Agnes de Paula Scheer

Pectina: da matéria-prima ao produto final

Pectin, probably the most complex macromolecule in nature is a hetero-polysaccharide containing predominantly residues of galacturonic acid (GalA). This polymer, which belongs to a group of dietary fibers, is widely used as a gelling agent and stabilizer in the food industry. The main industrial processing to obtain pectin is based on the solubilization of protopectin from apple pomace and citrus peels, which is done under low acidity and heated conditions. Recent studies have reported the extraction of pectin from new raw materials and using different extraction conditions, which influence the yield and quality of the final product, and may improve the rheological properties. This review describes the structure, sources, applications and industrial extraction processes, as well as the analysis methods of physicochemical characterization of pectin.

Organic fertilization in the production, yield and chemical composition of basil chemotype eugenol

Este trabalho foi realizado na UFPR, municipio de Pinhais-PR, de outubro de 2005 a junho de 2006. Avaliou-se a resposta do Ocimum gratissimum a adubacao orgânica com composto de esterco de carneiro, verificando a viabilidade dessa pratica para o aumento no rendimento de biomassa, na quantidade e qualidade de seu oleo essencial. As mudas foram plantadas com espacamento de 0,5 m entre plantas dentro das parcelas e 1 m entre as parcelas. Testaram-se 3 doses de adubacao com composto orgânico (4; 8 e 12 kg m-2) e uma testemunha, com 5 repeticoes e 8 plantas por parcela. As colheitas foram realizadas aos 150 e 226 dias apos o plantio, sendo avaliado o rendimento de massa fresca e massa seca total e de folhas, flores e caule, o teor de oleo essencial das folhas e flores e a sua composicao por cromatografo a gas acoplado a um detector de massas (CG-MS). Houve diferenca entre os tratamentos, quanto ao rendimento de biomassa na primeira colheita, onde o tratamento com 8 kg m-2 de composto orgânico foi superior a testemunha sem adubacao, para a massa fresca de flores por planta e massa seca total e de flores por planta, mas nao diferiu dos outros niveis de adubacao. Na segunda colheita nao houve diferenca entre os tratamentos. Quanto ao rendimento de oleo essencial nao houve diferenca entre os tratamentos nas duas colheitas. Tambem nao foram observadas grandes variacoes nos componentes do oleo essencial decorrente dos tratamentos aplicados. Entretanto, ocorreram variacoes na composicao do oleo essencial quando extraido das folhas e das flores, sendo o teor medio de eugenol de 90,4% nas folhas e 80,8% nas flores, na colheita em marco. Ja na colheita em junho, houve uma reducao do teor de eugenol nas folhas e uma elevacao dos teores, principalmente de alfa trans trans farneseno, beta bisaboleno, beta cariofileno, germacrene D e alfa selineno.

High Molecular Sericin from Bombyx mori Cocoons: Extraction and Recovering by Ultrafiltration

The present study focus on sericin extraction process from Bombyx mori cocoons using water in absence of chemical additives under different physical conditions aiming to obtain high molecular weight sericin. Separation and fractionation of sericin proteins to obtain high molecular weight material was also carried out using ultrafiltration process at different operating modes: batch, diafiltration and batch with back flushing water pulse. The molecular weight of extracted sericin protein using pure water showed in general a size distribution varying from 20 up to 400 kDa, with major peaks between 200 kDa and 100 kDa and peaks with fraction of sericin lower than 100 kDa, depending on conditions used in the extraction and concentration. The results demonstrated viability to separate sericin fractions having molecular size higher than 50 kDa, using the ultrafiltration process with 50 kDa cut-off membrane, however, a flux decline above 90 % was detected independent of operating mode. Increasing the concentration factor from 2 to 4 promotes the permeation of sericin molecules of high molecular weight, reducing the rejection coefficient of 71.1 % to 60.4 %.

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.

Modelling studies by adsorption for the removal of sunset yellow azo dye present in effluent from a soft drink plant

This paper reports a study on the adsorption of the dye sunset yellow, present in an aqueous synthetic solution and a real effluent from a soft drink plant, onto granular-activated carbon derived from coconut husks, using a batch system. The kinetic equilibrium was investigated using two different dye concentrations (102 and 103 mg L−1) at 25°C and 150 rpm. The adsorption isotherms and thermodynamics parameters were evaluated at 25°C, 35°C, 45°C and 55°C, using the synthetic and real effluents (5–103 mg L−1). Experimental data showed that the adsorbent was effective in the removal of sunset yellow dye and the contact time required to attain the adsorption equilibrium did not exceed 10 h. The adsorption capacity was not influenced within a wide range of pH values (1–12), although at high dye concentrations it increased with increasing temperature for both the synthetic and real effluents. The Redlich–Peterson isotherm best represented the equilibrium data of the system. The negative values obtained for Δ G0 and Δ H0 suggest that this adsorption process is spontaneous, favourable, and exothermic. The positive values for Δ S0 indicate an increase in the entropy at the solid/liquid interface. Based on the results of this study, adsorption appears to be a promising method for the removal of sunset yellow azo dye from effluent generated at soft drink plants.

