The antimicrobial effect of wine on Bacillus cereus in simulated gastro-intestinal conditions

This study aimed to evaluate the antimicrobial activity of wine against Bacillus cereus vegetative cells and spores. The results clearly show that wine exerts a strong inactivation effect against vegetative cells of B. cereus. The red wine tested inactivated stationary phase cultures to undetectable numbers in less than 10 s. Thus, further inactivation assays were carried out with wine diluted with water (1:4 and 1:8). Diluted wine 1:4 caused a reduction of approximately 5 log cycles on viable cell counts in 20 s. On the other hand, B. cereus spores were found to be highly resistant to wine exposure. The influence of wine components (organic acids, ethanol and phenolic compounds) was investigated on vegetative cells. The wine organic acids tested exhibited a strong inactivation effect, and, when combined with ethanol, a slight synergistic effect was observed. The wine phenolic compounds assayed displayed no activity against the vegetative cells at the concentrations tested. At the simulated gastric conditions studied (in the presence of food), wine diminished considerably the number of B. cereus viable cells in addition to the effect of the synthetic gastric fluid. The behaviour of B. cereus spores under gastro-intestinal conditions was also evaluated. In a consumption-like scenario, the addition of wine led to lower total counts (vegetative cells + spores) of B. cereus in the simulated intestine conditions, showing that wine inhibits the proliferation of the vegetative cells obtained from the germination of spores. This work provides evidence that consumption of wine during a meal may diminish the number of viable cells of B. cereus and reduces the impact of the germination of spores that may occur in the small intestine, thus lowering the risk of toxi-infection that may be caused by this pathogen.     

Protease activity of Oenococcus oeni viable cells on red wine nitrogenous macromolecular fraction in presence of SO2 and ethanol

The protease activity of Oenococcus oeni X₂L viable cells on red wine nitrogenous macromolecular fraction (NMF) as sole nitrogen source was determined. The enzyme releases growth factors for Oenococcus oeni. In presence of SO₂ and ethanol the rate of amino acids liberation was twofold higher. A peptide peak analyzed by HPLC with a retention time of 47 min diminishes markedly during the first 2 h incubation. O. oeni X₂L living cells are able to produce the exoprotease and to act on the red wine NMF in the presence of SO₂ and ethanol releasing essential amino acids for its survival.     

Volatile compounds contribution of Hanseniaspora guilliermondii and Hanseniaspora uvarum during red wine vinifications

This work aims to investigate the contribution of a selected non-Saccharomyces yeast species, Hanseniaspora guilliermondii, to higher alcohols, esters, fatty acids and heavy sulphur compounds composition of red wine. Red grape must vinifications of 100 l were performed and an inoculated fermentation with H. guilliermondii was compared to a spontaneous fermentation. The presence of apiculate yeasts was observed in both fermentations; however, Hanseniaspora uvarum was the only apiculate yeast isolated from the spontaneous fermentation. Apiculate yeasts dominated the fermentation until an ethanol concentration of 6% (v/v) was attained and remained in considerable high levels for an ethanol concentration of 12.5% (v/v). The grape must inoculated with H. guilliermondii led to the production of wine with higher concentrations of 1-propanol, 2-phenylethyl acetate and 3-(methylthio)propionic acid, and lower amounts of ethyl hexanoate, pentanoic acid, free fatty acids, 2-methyltetrahydrothiophen-3-one and acetic acid-3-(methylthio)propyl ester, than wine resulting from the spontaneous fermentation. The present study shows that the use of specific apiculate yeasts in grape must fermentations may lead to the production of wines with different chemical profiles, emphasising the importance of Hanseniaspora yeasts as mixed starter cultures with Saccharomyces cerevisiae, in winemaking.     

Changes in flavour characteristics and bacterial diversity during the traditional fermentation of Chinese rice wines from Shaoxing region

As a traditional alcoholic beverage, Chinese rice wine is quite popular for its unique flavor and high nutritional value. In this study, we investigated the changes of flavor compounds in varying stages of fermentation by HS-SPME-GC-MS and HPLC. In addition, 16s rDNA-PCR was utilized to analyze the changes of bacterial communities during fermentation of Chinese rice wine from the Shaoxing region. It was noted that the content of flavor compounds including esters, higher alcohols, amino acids and organic acids was different in varying stages of fermentation. In general, the flavor compounds of Chinese rice wine were mainly produced after pre-fermentation. The results also showed that the bacterial community structures and diversity of Chinese rice wine varied significantly during different fermentation stages, and more than 10 genera of bacteria was detected in Chinese rice wine fermentation broth. Among these specific bacteria identified in the study, Lactobacillus (the predominant genus) and Bacillus might take an active part in flavor development in Chinese rice wine. This implied that these bacteria might play significant contributions on the flavor of Chinese rice wine.     

