This work evaluates the immobilization of Candida antarctica lipase (Fraction B) using poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanoparticles as support. The effects of immobilization time (30-150 min) and pH (5-10) on lipase loading were evaluated. The stability of the immobilized enzyme towards temperature (40, 60, and 80 ºC), reuse and storage (at 4 ºC) were also determined. Furthermore, to assess its potential application in a system of interest, the immobilized lipase was used as a catalyst in the esterification of geraniol with oleic acid. The results indicated a time of 120 minutes and pH of 7 as optimal for immobilization. A 21 hour exposure of the PHBV-lipase derivative to 60 ºC showed a 33% reduction of the initial activity while storage at 4 ºC led to a residual activity (5% of the original activity). The derivative was used without significant loss of activity for 4 successive cycles. The use of the immobilized lipase as a catalyst in the production of geranyl oleate led to about 88% conversion of the initial reactants to products.

Neste trabalho foi avaliado o efeito alelopático comparativo do extrato aquoso de folhas de Cryptocarya moschata e Ocotea odorifera sobre a germinabilidade e desenvolvimento inicial de Lactuca sativa (alface). Os extratos foram preparados por maceração a frio, adicionando o material vegetal seco e moído à água destilada 1:10 (m v-1). As concentrações tratamento de 0; 0,25; 0,5; 0,625; 0,75; 0,875 e 1% foram obtidas por meio da solubilização do extrato bruto seco em água destilada. Observou-se potencial alelopático das folhas secas de Ocotea odorifera e Cryptocarya moschata sobre Lactuca sativa pela redução do percentual de germinação, do índice de velocidade de germinação e do comprimento das raízes, bem como pelas anormalidades estruturais encontradas nas plântulas. Observou-se alta correlação entre a concentração de extrato e efeito alelopático com ambos os extratos. O extrato de C. moschata não apresentou efeito sobre o comprimento do caule nas diferentes concentrações avaliadas.

The aim of this work was to compare the allelopathic effects of aqueous leaf extracts from Cryptocarya moschata and Ocotea odorifera on the seed germination and initial growth of Lactuca sativa (lettuce). The extracts were prepared by cold maceration, which was accomplished by adding distilled water to the dried plant material 1:10 (w v-1) and grinding. The treatment concentrations (0, 0.25, 0.5, 0.75 and 1%) were obtained by dissolving the dried crude extract in distilled water. The allelopathic potential of the dried Ocotea odorifera and Cryptocarya moschata leaves on Lactuca sativa was observed through reduction of the percentage of seeds that germinated, the index of germination and the length of the roots as well as structural abnormalities in L. sativa seedlings. For both extracts, the extract concentration and allelopathic effect were highly correlated. However, the C. moschata extract had no effect on caulicle length at the different tested concentrations.

This study investigated the chemical composition of five different extracts of Aloysia triphylla and their activity against Aeromonas sp. The extracts were obtained from the dried leaves by pressurized CO2 extraction at 30, 50 and 70ºC, and 100, 150, and 200 bar, and analyzed by GC/FID and GC-MS. The antibacterial activity was assayed by the microdilution method. The tested microorganisms comprised seven Aeromonas isolates obtained from the kidney of infected silver catfish, Rhamdia quelen. The yield, chemical composition and antibacterial activity of the extracts were dependent on the extraction conditions. Mono and sesquiterpenoids were the major constituents of all the extracts and the highest extraction yield was obtained at 70ºC and 200 bar. A. triphylla presented moderate antibacterial activity against Aeromonas sp.

Omega-3 enriched partial acylglycerols are beneficial for human health. The aim of this study was to obtain monoacylglycerols (MAG) and diacylglycerols (DAG) by means of glycerolysis of fish oil catalyzed by a lipase from Rhizomucor miehei in the presence of food grade surfactants (Tween 65, 80 or 85). Glycerolysis was successful in the reaction media for all the tested surfactants, showing their potential for use as additives in such a system. The best results, however, were obtained for the reaction medium in the absence of surfactant whose peroxide value was the lowest after glycerolysis.

