Low Concentrations Of Ethanol Research Articles

A fast and effective alternative to a high-ethanol disinfectant: Low concentrations of fermented ethanol, caprylic acid, and citric acid synergistically eradicate biofilm-embedded methicillin-resistant Staphylococcus aureus.

There is a growing need to develop a powerful bactericidal method with low ethanol concentrations due to the frequent ineffectiveness of traditional antibiotics against biofilms and the side effect of a high ethanol concentration. This study aims to develop a novel synergistic technique replacing a high-ethanol disinfectant. Low concentrations of fermented ethanol (FE, 10-20%) with naturally derived antimicrobials, citric acid (CTA, 0.5-1.0%) and caprylic acid (CAP, 0.05-0.15%), were examined against a methicillin-resistant S. aureus (MRSA) biofilm formed on silicone coupons (catheter materials). CTA and CAP were identified as effective antimicrobials that exhibited a synergistic interaction with FE. Complete eradication of MRSA biofilms (>7 log reduction) was obtained within 5min after treatment with 20% FE plus 1.0% CTA and 0.15% CAP at both 22 and 37°C, while individual treatments with each material showed negligible bactericidal effects (<1 log reduction except 0.15% CAP treatment at 37°C). No bacteria were recovered from the surface after the combined treatment (five enrichment tests). The developed compounds were able to disinfect surfaces with more than 5 log-reduction within only 1minat 22°C. Confocal microscopy images showed that the combination of all three materials resulted in remarkable membrane damage and cell detachment from the silicone surface. Application of FE plus CTA and CAP, therefore, can be a valuable decontamination technique for medical devices or can work as a surface disinfectant, reducing the concerns regarding undesirable high ethanol concentrations in disinfectants.

Basal catalase activity and high glutathione levels influence the performance of non-Saccharomyces active dry wine yeasts

Non-Saccharomyces wine yeasts are useful tools for producing wines with complex aromas or low ethanol content. Their use in wine would benefit from their production as active dry yeast (ADY) starters to be used as co-inocula alongside S. cerevisiae. Oxidative stress during biomass propagation and dehydration is a key factor in determining ADY performance, as it affects yeast vitality and viability. Several studies have analysed the response of S. cerevisiae to oxidative stress under dehydration conditions, but not so many deal with non-conventional yeasts. In this work, we analysed eight non-Saccharomyces wine yeasts under biomass production conditions and studied oxidative stress parameters and lipid composition. The results revealed wide variability among species in their technological performance during ADY production. Also, for Metschnikowia pulcherrima and Starmerella bacillaris, better performance correlates with high catalase activity and glutathione levels. Our data suggest that non-Saccharomyces wine yeasts with an enhanced oxidative stress response are better suited to grow under ADY production conditions.

Anxious Behavior of Adult CD1 Mice Perinatally Exposed to Low Concentrations of Ethanol Correlates With Morphological Changes in Cingulate Cortex and Amygdala.

Perinatal ethanol (EtOH) exposure is associated with high incidence of behavioral disorders such as depression and anxiety. The cerebral areas related with these consequences involve the corticolimbic system, in particular the prefrontal cortex, hippocampus, amygdala, and cingulate cortex, although the latter has not been thoroughly studied yet. Different animal models of prenatal or perinatal EtOH exposure have reported morphofunctional alterations in the central nervous system, which could explain behavioral disorders along life; these results focus on youth and adolescents and are still controversial. In the light of these inconclusive results, the aim of this work was to analyze adult behavior in CD1 mice perinatally exposed to low concentrations of EtOH (PEE) during gestation and lactation, and describe the morphology of the cingulate cortex and amygdala with a view to establishing structure/function/behavior correlations. Primiparous CD1 female mice were exposed to EtOH 6% v/v for 20 days prior to mating and continued drinking EtOH 6% v/v during pregnancy and lactation. After weaning, male pups were fed food and water ad libitum until 77 days of age, when behavioral and morphological studies were performed. Mouse behavior was analyzed through light–dark box and open field tests. Parameters related to anxious behavior and locomotor activity revealed anxiogenic behavior in PEE mice. After behavioral studies, mice were perfused and neurons, axons, serotonin transporter, 5HT, CB1 receptor (CB1R) and 5HT1A receptor (5HT1AR) were studied by immunofluorescence and immunohistochemistry in brain sections containing cingulate cortex and amygdala. Cingulate cortex and amygdala cytoarchitecture were preserved in adult PEE mice, although a smaller number of neurons was detected in the amygdala. Cingulate cortex axons demonstrated disorganized radial distribution and reduced area. Serotonergic and endocannabinoid systems, both involved in anxious behavior, showed differential expression. Serotonergic afferents were lower in both brain areas of PEE animals, while 5HT1AR expression was lower in the cingulate cortex and higher in the amygdala. The expression of CB1R was lower only in the amygdala. In sum, EtOH exposure during early brain development induces morphological changes in structures of the limbic system and its neuromodulation, which persist into adulthood and may be responsible for anxious behavior.

