Izabela Dutra Alvim

Microparticles obtained by complex coacervation: influence of the type of reticulation and the drying process on the release of the core material

Microparticles obtained by complex coacervation were crosslinked with glutaraldehyde or with transglutaminase and dried using freeze drying or spray drying. Moist samples presented Encapsulation Efficiency (%EE) higher than 96%. The mean diameters ranged from 43.7 ± 3.4 to 96.4 ± 10.3 µm for moist samples, from 38.1 ± 5.36 to 65.2 ± 16.1 µm for dried samples, and from 62.5 ± 7.5 to 106.9 ± 26.1 µm for rehydrated microparticles. The integrity of the particles without crosslinking was maintained when freeze drying was used. After spray drying, only crosslinked samples were able to maintain the wall integrity. Microparticles had a round shape and in the case of dried samples rugged walls apparently without cracks were observed. Core distribution inside the particles was multinuclear and homogeneous and core release was evaluated using anhydrous ethanol. Moist particles crosslinked with glutaraldehyde at the concentration of 1.0 mM.g –1 protein (ptn), were more efficient with respect to the core retention compared to 0.1 mM.g –1 ptn or those crosslinked with transglutaminase (10 U.g –1 ptn). The drying processes had a strong influence on the core release profile reducing the amount released to all dry samples.

Composição centesimal e valor protéico de levedura residual da fermentação etanólica e de seus derivados

Este trabalho teve por objetivo promover a autolise e o fracionamento da levedura (Saccharomyces sp.) para producao de autolisado e extrato, bem como para producao de concentrado proteico fosforilado, a partir da levedura residual das destilarias de alcool etilico. Foram estudados a composicao centesimal, o perfil de aminoacidos essenciais e o valor proteico dos tres derivados comparativamente a levedura integra nao processada. Proteina e carboidrato (fibra alimentar) foram os principais componentes da levedura integra e do autolisado. No extrato e no concentrado proteico predominaram proteina e minerais (cinzas). O autolisado e a levedura integra apresentaram os melhores indices de aminoacidos essenciais, seguidos pelo concentrado proteico e pelo extrato. A digestibilidade da proteina variou de 68% para a levedura integra a 91% para o extrato. Os indices de quociente de utilizacao liquida da proteina variaram de 2,1 para a levedura integra a 4,3 para a caseina (referencia). Nao houve diferenca estatistica no quociente de utilizacao liquida da proteina entre o autolisado (4,1), o extrato (3,9) e o concentrado proteico (4,2). O concentrado proteico promoveu o maior crescimento no periodo (21 dias), seguido do extrato e o autolisado. As celulas integras apresentaram a menor capacidade para promover crescimento em rato.

Produção de gelatina de pele de tilápia e sua utilização para obtenção de micropartículas contendo óleo de salmão

Summary The objective of this work was to extract and characterize gelatin from tilapia skin (Oreochromis niloticus) and use it as a substitute for mammalian gelatins in the production of micro-particles by complex coacervation. The gelatin and gum Arabic were used as the wall material and salmon oil as the core material. Tilapia skin gelatin was obtained by acid extraction and compared with pig gelatin, evaluating the gel strength (Bloom), hardness according to the texture profile analysis (TPA), melting point, molecular weight distribution, proximate composition, morphology, mean particle diameter and encapsulation efficiency. The pig gelatin showed the highest values for hardness (886.4 g) and melting point (27.5 °C) as compared to the fish gelatin with 794.4 g and 24.0 °C, respectively, but without significant difference (p > 0.05). The mean diameters of the microparticles were 99.0 µm and 103.8 µm with encapsulation efficiencies of 72.4 ± 10.6% and 69.9 ± 3.9% for the pig gelatin and fish gelatin, respectively. The use of salmon oil and fish gelatin did not change the morphology of the micro-particles, which maintained their spherical format and wall integrity even after drying and rehydration.

Efeito do enriquecimento de biscoitos tipo água e sal, com extrato de levedura (Saccharomyces sp.)