Analysis of lignin-derived phenolic compounds and their transformations in aged wine distillates

Aromatic aldehydes and acids derived from lignin were studied by capillary zone electrophoresis in barrel matured wine distillates used in brandy production. Different conditions of analysis were applied to set up the best separation and reproducibility. The optimal separation was performed using 25 mM borate buffer containing 8% v/v ethanol as modifier. Total amount of guaiacol-type compounds (coniferaldehyde, vanillin, and vanillic acid) and syringol-type compounds (sinapaldehyde, syringaldehyde, and syringic acid) increased with increasing ageing time for distillates aged from 1 to 25 years. Sum of concentrations of syringic and vanillic acids can be also used for characterizing aged distillates according to their ageing level. The developed analysis method is simple, precise and cost efficient. It provides good separation efficiency, and it is ideally suited for the analysis of aged wine distillates for determination of their overall quality, approximate ageing time and signs of counterfeiting.     

Rapid method for the determination of organic acids in wine by capillary electrophoresis with indirect UV detection

A capillary electrophoresis method for organic acids in wine was developed and validated. The optimal electrolyte consisted of 10 mmol/L 3,5-dinitrobenzoic acid (DNB) at pH 3.6 containing 0.2 mmol/L cetyltrimethylammonium bromide as flow reverser. DNB was chosen because it has an effective mobility similar to the organic acids under investigation, good buffering capacity at pH 3.6, and good chromophoric characteristics for indirect UV-absorbance detection at 254 nm. Sample preparation involved dilution and filtration. The method showed good performance characteristics: Linearity at 6 to 285 mg/L (r > 0.99); detection and quantification limits of 0.64 to 1.55 and 2.12 to 5.15 mg/L, respectively; separation time of less than 5.5 min. Coefficients of variation for ten injections were less than 5% and recoveries varied from 95% to 102%. Application to 23 samples of Brazilian wine confirmed good repeatability and demonstrated wide variation in the organic acid concentrations.     

Combined treatment with silver ions and organic acid enhances growth-inhibition of Escherichia coli O157:H7

Individual and combined treatment with silver ions and selected organic acids were evaluated for growth-inhibition of Escherichia coli O157:H7. The concentrations of silver ion were 0.1, 0.3, 0.5, and 1.0 ppm and, citric, lactic, maleic, succinic, and tartaric acids (0.05% and 0.1%) were used. The inhibitory effect was measured during the growth of E. coli O157:H7 in LB broth by optical density at 600 nm. For individual treatments, silver ion at all concentrations and organic acids at 0.1% had a stronger inhibitory effect than untreated control and 0.05% organic acid treatments. For combined treatments, 1.0 ppm of silver ion with 0.1% of organic acids had the greatest inhibitory effect on E. coli O157:H7 growth. With different concentrations, combination with 1.0 ppm of silver ion and 0.05% of organic acids showed greater inhibitory effect than combination with 0.3 ppm of silver ion and 0.1% of organic acids. Combined treatment with silver ion and organic acid showed the enhanced inhibitory effect of E. coli O157:H7 compared to individual treatments. The present study indicated that growth-inhibiting effect of combined treatment was dependant on the concentration of silver ion rather than that of organic acid.     

Effect of sulfur dioxide and ethanol concentration on fungal profile and ochratoxin a production by Aspergillus carbonarius during wine making

Fungal profiles and ochratoxin A (OTA) accumulation during wine making were investigated using five different wine grape cultivars, Cabernet Sauvignon, Pinot Noir, Merlot, Syrah and Petit Verdot and the intrinsic influences caused by sulfur dioxide, ethanol and combine effect of ethanol and reducing sugar were analyzed using Cabernet Sauvignon and inoculation of Aspergillus carbonarius. Aspergillus spp. and Penicillium spp. were found as the major fungi in all winemaking processes and were highly correlated with OTA accumulation in wine. Most fungi died and OTA production decreased after 48 h of alcoholic fermentation, being consistent with the period when ethanol accumulation increased. The addition of SO₂ significantly inhibited the growth and OTA production of A. carbonarius with complete inhibition at 500 mg/L. When the ethanol concentration in the must increased to the range of 2–4%, growth and OTA production of A. carbonarius were significantly inhibited. Reducing sugar concentration had no significant effect on the growth and OTA production of A. carbonarius within the levels changing during the winemaking. Therefore, the increase of ethanol concentration played an important role in causing the decrease of fungal contamination and OTA accumulation during winemaking.     