Beer spoilage and low pH tolerance is linked to manganese homeostasis in selected Lactobacillus brevis strains.

Beer is a harsh medium for bacteria to survive, however, lactic acid bacteria including Lactobacillus brevis have evolved the ability to grow in beer. Here, the influence of environmental factors such as low pH, ethanol or hop content was assessed. A transcriptomic analysis of two Lact. brevis beer-spoiling strains was performed comparing growth in nutritive media with or without the imposition of a stressor related to the beer environment. This allowed the identification of a manganese transporter encoding gene that contributes to low pH tolerance. We report on the importance of a manganese transporter associated with pH tolerance and beer spoilage in Lact. brevis. The importance of manganese for Lact. brevis growth in a low pH environment was highlighted. Bacterial spoilage of beer may result in product withdrawal with concomitant economic losses for the brewing industry. A limited number of genes involved in beer spoilage have been identified but none of them are universal. It is clear that other molecular players are involved in beer spoilage. The study highlights the complexity of the genetic requirements to facilitate beer spoilage and the role of multiple key players in this process.

Characterization of enhanced ethanol tolerance in Paramecium caudatum after exposure to low ethanol concentrations

Characterization of enhanced ethanol tolerance in Paramecium caudatum after exposure to low ethanol concentrations

Using fiber-optic sensors to give insight into liquid-solid phase transitions in pure fluids and mixtures

Fiber optic sensors offer a new and unique way to detect and analyze phase transitions, due to their small thermal mass and inert material. This paper presents and demonstrates a dual-sensor system to detect and analyze phase transitions in pure water and aqueous ethanol mixtures. With a multi-mode interferometer based on a thin-core fiber, and a fiber Bragg grating sensor, it is possible to differentiate between refractive index, temperature and strain in the sample system. The three parameters supply important information during a phase transition, but also in the characterization of the liquid and solid phases. Binary mixtures at non-eutectic concentrations are expected to separate into a solid phase consisting of only one constituent, and the sensors are demonstrated to be able to estimate the concentration in the remaining liquid phase. For pure water and low ethanol concentrations, the progression of the phase transition was found to be limited by heat transfer, whereas for higher concentrations the process becomes mass transfer limited. In pure water, strain due to thermal expansion of the ice hinderes temperature measurements in the solid phase. The reflection-based geometry enables insertion probes that measure the properties inside the samples, with little or no disturbance of the system. By interpreting the sensor response in a known system, the sensing capabilities in unknown substances can be evaluated. The sensor system is able to capture the dynamics of the phase transition, which can be difficult to predict theoretically due to the multitude of contributing effects. Analysis of the combined signal from the two sensors enables the determination of the ethanol mixture melting points in agreement with the literature, within the uncertainty of the system (0.25 K).

Promoting enzymatic saccharification of organosolv-pretreated poplar sawdust by saponin-rich tea seed waste.

