior atencao.

Avaliação do potencial antioxidante do pólen apícola produzido na região sul do Brasil

The contents of total phenolics, flavonoids, and antioxidant activity of bee pollen ethanolic extract were determined and compared to those of commercial antioxidants. Bee pollen extract from the state of Rio Grande do Sul presented antioxidant activity statistically equal to that of α -tocopherol and higher than those of BHT and BHA. A statistically significant correlation was observed between the antioxidant activity and the total phenolics and total flavonoids contents of bee pollen extracts. HPLC technique made the identification of high contents of rutin and myricetin possible, which may partially explain the high antioxidant activity of Brazilian bee pollen.

Instrumental color and sensory acceptance of soy-based emulsions: a response surface approach

A Metodologia de Superficie de Resposta (MSR) foi aplicada para avaliar as caracteristicas cromaticas de emulsoes compostas de Proteina de Soja (PS) e Suco de Goiaba vermelha (SG). Os parâmetros analisados foram: cor instrumental baseada nas coordenadas a* (vermelho), b* (amarelo), L* (luminosidade), C* (cromaticidade), h* (tonalidade), cor, aceitacao e aparencia. As analises dos resultados mostraram que o SG foi responsavel pelos altos valores de cor vermelha, tonalidade, cromaticidade, aceitacao e cor, ao passo que a PS aumentou a cor amarela das emulsoes. O parâmetro de cor vermelha (R2adj = 74,86%, p 0,05), obtendo-se baixos coeficientes de Pearson. A analise dos resultados indicou que a MSR e uma tecnica util no desenvolvimento de emulsoes a base de soja e pode ser usada para modelar alguns parâmetros cromaticos de emulsoes elaboradas com SG.

Rheological Properties of Butia Pulp

Rheological parameters of Butia pulp were determined at different temperatures using a concentric cylinder Haake Rotovisco rheometer, model RV-20, with measurement system ZA-30. Butia pulp was found to exhibit non-Newtonian, pseudoplastic behavior at all temperatures and the rheological parameters were adequately described by the Herschel-Bulkley model. Yield stress, flow behavior index, and consistency coefficient were significantly affected by temperature. The yield stress decreased exponentially with process temperature and ranged between 36.60 and 21.70 Pa. Apparent viscosity calculated through the Herschel-Bulkley model decreased with an increase in temperature. The Arrhenius model gave a good description of temperature effect on apparent viscosity of the pulp.

Propriedades reológicas da polpa de manga (Mangifera indica L. cv. Keitt) centrifugada

Objetivou-se com este trabalho estudar experimentalmente o comportamento reologico da polpa de manga centrifugada na faixa de temperatura de 10°C a 60°C. As medidas reologicas foram feitas no reometro Haake Rotovisco modelo RV 20, utilizando o sistema de medida de cilindros concentricos. A polpa integral foi produzida em uma despolpadeira com tela de 1,6 mm, congelada em um congelador de placas e armazenada a -15oC e centrifugada a 15000 rpm (29000 G), durante 40 minutos. O comportamento reologico da polpa de manga centrifugada (reogramas) foi ajustado pelo modelo de Ostwald de Waelle (Lei da Potencia) e as curvas de viscosidade aparente ajustadas pelo modelo de Mizrahi-Berk. Observou-se um comportamento pseudoplastico para a polpa de manga centriguda (n<1) e uma diminuicao na viscosidade aparente com o aumento da taxa de deformacao e temperatura, sendo que a viscosidade aparente da polpa de manga centrifugada tendeu a ficar constante a partir 200s-1.

