Use Of Sulfur Dioxide Research Articles

Long-Term Storage Quality of Table Grapes as Influenced by Pre-Harvest Yeast Applications and Post-Harvest Use of Controlled Atmosphere

The effects of pre-harvest applications of antagonistic yeast and controlled atmosphere storage treatments on inhibiting Botrytis cinerea decay and maintaining the quality of table grapes were compared to identify a treatment that could replace the use of sulphur dioxide (SO2) during post-harvest handling. Treatments for this study included pre-harvest application of antagonistic yeasts Cryptococcus albidus (Yieldplus®), Cryptococcus sp. (LF) and Candida pelliculosa (R951) on table grapes (cvs. ‘Barlinka’, ‘Dauphine’, ‘Red Globe’, ‘Sunred Seedless’ and ‘Thompson Seedless’) from 2001 to 2003. Grapes were stored under regular (air), controlled atmosphere (CA, O2 + CO2) and SO2 conditions at -0.5°C and subsequent storage at a 15°C to simulate shelf-life conditions. Results of this study showed that Botrytis decay levels did not develop rapidly due to low temperatures (-0.5°C vs 15°C), shorter storage periods (4 vs 8 weeks or 0 vs 7 vs 14 days), and CA treatment effects. The CA gas mixtures maintained commercially important low levels (less than 1%) of B. cinerea decay during the cold storage period at -0.5°C. However, during shelf-life storage at 15°C these low levels of decay could only be maintained by some of the SO2 treatments. A necessary commercial requirement is to maintain low decay levels for longer at higher shelf-life temperatures, for which this study cannot conclusively recommend a CA and/or antagonistic yeast treatment as an alternative to SO2. However, pre-harvest applications of the yeast and CA limited the general quality deterioration of the grapes at -0.5°C and 15°C compared to SO2 treatments. Inclusion of macro- or micro-perforated polyethylene packaging liners in combination with CA and pre-harvest yeast treatments did not show obvious negative effects on quality parameters in this study. Discovery and selection of yeast strains that survive under low temperatures and CA conditions would make suitable candidates for continued control of decay development on the fruit surface during shelf-life storage periods.

Analysis of free and total sulfur dioxide in wine by using a gas-diffusion analytical system with pH detection.

The use of sulfur dioxide as preservative in winemaking industry has a direct impact on wine quality. The standard methods to analyze this parameter require several processes and are time consuming. In this paper a simple and rapid analytical method for free and total sulfur dioxide detection is proposed. This method is based on the separation of the analyte from the sample with a permeable gas diffusion membrane and its indirect detection with a pH sensor. The system has been validated and optimized for free sulfur dioxide detection in the range of 1-60mgL-1 and for total sulfur dioxide in the range of 30-300mgL-1 with a limit of detection of 0.5mgL-1. Validation of the system has been carried out using a total of 70 samples of white and red wines and two standard methods, the Ripper and the Paul method. The obtained values have demonstrated a good agreement for both methods.

Effect of chitosan and SO2 on viability of Acetobacter strains in wine

Wine spoilage is an important concern for winemakers to preserve the quality of their final product and avoid contamination throughout the production process. The use of sulphur dioxide (SO2) is highly recommended to prevent wine spoilage due to its antimicrobial activity. However, SO2 has a limited effect on the viability of acetic acid bacteria (AAB). Currently, the use of SO2 alternatives is favoured in order to reduce the use of chemicals and improve stabilization in winemaking. Chitosan is a biopolymer that is approved by the European authorities and the International Organization of Vine and Wine to be used as a fining agent and antimicrobial in wines. However, its effectiveness in AAB prevention has not been studied.Two strains of Acetobacter, adapted to high ethanol environments, were analysed in this study. Both chitosan and SO2 effects were compared in artificially contaminated wines. Both molecules reduced the metabolic activity of both AAB strains. Although AAB populations were detected by culture independent techniques, their numbers were reduced with time, and their viability decreased following the application of both products, especially with chitosan.

