Abstract In this study, succinoglycan was produced from whey and its rheological and structural characteristics were elucidated. Eight culture media were prepared with different ions for bioconversion of whey into succinoglycan. The formulation composed of deproteinized whey, monobasic potassium phosphate and magnesium sulfate allowed the production of 13.7 ± 0.43 g/L of succinoglycan. The apparent molar mass of succinoglycan was estimated to be 9.033 × 105 g/mol and the polydispersity index was 1.044, representing the homogeneity of the sample. Monosaccharide composition of glucose and galactose for the succinoglycan produced was 6.6:1.0. The 1H RMN analysis revealed the non-saccharide substituent content of 1.2%, 3.0% and 8.1% for acetyl, succinate and pyruvate, respectively. The rheological results showed that the apparent viscosity of the succinoglycan solutions was directly proportional to the concentration, and the solution showed pseudoplastic behavior. Dynamic frequency sweep tests identified that a concentration of 2.0% of succinoglycan is required for formation of the gel system. Temperature influenced the viscoelastic behavior of succinoglycan and revealed the melting point and reversibility of the gel. Whey was shown to be a promising carbon source for the production of succinoglycan with thickening potential and viscosity modifier.

Abstract This study evaluated extracellular production of biopolymer using fungus Mucor racemosus Fresenius and glycerol as a carbon source. Initially employing conical flasks of 500 mL containing 100 mL of cultive medium with 0.18 ± 0.03 g.L–1 of microorganisms, the results showed that the best conditions of the variables studied were: initial concentration of glycerol 50 g.L–1, fermentation time of 96 h, inoculum cultivation time of 120 h, and aeration in two stages–the first 24 hours without aeration and 72 hours fermentation with aeration of 2 vvm and 2 g.L–1 of yeast extract. The experiments conducted in a Biostat B fermenter with a 2.0 L capacity that contained 1.0 L of medium showed production of 16.35 g.L–1 gum formed and 75% glycerol consumption. These conditions produced a biopolymer with the molecular weight and total sugar content of 4.607×106 g.mol–1 (Da) and 89.5%, respectively.

Foram processar quatro formulações de doces em massa de gabiroba e avaliar às suas características físico-químicas, funcionais, perfil reológico e aceitabilidade dos doces. As características físico-químicas e físicas avaliadas foram: atividade de água, acidez titulável, pH, açúcares redutores e não redutores, proteínas, cinzas, fibra alimentar, cor, firmeza. Para avaliação funcional das formulações foram determinados os teores de vitamina C, compostos fenólicos, carotenóides. O potencial antioxidante foi determinado através dos métodos ABTS+ e DPPH•. As análises reológicas foram realizadas em reômetro HAAKE RS 75 Rheoestress com o sensor placa-placa. O comportamento das curvas de fluxo foi ajustado pelos modelos de Lei da Potência e Herschel-Bulkley. A avaliação sensorial foi realizada por 52 provadores não treinados utilizando escala hedônica estruturada de nove pontos. Os doces apresentaram teores de compostos fenólicos totais entre 322,09 e 728,48 mg 100 g-1. A variação do teor de vitamina C foi de 97,39 a 123,39 mg 100 g-1. As amostras também apresentaram uma boa retenção de beta caroteno. Todas as amostras apresentaram módulo de armazenamento (G') superior ao módulo de perda (G"). O estudo de análise sensorial revelou uma aceitação satisfatória para formulações de doce em massa de gabiroba.

Four formulations of gabiroba jam were processed, and their physicochemical and functional characteristics, rheological profile and jam acceptance were assessed. The physicochemical and chemical characteristics evaluated were water activity, titratable acidity, pH, reducing and non-reducing sugars, proteins, ashes, dietary fibers, color, and firmness. For functional analyses of the formulations, vitamin C, phenolic compounds and carotenoid contents were determined. The ABTS+ and DPPH• methods were employed to evaluate the antioxidant potential. Rheological analysis was performed in a HAAKE RS 75 Rheoestress rheometer with a plate/plate sensor. The flow curve behavior was adjusted using the Power Law and Herschel-Bulkley models. Sensory analyses were performed by 52 untrained testers using a 9-point structured hedonic scale. The content of total phenolic compounds in the jam was between 322.09 and 728.48 mg 100 g-1. The variation of vitamin C content was 97.39 to 123.39 mg 100 g-1. The samples also showed good retention of beta carotene. All samples showed a higher storage modulus (G') than loss (G") Thsensory evaluation revealed a satisfactory acceptance of the gabiroba jam formulations.

Este trabalho teve como objetivo desenvolver estudos sobre a tolerância a desidratação das sementes de Blepharocalyx salicifolius e Casearia decandra. Para verificar os efeitos da secagem nas sementes, estas foram colocadas em dessecadores contendo solução salina saturada de acetato de potássio (23,5% UR) na temperatura de 15 ºC. Após a obtenção dos graus de umidade desejados, as sementes foram submetidas aos testes de germinação, de vigor, de tetrazólio e de condutividade elétrica. Diante dos resultados obtidos pode-se concluir que em condições de secagem lenta, as sementes de B. salicifolius e C. decandra foram sensíveis à redução de umidade entre 29% e 25% e perderam a viabilidade em torno de 14% e 8% de umidade, respectivamente. Quanto às alterações fisiológicas ocorridas durante a secagem das sementes, observou-se diminuição da viabilidade e do vigor e aumento nos valores de condutividade elétrica a partir de 25% de umidade.

