Produção de isomaltulose, um substituto da sacarose, utilizando glicosiltransferase microbiana

Isomaltulose, a functional isomer of sucrose, is a non-cariogenic reducing disaccharide; has a low glycemic index; selectively promotes growth of beneficial bifidobacteria in the human intestinal microflora; and has greater stability than sucrose in some foods and beverages. Isomaltulose is a nutritional sugar that is digested more slowly than sucrose, and has health advantages for diabetics and nondiabetics. Immobilization techniques, especially entrapment of the cells, are widely used for conversion of sucrose into isomaltulose. Immobilization offers advantages such as minimum downstream processing, continuous operation and reusability of cells. Isomaltulose is currently considered to be a promising sugar substitute.

Classificação de refrigerantes através de análise de imagens e análise de componentes principais (PCA)

This paper describes an approach for the colour-based classification of RGB (red-green-blue) images, acquired using a common scanner, of commercial carbonated soft drinks. Mean histograms of image colour channels were evaluated for the PCA classification of 29 brands of Guaraná, Cola, and orange flavors. Loadings for principal component axes resulted in different patterns for sample grouping on score plots according to RGB histograms. pH, sorbic acid and sucrose measurements were also correlated to the analyzed brands through PCA score plots of the digitalized images.

Atividade antiinflamatória de carboidrato produzido por fermentação aquosa de grãos de quefir

Kefir, a symbiont microorganism suspension, presents benefic effects to health. Some kefir grains were cultivated in brown sugar, allowing to isolate a substance named CSQ. This was evaluated on a biologic essay of mouse foot edema, presenting an inhibitory activity of 30+4 % against carrageenan after the stimulus. It was observed that a cultivation mean containing sucrose, and not the milky mean, lead to the production of different sugar polymeric chains of kefir. The results in vivo suggest that the CSQ exerted an anti-inflammatory activity.

Alginato bacteriano: aspectos tecnológicos, características e produção

Alginate is a biopolymer used for a variety of industrial applications, for example, in the textiles, cosmetics, foods, agricultural and biotechnological industries. This biopolymer is traditionally extracted from some brown seaweeds (Phaeophyceae) and can be produced by bacteria isolated from soil, as Azotobacter vinelandii, like capsular polysaccharide using glucose, sucrose, among others as carbon sources. The main difference between the alginate of seaweed and the bacterial ones, is the biggest degree of acetylation of this last one, with great influence in the gel force. These chemical characteristics and production of bacterial alginate are presented in this work.

Potencialidades e oportunidades na química da sacarose e outros açúcares

Non-renewable biomass, such as coal, oil and natural gas are not only energy sources but also important starting materials for the production of a variety of chemicals ranging from gasoline, diesel oil and fine chemicals. In this regard, carbohydrates, the most abundant class of enantiopure organic compounds, are very suitable for generation of chemicals of great practical value. Their bulk-scale availability associated with low cost make them unique starting materials for organic preparative purpose. They are a most attractive alternative for construction of enantiopure target molecules by asymmetric synthesis. This review addresses, in addition to the use of low molecular weight carbohydrates, issues related to renewable biomass from photosynthesis and alternatives for the production of bulk and fine chemicals.

Modelagem e simulação da desidratação osmótica em pedaços de abacaxi utilizando o método de elementos finitos

Water loss and sugar gain were modelling during the osmotic dehydration process of pieces of pineaplle. The transfer of solute to the fruit and the water to the solution was based on Fick's 2nd law. The three dimensional model was solved by the finite element method with the usage of the software COMSOL Multiphysics 3.2. The main and cross diffusion coefficients and the Biot number were determined on the simulation and the deviation between the experimental and the simulated data were 4,28% to sucrose and 1,66 to the water.

Interferência do acido ascórbico na determinação de açúcares redutores pelo método de Lane e Eynon

Two studies, both set up as completely randomized design, in a 5x5 and 7x5 factorial schemes, evaluated the interference of 5 and 7 ascorbic acid concentrations and 5 glucose or 5 sucrose concentrations, respectively, on the determination of total and reducing sugars by Lane and Eynon method. The ascorbic acid reducing power (AARP) over the Fehling liquor interfered in the results of total and reducing sugars. On average the AARP was equivalent to 74.83 and 69.71% of the reducing power of glucose and of hydrolyzed sucrose, respectively. The ascorbic acid was stable in all study conditions.