Organosolv pretreatment with two ethanol concentrations (25% and 50%, v/v) was performed to improve enzymatic saccharification of poplar sawdust. It was found that lower ethanol concentration (25%, v/v) pretreatment resulted in a higher enzymatic digestibility of poplar (38.1%) due to its higher xylan removal and similar lignin removal ratios, compared to that pretreated with 50% (v/v) ethanol pretreatment (27.5%). However, the residual lignin still exhibited a strong inhibition on enzymatic hydrolysis of organosolv-pretreated poplar (OP). Bio-surfactant preparations including tea saponin (TS), TS crude extract, and tea seed waste were applied in enzymatic hydrolysis of OP, due to their potential ability of reducing enzyme non-productive binding on lignin. Their optimal loadings in enzymatic hydrolysis of OP were optimized, which indicated that adding 0.075g/g glucan of TS improved the 72-h glucose yield of OP by 48.3%. Moreover, adding TS crude extract and tea seed waste exhibited the better performance than TS for improving enzymatic hydrolysis of OP. It was verified that the presence of protein in TS crude extract and tea seed waste accounted for the higher improvement. More importantly, the directly application of tea seed waste in enzymatic hydrolysis could achieve the similar improvement on enzymatic hydrolysis of OP, where chemosynthetic surfactant (PEG6000) was added. The residual enzyme activities in supernatant of enzymatic hydrolysis were also determined to reveal the changes on enzyme adsorption after adding surfactants. Generally, tea seed waste could be directly applied as an alternative to chemosynthetic surfactants to promote enzymatic hydrolysis of lignocelluloses.

Sequential Non-Saccharomyces and Saccharomyces cerevisiae Fermentations to Reduce the Alcohol Content in Wine

Over the last decades, the average alcohol content of wine has increased due to climate change and consumer preferences for particular wine styles that resulted in increased grape sugar levels at harvest. Therefore, alcohol reduction is a current challenge in the winemaking industry. Among several strategies under study, the use of non-conventional yeasts in combination with Saccharomyces cerevisiae plays an important role for lowering ethanol production in wines nowadays. In the present work, 33 native non-Saccharomyces strains were assayed in sequential culture with a S. cerevisiae wine strain to determine their potential for reducing the alcohol content in Malvar white wines. Four of the non-Saccharomyces strains (Wickerhamomyces anomalus 21A-5C, Meyerozyma guilliermondii CLI 1217, and two Metschnikowia pulcherrima (CLI 68 and CLI 460)) studied in sequential combination with S. cerevisiae CLI 889 were best able to produce dry wines with decreased alcohol proportion in comparison with one that was inoculated only with S. cerevisiae. These sequential fermentations produced wines with between 0.8% (v/v) and 1.3% (v/v) lower ethanol concentrations in Malvar wines, showing significant differences compared with the control. In addition, these combinations provided favorable oenological characteristics to wines such as high glycerol proportion, volatile higher alcohols, and esters with fruity and sweet character.

In vitro fermentation and camellia oil emulsification characteristics of konjac glucomannan octenyl succinate.

It is important to select an appropriate emulsifier to overcome the poor stability and dispersibility of the vegetable oils in food system. Previous studies suggest that OSA‐modified konjac glucomannan (KGOS) has potential to be used as a food emulsifier. In this study, in vitro fermentation suggested that KGOS could promote the growth of the important intestinal probiotics Lactobacillus and Bifidobacterium and then promote intestinal fermentation to produce gas and short chain fatty acids. The emulsification experiments indicated that KGOS had good emulsification ability and stability for camellia oil. Under 40 MPa for 90 s homogenization, 0.2% (w/w) KGOS could encapsulate 20% (w/w) camellia oil. The nanoemulsion was stable at a low pH and high concentration of NaCl and ethanol. Konjac glucomannan octenyl succinate encapsulation could prevent the oxidation of camellia oil at 25°C and storage for 30 days.

Dynamic of Lachancea thermotolerans Population in Monoculture and Mixed Fermentations: Impact on Wine Characteristics