Postharvest ozone fumigation of Petit Verdot grapes to prevent the use of sulfites and to increase anthocyanin in wine

Background and Aims The request by the consumer for safer food is also pushing the wine sector to find alternative solutions to sulfur dioxide. The aim of this research has been to evaluate the application of ozone as a sanitising agent of grapes before vinification in order to avoid the use of sulfur dioxide. Methods and Results Postharvest ozone fumigation overnight of Petit Verdot grapes increased anthocyanin concentration by 19% versus 9% in the Control (untreated) during fermentation/maceration. Fermentation kinetics were faster in wine made from ozone-treated grapes (16 vs 21 days for the Control), and extraction of phenolic substances and anthocyanin was more rapid than that in the Control wines, Ozone treatment significantly reduced the count of Saccharomyces cerevisiae and non-Saccharomyces yeasts but also significantly decreased the acetic acid bacteria. The final wine produced from ozone-treated grapes was characterised by low volatile acidity (similar to that of the Control wine) with a significant reduction in sulfur dioxide (17 and 8 mg/L, respectively, total and free sulfur dioxide). Sensory evaluation revealed a strong fruity aroma. Conclusions Ozone gas treatment of grapes reduced the microbial count significantly and increased the extraction of phenolic substances and the aroma of the final wine. Significance of the Study Postharvest ozone fumigation can be used to produce wine without sulfur dioxide.

Hen egg white lysozyme is a hidden allergen in Italian commercial ciders

ABSTRACTHen egg white lysozyme (HEWL) is an enzyme used in alcoholic fermentation for its ability to control the growth of Gram-positive and spoilage bacteria, without inhibiting yeast growth, and it allows a reduction in the use of sulphur dioxide. Nevertheless, considering the potential allergenicity of this protein, the presence of HEWL should be declared on the label of the final product. In this work, we analysed 18 commercial Italian ciders by LC-MS/MS and found traces of HEWL in 12 samples without label declaration. We used Western blot and enzyme-linked immunosorbent assay (ELISA) to verify the immunological activity of HEWL, and to quantify its content in the ciders. Two out of 18 samples were found to be positive both by immunoblot and ELISA. The results indicate the requirement of a more stringent control of commercial ciders and the need of label declaration for ciders treated with such compounds.

Simultaneous Extraction of Selenium from Indermediate Products of Extraction Reprocessing of Washing Acid of Copper Production

Background: In pyroprocessing sulphide complex copper ores, considerable amount of selenium along with radio genic osmium and rhenium concentrated in the solid-phase products of acid wash is disappearing with waste chromium containing solutions. Methods: Studying the peculiarities of selenium recovery in sulfuric acid chromium-containing medium is an important task, which will prevent channel losses of selenium with intermediates of sulphate production at complex processing of sulfide polymetallic raw materials and thereby increase up the production. On the basis of analysis of the literature and patent data as the most promising methods for the extraction of selenium and selenium from sulfuric acid solutions, recovery methods were chosen. Results: The thermodynamic evaluation of the possibility of extracting selenium from sulfuric acid solutions at the temperatures of 298-348 K, with the use of sulfur dioxide and sodium sulfite proved a high probability of recovering selenite-ions SeO 3 2- and to a lesser extent, selenate-ions SeO 4 2- . The experiment on precipitation of selenium were carried out on the basis of synthetic sulfuric solutions, containing, (g/l): 5-15 Se (IV), 5 Se (VI), 60 Cr (III), 5 Cr (VI), 100-250 H 2 SO 4 . It has been found that the temperature increase adversely affects the process of recovering selenium with sulfur dioxide, which is caused by reduction of the solubility of sulfur dioxide. The selenium selection process using sodium sulfate is characterized by significantly higher recovery rate due to removal of the diffusion constraints associated with the dissolution of sulfur dioxide. By using all studied reducing agents in the optimum conditions, almost complete recovery of selenium is ensured, selenium is at that recovered with not more than 60%. Conclusion: Taking into account high rates of extraction of selenium from sulphate chrome-bearing solutions, sulfur dioxide and sodium sulfite, choice of selenium recovery, largely determined by specific features of an enterprise.