Estudo da produção de biossurfactante em caldo de fermentação

A bacterium isolated from soil contaminated by hydrocarbon was studied and, by biochemical tests and analysis of PCR, the presence of Bacillus pumilus was identified. The production of biosurfactant was optimized, test of oil degradation and antimicrobial activity determination. The results showed that pH 5.0 and 7.0, 72 h of fermentation, sucrose and sugar cane juice (2%) had best yields. The bacterium is able to degrade crude oil and displays bacteriostatic and fungistatic activity. From the analysis of proximate composition of biosurfactant found the presence of biopolymer formed by a lipopolysaccharide-protein complex.

Qualidade dos méis produzidos por Melipona fasciculata Smith da região do cerrado maranhense

The honey of Melipona fasciculata is few known in terms of composition, and therefore generally associated with the characteristics of the honey of Apis mellifera. This study contributes to the knowledge of the physico-chemical characteristics of honey of M. fasciculata of the municipalities of Barra do Corda, Jenipapo dos Vieiras, Fernando Falcão, Carolina and Riachão, in cerrado region from Maranhão. The parameters studied were: moisture, pH, acidity, reducing sugars, apparent sucrose, hydroxymethylfurfural, diastase activity, insoluble solids, ash and color. Some of the observed patterns may conform to the established for A. mellifera, but others must be accompanied by a specific legislation.

Caracterização por ressonância magnética nuclear de sucos de maçã obtidos por preparações enzimáticas

In this work, ¹H Nuclear Magnetic Resonance (¹H NMR) was employed to evaluate changes in apple juice in response to the addition of Panzym® Yieldmash and Ultrazym® AFP-L enzymatic complexes and compare it with premium apple juice. The juice was processed at different temperatures and concentrations of enzymatic complexes. The differences in the results were attributed mainly to the enzyme concentrations, since temperature did not cause any variation. A quantitative analysis indicated that the concentration of fructose increased while the concentrations of sucrose and glucose decreased in response to increasing concentrations of the enzymatic complexes.

UDP-N-acetilglicosamina enolpiruvil transferase: determinação dos estados de protonação de resíduos de aminoácidos do sítio ativo pelo método PM6

UDP-N-acetylglucosamine-enolpyruvyl transferase (MurA) catalyzes the reaction between phosphoenol pyruvate and UDP-N-acetylglucosamine. We present a theoretical approach using the semiempirical PM6 method for defining protonation state of three active site residues, K22, H125, and K160. Prior comparison with neutron diffraction data showed that PM6 accurately predicted protonation states of active site residues of b-trypsin and D-xylose isomerase. Using the same methodology with MurA crystallographic data, we conclude that when reaction intermediate is located at the active site, H125 and K22 are in protonated form and K160 in neutral form.

Miniprojeto para ensino de química geral experimental baseado na fermentação do caldo de cana-de-açúcar

This paper describes a five-week mini-project for a general chemistry laboratory course. Activities are included preparations of ethanol and sucrose solutions, calculation of concentrations, determination of densities with densimeters, sugarcane juice fermentation with CO2 capture in alkaline solution, distillation, and determination of amounts of ethanol and CO2 formed. Abilities and concepts normally present in practical general chemistry courses are covered: use of balances, volumetric glassware and densimeters, preparation of solutions, performing of dilutions, determination of solution densities, observation of chemical reactions, stoichiometric calculations, separation of mixtures, and titration.