Lachancea thermotolerans is a non-Saccharomyces yeast appreciated for its potential of acidification due to the production of lactic acid; however, this species also synthetizes other metabolites that modulate organoleptic wine properties. The aim of this study was to evaluate the strain L. thermotolerans Lt93 to ferment ‘Treixadura’ and ‘Mencía’ musts and its impact on yeast population dynamics and wine characteristics. Fermentations using monocultures of L. thermotolerans Lt93 and S. cerevisiae strains, sequential inoculation and spontaneous process were performed. The dynamic of yeast population and wine composition were analyzed following standard methodology. L. thermotolerans Lt93 was unable to overgrow wild yeast population in ‘Treixadura’ white must; however, with ‘Mencía’ red must, Lt93 was the predominant yeast at the beginning of fermentation and remained at high frequency until the end. Lt93 Treixadura wines had slightly higher acidity and higher content of esters and acids than ScXG3 wines. Lt93 Mencía wines presented higher acidity (10.1 g/L) and 0.8% (v/v) lower ethanol content than Sc71B wines. The content of esters and fatty acids was 3.3 and 4.0 times lower, respectively, in Lt93 than in Sc71B Mencía wines. It was possible to increase wine acidity and modulate the chemical wine profile by using Lt93.

Study of kefir drinks produced by backslopping method using kefir grains from Bosnia and Herzegovina: Microbial dynamics and volatilome profile

Kefir is a well-known health-promoting beverage that can be produced by using kefir grains (traditional method) or by using natural starter cultures from kefir (backslopping method). The aim of this study was to elucidate the microbial dynamics and volatilome profile occurring during kefir production through traditional and backslopping methods by using five kefir grains that were collected in Bosnia and Herzegovina. The results from conventional pour plating techniques and amplicon-based sequencing were combined. The kefir drinks have also been characterized in terms of their physico-chemical and colorimetric parameters. A bacterial shift from Lactobacillus kefiranofaciens to Acetobacter syzygii, Lactococcus lactis and Leuconostoc pseudomesenteroides from kefir grains in traditional kefir to backslopped kefir was generally observed. Despite some differences within samples, the dominant mycobiota of backslopped kefir samples remained quite similar to that of the kefir grain samples. However, unlike the lactic acid and acetic acid bacteria, the yeast counts decreased progressively from the grains to the backslopped kefir. The backslopped kefir samples showed higher protein, lactose and ash content and lower ethanol content compared to traditional kefir samples, coupled with optimal pH values that contribute to a pleasant sensory profile. Concerning the volatilome, backslopped kefir samples were correlated with cheesy, buttery, floral and fermented odors, whereas the traditional kefir samples were correlated with alcoholic, fruity, fatty and acid odors. Overall, the data obtained in the present study provided evidence that different kefir production methods (traditional vs backslopping) affect the quality characteristics of the final product. Hence, the functional traits of backslopped kefir should be further investigated in order to verify the suitability of a potential scale-up methodology for backslopping.

Lower-alcohol wines produced by Metschnikowia pulcherrima and Saccharomyces cerevisiae co-fermentations: The effect of sequential inoculation timing

In Latin, ‘pulcherrima’ is a superlative form of an adjective that translates as beautiful. Apart from being ‘the most beautiful’ yeast, Metschnikowia pulcherrima has a remarkable potential in production of wines with lower ethanol content. The oenological performance of six M. pulcherrima strains was hereby tested in sequential cultures with Saccharomyces cerevisiae. The best-performing strain MP2 was further characterised in fermentations with different S. cerevisiae inoculation delays in both white grape juice and Chemically Defined Grape Juice Medium (CDGJM). The analysis of main metabolites, undertaken prior to sequential inoculations and upon fermentation completion, highlighted metabolic interactions and carbon sinks other than ethanol in MP2 treatments. Depending on the inoculation delay, MP2 white wines contained between 0.6% and 1.2% (v/v) less ethanol than the S. cerevisiae monoculture, with even larger decreases detected in the CDGJM. The MP2 treatments also contained higher concentrations of TCA cycle by-products (i.e. fumarate and succinate) and glycerol, and lower concentrations of acetic acid. The analysis of volatile compounds showed increased production of acetate esters and higher alcohols in all MP2 wines, alongside other compositional alterations arising from the S. cerevisiae inoculation delay.