Improving the Representation of Cross-Boundary Transport of Anthropogenic Pollution in East Asia Using Radon-222

The authors wish to thank Ot Sisoutham and Sylvester Werczynski at the Australian Nuclear Science and Technology Organisation for their support of the radon measurement program at Gosan Station. This work was funded by the Korea Meteorological Administration Research and Development Program under Grant KMIPA 2015-2050, and we gratefully acknowledge the use of sulphur dioxide and carbon monoxide data monitored by the Korean Ministry of Environment. Also, the NOAA Air Resources Laboratory (ARL), for providing the HYSPLIT v4 transport and dispersion model and relevant input files for generation of back trajectories. KHK acknowledges partial support made by a grant from the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (MEST) (No. 2009-0093848).

New challenges in the application of biocompatible silver nanoparticles in enology: Antimicrobial capacity, digestibility and potential cytotoxicity

In the search for new substitutes to the use of sulfur dioxide (SO2 ) in oenology, a new line of research based on nanotechnology has been launched. Within this line, this paper evaluates the suitability of two new biocompatible silver nanoparticles (Ag-NPs) to control microbial growth in wine as well as their stability and potential risks at intestinal level. Antimicrobial activities against spoilage wine microorganisms were carried out in both culture media and wines. In addition, in vitro simulations (static and dynamic) were conducted to monitor the passage of Ag-NPs through the buco-gastrointestinal tract and also to assess their effects on the gut microbiota and intestinal epithelial cells. Both Ag-NPs proved to be highly efficient for the control of wine undesirable bacteria in culture media and microvinification assays, and to a lesser extent, for reducing Brettanomyces populations in wine. Furthermore, undigested Ag-NPs as their corresponding digests after gastrointestinal simulation were not toxic to intestinal microbiota either epithelial cells, at least at the conditions used in these experiments.

Improvement of wine aromatic quality using mixtures of lysozyme and dimethyl dicarbonate, with low SO2 concentration

The use of sulphur dioxide (SO2) in the treatment of foodstuffs presents some problems as it could lead to pseudo-allergies in some people. The aim of this research work was to study the addition of different preservative mixtures and their influence on the concentration of volatile compounds and sensorial quality in wine. To do so, vinifications were carried out using Garnacha must to which lysozyme, dimethyl dicarbonate (DMDC) and mixtures of these with SO2 were added at different doses (25 and 50 mg l−1). The results were compared with a control sample to which only SO2 had been added (50 mg l−1). In general, mixtures of SO2 with lysozyme and DMDC favoured the formation of volatile compounds in the wines. Wines obtained from the mixtures of lysozyme and DMDC with 25 mg l−1 of SO2 had better sensorial quality than the wines obtained with 50 mg l−1 as the only preservative used.

Non-Saccharomyces Killer Toxins: Possible Biocontrol Agents Against Brettanomyces in Wine?

Red wine spoiled by the yeast Brettanomyces bruxellensis is characterised by off-odours commonly described as horse sweat, phenolic, varnish and band-aid. The growth of this yeast in wine is traditionally controlled by the use of sulphur dioxide (SO2). However, the concentration of SO2, the pH of the wine, the presence of SO2-binding chemical compounds in the wine, as well as the strain of B. bruxellensis, determine the effectiveness of SO2. Other chemical preservatives have been tested, but are not much more efficient than SO2, and methods used to clean barrels are only partially effective. Filtration of wine and the use of electric currents/fields are also reported to alter the physical and sensory properties of wine. In this context, alternative methods are currently sought to achieve full control of this yeast in wine. Killer toxins have recently been proposed to fulfil this purpose. They are antimicrobial compounds secreted by Saccharomyces and non-Saccharomyces yeasts, displaying killer activity against other yeasts and filamentous fungi. They are believed to play a role in yeast population dynamics, and this killer phenotype potentially could be exploited to inhibit the growth of undesired microorganisms within a microbial ecosystem such as that occurring in wine. In this review, non-Saccharomyces killer toxins are described and their potential application in inhibiting B. bruxellensis in wine is discussed in comparison to other tried methods and techniques.

