Impact of yeast starter formulations on the production of volatile compounds during wine fermentation

The most diffused starter formulation in winemaking is actually represented by active dry yeast (ADY). Spray‐drying has been reported as an appropriate preservation method for yeast and other micro‐organisms. Despite the numerous advantages of this method, the high air temperatures used can negatively affect cell viability and the fermentative performance of dried cells. In the present study, 11 wine S. cerevisiae strains (both indigenous and commercial) were submitted to spray‐drying; different process conditions were tested in order to select the conditions allowing the highest strain survival. The strains exhibited high variability for tolerance to spray‐drying treatment. Selected strains were tested in fermentation at laboratory scale in different formulations (free fresh cells, free dried cells, immobilized fresh cells and immobilized dried cells), in order to assess the influence of starter formulation on fermentative fitness of strains and aromatic quality of wine. The analysis of volatile fraction in the experimental wines produced by selected strains in different formulations allowed identification of > 50 aromatic compounds (alcohols, esters, ketones, aldehydes and terpenes). The results obtained showed that the starter formulation significantly influenced the content of volatile compounds. In particular, the wines obtained by strains in dried forms (as both free and immobilized cells) contained higher numbers of volatile compounds than wines obtained from fresh cells. Copyright © 2014 John Wiley & Sons, Ltd.     

Antimicrobial Effect of Edible Coating Blend Based on Turmeric Starch Residue and Gelatin Applied onto Fresh Frankfurter Sausage

The microbial and physicochemical properties of edible coating blend based on turmeric starch and bovine gelatin on frankfurter sausage were studied during the product’s shelf life. Three edible films were prepared and their thermal, mechanical, and barrier properties evaluated one with turmeric starch (TF), one with gelatin (GF), and one with a blend of turmeric-starch and gelatin (BF). Physicochemical and bacteriostatic effects of the blend on the sausage were measured. Water vapor permeability (8.01 g day^?1 m^?2 atm^?1) and tensile strength of the BF showed intermediate values (5 MPa) compared with results of the films containing turmeric (5.88 g day^?1 m^?2 atm^?1; 4 MPa) or gelatin (13.4 g d^?1 m^?2 atm^?1; 13 MPa) separately. Tensile strength was higher to GF (13 MPa), lower value (4 MPa) was obtained to TF, and intermediate value to BF (5 MPa). Elastic modulus was lower to BF (85 MPa) when compared to TF (126 MPa) and GF (271 MPa). Elongation at break of BF (42%) was higher among the three edible films (TF 7% and GF 36%). Emulsion stability measured by thermal analysis in DSC showed complete miscibility to BF, observed through melting point of polymers. The effect of the turmeric-gelatin blend coating on sausages stored at 5 and 10 °C showed a significant (p ≥ 0.05) positive effect on decrease of microbial growth over 30 days. Physicochemical characteristics such as pH, texture profile, moisture, and color remained constant compared to control. Thus, the edible coating based on turmeric starch and gelatin blend is an alternative to replace the synthetic casing in frankfurter sausage.     

Performance assessment of membrane distillation for skim milk and whey processing

Membrane distillation is an emerging membrane process based on evaporation of a volatile solvent. One of its often stated advantages is the low flux sensitivity toward concentration of the processed fluid, in contrast to reverse osmosis. In the present paper, we looked at 2 high-solids applications of the dairy industry: skim milk and whey. Performance was assessed under various hydrodynamic conditions to investigate the feasibility of fouling mitigation by changing the operating parameters and to compare performance to widespread membrane filtration processes. Whereas filtration processes are hydraulic pressure driven, membrane distillation uses vapor pressure from heat to drive separation and, therefore, operating parameters have a different bearing on the process. Experimental and calculated results identified factors influencing heat and mass transfer under various operating conditions using polytetrafluoroethylene flat-sheet membranes. Linear velocity was found to influence performance during skim milk processing but not during whey processing. Lower feed and higher permeate temperature was found to reduce fouling in the processing of both dairy solutions. Concentration of skim milk and whey by membrane distillation has potential, as it showed high rejection (>99%) of all dairy components and can operate using low electrical energy and pressures (<10 kPa). At higher cross-flow velocities (around 0.141 m/s), fluxes were comparable to those found with reverse osmosis, achieving a sustainable flux of approximately 12 kg/h·m² for skim milk of 20% dry matter concentration and approximately 20 kg/h·m² after 18 h of operation with whey at 20% dry matter concentration.     

Source and nature of inhaled atmospheric dust from trace element analyses of human bronchial fluids

Rapid volcanic eruptions quickly ejecting large amounts of dust provoke the accumulation of heavy metals in people living in surrounding areas. Analyses of bronchoalveolar lavage samples (BAL) collected from people exposed to the paroxysmal 2001 Etna eruption revealed a strong enrichment of many toxic heavy metals. Comparing the BAL to the dust composition of southeastern Sicily, we found that only V, Cr, Mn, Fe, Co, and U enrichment could be related to the volcanic event, whereas Ni, Cu, Cd, and Pb contents come from the dissolution of particles of anthropogenic origin. Furthermore, the nature of these inhaled anthropogenic particles was revealed by anomalous La and partially Ce concentrations in BAL that were consistent with a mixture of road dust and petroleum refinery emissions. Our results indicate that trace element distribution in BAL is a suitable tracer of human exposure to different sources of inhaled atmospheric particulates, allowing investigations into the origin of source materials inhaled by people subjected to atmospheric fallout.     