Porous CoTiO3 with highly surface defects as effective sensing materials for ethanol detection

A series of nano/micro-structured CoTiO3 powders were synthesized using a facile mixed-solvothermal method, by adjusting the volume ratio of ethylene glycol (EG) to anhydrous ethanol in the mixed solvent. Nitrogen adsorption–desorption and electron microscopic analyses revealed that the as-prepared CoTiO3 products possess a bimodal porous structure with interconnected pore channels, which have great advantages for the diffusion of target gas and the effective utilization of active sites. The porous CoTiO3 obtained at the volume ratio of EG to anhydrous ethanol of 1:2 in the mixed solvent demonstrated the highest sensitivity (20.3) and rapid response time (7 s) to low concentration ethanol (20 ppm) at working temperature 300 °C. Moreover, excellent reproducibility and stability can be achieved within six cycles. Photoluminescence (PL) results illustrated that the porous CoTiO3 with the best sensing performance has more abundant surface defects than other samples. These defects can act as reactive sites to facilitate more O2 adsorption, leading to the enhanced accumulation of positive holes on the surface and an increase in the gas sensitivity. In view of the excellent sensing characteristics to low concentration ethanol and the facile preparation method, the obtained porous CoTiO3 products are promising candidates for fabricating effective ethanol sensors.

Oral persistence of esters is affected by wine matrix composition

The present work evaluated for the first time the influence of wine matrix composition on oral ester persistence. To do that, the in mouth behaviour (oral retention and persistence) of six esters was followed in nine individuals after they rinsed their mouths with four rosé wines presenting two levels (low and moderate) of ethanol (0.5% or 10% v/v) and polyphenols (402 ± 10 or 661 ± 33 mg gallic acid/L). Overall, polyphenols and specially, ethanol, affected the oral retention of esters and their subsequent oral persistence, in an individual, compound and concentration dependent manner. The wine with moderate ethanol and low polyphenol content and the wine with low ethanol and moderate polyphenol content presented an increased oral ester persistence respect to the control wine (low ethanol/polyphenol content). However, the wine with moderate ethanol/polyphenol content showed most likely a lower oral ester persistence compared to the rest of the wines. Thus, an interaction between ethanol and polyphenols at specific concentrations could reduce oral ester persistence, and likely the fruity character of wines. The information generated in this research can be used by winemakers to understand how different winemaking techniques, which might alter wine ethanol and polyphenol content, may also affect wine aroma quality.

(Invited) Microfluidic Sensors based on Molecularly Imprinted Polymers for the Selective Detection of Volatile Organic Compounds