Organic thyme oil emulsion as an alternative washing solution to enhance the microbial safety of organic cantaloupes

Emulsions of organic essential oils may be used as postharvest alternative washing solutions in fresh produce production. In the present study, organic thyme oil was emulsified with whey protein concentrate, gum arabic, lecithin, or their equal mass mixtures without using specialized equipment. The stability of these emulsions was monitored by measuring hydrodynamic diameter during ambient storage up to 7 days. The antimicrobial activity of these emulsions against Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). All emulsions had lower MIC and MBC than free thyme oil pre-dissolved in ethanol. Thyme oil emulsified with gum arabic had the smallest and most stable hydrodynamic diameter (156–239 nm) and was chosen as the washing solution to evaluate its efficacy in reducing pathogens on organic cantaloupes. Cantaloupes inoculated with pathogens were immersed in 0.1%, 0.2%, or 0.5% emulsified or free thyme oil for 2 min. The counts of the three cultures inoculated on cantaloupes were reduced by either 0.2% or 0.5% thyme oil and the emulsions were more effective than free thyme oil (P < 0.05). Organic load (2% or 5%) had no effect on their antimicrobial efficacy (P > 0.05). During ambient storage (21 °C) up to 10 days, the counts for all three bacteria gradually declined for all treatments and the emulsion treatment had consistently lower populations than unwashed and water-washed treatments. Therefore, emulsions of organic essential oils have potential applications as postharvest washing solutions to improve the microbiological safety of organic fresh produce.     

Organic wine safety: UPLC-FLD determination of Ochratoxin A in Southern Italy wines from organic farming and winemaking

A fast reversed-phase UPLC method was utilized for Ochratoxin A (OTA) determination in 55 different wine samples (red and white) produced in Southern Italy, during two vintages. All the samples came from vineyards in which the plants were subjected to organic farming and were produced according to an organic winemaking, following strict rules on processing aids. Analytical methods included the clean-up purification by using commercial immunoaffinity columns and an Acquity UPLC^® system equipped with a fluorescent detector; the sensitivity of the analytical method was 0.01 ng mL⁻¹. OTA was detected in all wine samples analyzed and the levels were always below the maximum tolerable EU limit (2 ng mL⁻¹); the red wine samples proved to be more contaminated than the white ones.The occurrence incidence of OTA in wines produced according organic farming and winemaking was comparable with that of commercial wines conventionally produced and wines obtained from organic farming only. The results of this study indicate a low risk of exposure to OTA by consumption of these wines.     

Bordeaux red wines display variable intrinsic ability to support Brettanomyces bruxellensis growth

Red wines constitute a major production in Bordeaux vineyards but to ensure the quality of these wines, winemakers should limit the development of the spoilage yeast Brettanomyces bruxellensis. Therefore, the growth of five representative strains of B. bruxellensis in 53 sulphite-free Bordeaux red wines was examined and differences between them were found regarding the ability to support the yeast growth. Thanks to a notation method and unsupervised classification analysis, we classified the wines according to their “permissiveness”. The key factors modulating the permissiveness score were the wine ethanol content, the yeast strain and the wine itself (domain, vintage or batch). The pH had little effect. The wine composition analysis (Proton Nuclear Magnetic Resonance (¹H NMR) analysis of 43 compounds) did not enable to find the molecules responsible for the wine permissiveness.     

Combining basic electrolyzed water pretreatment and mild heat greatly enhanced the efficacy of acidic electrolyzed water against Vibrio parahaemolyticus on shrimp

The objective of this study was to investigate the efficacy of acidic electrolyzed water (AEW) against Vibrio parahaemolyticus on shrimp. The shrimp was initially inoculated with V. parahaemolyticus(7-8 log CFU/g), and treated with AEW (AEW1 containing 51 mg/L of chlorine or AEW2 containing 78 mg/L of chlorine) or organic acids (2% AA and 2%LA) for 1 min or 5 min under different treated conditions. The effect of AEW was better than that of organic acids, the number of survival V. parahaemolyticus cells on shrimp was reduced by 0.9 log CFU/g after treatment for 5 min with AEW without vibration, while 1.0 log CFU/g bacteria cells reduced with vibration. No significant difference (p > 0.05) was observed between AEW and organic acids in the bactericidal activity with or without vibration. The effective order of temperatures on bactericidal activities of AEW was 50 °C > 20 °C > 4 °C, and a 3.1 log CFU/g reduction of V. parahaemolyticus cells on shrimp was detected with treatment of AEW at 50 °C. Mild heat greatly enhanced efficacy of electrolyzed water against V. parahaemolyticus. Basic electrolyzed water (BEW) (50 °C) pretreatment combined with AEW (50 °C) treatment remarkably reduced bacterial cells by 5.4 log CFU/g on shrimp after treatment for 5 min. There was a significant change in physicochemical properties (pH, ORP, ACC) of AEW, after it was used to wash shrimp (P < 0.05). This study suggests that BEW (50 °C) pretreatment followed by AEW (50 °C) treatment could be a possible method to effectively control V. parahaemolyticus contamination on shrimp.     