The objective of this investigation was to establish the composition of the yeast (Saccharomyces sp.) obtained as a byproduct of the alcoholic fermentation industry, in the form of an autolysate (AT) and their derivatives, extract (Ex) and insoluble fraction (FI). The total autolysate (AT) and the extract (Ex), after dehydration in spray dryer, were utilized as flavour enhancers in salted biscuits. Addition to the biscuits of 5% Ex improved the essential amino acid score (EAE) from 38 to 60%, and the net protein utilization index (NPR) from 1.0 to 2.0 (100%). There was also a significant improvement in the acceptability and preference of the enriched biscuits by the consumers.

Desenvolvimento de farinhas mistas extrusadas à base de farinha de milho, derivados de levedura e caseína

O presente trabalho teve como principal objetivo o desenvolvimento de farinhas mistas extrusadas a base de farinha de milho, derivados de levedura (autolisado ou extrato) e caseina como ingredientes. Utilizou-se a extrusao como processo, sem a pretensao de otimiza-lo, mas buscando as condicoes que permitissem uma boa operacionalidade do extrusor e produtos extrusados com boas propriedades funcionais, boa aceitacao e elevado valor nutritivo. As condicoes adotadas para o processo foram: alimentacao do extrusor, 85g/min; velocidade do parafuso, 150rpm; relacao de compressao do parafuso, 1:3; umidade inicial da amostra, 25%; e temperatura de extrusao 170oC. A melhoria das caracteristicas nutritivas foi assegurada pela elevacao dos teores de proteina e de fibra e diminuicao do teor de carboidrato, em relacao a farinha sem adicao. A extrusao promoveu um adequado grau de expansao radial (GER), aumentou os indices de absorcao e de solubilidade em agua e diminuiu sensivelmente a viscosidade, em relacao a farinha de milho crua.

Enriquecimento de macarrão tipo tubo (massa curta) com derivados de levedura (Saccharomyces sp.): impacto nutricional e sensorial

The objective of this work was to investigate the technical possibility and best levels of addition to noodles of yeast autolysate (AT) and extract (Ex) aiming at improving nutritive value without a decrease in consumer acceptance. Addition of 5 or 7.5% yeast derivative improved essential aminoacid score (EAS) of 9 and 19%, respectively, for the AT and the Ex. The growth promoting index (NPR) increased 25 and 40% for the 7.5% addition of AT or Ex, respectively. In the white noodles, 5% addition of extract did not alter the acceptance of the product, however 5% addition of autolysate produced a negative impact on the consumer acceptance. Addition to the mass of spinach extract (green noodle) and 7.5% of yeast derivative affected only the appearance of the noodle added of yeast Ex and also the appearance and color of the noodle added of AT, compared with the noodle added of spinach extract only. Addition to the mass of spinach extract improved the sensorial properties of the noodle added of 7.5% AT. The manufacturing technological characteristics of the noodles were not altered by the addition to the mass of yeast derivatives.

Composição lipídica, características físicas e sensoriais de recheios de morango em biscoitos

Recheios de biscoito de cinco marcas comerciais brasileiras foram avaliados quanto a teor de lipidios, composicao em acidos graxos, atividade de agua, diâmetro medio e distribuicao do tamanho de particula, aspecto morfologico, textura (firmeza e adesividade), alem de avaliacao sensorial, por teste de aceitacao, quanto aos atributos: sabor global, sabor de morango, cor, arenosidade, cerosidade e firmeza. Os cinco recheios comerciais avaliados apresentam valores de atividade de agua de 0,47 a 0,50. Apenas um diferiu quanto ao tamanho de particula, apresentando o maior diâmetro medio e a menor aceitacao da arenosidade. Quanto a firmeza, houve maior variacao entre as marcas comerciais (37,41 a 124,04 gf), assim como na composicao em acidos graxos, indicando diferentes fontes lipidicas nas gorduras destinadas aos recheios. O teor medio de lipidios encontrado, 27,5%, esta proximo ao da literatura, de 30%; porem, de acordo com a composicao em acidos graxos, o valor medio de acidos graxos trans encontrado indica que a industria pode estar realmente reduzindo os teores desses acidos graxos, nao obstante os valores de acidos graxos saturados ainda mostrarem-se altos.