Ochratoxin A removal from red wine by several oenological fining agents: bentonite,egg albumin,allergen-free adsorbents,chitin and chitosan

The ability of several oenological fining agents to remove ochratoxin A (OTA) from red wine was studied. The adsorbents tested were activated sodium bentonite, egg albumin, allergen-free adsorbents (complex PVPP, plant protein and amorphous silica (complex) and high molecular weight gelatine), and the non-toxic biodegradable polymers (chitin and chitosan). Several dosages within the oenological use range were tested and the wine pH, colour parameters and polyphenol concentration impact associated with each fining agent were studied. Generally, OTA removal achieved in all treatments was higher when the adsorbent dosage increased, but the impact on wine quality also was higher. Chitin at 50?g?hl^?1 removed 18% the OTA without affecting significantly the wine-quality parameters. At the highest dosage tested the gelatine and complex treatments achieved greater OTA removal (up to 39–40%) compared with bentonite, egg albumin and chitin. Moreover, the gelatine and the complex had a lower impact on colour parameters and polyphenol concentration compared with chitosan, whilst OTA was reduced to around 40%. Chitosan achieved the greatest OTA removal (67%), but it strongly affected the wine-quality parameters. Otherwise, bentonite showed a relative efficiency to remove OTA, but the CI value decreased considerably. The egg albumin treatment only removed OTA up to 16% and moreover affected strongly the CI value and CIELab parameters. The results of this survey showed that the non-toxic chitin adsorbent and the allergen-free adsorbents tested could be considered as alternative fining agents to reduce OTA in red wine.     

Clarifying effect of different fining agents on mulberry wine

Fining experiments have been conducted on mulberry wine, in which five fining agents (bentonite, gelatin, casein, egg albumin and PVPP) were investigated. The effect of these agents on polyphenol content, colour intensity, antioxidant activity and aromatic profile has been determined. In general, all treatments improved the limpidity of the mulberry wines to some extent. The wine was mostly negatively affected by gelatin and led to the greatest reduction of phenol content (16.61%), colour intensity (32.26%) and antioxidant activity. Concerning aroma, the addition of PVPP, casein and bentonite both significantly altered the aroma profile. It is noteworthy that egg albumin led to the lowest diminution total phenol value (5.74%) and improvement of antioxidant capacity and colour among the tested fining agents. Furthermore, the aroma profile remained mostly unaffected by egg albumin. As consequence, the optimal fining agent for mulberry wine was egg albumin.     

Heat-unstable protein removal by different bentonite labels in white wines

The relationship between heat-unstable wine proteins and bentonite fining is still a matter of debate. Some authors have suggested that bentonite removes protein according to matrix parameters, but others have described it as selective for some protein classes. The aim of our work was to characterize the fining effects of five different types of activated sodium bentonite on two international white wines (Chardonnay and Sauvignon blanc). The physical properties of the bentonite samples and the general wine characteristics were determined, and protein removal was evaluated with gradient SDS-PAGEs, protein quantification and subsequent band identification by MALDI-TOF mass spectrometry. For the Chardonnay and Sauvignon blanc tested in the study, fining with specific bentonite labels to remove select residual proteins, some of which are potential allergens, was very promising. The removal of a single protein by bentonite affected the wine’s thermal stability.     

Use of patatin, a protein extracted from potato, as alternative to animal proteins in fining of red wine