Improvement in regression of corn yield with plant height using relative data

BACKGROUND: The traditional approach of analyzing absolute variable data across multiple locations and/or years has drawbacks in precision agriculture. This study was conducted to evaluate the impacts of using relative yield and plant height data of corn (Zea mays L.) on the regression of yield with plant height using linear and exponential models in a nitrogen (N) rate field trial under four cropping systems. RESULTS: The use of relative yield to replace absolute yield frequently increased the determination coefficient (R²) values in the regression of yield with plant height on datasets combined across cropping systems or/and years. Relative yield and relative plant height sometimes further enhanced the R² values compared with relative yield and absolute plant height. All these improvements mostly occurred when the fit of the model was not strong with absolute yield and absolute plant height or relative yield and absolute plant height. The advantages of using relative data of yield or/and plant height were similar for the two regression models. CONCLUSION: The use of relative yield or relative data of both yield and plant height may be effective in improving the regression of corn yield with plant height across multiple cropping systems/locations and years in precision agriculture. Copyright © 2011 Society of Chemical Industry     

In situ Raman spectroscopy to monitor the hydrolysis of acetal in microreactors

In order to obtain a better understanding of the physical and chemical processes within micromixers or microreactors and to optimize these devices it is necessary to monitor the concentrations within the microchannels. To get chemical information, laser Raman spectroscopy can be used. This method is very selective for individual chemical compounds, allows a spatial resolution of 10 μm within fluids and a quantitative analysis. We examined the hydrolysis of the acetal 2,2-dimethoxypropane to acetone and methanol in the presence of hydrogen ions as catalyst. This reaction can be used to characterize micromixers. The aim of this work is the in situ monitoring of concentrations of acetal and its products, acetone and methanol, during the hydrolysis of acetal within a T-shaped micromixer with a channel width of 0.4 mm and a channel depth of 0.2 mm. In these experiments a continuous-wave argon ion laser was used as an excitation source. The laser radiation was coupled into a microscope and into the micromixer covered with a quartz plate. A special microscope objective was used. It allows the correction of optical aberrations resulting from quartz plates up to a thickness of 2 mm. Concentration profiles of acetal, methanol, and acetone were measured across the width of the microchannel.     

Corrosion behavior of Al2024‐T3, Al5052‐H32, and Al6061‐T6 aluminum alloys coated with DLC films in aviation fuel medium,Jet A‐1 and AVGAS 100LL

In aircraft and storage fuel tanks, many environmental corrosion factors can be present, which can cause breakdown to the passive film of aluminum causing severe localized corrosion. Aiming to a solution to this problem, diamond‐like carbon (DLC) films were deposited on substrates Al 2024‐T3, Al 5052‐H32, and Al 6061‐T6. The substrates with and without DLC films were submitted to a corrosive immersion test with aviation fuel Jet‐A1 and AVGAS 100LL. The surface morphology from aluminum substrates with and without DLC films was analyzed before and after 7 and 30 days of corrosive immersion tests by SEM. The adhesion of the DLC films was evaluated according to the ASTM‐C1624 scratching test standard, and the optical profilometry was used to measure the thickness and roughness. Silver nanoparticles were also added in DLC films samples due to its antibacterial properties to check the stability and resistance against corrosive fuel medium. The results indicated an improvement of corrosion resistance just with DLC films. The silver nanoparticles did not present any advantages in this corrosion protection, and the aluminum alloys suffered more corrosion than when protected by DLC films.     

Chronic Kidney Disease-Associated Inflammation Increases the Risks of Acute Kidney Injury and Mortality after Cardiac Surgery

Cardiovascular mortality increases with decreasing renal function although the cause is yet unknown. Here, we have investigated whether low chronic inflammation in chronic kidney diseases (CKD) could contribute to increased risk for coronary artery diseases (CAD). Thus, a prospective case–control study was conducted in patients with CAD and CKD undergoing coronary artery bypass graft surgery with the aim of detecting differences in cardiovascular outcomes, epicardial adipose tissue volume, and inflammatory marker activity associated with renal dysfunction. Expression of membrane CD14 and CD16, inflammatory cytokines and chemokines, mitogen-activated protein (MAP) kinases and hsa-miR-30a-5p were analyzed in peripheral blood mononuclear cells (PBMCs). Epicardial fat volume and tissue inflammation in perivascular adipose tissue and in the aorta were also studied. In the present study, 151 patients were included, 110 with CAD (51 with CKD) and 41 nonCAD controls (15 with CKD). CKD increased the risk of cardiac surgery–associated acute kidney injury (CSA-AKI) as well as the 30-day mortality after cardiac surgery. Higher counts of CD14⁺⁺CD16⁺ monocytes were associated with vascular inflammation, with an increased expression of IL1β, and with CKD in CAD patients. Expression of hsa-miR-30a-5p was correlated with hypertension. We conclude that CKD patients show an increased risk of CSA-AKI and mortality after cardiovascular surgery, associated with the expansion of the CD14⁺⁺CD16⁺ subset of proinflammatory monocytes and with IL1β expression. We propose that inflammation associated with CKD may contribute to atherosclerosis (ATH) pathogenesis.