Química Sem Fronteiras: o desafio da energia

Coal, natural gas and petroleum-based liquid fuels are still the most widely used energy sources in modern society. The current scenario contrasts with the foreseen shortage of petroleum that was spread out in the beginning of the XXI century, when the concept of "energy security" emerged as an urgent agenda to ensure a good balance between energy supply and demand. Much beyond protecting refineries and oil ducts from terrorist attacks, these issues soon developed to a portfolio of measures related to process sustainability, involving at least three fundamental dimensions: (a) the need for technological breakthroughs to improve energy production worldwide; (b) the improvement of energy efficiency in all sectors of modern society; and (c) the increase of the social perception that education is a key-word towards a better use of our energy resources. Together with these technological, economic or social issues, "energy security" is also strongly influenced by environmental issues involving greenhouse gas emissions, loss of biodiversity in environmentally sensitive areas, pollution and poor solid waste management. For these and other reasons, the implementation of more sustainable practices in our currently available industrial facilities and the search for alternative energy sources that could partly replace the fossil fuels became a major priority throughout the world. Regarding fossil fuels, the main technological bottlenecks are related to the exploitation of less accessible petroleum resources such as those in the pre-salt layer, ranging from the proper characterization of these deep-water oil reservoirs, the development of lighter and more efficient equipment for both exploration and exploitation, the optimization of the drilling techniques, the achievement of further improvements in production yields and the establishment of specialized training programs for the technical staff. The production of natural gas from shale is also emerging in several countries but its production in large scale has several problems ranging from the unavoidable environmental impact of shale mining as well as to the bad consequences of its large scale exploitation in the past. The large scale use of coal has similar environmental problems, which are aggravated by difficulties in its proper characterization. Also, the mitigation of harmful gases and particulate matter that are released as a result of combustion is still depending on the development of new gas cleaning technologies including more efficient catalysts to improve its emission profile. On the other hand, biofuels are still struggling to fulfill their role in reducing our high dependence on fossil fuels. Fatty acid alkyl esters (biodiesel) from vegetable oils and ethanol from cane sucrose and corn starch are mature technologies whose market share is partially limited by the availability of their raw materials. For this reason, there has been a great effort to develop "second-generation" technologies to produce methanol, ethanol, butanol, biodiesel, biogas (methane), bio-oils, syngas and synthetic fuels from lower grade renewable feedstocks such as lignocellulosic materials whose consumption would not interfere with the rather sensitive issues of food security. Advanced fermentation processes are envisaged as "third generation" technologies and these are primarily linked to the use of algae feedstocks as well as other organisms that could produce biofuels or simply provide microbial biomass for the processes listed above. Due to the complexity and cost of their production chain, "third generation" technologies usually aim at high value added biofuels such as biojet fuel, biohydrogen and hydrocarbons with a fuel performance similar to diesel or gasoline, situations in which the use of genetically modified organisms is usually required. In general, the main challenges in this field could be summarized as follows: (a) the need for prospecting alternative sources of biomass that are not linked to the food chain; (b) the intensive use of green chemistry principles in our current industrial activities; (c) the development of mature technologies for the production of second and third generation biofuels; (d) the development of safe bioprocesses that are based on environmentally benign microorganisms; (e) the scale-up of potential technologies to a suitable demonstration scale; and (f) the full understanding of the technological and environmental implications of the food vs. fuel debate. On the basis of these, the main objective of this article is to stimulate the discussion and help the decision making regarding "energy security" issues and their challenges for modern society, in such a way to encourage the participation of the Brazilian Chemistry community in the design of a road map for a safer, sustainable and prosper future for our nation.

"Serpentes de Faraó": a história de uma brincadeira pirotécnica e sua aplicabilidade no ensino de princípios químicos básicos

Fun methodologies developed with alternative materials for teaching chemical reactions of carbon are interesting activities for discussing concepts of stoichiometry and thermochemistry. The decomposition of organic matter, CO2 production and coal formation can be demonstrated in the experiment "Pharaoh´s snake". This experiment is attractive since the simple combustion of sucrose generates a peculiar structure of coal. This paper proposes a simple methodology for making the sugar tablets used in the experiment and contextualizes the experimental observations with the chemical reaction of carbon which leads to coal and to the thermodynamics involving combustion processes.

CHEMICAL COMPOSITION AND ANTI-INFLAMMATORY ACTIVITY OF Roldana platanifolia

The chemical study of Roldana platanifolia led to the isolation of β-caryophyllene, five eremophilanolides, chlorogenic acid, and a mixture of β-sitosterol-stigmasterol, β-sitosteryl glucopyranoside, and sucrose. The anti-inflammatory activities of the extracts and isolated products were tested using the 12-O-tetradecanoylphorbol-13-acetate (TPA) model of induced acute inflammation. The acetone and methanol extracts showed dose dependent activities (ID50 0.21 and 0.32 mg/ear, respectively), while none of the isolated compounds exhibited relevant edema inhibition. The active extracts were also evaluated with the myeloperoxidase assay technique (MPO) to determine their ability to prevent neutrophil infiltration. Results showed that the anti-inflammatory activity was related to the compound’s ability to inhibit pro-inflammatory mediators such as neutrophils.