Application of dry-ice blasting for barrels treatment

The main aim of this work was to test a dry-ice basting method to regenerate the barriques in order to prolong their life. In addition, this treatment for barrels can also represent an alternative to the use of sulfur dioxide for the barrique sanitization, in line with the guidelines of oenological practices for sustainable development proposed by the OIV (International Organization of Vine and Wine) (sustainable development, food security: reduction the content of sulfites in wine). The effect of the blasting with dry ice for the treatment of barrique has been studied from a microbiological and sensory point of view. Microbiological analyses were carried out using wine contaminated with Brettanomyces and Lactobacillus ; results showed a reduction of contaminant of 98–100%. Finally, it was evaluated the impact of this treatment on the sensory profile of wine. In this regard the wine aged in a barrique dry-ice blasted was compared with a wine aged in a barrique treated with sulfur dioxide. From the sensory analysis emerged that the dry-ice blasting treatment can regenerate the barriques, this confers to the wine increased notes of vanilla and boise. The benefits that derive from the use of this method are: a good sanitization of the barrel, a positive impact on the organo- leptic characteristics of the wine and the ability to regenerate and reuse a barrel, with a positive effect on sustainability.

Sulfur Dioxide Treatment Alters Wine Microbial Diversity and Fermentation Progression in a Dose-Dependent Fashion

The use of sulfur dioxide (SO2) as an antimicrobial in winemaking is a well-established, common practice. Although much is known about the antimicrobial effects of SO2 at single concentrations, little is known about its effects on microbial growth dynamics across a range of concentrations or when used in conjunction with yeast inoculation. Using high-throughput marker-gene sequencing, we investigated the cumulative impacts of yeast inoculation and SO2 treatments across a broad concentration range (0 to 150 mg/L SO2) on the bacterial and fungal communities in wine fermentations. Our results indicated a dose-dependent effect of SO2, with lactic acid bacteria and Gluconobacter proliferating in fermentations with

Effect of UV-C treatment on the microbial population of white and red wines, as revealed by conventional plating and PMA-qPCR methods

Abstract Ultraviolet C (UV-C) irradiation is one of the emerging techniques for the inactivation of microorganisms in liquid food products, and it holds considerable promise also for treatment of wine. This application can be of particular interest to reduce or even eliminate the use of sulphur dioxide as a preservative in winemaking, given its potential health risks. In this study, UV-C light treatment was applied to ten different white and red wines during winemaking, for the first time at industrial scale, using a commercial turbulent flow system. The effect of 1.0 kJ/l dosage treatment on the viability of the natural microbial population, i.e., total yeasts, lactic acid bacteria and acetic acid bacteria, was investigated both with conventional plating and optimized specific propidium monoazide (PMA)-qPCR. Results of the two methods were mainly concordant for control and UV-C treated samples, and, in some cases, PMA-qPCR was able to detect small amounts of viable cells, probably in the VBNC state. Remarkably, PMA-qPCR allowed to obtain reliable results much faster than conventional plating methods. Data indicated that the UV-C irradiation was effective in reducing microbial counts for up to five log CFU/ml, depending on the wine (white or red) and on the microbial load of the sample. The treatment was much more effective in white wines: a statistically significant decrease was observed for putative spoilage-related bacteria, besides the most pronounced effect on yeast cells. Outcomes strongly support the applicability of UV-C treatment for white wine production, thanks to its efficacy towards all the microbial groups considered.