Introduction Selective and sensitive detection of volatile organic compounds (VOCs) is of great importance in applications involving monitoring of hazardous chemicals or non-invasive diagnosis. Diffusion-base microfluidic gas sensors are a new generation of gas detectors. These sensors have increased selectivity; this is primarily due to the effect of diffusion and adsorption/desorption (highly influenced by the coating materials and dimensions of the microfluidic channel) of the analyte molecules along the microfluidic channel (1,2). Therefore, the combination of the diffusion and adsorption/desorption rates of different analytes with different concentrations leads to a unique response (i.e., “smell print”) from the embedded sensor (3). In addition to the coating (or the combination of the layers coated) the surface roughness can affect adsorption and desorption phenomena and hence the performance (mainly selectivity) of the sensors. There are several ways to change the coating and roughness of the channel. One interesting method, which changes the surface material of the microchannel and interaction with the analyte, is the integration of molecularly imprinted polymer nanoparticles (MIP NPs) in to the channel.Column CoatingMIP is a synthetic polymer possessing selective molecular recognition properties (due to its binding sites) with size, shape and functionalities complementary to the target molecules. MIPs, often called artificial antibodies or receptors, are alternatives to antibodies in a variety of applications. The advantages of MIPs over natural antibodies include easy and low-cost preparation, longer life cycles (up to several years), highly tailorable recognition properties, solvents and thermal stability, robustness and resistance to a wide range of pH, and ease of regeneration and sterilization.For the first time, MIP NPs were synthesized with acetone recognition sites due to its importance as a biomarker for the non-invasive diagnosis of several diseases like diabetes. The synthesized MIP NPs were integrated into a 3D-printed dual-channel platform (one channel without and the other with MIP NPs) to develop a highly selective detection device against various VOCs (alcohols, ketones, nitrile, and aromatic compounds). Method The MIP NPs with acetone recognition sites were prepared for the first time using the simple precipitation procedure. After polymerization, the solution was centrifuged and the final polymer was ground into a powder. To remove the template, the MIP powder was washed with acetonitrile, followed by heating the powder at 80ºC for 48 h. The morphology and chemical structure of MIP NPs were investigated by field emission scanning electron microscope (FE-SEM, FEI-Nova NanoSEM 450) and Fourier-transform infrared spectroscopy (FTIR, Shimadzu FTIR Prestige 21).The microfluidic-based gas platform consists of two microfluidic channels and gas sensors (embedded at the channel terminus). The microchannels were fabricated from VeroClear RGD810 using a 3D-printer (Connex 500). Each microchannel has equal dimensions of 500 µm in height, 3 mm in width, and 3 cm in length. The inner surfaces of the microchannels are coated with Parylene C using a chemical vapor deposition (CVD) coating machine (SCS PDS 2010 Labcoater). To investigate the effect of treating the channel with MIP NPs on the selectivity of the sensors, one channel was coated with MIP NPs (referred to as the MIP channel) and another one was left uncoated (referred to as the control channel). For this purpose, a certain amount of synthesized MIP NPs dispersed in acetonitrile was drop-casted on the surface of the MIP channel and dried for a day in a clean air chamber. VOCs flow into the channel inlet, diffuse along the microfluidic channel, and reach gas detectors placed at the end of the microchannels, when exposed to the device.The synthesized MIP NPs were integrated into a 3D-printed dual-channel platform (one channel without and the other with MIP NPs) to develop a highly selective detection device against various VOCs (alcohols, ketones, nitrile, and aromatic compounds). A simple feature extraction method was used to distinguish signals arising from different VOCs. The differences between the feature extraction of the two channels showed that in general this platform was specific to acetone, proving the potential application of the MIP NPs in artificial olfaction platforms. Results and Conclusions Fig. 1 shows the response of the dual-channel detector when exposed to 200, 400, 800, 2000, 4000 ppm concentrations of several VOCs. The responses of both detectors increase with increasing concentrations of the target VOC. Although the response of the two detectors to the same target analyte was significantly different, with the increase in the concentration the magnitude of signals increases; however, the time of the maximum response still remains the same. It was also observed that for the low concentration of acetone, butanone and ethanol, the responses from the nano MIP-coated detector are not distinguishable. This again confirms the interaction between these analytes and the MIP NPs.

A study on the performance analysis of bioethanol produced from sugarcane molasses in SI engine

Recently with ethanol being a renewable, bio-based and ecofriendly, it is projected to be the best replacement for petrol as a fuel in SI engines. Ethanol is derived mainly from sugarcane, cassava, corn and other waste biomass materials. These materials are rich in calories and could be utilized either as complements or as alternatives for conventional fuel sources. This paper aims to experimentally determine the properties of ethanol/gasoline blends and tests its performances in an SI engine. The E10, E20 and E30 ethanol-gasoline blends were studied and compared to gasoline fuel. It was found that the performance of the engine using bioethanol blends was almost comparable to that of pure gasoline, especially at lower ethanol content blends. Yet, increasing the ethanol content only gives adverse effects to the overall engine performance, resulting in 8.86% power loss at 2000 rpm for E20 and 8.18% for E30 compared to E0. Suggestively, with more research and experiments, bioethanol-fuel blends can replace pure gasoline fuels easily and with many added benefits on the same or slightly modified engines.

The impact of broad-based vs targeted taxation on youth alcohol consumption in Lebanon

This study aims to model youth's off-premise alcohol demand and forecasts ethanol intake responsiveness to alcohol taxes. Using stated preference alcohol purchase data from a survey of 1024 university students in Lebanon, we derive price elasticities that we use to forecast the effects of two excise tax scenarios on overall ethanol intake. The first scenario imposes a broad-based 20% tax on all types of alcoholic beverages, and the second scenario imposes a targeted 20% tax only on the high ethanol content, while exempting the lower ethanol beverages. Overall, targeted taxes are found to achieve a reduction in ethanol intake that is nearly three times that achieved by broad taxes (15.7% vs 5.3%). For 'past-month binge drinkers', targeted taxes would decrease alcohol intake by 16.3%, while broad taxes increase it by 3.3%. Finally, ethanol intake among participants who prefer low ethanol content would decrease under targeted taxes by more than five times as much as under broad taxes. For 'high-ethanol drinkers', targeted taxes decrease alcohol intake by an even larger proportion than for 'low-ethanol drinkers' (19.0% vs 15.6%), while broad taxes increase their ethanol intake by ∼16.0%. This study contributes evidence that taxation policy substantially reduces alcohol consumption and that alcohol consumption patterns should be accounted for when designing taxes.