The present work aimed to develop studies on the tolerance to dehydration of Blepharocalyx salicifolius and Casearia decandra seeds. In order to verify the effect of drying on the seeds, they were placed in desiccators containing a saline solution saturated with potassium acetate (23.5% RH) at temperature of 15 °C. After obtaining the desired moisture contents, the seeds were submitted to the germination, vigor, tetrazolium and electrical conductivity tests. It can be concluded that under slow drying conditions, the seeds of B. salicifolius and C. decandra were sensitive to moisture reduction of 29% to 25%, and lost viability at around 14% and 8% of moisture content, respectively. The physiological changes occurring during seed drying showed there was a decrease in viability and vigor and an increase in electrical conductivity values starting at 25% seed moisture content.

Substâncias pécticas de 11 amostras de bagaço desidratado de maçã foram extraídas usando um procedimento ácido (HNO3 100 Mm, 10 min., 80º C), desidratadas, moídas e armazenadas em atmosfera de P2O5. O grau de esterificação das amostras foi determinado pelo método titulométrico, confirmado pelo instrumental FTIR. As amostras mostraram DE médio de 73% e o fingerprint característico no espectrograma em infravermelho. Os cromatogramas de exclusão estérica, obtidos com o detector para espalhamento multiangular de luz a laser (MALLS) e com o índice de refração (RI), indicaram que todas as amostras apresentam fração de elevada massa molar, eluída a 36-38 min. e outra grande família de polissacarídeos com tempo de eluição de 43 min. Outros oligossacarídeos de baixo peso molecular aparecem aos 58-6o min em algumas das amostras. A cromatografia gasosa dos alditóis derivatizados permitiu estimar as proporções de açúcares neutros das amostras. A razão entre os açúcares ácidos com a ramnose pode ser usada com parcimônia para a determinação do tamanho médio das cadeias de ácido poligalacturônico.

Pectic substances from eleven samples of dried apple pomace were extracted using an acid procedure (100 mM HNO3, 10 min., 80ºC), dried, ground and stored in a P2O5 atmosphere. The degree of esterification was determined by the classical titrimetric method and confirmed by the instrumental FTIR method. The samples showed an average DE of 73% and the typical fingerprint in IR spectrogram. The steric exclusion chromatograms obtained with the multi-angle laser light scattering (MALLS) and refraction index (RI) detectors showed that all samples had a high molar fraction eluted at 36-38 min., another large polysaccharide family had an elution time around 43 min, and some samples showed yet another low molecular oligosaccharide that appeared at 58-60 min. Gas chromatography of alditol acetate allowed estimates of the proportion of the neutral sugar in the samples. The ratio of galacturonic acid and rhamnose may give the average size of the galacturonan fraction. These results showed that yields of pectin extracted by the same acid procedure were slightly different. However, the degree of esterification of pectin was similar, with both factors pointing to the best sources in this group of varieties.

Psidium cattleianum, árvore nativa do sul do Brasil, produz frutos popularmente conhecidos como araçá e que muitas vezes não são colhidos e estragam nos campos. Neste trabalho, os frutos de P. cattleianum foram utilizados como fonte de polissacarídeos ácidos. Frações de pectinas foram obtidas por extrações seqüenciais com água, agente quelante (EDTA) e carbonato de sódio (4 e 25ºC). A composição monossacarídica, os teores de açúcar total, ácidos urônicos e proteínas foram determinados para cada fração. O rendimento das frações solúveis em água e EDTA e o elevado teor de ácidos urônicos são consistentes com a presença de pectinas oriundas provavelmente da lamela média. Por outro lado, as pectinas solúveis em carbonato de sódio têm o maior teor de açúcares neutros, indicando a presença de polissacarídeos altamente ramificados nestas frações, consistentes com pectinas da parede celular.

The aim of this work was to study the acidic polysaccharides of Psidium cattleianum. Pectic fractions were obtained by successive extractions with water, EDTA and sodium carbonate (4 and 25ºC). Monosaccharide composition, total carbohydrates, uronic acids and protein contents were determined for each fraction. The yield of water and EDTA-soluble fractions and high content of uronic acid were consistent with the presence of pectins probably arising from the middle lamellae. On the other hand, sodium carbonate-soluble pectins had a higher neutral sugar content, indicating highly branched polysaccharides in these fractions, consistent with pectins from cell wall.

A partir do fruto de araçá vermelho, elaboraram-se dois tipos de sucos, mediante processamento mecânico, em que se obteve o suco S-1 e após tratamento enzimático de S-1 obteve-se o suco S-2, os quais foram analisados e monitorados durante quatro meses. As amostras de suco foram avaliadas reologicamente e quanto à estabilidade por análises físico-químicas e microbiológicas. A aceitabilidade dos sucos foi avaliada por meio de análise sensorial, utilizando escala hedônica. O suco S-2 apresentou um rendimento de 73%. O tratamento enzimático elevou o rendimento do suco e reduziu a viscosidade, além de preservar a composição química e aumentar a extração de compostos fenólicos, resultando em um produto final com aspectos sensoriais pronunciados.

From the red araçá fruit two types of juice were elaborated: S-1, obtained by mechanical processing and S2 obtained from the enzymatic treatment of S-1. The juices were analyzed and monitored for four months. The samples were evaluated rheologically and also for stability by, physiochemical and microbiologic analyses. The acceptability of the juices was evaluated by sensorial analysis using hedonic scale. The juice S-2 presented a high yield of 73%. The enzymatic treatment raised juice yield and reduced viscosity. In addition it preserved the chemical composition and raised the extraction of phenolic compounds, resulting on a final product of remarkable sensorial aspects.