Application of low concentrations of ozone during the cold storage of table grapes

The control by ozone of postharvest decay of table grapes, caused by Botrytis cinerea and other pathogens, was evaluated in chambers and commercial storage facilities. Ozone at 0.100μL/L or higher inhibited the spread of gray mold among stored grapes. Ozone diffusion into many types of commercial packaging was measured. Boxes made of uncoated paper corrugate inhibited diffusion more than those composed of coated paper corrugate, plastic corrugate, hard plastic, or expanded polystyrene. Internal packaging of hard plastic clamshell containers inhibited diffusion less than low density polyethylene cluster bags. Atmospheres of 0.100μL/L ozone in the day and 0.300μL/L at night reduced the natural incidence of gray mold by approximately 65% after 5–8 weeks of storage. Its effectiveness to control postharvest decay was compared to sulfur dioxide fumigation. After 68 days at 1°C the incidence of gray mold among grapes stored in air, ozone, or with weekly sulfur dioxide fumigation was 38.8%, 2.1%, and 0.1%, respectively. However, decay by other fungi, such as Alternaria spp. and Penicillium spp., was controlled by sulfur dioxide, but not by ozone. In some tests, rachis appearance was moderately harmed by ozone. The combination of ozone use in storage following a single initial sulfur dioxide fumigation, or its use in between biweekly sulfur dioxide fumigations, controlled both gray mold and other pathogens and matched the commercial practice of initial and weekly sulfur dioxide fumigation. The use of both gases in this way reduced sulfur dioxide use greatly. Differences in flavor of grapes treated with ozone were not detectable compared to those stored in air, and grapes treated with ozone were preferred over those treated with sulfur dioxide.

Use of the evapo-destillation of reverse flow to obtein new products derived from grape

The aim of this communication is to show the advantages of the use of wine alcohol as a preservative of must and its recovery through a system of evapo-destillation of reverse flow. Currently, the industry uses sulfur dioxide in the conservation of musts destined for concentration. The problem about the use of sulfur dioxide in the conservation of musts is that not ensure an anti-fermentative stability whole, but mainly in that it is not recovered, thereby producing a consequent pollution. Moreover concentrated musts usually contain a small presence of ethanol from micro-fermentations.

Biotechnological Strategies for Controlling Wine Oxidation

Apart from the controversial positive effects of moderate wine consumption on human health, wine antioxidant capacity plays a key role in winemaking technology. From juice extraction to bottle storage, oxygen management is one of the most critical points for making quality wines. In the past, the protection of juice and wine from oxidations was based on the sole use of sulfur dioxide; more recently, the toxicity and the allergenic potential of this additive, together with the increased knowledge on wine oxidation mechanisms, have given rise to new biotechnological approaches and producing trends, leading to a significant reduction of sulfites in winemaking. The aim of this paper is to review the oxidation mechanisms of grape juice and wine and to discuss the opportunities to reduce as much as possible sulfur dioxide addition by a proper management of alcoholic and malolactic fermentation and by the supplementation of some important yeast nutritional factors (e.g., thiamine). The use of natural antioxidants complementing the activity of sulfites (i.e., ascorbic acid, glutathione, yeast lees, and yeast derivatives) is also discussed.

Effect of high pressure treatments on the physicochemical properties of a sulphur dioxide-free red wine

The application of high hydrostatic pressure (HHP) in winemaking for substitution of the use of sulphur dioxide is still at a very early stage of development, since knowledge about the effect on physicochemical and sensorial characteristics of the wine during storage is very scarce. In this work, the evolution of colour, antioxidant activity and total phenolic compounds of SO2-free red wines treated by HHP and aged in bottles was followed for 12months. The pressurised wines were compared with wine samples prepared with addition of 40ppm of SO2 and without any of these two treatments. After 12months, the pressurised wines presented higher values of CIELab parameters (a∗, b∗, and L∗) and a lower monomeric anthocyanin content (45–61%) when compared to the unpressurised ones. The pressurised wines showed also a better global sensorial assessment, with the pressure treatments imparting aged-like characteristics to the wines. The wine deposits of pressurised wines had higher total phenolic content, namely proanthocyanidins (3- to 10-fold). The results demonstrate that HHP can influence long term red wine physicochemical and sensorial characteristics, hypothesised to be due to an increase of condensation reactions of phenolic compounds, forming compounds with higher degree of polymerisation that became insoluble in wine along storage.