Stability studies and shelf life estimation of a soy-based dessert

This work is aimed at evaluating the physicochemical, physical, chromatic, microbiological, and sensorial stability of a non-dairy dessert elaborated with soy, guava juice, and oligofructose for 60 days at refrigerated storage as well as to estimate its shelf life time. The titrable acidity, pH, instrumental color, water activity, ascorbic acid, and physical stability were measured. Panelists (n = 50) from the campus community used a hedonic scale to assess the acceptance, purchase intent, creaminess, flavor, taste, acidity, color, and overall appearance of the dessert during 60 days. The data showed that the parameters differed significantly (p < 0.05) from the initial time, and they could be fitted in mathematical equations with coefficient of determination above 71%, aiming to consider them suitable for prediction purposes. Creaminess and acceptance did not differ statistically in the 60-day period; taste, flavor, and acidity kept a suitable hedonic score during storage. Notwithstanding, the sample showed good physical stability against gravity and presented more than 15% of the Brazilian Daily Recommended Value of copper, iron, and ascorbic acid. The product shelf life estimation found was 79 days considering the overall acceptance, acceptance index and purchase intent.

Vacuum Drying Kinetics of Yacon (Smallanthus sonchifolius) and the Effect of Process Conditions on Fractal Dimension and Rehydration Capacity

This work aimed at studying the drying kinetics of yacon slices during vacuum drying and evaluating the effect of drying temperature, slice thickness, and citric acid concentration in the enzymatic inhibition solution on the fractal dimension and rehydration ratio of yacon slices. The drying kinetics was tentatively fitted to various thin-layer drying models, and the best fit was obtained using the modified Page model. The fit was validated after evaluating the values of coefficient of determination and parameters percentage error. The final products fractal dimension, as calculated by the box counting method, was be between 1.5904 and 1.8358, which confirms that vacuum-dried yacon slices are fractals. Among the studied factors, drying temperature was found to negatively affect the fractal dimension and slice thickness was found to negatively affect the rehydration ratio. A good correlation was established between fractal dimension and moisture content, rehydration ratio, and hue angle, suggesting that the moisture, rehydration, and color measurements during yacon vacuum drying could be substituted or complemented by an image analysis.

Comportamento reológico de sistemas pécticos de polpas de frutas vermelhas

In this work, the rheological behavior of pectic systems formulated with pectins extracted from strawberry, blackberry, and raspberry pulps was investigated by means of oscillatory rheological tests. In addition, the chemical properties of these pectins were studied. The pectic systems from those red fruit pulps showed a strong gel character according to the rheological tests showing that the strawberry pectin presented the strongest gel character, which was confirmed by the Cox-Merz experiment, degree of esterification, and average molecular weight data. The galacturonic acid is directly related to the formation of the pectin network. Besides, the difference between the strength of the three pectic gels can be attributed to the esterification degree values and the average molecular weight of these biopolymers. The pectins extracted from the red fruits studied in this work can be classified as high methoxy pectins with a degree of esterification higher than 50%. The pectic gels exhibit good stability with an increase in temperature and in the shear-oscillatory constant time.

Polyphenols and palynological origin of bee pollen of Apis mellifera L. from Brazil. Characterization of polyphenols of bee pollen

The aim of this work was to study the chemical composition, botanical origin and the antioxidant activity of ethanolic extracts of bee pollen. The antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH•) scavenging method and β-carotene-linoleic assay. The pollen extracts were purified using a XAD2 resin and the amount of phenolic compounds and flavonoids were identified by reverse phase-high performance liquid chromatography (RP-HPLC) and gas chromatography–mass spectrometry (GC–MS) analyses. The phenolic content of bee pollen extracts before and after the resin were 38.6 and 17.8 mg/g of gallic acid equivalent in bee pollen, respectively. Two different flavonoids (rutin and myricetin) which can be accounted by the high antioxidant activity of bee pollen extracts were identified and quantified. The total antioxidant capacity measured by the DPPH• radical method increased significantly in bee pollen extracts purified with hydrophobic resin: 24.84–94.75% (Palmeira). All samples were considered heterofloral, which were composed by pollen from Myrtaceae eucalyptus, Asteraceae and Brassicaceae families, and among others.