This work is focused on the chemical distribution of volatile and semi-volatile compounds of 18 native populations of Maytenus ilicifolia collected all over Brazil. The extracts of bulk samples (30 plants) of each population were obtained by supercritical CO2 extraction technique, and analyzed by GC/MS. The quantification of compounds (phytol, squalene, vitamin E, limonene, stigmasterol, friedelan-3-ol, friedelin, fridelan-3-one, palmitic acid and geranyl acetate) showed significant variations within the different populations, which could be related tom microclimate characteristics.

O presente trabalho tem por objetivo reportar valores experimentais de condutividade térmica e viscosidade dinâmica dos óleos vegetais refinados de soja, milho, girassol, algodão, canola, oliva e de farelo de arroz. As medidas de condutividade térmica foram realizadas em célula acoplada a um banho termostático no intervalo de temperatura de 20 a 70 °C, utilizando uma sonda de fio quente. Os resultados obtidos demonstram que para todos os óleos vegetais investigados a condutividade térmica possui fraca dependência com a temperatura, apresentando ligeiro decréscimo com o aumento desta variável. O método gravimétrico foi empregado para a medida da densidade dos óleos vegetais estudados à temperatura ambiente, não tendo sido verificada diferença significativa entre os valores encontrados. Para as medidas de viscosidade dos óleos vegetais foi utilizado um viscosímetro do tipo Brookfield, acoplado a um banho termostatizado com controle de temperatura. A partir dos resultados obtidos verificou-se que a viscosidade decresce acentuadamente com o aumento da temperatura para todos os óleos vegetais.

This work reports experimental data of thermal conductivity and dynamic viscosity of the following refined vegetable oils: rice, soybean, corn oil, sunflower, cottonseed, and olive oil. Measurements of thermal properties were carried out in a cell coupled to a thermostatic bath in the temperature range of 20-70 °C, using a single-needle stainless steel sensor. It was experimentally observed that the thermal conductivity decreased slightly with increasing temperature for all samples investigated. The gravimetric method was employed for density data acquisition, and revealed no significant difference among the values obtained. The Brookfield apparatus was employed in measuring the dynamic viscosity and it was verified that a raise in temperature led to a sharp decrease for this property for all samples investigated.

O presente trabalho reporta resultados referentes à testes de atividade antimicrobiana do óleo essencial de orégano (Origanum vulgare) contra várias bactérias em lingüiça. A concentração inibitória mínima (CIM) foi determinada para 9 bactérias aeróbicas heterotróficas. Com base no maior valor encontrado da CIM, testou-se a atividade antimicrobiana para distintas concentrações do óleo essencial in lingüiça fresca. Amostras do sistema alimentar escolhido foram inoculadas com Escherichia coli numa determinada concentração e a evolução temporal do produto concernente ao crescimento microbiano foi monitorada avaliando-se o efeito das diferentes concentrações de óleos essencial aplicadas ao produto inoculado. Os resultados das análises microbiológica e sensorial mostraram que a adição do óleo essencial de orégano a linguiça fresca coloca-se como promissora tendo em vista os efeitos bacteriostáticos observados em baixas concentrações do óleo essencial, inferiores a CIM.

This work reports antimicrobial activity of oregano (Origanum vulgare) essential oil against several bacteria in sausage. The in vitro minimum inhibitory concentration (MIC) was determined for 9 selected aerobic heterotrofic bacteria. The antimicrobial activity of distinct concentrations of the essential oil on the basis of the highest MIC found was tested in a food system comprised of fresh sausage. Batch food samples were also inoculated with Escherichia coli with a fixed concentration and the time course of the product was evaluated with respect to the action of the different concentrations of essential oil. Sensory analysis were conducted, and results showed that the addition of oregano essential oil to sausage may be a promising route as bacteriostatic effect was verified for oil concentrations lower than the MIC.

This work reports extraction yield and chemical characterization of the extracts obtained by high-pressure CO2 extraction of a cultivar of Ocimum basilicum L. The experiments were performed in the temperature range of 20 to 50 °C, from 100 to 250 atm of pressure. Chemical analyses were carried out by gas chromatography coupled to mass spectrometry, permitting to identify 23 compounds that were grouped into five chemical classes. Results showed that temperature and solvent density influenced positively the extraction yield. At 20 °C and 0.41 g cm-3 occurred a rise in the concentration of monoterpenes, oxygenated monoterpenes, sesquiterpenes and oxygenated sesquiterpenes.