Influence of yeast strain, extended lees contact and nitrogen supplementation on glutathione concentration in wine

Background and Aims Glutathione (GSH) is an antioxidant that plays several important roles in wine, including the limitation of browning and of atypical ageing off-flavours and the preservation of important varietal aroma compounds. In finished wines, however, GSH concentration varies significantly. The influence of several oenological factors, including yeast strain, extended lees contact and yeast assimilable nitrogen content, on the concentration of GSH in wine and in a model wine has been investigated. Methods and Results The influence of 20 commercial Saccharomyces cerevisiae wine yeast strains on the GSH content after alcoholic fermentation was evaluated in a chemically defined grape juice (CDGJ). A significant difference was observed between strains, with some strains resulting in a GSH content sevenfold higher than that of other strains. In Sauvignon Blanc grape juice with a range of initial GSH concentration, the concentration of GSH fluctuated during fermentation. After alcoholic fermentation, however, GSH concentration was generally lower than that initially present in the juice; strains that resulted in the highest GSH concentration in the wines prepared from CDGJ did not necessarily display a similar trend in grape juice. Conclusions Yeast strains have a significant impact on the GSH concentration in finished wines, but specific outcomes are dependent on as yet unknown environmental factors. Yeast assimilable nitrogen concentration in a CDGJ did not impact on GSH concentration after fermentation, and GSH concentration generally decreases during ageing irrespective of the yeast strain or the presence of lees. Significance of the Study The data highlight the influence of certain vinification practices on the GSH concentration in wine and suggest strategies to increase the GSH concentration in commercial wines. Such strategies may help to reduce the use of sulfur dioxide by the industry.

Effect of sulfurdioxide on cobalt electrowinning

The study focused on the use of sulfurdioxide on the cobalt electrowinning and its advantages over conventional electrowinning cell practice are reported. The results indicated that addition of sulfur dioxide in the electrowinning cell reduces the sludge formation with small increase in the current efficiency. SEM response showed an improvement in morphology and DSC analysis gave an idea of the microstructure which is close to FCC lattice system.

Antimicrobial phenolic extracts able to inhibit lactic acid bacteria growth and wine malolactic fermentation

The purpose of this study was to determine whether phenolic extracts with antimicrobial activity may be considered as an alternative to the use of sulfur dioxide (SO2) for controlling malolactic fermentation (MLF) in winemaking. Inhibition of the growth of six enological strains (Lactobacillus hilgardii CIAL-49, Lactobacillus casei CIAL-52, Lactobacillus plantarum CIAL-92, Pediococcus pentosaceus CIAL-85, Oenococcus oeni CIAL-91 and O. oeni CIAL-96) by phenolic extracts (n = 54) from different origins (spices, flowers, leaves, fruits, legumes, seeds, skins, agricultural by-products and others) was evaluated, being the survival parameter IC50 calculated. A total of 24 extracts were found to significantly inhibit the growth of at least two of the LAB strains studied. Some of these extracts were also active against two acetic acid bacteria (Acetobacter aceti CIAL-106 and Gluconobacter oxydans CIAL-107). Transmission electron microscopy of the bacteria cells after incubation with the phenolic extract confirmed damage of the integrity of the cell membrane. Finally, to test the technological applicability of the extracts, the eucalyptus extract was added (2 g/L) to an industrially elaborated red wine, and the progress of the MLF was evaluated by means of residual content of malic acid. Addition of the extract significantly delayed the progress of both inoculated and spontaneous MLF, in comparison to the control wine (no antimicrobial agent added), although not as effective as K2S2O5 (30 mg/L). These results demonstrated the potential applicability of phenolic extracts as antimicrobial agents in winemaking.