The use of plant-derived proteins as wine fining agent has gained increased interest owing to the potential allergenicity of animal proteins in susceptible subjects. Patatin P is the name of a family of glycoproteins that can be recovered from potato aqueous by-product. In this study, a comparative fining trial simulating industrial procedures with 10, 20 and 30?g/hL of commercial preparations of patatin, potassium caseinate, gelatin and egg albumin on an Aglianico (Vitis vinifera L.) red wine was performed. Color indexes and phenolics were analyzed by spectrophotometric methods and HPLC. The potential astringency has been evaluated by an index based on the ability of wine to precipitate salivary proteins (SPI, Saliva Precipitation Index). Patatin is a suitable alternative to animal proteins used as fining agent because: (i) a decrease in total phenolics and tannins after the treatments with 10, 20 and 30 g/hL of commercial preparation containing P was detected; (ii) Patatin, as well as all the fining agents used in this experiment, is able to diminish astringency and the content of red wine phenolics able to react with salivary proteins. Considering all concentrations tested, the effectiveness in reducing proteins reactive towards wine polyphenols was patatin?=?gelatine > egg albumin > casein (p?<?0.05); (iii) at each concentration considered, the treatment with patatin causes no depletion of chromatic characteristics of red wine although a significant slight loss of individual anthocyanins was observed.     

Evolution of ochratoxin A content during red and rose vinification

BACKGROUND: This work aims to investigate the effects of the common vinification steps on the fate of the ochratoxin A (OTA) during wine making. Two assays of red and rose microvinification, with artificially contaminated grapes, were performed. The content of this mycotoxin was also monitored throughout the process of red wine making from naturally contaminated grapes in a winery. RESULTS: The results from the different assays revealed that the maceration of pomace have a significant effect on the increase of OTA content in red wine (P < 0.05) whereas the alcoholic fermentation had a reducing effect. However, the spontaneous malolactic fermentation showed no significant effect on the OTA content in wine (P > 0.05). Storage of red wine in tanks followed by draining caused a significant decrease of OTA of about 55%. Clarification with a gelatin oenological fining agent contributed to the removal of up to 58% of OTA from red wine. CONCLUSION: Overall, a consistent decrease in OTA concentration was noticed throughout either red or rose vinification. This work has contributed to the understanding of the fate of OTA during different vinification processes, especially from naturally contaminated grapes. Copyright © 2008 Society of Chemical Industry     

Removal of Ochratoxin A (OTA) from Naturally Contaminated Wines During the Vinification Process

In this study, 28 red and 18 white musts, from seven different local wineries in Turkey, were investigated to determine their ochratoxin A (OTA) content following the 2006 harvest period. The removal conditions of OTA during the main stages of the wine making processes (alcoholic fermentation, malolactic fermentation, racking, fining and storage) were investigated using HPLC techniques. In addition, the removal of OTA from two samples of red musts containing more than 1.0 μg/L of OTA and one sample of white must containing 0.83 μg/L of OTA were studied. The percentage of OTA removal in the final wine was found to be 41.8% (Sample A) and 53.7% (Sample B) in red wine and 44.7% in the white wine. The activated carbon had no greater effect on removing OTA than the other fining agents. The wine bottle ageing processes decreased the OTA content of the red wine between 11.8% and 17.6% during 12 and 18 months of storage, respectively. The 24 month ageing period did not affect the OTA level of the red wine further compared to the 18 month period.     

三种常用澄清剂对樱桃酒澄清效果的影响

利用明胶、皂土、壳聚糖对樱桃原酒分别进行了单一澄清剂和复合澄清剂的试验,测定加入澄清剂处理之后的樱桃酒的透光率、吸光度、总酚、单宁和蛋白质含量并进行比较。结果表明:单一使用壳聚糖0.6 g/L处理樱桃酒可起到最好的澄清效果,透光率达94.7%;复合澄清剂确定其在樱桃酒澄清中的最佳组合,即:明胶0.096 g/L、皂土0.8 g/L、壳聚糖0.4 g/L,但对樱桃酒澄清效果较单一澄清剂并无显著优势。     

Chitosan, chitin-glucan and chitin effects on minerals (iron, lead, cadmium) and organic (ochratoxin A) contaminants in wines

