Ethyl carbamate kinetics in double distillation of sugar cane spirit

The aim of this study was to verify the effect of a double distillation on the reduction of the ethyl carbamate content in sugar cane spirit. Ethyl carbamate is a potentially carcinogenic compound normally present at critical levels in sugar cane spirit, constituting a public health problem and therefore hindering the export of this beverage. The ethanol, copper and ethyl carbamate contents were evaluated, using gas chromatography/mass spectroscopy, during a double distillation of the fermented sugar cane juice. The distillate fraction from the first distillation accumulated 30% of the ethyl carbamate formed. In the second distillation, the ethyl carbamate and the copper content increased during the process as the alcohol content decreased, and only 3% of the ethyl carbamate formed was collected in the spirit. Double distillation decreased the ethyl carbamate content in the sugar cane spirit by 97%. (C) Copyright 2012 The Institute of Brewing & Distilling

Direct Determination of Sugar Cane Quality Parameters by X-ray Spectrometry and Multivariate Analysis

Current methods for quality control of sugar cane are performed in extracted juice using several methodologies, often requiring appreciable time and chemicals (eventually toxic), making the methods not green and expensive. The present study proposes the use of X-ray spectrometry together with chemometric methods as an innovative and alternative technique for determining sugar cane quality parameters, specifically sucrose concentration, POL, and fiber content. Measurements in stem, leaf, and juice were performed, and those applied directly in stem provided the best results. Prediction models for sugar cane stem determinations with a single 60 s irradiation using portable X-ray fluorescence equipment allows estimating the % sucrose, % fiber, and POL simultaneously. Average relative deviations in the prediction step of around 8% are acceptable if considering that field measurements were done. These results may indicate the best period to cut a particular crop as well as for evaluating the quality of sugar cane for the sugar and alcohol industries.

Increased Antioxidant Content in Juice Enriched with Dried Extract of Pomegranate (Punica granatum) Peel

Antioxidants are compounds responsible for free radical scavenging in the body. They protect the organism from oxidative modification of cells and tissues. These modifications have been associated with degenerative diseases, atherosclerosis and carcinogenesis. Punica granatum displays high antioxidant potential due to the presence of phenolic compounds, which are capable of disease prevention. The present study showed the highest antioxidant activity in pomegranate peel than in seeds and pulp. Based on these results, pomegranate peel was used to produce dried extract that was added to commercial tomato juice and orange juice with strawberries. Analysis to determine the content of phenolic compounds and antioxidant activity was performed on pomegranate pulp, seeds and peel and in juices enriched with dried extract of pomegranate peel. The dried extract was responsible for a significant increase in antioxidant activity of the juices, proportional to the concentrations added. However, although both flavors of enriched juices displayed high antioxidant levels, the samples with higher dried extract concentrations received the lowest scores from sensory analysis participants due to the characteristic astringent flavor of pomegranate peels. Therefore, to obtain greater acceptance in the consumer market, we concluded that the maximum addition of dried pomegranate peel extract is 0.5% in tomato juice and orange juice with strawberries.

An Alternative Method for the Simultaneous Determination of Copper and Lead for Quality Control of Sugar Cane Spirit using a Nanotube-Based Sensor

The development of an electroanalytical method for simultaneous determination of copper and lead ions in sugar cane spirit (cachaca) using carbon paste electrode modified with ascorbic acid and carbon nanotubes (CPE-AaCNT) is described. Squarewave voltammetry (SWV) with anodic stripping was employed, and this technique was optimized with respect to the following parameters: frequency (50 Hz), amplitude (100 mV) and scan increment (9 mV). The analytical curves were linear in the range from 0.0900 to 7.00 mg L-1 for lead and copper. The limits of detection were 48.5 and 23.9 mu g L-1 for lead and copper, respectively. The developed method was applied to the simultaneous determination of copper and lead in five commercial samples of sugar cane spirit. The results were in good agreement with those obtained by F AAS/GF AAS (flame atomic absorption spectrometry/graphite furnace atomic absorption spectrometry) and showed that CPE-AaCNT can be successfully employed in the simultaneous determination of these metals in real sugar cane spirit samples.

Response of Saccharomyces cerevisiae to Cadmium and Nickel Stress: The Use of the Sugar Cane Vinasse as a Potential Mitigator

Most of the metals released from industrial activity, among them are cadmium (Cd) and nickel (Ni), inhibit the productivity of cultures and affect microbial metabolism. In this context, the aim of this work was to investigate the capacity of sugar cane vinasse to mitigate the adverse effects of Cd and Ni on cell growth, viability, budding rate and trehalose content of Saccharomyces cerevisiae, likely because of adsorption and chelating action. For this purpose, the yeast was grown batch-wise in YED medium supplemented with selected amounts of vinasse and Cd or Ni. The negative effects of Cd and Ni on S. cerevisiae growth and the mitigating one of sugar cane vinasse were quantified by an exponential model. Without vinasse, the addition of increasing levels of Cd and Ni reduced the specific growth rate, whereas in its presence no reduction was observed. Consistently with the well-proved toxicity of both metals, cell viability and budding rate progressively decreased with increasing their concentration, but in the presence of vinasse the situation was remarkably improved. The trehalose content of S. cerevisiae cells followed the same qualitative behavior as cell viability, even though the negative effect of both metals on this parameter was stronger. These results demonstrate the ability of sugar cane vinasse to mitigate the toxic effects of Cd and Ni.

