ABSTRACT
Abstract The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress.
Subject(s)
Alkalies/toxicity , Polysaccharides, Bacterial/chemistry , Polysaccharides, Bacterial/metabolism , Stress, Physiological , Xanthomonas campestris/metabolism , Xanthomonas campestris/ultrastructure , Cell Membrane/ultrastructure , Cytoplasm/ultrastructure , Organelles/ultrastructure , Xanthomonas campestris/drug effectsABSTRACT
The influence of additives (sucrose, propylene glycol and soybean oil) and process parameters (pH and temperature), on bio-based cassava starch-gelatin films stability during storage have been evaluated factorial experiment design. X-ray diffractograms have indicated that only sucrose influenced film stability resulting in crystallization during storage (60 days), which was also observed by scanning electron and light microscopy images. Light micrographs, besides indicated sucrose crystallization, also allowed observing phase separation. All biofilm samples presented a high lightness and low redness and yellowness, indicating to be almost colorless. Although temperature did not influence film microstructure and color, casting temperature of 60ºC had completely destroyed samples, and it has not been recommended for further investigations.
Subject(s)
Biofilms , Color , Crystallization , Food Additives , Food Storage , Food TechnologyABSTRACT
Este estudo investigou o efeito da alimentação com dejetos suínos na composição centesimal e no perfil de ácidos graxos do músculo de carpas. Amostras de carpas com 4-10 meses de idade, recolhidas em Santa Catarina, foram filetadas, trituradas e acondicionadas em atmosfera de nitrogênio (-18°C). Os valores ( por cento) de umidade, proteína e cinzas foram: 72,24; 14,85; e 2,16, respectivamente, para carpas alimentados com ração; e 83,33; 14,48; e 3,49 para carpas alimentadas com dejetos suínos. Os valores de sódio e potássio foram: 0,491 por cento e 1,20 por cento carpas/ração; e 2,28 por cento e 0,367 por cento carpas/dejetos suínos, respectivamente. Os teores de lipídios totais também apresentaram diferenças significativas: 9,88 por cento carpas/ração e 1,69 por cento carpas/dejetos suínos. O perfil de ácidos graxos mostrou tendências similares nos dois músculos. Portanto, verificou-se um efeito significativo da alteração da dieta sobre a composição do tecido muscular de carpas alimentadas com dejetos suínos, principalmente no conteúdo de minerais e de lipídios totais, embora a variação observada no conteúdo de lipídios totais não tenha se refletido na composição de ácidos graxos.
This study investigated the proximate composition and fatty acid profile of the carp muscle fed with pig manure. Carp with 4-10 months of age were collected in Santa Catarina. Muscle samples were sliced and then triturated in a multiprocessor and stored under gaseous nitrogen atmosphere (-18°C). The moisture, protein, and ash contents ( percent) were as follows: 72.24; 14.85; e 2.16, respectively, for carp feed artificial food; and 83.33; 14.48; e 3.49 for carp feed pig manure. The contents of sodium and potassium were: 0.491 percent and 1.20 percent carp/artificial food; 2.28 percent and 0.367 percent carp/pig manure. The total lipids contents also presented significant differences: 9.88 percent carp/artificial food, and 1.69 percent carp/pig manure. Fatty acid profile showed similar tends in both muscles. Therefore, a significant difference in the total lipids and mineral contents of the carp tissue feed pig manure was detected, though the observed variation in total lipid content wasnÆt reflected in the fatty acid composition.
ABSTRACT
Com este trabalho, avaliou-se a produção de biopolímero sintetizado por Sphingomonas capsulata ATCC 14666, utilizando-se os meios industriais melaço bruto e pré-tratado e resíduo de proteína texturizada de soja (PTS). Foram testadas diferentes concentrações de meios industriais (2,66, 4, 6 e 8 por cento), cujas condições de fermentação utilizadas foram 28° ± 2°C, 208 rpm, 72 h. Os ensaios foram realizados em triplicata e os resultados foram avaliados estatisticamente mediante o teste de Tukey. As melhores produtividades foram obtidas para melaço pré-tratado 8 por cento (0,290 gL-1h-1), seguida de extrato aquoso de resíduo de PTS 6 por cento (0,240 gL-1h-1) e melaço bruto 8 por cento (0,190 gL-1h-1). A qualidade reológica das gomas foi demonstrada através da leitura de viscosidade aparente de soluções aquosas e salinas a 25 e 60°C.
This work studied the biopolymer production by Sphingomonas capsulata ATCC 14666 using industrial raw material and pretreated molasses and aqueous extract of textured soy protein (TSP). Different concentrations of industrial media (2.66, 4, 6 and 8 w/t percent) were evaluated at 28° ± 2°C, 208rpm, 72h, were the fermentation conditions utilized. Triplicate assays were conducted and Tukey's test was used. The highest productivity were obtained for 8 percent of pretreated molasses (0,290 gL-1h-1), 6 percent of aqueous extract of TSP (0,240 gL-1h-1) and 8 percent raw molasses (0,190 gL-1h-1), respectively. The rheological behavior of aqueous and saline (NaCl and CaCl2 3 percent wt/v) solutions of biopolymers were investigated by apparent viscosity analysis at 25 and 60°C.
ABSTRACT
A própolis é uma substância resinosa coletada pelas abelhas de diversas partes da planta. Sua composiçäo depende da época, vegetaçäo e área de coleta. Própolis produzida por abelhas Apis mellifera africanizada do sul do Brasil, Argentina e Uruguai foram investigadas por meio de técnicas cromatográficas. De acordo com os resultados obtidos por CCDAE-FR, CLAE-FR e CG-EM, as própolis do sul do Brasil foram classificadas em 5 grupos distintos. Com base nas evidências fitoquímicas, Populus alba foi identificada como a principal fonte da própolis do grupo 3 do sul do Brasil, Argentina e Uruguai