Chitosan (F7), chitin (F2), chitin-glucan (F1) and chitin glucan hydrolysate (F5) of fungal origin were tested for removal of mineral (Fe or Pb and Cd) and organic (ochratoxin A: OTA) contaminants in wines. Red, white and sweet wines are spiked with either Fe (20 mg L⁻¹), or Pb (500 μg L⁻¹) and Cd (20 μg L⁻¹) or OTA (5 μg L⁻¹). The wines were then treated with F1, F2, F5 or F7 at doses of 0.1 g, 0.5 and 2 g L⁻¹. After 2 days, the levels of iron, copper, lead and cadmium were measured using a flame and graphite furnace atomic absorption spectrophotometer. Depending on the treatment red wines showed reductions of iron by 73–90%, cadmium by 29–57% and lead by 33–74%. The same treatments with white wine gave reductions for iron of 32–91%, cadmium fell by 11–23%, lead by 50–65%. In the case of sweet wines iron was reduced by 51–90%, cadmium by 17–25%, and lead by 38–84%. For wine enriched in OTA, treatments with F1, F2, F5, F7 were carried out at doses of 2 and 5 g L⁻¹. After 2 days, the levels of OTA in wines were analyzed by HPLC with fluorimetric detection. OTA was reduced by 56.7–83.4% in red wine, by 53.4–64.5% in white wine and 26.1–43.5% in sweet wine. These findings indicate that chitosan, chitin, chitin-glucan, or chitin glucan hydrolysate from fungal origin may be useful ancillaries for wine limpidity prevention by reducing levels of Fe, heavy metals (Pb, Cd) and mycotoxins (OTA) and thereby improving wine safety.     

几种澄清剂在水蜜桃发酵酒中的应用

主要研究比较三种澄清剂:明胶,皂土和壳聚糖在水蜜桃发酵酒中的澄清效果。研究表明:用450nm处的吸光度和680nm处的透光率可作为水蜜桃发酵酒色度和澄清度的指标;3种澄清剂中,除明胶基本上无澄清效果外,其他澄清剂均有较理想的澄清效果。澄清剂最适添加量为:皂土2·0g/L,壳聚糖0·8g/L,其中壳聚糖澄清速度快,效果最好,透光率可达97·3%。     

Effects of fining agents on trans-resveratrol concentration in wine

Resveratrol has been identified as a wine component related to moderate wine consumption and a reduction in serum cholesterol levels. Processes such as wine fining that result in loss of resveratrol during winemaking are therefore of interest, and led to these present studies. A number of agents were compared and were found to lower resveratrol levels in all wines to some extent. Results from two studies (1996 and 1997) are reported. The standard addition method was used in combination with High Pressure Liquid Chromatography to calculate resveratrol levels. In Study 1 (1996), recommended maximum levels of all fining agents (Level 3), bentonite, egg white, gelatin + kieselsol and polyvinylpolypyrrolidone (PVPP), lowered resveratrol levels significantly compared to controls (Level 0). Nevertheless, addition of fining agents at Level 0 resulted in resveratrol levels that were significantly higher than those at Level 3, but resveratrol levels in wine from Level 0 were not significantly different from Level 1. In Study 2 (1997), carbon + egg white, and gelatin + kieselsol fining was studied, and their effects differed according to grape variety. Least removal of resveratrol by carbon fining occurred in wine from Cabernet Sauvignon (Vitis vinifera) whereas most removal occurred in wines from Cynthiana (Vitis aestivalis) and Noble (Vitis rotundifolia). Resveratrol levels of control wine were significantly higher than resveratrol levels of wine treated with recommended maximum addition of fining agent in all varieties. Taken overall, any addition of any fining agent lowered resveratrol levels in all wines to some extent, but complex interactions between fining agent and wine variety resulted in different regression trends. While recognising the constraints set by our particular data that could reflect unique circumstances, we are nevertheless able to infer from these trends that low levels of fining agents can be used without statistically significant loss of resveratrol.     