Dilute Acid Hydrolysis of Sugar Cane Bagasse at High Temperatures: A Kinetic Study of Cellulose Saccharification and Glucose Decomposition. Part I: Sulfuric Acid as the Catalyst

The kinetics of sugar cane bagasse cellulose saccharification and the decomposition of glucose under extremely low acid (ELA) conditions, (0.07%), 0.14%, and 0.28% H2SO4, and at high temperatures were investigated using batch reactors. The first-order rate constants were obtained by weight loss, remaining glucose, and fitting glucose concentration profiles determined with HPLC using the Saeman model. The maximum glucose yields reached 67.6% (200 degrees C, 0.07% H2SO4, 30 min), 69.8% (210 degrees C, 0.14% H2SO4, 10 min), and 67.3% (210 degrees C, 0.28% H2SO4, 6 min). ELA conditions produced remarkable glucose yields when applied to bagasse cellulose. The first-order rate constants were used to calculate activation energies and extrathermodynamic parameters to elucidate the reaction mechanism under ELA conditions. The effect of acid concentration on cellulose hydrolysis and glucose decomposition was also investigated. The observed activation energies and reaction orders with respect to hydronium ion for cellulose hydrolysis and glucose decomposition were 184.9 and 124.5 kJ/mol and 1.27 and 0.75, respectively.

CHEMICAL COMPOSITION OF SUGAR CANE SPIRITS FERMENTED BY DIFFERENT Saccharomyces cerevisiae YEAST STRAINS

CHEMICAL COMPOSITION OF SUGAR CANE SPIRITS FERMENTED BY DIFFERENT Saccharomyces cerevisiae YEAST STRAINS. The aim of this study was to evaluate the chemical composition of sugar cane spirits, fermented by different commercial Saccharomyces cerevisiae yeast strains and double distilled by pot still. Sugar cane juices were separately fermented by yeasts CA-11, Y-904, BG-1, PE-2, SA-1 and CAT-1 and distilled by pot still according to the methodology used for whisky production. The alcoholic liquids from first and second distillations were analyzed for concentrations of ethanol, volatile acidity, aldehydes, esters, furfural, higher alcohols and methanol. The sugar cane spirits derived from fermentation by the different yeast strains presented distinct chemical compositions.

Endophytic and rhizospheric enterobacteria isolated from sugar cane have different potentials for producing plant growth-promoting substances

Background and aims Endophytic and rhizospheric environments differ in many respects, leading to the presence of different bacterial communities at each site. However, microorganisms such as enterobacteria can be found both within plants and in the surrounding soil. Bacteria must present differences in the traits that affect such environments in order to successfully colonise them. The present study compared the plant growth-promoting potential of diazotrophic enterobacteria isolated from the rhizosphere and from within surface-disinfected plants. Methods A total of 46 diazotrophic enterobacterial strains (21 rhizospheric and 25 putatively endophytic) belonging to the Klebsiella and Enterobacter genera, which are prevalent in sugar cane plantations, were isolated from the rhizosphere and from surface-disinfected plants. Their ability to synthesise amino acids using combined nitrogen obtained from nitrogen fixation, and their ability to synthesise indole-3-acetic acid (IAA) were determined by high performance liquid chromatography. Endogenous ethylene production by the bacteria was measured using gas chromatography, and biocontrol of phytopathogenic fungi was determined qualitatively using a dual culture technique. Results The putative endophytes released significantly higher amounts of amino acids than the rhizospheric bacteria, whilst the latter produced higher quantities of ethylene and were more actively antagonistic to fungi. Both types of bacteria released similar amounts of IAA. Conclusion Endophytic and rhizospheric bacteria differ in their capacity to release plant growth-promoting substances, which may be a reflection of their adaptations and an indication of their potential impact on their natural environment.

Conductive polymer gas sensor for quantitative detection of methanol in Brazilian sugar-cane spirit

A low-cost chemiresistive gas sensor is described, made by the deposition of a thin film of a conductive polymer, poly(2-dodecanoylsulfanyl-p-phenylenevinylene), doped with dodecylbenzenesulfonic acid (10%, w/w), onto interdigitated electrodes. The sensor exhibits linear electrical conductance changes in function of the concentration of methanol present in sugar-cane spirit in the range between 0.05% and 4.0%. Since the sensor is cheap, easy to fabricate, durable, presents low power consumption, and is not sensitive to ethanol, acetic acid or water, it can be used in portable equipments for monitoring methanol levels in distilled alcoholic beverages such as Brazilian sugar-cane spirit (cachaca). (C) 2011 Elsevier Ltd. All rights reserved.