ACID BASE PHENOMENA IN DISTILLATE FUEL STABILITY

Carboxylic and organic sulfonic acids, added to distillate fuel blends containing catalytically cracked stock, Increase deposit formation, sometimes very dramatically. The carboxylic acids data fitted into a unified treatment in relationship to hydrogen ion concentration calculated from pK_a values for aqueous solutions. These acids enhance deposit formation by catalytic action and are not Incorporated into the deposit. Organic sulfonic acids may fit into the unified acid catalysis pattern but await resolution of ionization phenomena in non-aqueous solution.

A tertiary aliphatic amine stabilizer was effective for reducing deposit amounts from fuel blends containing acids. This amine acts on a stoichiometric basis to counteract strong acids in the fuels. For weak acids, the amine stabilizer exhibited an effect slightly more than that for a 1:1 basis with the amount of acid in the fuel. Other amines exerted favorable behavior only if they were strong organic bases.     

Effect of ethanol on the ability of Oenococcus oeni to remove ochratoxin A in synthetic wine-like media

The study focused on the changes in bacterial population, malolactic fermentation and ochratoxin A (OTA) levels in cultures of Oenococcus oeni performed in synthetic medium supplemented with ethanol and OTA. Growth was better in cultures containing 5% ethanol and was not observed in cultures containing 15% ethanol. The OTA removal ability of O. oeni depended on ethanol and initial OTA levels. The highest toxin removal percentage was observed in cultures containing 5% ethanol and 2 μg OTA/l. In ethanol-containing medium part of OTA was not sorbed by O. oeni and remained in the liquid medium. Thus, it cannot efficiently eliminate OTA in acidic ethanol-containing beverages, such as wine. The effect of ethanol on the OTA removal ability of O. oeni is described for the first time.     

Antimicrobial activity of phenolic compounds of wine against Campylobacter jejuni

Campylobacter jejuni is a food pathogen which causes gastrointestinal conditions with an ever-increasing incidence at a global level. The antimicrobial power of wine and its components has been studied. Wines having 11.5% ethanol significantly reduced the viability of C. jejuni when they were diluted to 25% in water. The microbicidal power of red wine was higher than that of white wine. While pH does not seem to affect the viability of this pathogen, different phenolic compounds have an effect on it when tested at concentrations from 0 to 1000 mg/L. Gallic acid and p-hydroxybenzoic acid reduced the viability of C. jejuni at concentrations as low as 1 mg/L, but quercetin and catechin did not even affect it at concentrations of 1000 mg/L. Methyl gallate, epicatechin, synaptic acid, vanillic acid, and caffeic acid were microbicidal at concentrations starting at 10 mg/L. Tryptophol, ferulic acid, and cumaric acid were effective starting at 100 mg/L. According to this, wine constitutes an adverse environment for the survival of this pathogen. Furthermore, it would be interesting to study the possible use of phenolic compounds in wine as an alternative to the use of antimicrobial growth promoters against these bacteria in broilers.     

Evaluation of volatile compound and food additive contents in blackberry wine

In addition to the biologically nutritious components present in wine, there can be substances that are harmful to human health. For this reason, the purpose of this study was to evaluate the contents of volatile compounds and food additives in blackberry wine samples produced from conventionally and organically grown blackberries and compare their concentrations with the maximum acceptable levels in wines for the first time. Volatile compounds were analyzed in 15 blackberry wines using a GC-FID method, while the contents of food additives were determined using a newly developed HPLC method. Both methods were validated for their linearity, sensitivity, repeatability, and intermediate precision. The major volatile compound in blackberry wine samples was ethanol (7.11–15.33%). The second most prevalent volatile compound found in all blackberry wine samples was methanol (174.2–641.4 mg/L), which is highly toxic. The amount of ethyl acetate in the investigated samples ranged from 53.8 to 188.4 mg/L, while propan-1-ol was found in three of the organic samples. Although isoamyl alcohol was found in all samples, the measured values ranged from 56.7 to 226.9 mg/L. The obtained results demonstrated that the concentrations of benzoic acid in the analyzed blackberry wines varied from 4.36 to 18.55 mg/L. The presence of sorbic acid has was detected in seven samples, and the values were in the range of 1.43–54.48 mg/L. Salicylic acid is a natural component of blackberry fruit, and the contents of this phytochemical in the studied wines were between 1.99 and 13.55 mg/L. The saccharin concentrations were detected in three samples, and the highest value was 31.51 mg/L. The concentrations of amyl alcohol, acesulfame, aspartame and caffeine were found to be below the quantitation limits of the method in the investigated blackberry wines. Furthermore, the obtained data provide evidence that the contents of methanol in blackberry wines were above the permissible limits, except for four conventional blackberry wines. Thus, the concentrations of analyzed volatile substances measured in blackberry wines necessitate more extended investigations of these volatile compounds in this popular fruit wine.     