Granules morphology and rheological behavior of green banana (Musa cavendishii) and corn (Zea mays) starch gels

No presente trabalho foi utilizado amido obtido de banana verde (Musa cavendishii) e amido de milho (Zea mays) comercial, com o objetivo de comparar a morfologia dos grânulos e o comportamento reologico dos geis. As imagens da morfologia dos grânulos foram obtidas por microscopia eletronica de varredura. Os grânulos de amido da banana apresentaram forma oval e elipsoidal com diâmetros irregulares, todavia, os grânulos do amido de milho mostraram forma poliedrica e diferentes tamanhos. As analises reologicas dos geis das solucoes de amido mostraram carater nao-newtoniano, pseudoplastico. O modelo de Herschel-Bulkley foi o que melhor representou comportamento reologico dos geis. O gel de amido de banana verde obteve maiores valores de tensao de cisalhamento e viscosidade aparente quando comparada ao gel de amido de milho. Ocorreu um decrescimo progressivo na tensao de cisalhamento e na viscosidade com a adicao de cloreto de sodio e sacarose aos geis.

Equilibrium, kinetic, and thermodynamic studies on the biosorption of Bordeaux S dye by sericin powder derived from cocoons of the silkworm Bombyx mori

AbstractThe biosorption of Bordeaux S dye onto sericin powder derived from silkworm cocoons was studied in a batch adsorption system to determine the kinetic mechanism, the equilibrium, and thermodynamic parameters. The Langmuir, Freundlich, and Temkin isotherm models were used for the equilibrium modeling. In order to describe the kinetics, the fits of pseudo-first-order, pseudo-second-order, Weber–Morris, Crank, and external liquid film diffusion models were evaluated. The adsorption occurs favorably at pH below 3.2. The kinetic and equilibrium studies showed fast adsorption and interaction were limited to the monolayer surface, with pseudo-second-order and Langmuir models providing the best fits. Thermodynamic studies indicated that the system is spontaneous and exothermic and that physical interactions govern the adsorption process. The results revealed that sericin powder has the potential to be used as a biosorbent for the treatment of wastewater containing the dye Bordeaux S.

Study of the Rheological Parameters of Honey Using the Mitschka Method

In this work the rheological behavior of two varieties of honey were evaluated using a Brookfield viscometer R.V.T in a temperature range of 5-20°C. In order to interpret the experimental results in terms of viscosity, the torque-speed data and scale readings were converted into shear stress-shear rate relations using numerical conversion values proposed by Mitschka. This method offers excellent potential for quality control testing in the food industry. Samples exhibited Newtonian behavior and the temperature effect on the viscosity followed an Arrhenius-type relationship.

Rheological properties of emulsions stabilized by green banana (Musa cavendishii) pulp fitted by power law model.

No presente trabalho, foi estudado o comportamento reologico de emulsoes adicionadas de polpa de banana verde utilizando a metodologia de superficie de resposta e tambem foram investigadas a estabilidade das emulsoes. Foram desenvolvidas cinco formulacoes, de acordo com o delineamento para superficies limitadas e misturas, com as proporcoes respectivamente: agua/oleo de soja/polpa de banana verde: F1 (0,10/0,20/0,70), F2 (0,20/0,20/0,60), F3 (0,10/0,25/0,65), F4 (0,20/0,25/0,55) e F5 (0,15/0,225/0,625). As propriedades reologicas foram realizadas em reometro Haake Rheostress 600, com sensor de geometria cone e placa (60-mm diâmetro, 2o ângulo de cone), usando uma distância de abertura de 1mm. As emulsoes mostraram comportamento pseudoplastico e foram descritas adequadamente pelo modelo Lei da Potencia. O comportamento reologico foi influenciado pelas diferentes proporcoes de polpa de banana verde e tambem pelas temperaturas (10 e 25oC). As formulacoes com alto teor de polpa (F1 e F3) apresentaram maior tensao de cisalhamento e viscosidade aparente. Relativo a metodologia de superficie de resposta, descrita pelo modelo quadratico, pode-se observar que o coeficiente de consistencia aumentou com a interacao entre a polpa de banana verde e a concentracao de oleo de soja e a agua contribuiu com o aumento do indice de comportamento para todas as amostras de emulsoes. A Analise de Variância mostrou que o modelo de segundo ordem nao apresentou falta-de-ajuste com valor F significativo, indicando que o modelo quadratico representou bem os dados experimentais. As emulsoes que apresentaram melhor estabilidade foram as formulacoes F4 (0,20/0,25/0,55) e F5 (0,15/0,225/0,625).

Chemical composition and biological activity of Eupatorium intermedium essential oil

Abstract This article reports a study on the extraction and evaluation of essential oil obtained from dried flowers of Eupatorium intermedium, a plant native to southern Brazil that belongs to the Asteraceae family. The hydrodistillation achieved a maximum yield of 1.01 wt% of essential oil. Regarding the chemical composition, by a qualitative analysis, the identified substances were α-pinene, sabinene, β-pinene, limonene, caryophyllene (E), germacrene D, spathulenol and caryophyllene oxide. The antioxidant activity of the essential oil obtained was evaluated using the DPPH method, phosphomolybdenum reducing method and total phenolic content. The total phenolic content was 4.26 mg GAE/g of oil. The antioxidant activity obtained by the DPPH method was 0.82 wt%, at a concentration of 250 mg/mL. The antioxidant activity obtained through the reduction of the phosphomolybdenum complex was 1154.69 mg α-tocopherol/g of oil. Antibacterial activity assays were performed using the agar well method. The oil presented antibacterial effects against the Gram-positive bacteria tested.