Ethanol shock enhances the recovery of anthocyanin from lowbush blueberry

Deactivation of polyphenol oxidase (PPO) in natural products is essential for downstream processing of functional molecules used as food or food additives, particularly those served as antioxidants. In the present work, we identified two proteins with PPO activity from lowbush blueberry using ammonium sulphate precipitation and chromatography procedures. Deactivation of these proteins was studied using aqueous solutions of ethanol of different concentrations. The PPO activity was recovered after ethanol removal for the protein samples previously soaked in a low concentration ethanol solution. A complete and unrecoverable deactivation of the proteins was achieved using ethanol with concentration over 70% (v/v), as manifested by the significant changes in circular dichroism (CD) and fluorescence spectroscopy measurements. Based on these findings, we propose a new extraction process for blueberry anthocyanin, in which an ethanol shock, i.e. soaking blueberry fruit in a 70% (v/v) ethanol solution for 1 h, is implemented before subsequent procedures. This new process increases the anthocyanin yield by 55% in comparison to that without the ethanol shock.

Enhanced ethanol sensing performances of hetero-assembly Zn1-xFexO/rGO nanocomposites

Nanocomposites of Zn1-xFexO/reduced graphene oxide (Zn1-xFexO/rGO, x = 0∼0.15) with carpet-like mesoporous structures have been simply synthesized via a low temperature hydrothermal method. FESEM and TEM results show that the hetero-assembly trend of Zn1-xFexO and rGO is much more striking than that of Zn1-xFexO self-assembly at 100 °C hydrothermal condition. The specific surface area and pore size tests indicate that rGO leads to the formation of slit holes with inclined panel structure, providing a large specific surface area for the nanocomposites. Mesoporous Zn0.89Fe0.11O has been proved to have the optimal gas response to ethanol at high operating temperatures, while Zn0.89Fe0.11O/rGO-10 (the content of rGO is 10 %) composite has a remarkable gas response (4.37) at low operating temperature and low ethanol concentration (160 °C, 2 ppm). In addition, the charge transport process and potential mechanism of gas response enhancement of Zn1-xFexO/rGO composite have been discussed in detail, and this may be ascribed to the combined effect of P-N junctions and the interfacial coupling between Zn1-xFexO and rGO.

Temperature-dependent response to C3H7OH and C2H5OH vapors induced by deposition of Au nanoparticles on SnO2/NiO hollow sphere-based conductometric sensors

Pure SnO2, SnO2/NiO, and Au-loaded SnO2/NiO hollow spheres with different Au content were synthesized through a 1-step hydrothermal synthesis. The surface morphology and structural as well as chemical composition of the synthesized Au-loaded SnO2/NiO hollow spheres were carefully investigated. The performance of the pure SnO2, SnO2/NiO, and Au-loaded SnO2/NiO gas sensors in the detection of low concentrations of propanol (C3H7OH) and ethanol (C2H5OH) was evaluated. The as-fabricated Au (2.5 wt. %)-loaded SnO2/NiO gas sensors demonstrated enhanced gas sensing characteristics and were highly sensitive, selective, and stable to C2H5OH vapor at a low operating temperature of 75 °C, whereas an improved response to C3H7OH was observed at 150 °C. The results indicated that compared to pure SnO2 and SnO2/NiO, the Au-loaded SnO2/NiO hollow sphere-based sensor exhibited a significant improvement in the gas sensing response at a lower optimum operating temperature. The long-term stability analyses indicated that the Au (2.5 wt. %)-loaded SnO2/NiO sensor was stable even after 35 days. These findings clearly demonstrated the ability of a 2.5 wt. % Au-loaded SnO2/NiO gas sensor to detect C2H5OH and C3H7OH vapors by adjusting the operating temperature suitably.