Influence of intrinsic factors on conventional wine protein stability tests

The influence of intrinsic factors on the results of ethanol, tannin and heat tests, routinely used to assess wine protein stability, was studied. Experiments were performed on 23 Portuguese and Austrian wines. The factors considered were total protein content, pH, ethanol content and the amount of several relevant cations (calcium, iron, copper, sodium and potassium). The protein profiles were analysed by HPLC fractionation. The heat test was a good indicator of total protein content while the ethanol and the tannin tests showed significant interference by the other factors. A factorial design at two levels in selected samples was also performed to assess the influence of pH, storage temperature, tannin concentration and ethanol concentration on the development of turbidity. Results indicated that ethanol content had no significant influence, and that pH and storage temperature had a significant influence, though only when tannin was added.     

有机酸对NiW/Al2O3加氢脱硫催化剂性能的影响

在NiW/Al2O3催化剂的制备过程中分别添加丁酸、丁二酸、柠檬酸有机助剂,采用程序升温还原（TPR）、X射线衍射（XRD）、高分辨透射电镜（HRTEM）、扫描电子显微镜(SEM)- EDS能谱等对催化剂进行表征,考察不同有机酸对催化剂性质和柴油加氢脱硫活性的影响。结果表明,催化剂制备过程中添加有机酸减弱了金属组分与载体间的相互作用,增加了活性金属的硫化度和WS2晶粒的堆垛层数,减少了金属组分的聚集。除丁酸外,添加丁二酸和柠檬酸催化剂的加氢脱硫活性均高于对比NiW/Al2O3催化剂。     

Effect of certain lead and copper compounds as ballistic modifier for double base rocket propellants

Abstract

During our search for better burn rate catalysts and platonizers the effect of lead oxide with lead copper salts of organic acids was studied. Basic lead and copper salts of aliphatic acids have been found to produce more or less similar catalytic and plateau effects, whereas basic copper salts of aromatic acids were comparatively more effective in producing higher burn rates than basic lead salts, although reduction of pressure index values was more pronounced with basic lead salts. The results have been explained in the light of existing theories on catalysis and platonization.     

Characterization and suitability of polyphenols-based formulas to replace sulfur dioxide for storage of sparkling white wine

The sparkling wine protection against air is of interest for maintaining its sensorial profile and it is achieved through the use of antioxidants while disgorging. Sulfur dioxide (SO₂) is commonly added, but its amount should be limited due to human health problems. The suitability of three polyphenols-based commercial formulas containing plant gallic and ellagic acids extracted from grape (Vitis vinifera L.) (AO1), plant ellagic acid and gum arabic (AO2), and plant gallic, ellagic acids and Saccharomyces cerevisiae cell-wall fractions (AO3) was evaluated after 7 months storage (at 15 °C and 25 °C) of disgorged sparkling white wine. The phenolic composition of these formulas was investigated through spectrophotometric measurements. Moreover, the phenols were characterized and quantified by HPLC-MS analyses. The sotolon concentration and the absorbance values at 420 nm were determined in wines. The HPLC-MS analysis showed that the formula AO1 mainly contained gallotannins, ellagic tannins and flavan-3-ols, while AO2 had high levels of flavan-3-ols and gallotannins. Flavan-3-ols were the only phenols found in AO3. The addition of these formulas increased the yellow hue. Sotolon was higher than the perception threshold in the samples with AO2 and at trace amount in the samples with both AO1 and AO3 only stored at 25 °C. The tested antioxidant formulas seemed to be less effective of SO₂ for the storage of sparkling white wine. However, the investigation of phenolics in antioxidant formulas could be helpful for the proper choice of a potential substitute of SO₂ due to increase interest in sulfur-free wine production.