几种澄清剂对茯苓发酵酒的澄清效果比较研究

采用单一澄清剂蛋清、琼脂、明胶、皂土、壳聚糖和复合澄清剂皂土与壳聚糖对茯苓发酵酒进行澄清研究.结果表明,复合澄清剂的澄清效果明显好于单一澄清剂,经皂土与壳聚糖处理的茯苓发酵酒透光率达到98%,还原糖保存率为97%,总酸保存率95%.皂土和壳聚糖添加量分别为0.16%和0.08%,澄清后的酒体稳定性增加.     

Protein stabilisation of Chardonnay wine using trisacryl and bentonite: a comparative study

The stabilisation of a Chilean Chardonnay wine by SP-Trisacryl-M and bentonite was investigated, evaluating protein, polyphenol and polysaccharide adsorption, turbidity and wine quality. The wine could be stabilised by adding at least 0.3 kg m⁻³ of bentonite or 12 kg m⁻³ of trisacryl, removing 95% and 76% of the wine proteins, respectively. The protein adsorption data for bentonite and trisacryl were fitted using the Freundlich isotherm. The wine protein adsorption isotherm on trisacryl was unfavourable. Protein removal from Chardonnay by trisacryl in a packed column at continuous operation was about 50% during the first 70 bed volumes (BV) of treated wine and decreased progressively until the end of the treatment (100 BV). The adsorbents showed a higher selectivity for proteins than for polyphenols and polysaccharides. A sensorial panel could not detect statistically significant differences between the bentonite and trisacryl treatments of wine at P  ≤ 0.05.     

Influence of fining agents on the sensorial characteristics and volatile composition of mead

Mead, one of the oldest fermented drinks, is derived from the fermentation of diluted honey by yeasts. In the context of wine production, several procedures are applied to stabilize the beverage and to improve its organoleptic properties. This study aims to evaluate the impact of adding fining agents on the production of mead. In general, the best results were obtained for the samples containing just one fining agent instead of two combined. However, the best performance was obtained for the combined fining agents (bentonite + gelatine + egg albumin). Tannins decreased significantly the content of volatile compounds. On the other hand, silica appears to be the best fining agent, resulting in the lowest loss of volatile compounds. Thirty‐six volatile compounds were determined by gas chromatograph–flame ionization detector and gas chromatography–mass spectrometry, including alcohols (42.5%), carbonyl compounds (40.4%), acetates (14.4%) and esters (1.8%). Eleven volatile compounds had odour activity values >1, representing those with a major impact on the aroma of mead. Significant differences (p  < 0.05) were found in 10 volatile compounds independently to the type of treatment used and no differences (p  > 0.05) were observed for remaining compounds. Copyright © 2017 The Institute of Brewing & Distilling     

In vitro removal of ochratoxin A by wine lactic acid bacteria

A study was carried out to determine the in vitro interaction between ochratoxin A (OTA) and wine lactic acid bacteria (LAB). Fifteen strains belonging to five relevant oenological LAB species were grown in liquid synthetic culture medium containing OTA. The portion of OTA removed during the bacterial growth was 8 to 28%. The OTA removed from the supernatants was partially recovered (31 to 57%) from the bacterial pellet. Cell-free extracts of three representative strains were produced by disrupting cells in a French pressure cell. The ability of crude cell-free extracts to degrade OTA was studied. OTA was not degraded by cell-free extracts of wine LAB strains, and no degradation products of OTA were detected in the high-performance liquid chromatograms of the methanol extract of the bacterial pellet. On the basis of these results, we conclude that OTA removal by wine LAB is a cell-binding phenomenon. The chemistry and the molecular basis of OTA binding to wine LAB remains unknown.     