An alternative method for the simultaneous determination of copper and lead for quality control of sugar cane spirit using a nanotube-based sensor

The development of an electroanalytical method for simultaneous determination of copper and lead ions in sugar cane spirit (cachaça) using carbon paste electrode modified with ascorbic acid and carbon nanotubes (CPE-AaCNT) is described. Squarewave voltammetry (SWV) with anodic stripping was employed, and this technique was optimized with respect to the following parameters: frequency (50 Hz), amplitude (100 mV) and scan increment (9 mV). The analytical curves were linear in the range from 0.0900 to 7.00 mg L- 1 for lead and copper. The limits of detection were 48.5 and 23.9 µg L- 1 for lead and copper, respectively. The developed method was applied to the simultaneous determination of copper and lead in five commercial samples of sugar cane spirit. The results were in good agreement with those obtained by F AAS/GF AAS (flame atomic absorption spectrometry/graphite furnace atomic absorption spectrometry) and showed that CPE-AaCNT can be successfully employed in the simultaneous determination of these metals in real sugar cane spirit samples.

Rainwater major and trace element contents in Southeastern Brazil: an assessment of a sugar cane region in dry and wet period

The purpose of this study was to assess the composition of the rainwater in Araraquara City, Brazil, a region strongly influenced by pre-harvest burning of sugar cane crops. Chemical and mineralogical variables were measured in rainwater collected during the harvest, dry period of 2009 and the non-harvest, wet period of 2010. Ca2+ and NH4+ were responsible for 55% of cations and NO3- for 45% of anions in rainwater. Al and Fe along with K were the most abundant among trace elements in both soluble and insoluble fractions. High volume weighted mean concentration (VWM) for most of the analyzed species were observed in the harvest, dry period, mainly due to agricultural activities and meteorological conditions. The chemistry of the Araraquara rainwater and principal component analysis (PCA) quantification clearly indicate the concurrence of a diversity of sources from natural to anthropogenic especially related to agricultural activities.

Synthesis of Carbon Nanomaterials through Up-Cycling Agricultural and Municipal Solid Wastes

This work addresses the synthesis of carbon nanomaterials (CNMs) by up-cycling common solid wastes. These feedstocks could supersede the use of costly and often toxic or highly flammable chemicals, such as hydrocarbon gases, carbon monoxide, and hydrogen, which are commonly used as feedstocks in current nanomanufacturing processes for CNMs. Agricultural sugar cane bagasse and corn residues, scrap tire chips, and postconsumer polyethylene (PE) and polyethylene terephthalate (PET) bottle shreddings were either thermally treated by sole pyrolysis or by sequential pyrolysis and partial oxidation. The resulting gaseous carbon-bearing effluents were then channeled into a heated reactor. CNMs, including carbon nanotubes, were catalytically synthesized therein on stainless steel meshes. This work revealed that the structure of the resulting CNMs is determined by the feedstock type, through the disparate mixtures of carbon-bearing gases generated when different feedstocks are pyrolyzed. CNM characterization was conducted by scanning and transmission electron microscopy as well as by Raman spectroscopy and by thermogravimetric analysis. Gas chromatography was used to characterize the gases in the synthesis chamber. This work demonstrated an alternative method for efficient manufacturing of CNMs using both biodegradable and nonbiodegradable agricultural and municipal carbonaceous wastes.

Response surface methodology (RSM) to evaluate moisture effects on corn stover in recovering xylose by DEO hydrolysis

Response surface methodology (RSM), based on a 2(2) full factorial design, evaluated the moisture effects in recovering xylose by diethyloxalate (DEO) hydrolysis. Experiments were carried out in laboratory reactors (10 mL glass ampoules) containing corn stover (0.5 g) properly ground. The ampoules were kept at 160 degrees C for 90 min.(-) Both DEO concentration and corn stover moisture content were statistically significant at 99% confidence level. The maximum xylose recovery by the response surface methodology was achieved employing both DEO concentration and corn stover moisture at near their highest levels area. We amplified this area by using an overlay plot as a graphical optimization using a response of xylose recovery more than 80%. The mathematical statistical model was validated by testing a specific condition in the satisfied overlay plot area. Experimentally, a maximum xylose recovery (81.2%) was achieved by using initial corn stover moisture of 60% and a DEO concentration of 4% w/w. The mathematical statistical model showed that xylose recovery increases during DEO corn stover acid hydrolysis as the corn stover moisture level increases. This observation could be important during the harvesting of corn before it is fully dried in the field. The corn stover moisture was an important variable to improve xylose recovery by DEO acid hydrolysis. (c) 2011 Elsevier Ltd. All rights reserved.