Protein stabilisation of white wines using zirconium dioxide enclosed in a metallic cage

Backgrounds and Aims: White wines are stabilised by removing the heat unstable proteins through adsorption by bentonite. Bentonite fining is not an efficient wine processing step and can also remove other wine components. Alternative absorbents are thus sought; zirconium dioxide (zirconia) is recognised as a promising candidate. The aim of this work was to assess the viability of zirconia treatments to stabilise white wines, with particular attention on process development. Methods and Results: Effective treatment was achieved by enclosing zirconia pellets into a metallic cage submerged in the wine. With this method, the wine could be treated with the adsorbent for the time required for protein stabilisation, and then removed without further manipulation. Zirconia treatments of three unstable wines partially or fully stabilised them without detectable modifications of their physicochemical parameters and colours, apart from the removal of metals and some acids, particularly when wines were treated for long times and with high dosages of the adsorbent. A simple and inexpensive zirconia regeneration method was also developed. Conclusions: The zirconia application to wine was very effective in removing proteins, and the proposed regeneration procedure could facilitate the uptake and development of zirconia‐based solutions for the wine industry. Significance of the Study: This study confirmed the effectiveness of zirconia in removing wine proteins and demonstrated that the proposed method of application has the potential to become a viable alternative to bentonite.     

The use of thaumatin and bovine serum albumin as proteins in model wine solutions in bentonite fining

This study examined the viability of using thaumatin and bovine serum albumin (BSA) as proteins in model wine solutions for bentonite fining studies and compared them with unfined New Zealand sauvignon blanc (SB) wine. Bentonite fining trials were performed on model wine solutions and unfined SB wines (pH range 3.5–4.3). Thaumatin was more readily adsorbed onto bentonites of all types than BSA and its adsorption onto bentonite was less affected by the pH of the solution. Specifically, the amount of BSA adsorbed onto bentonite decreased significantly as the pH of the solution approached the isoelectric point (pI) of BSA while thaumatin was adsorbed at that pH due to its higher pI. Changing pH affected protein adsorption of real wine less noticeably than of BSA and thaumatin, and decreasing pH increased protein adsorption in contrast to the model solutions. Neither of the model solutions can fully represent the response of real wine to bentonite fining but they are simple and cost effective to prepare and reacted to changes in bentonite concentration similar to real wine. Thaumatin is potentially a better protein to use in simple model solutions for wine stabilisation studies like filtration where molecular weights are important consideration.     

甜橙果酒澄清技术研究

甜橙是柑橘属中一个较优良的加工品种,以其酿制的果酒营养丰富,但是果酒的澄清度会影响其品质。为了提高甜橙果酒的品质,通过添加蛋清、明胶、壳聚糖、果胶酶、皂土等不同的澄清剂处理果酒,以透光率作为澄清效果的评价指标,并对处理后的果酒进行酒精度测定和感官评价。结果表明,单一澄清剂对甜橙果酒有澄清作用,其中蛋清、明胶、壳聚糖、果胶酶、皂土最适添加量分别为0.08%、2.0%、0.08%、1.5%和9%,以皂土澄清效果最佳;将明胶及皂土组合得到复合澄清剂,透光率达96.20%,感官评价得分最高为89.6分,对酒精度影响最小。综上,以明胶-皂土的最佳配比明胶2.0%、皂土9%效果最为理想,经过澄清处理后的甜橙果酒呈金黄色,澄清透明,酒体丰满,具有良好的品质。     

Selection of low swelling materials for protein adsorption from white wines

Summary The protein adsorption capacity of different materials was evaluated to assess their potential efficacy as alternative adsorbents for the removal of proteins from wines, with the purpose of finding suitable low-swelling materials that could be used in a percolated bed. The adsorbents tested were thermally treated sodium bentonite, low-swelling adsorbing clays, ion exchange resins and other protein adsorbents (silica gel, hydroxyapatite and alumina). The materials were evaluated by analysing both the capacity to stabilize untreated white wines, according to a heat test, and by characterizing the adsorption isotherms of bovine serum albumin (BSA) in a model wine (water, ethanol and K-bitartrate). Breakthrough curves in a packed bed were determined experimentally for some materials, showing the influence of the adsorption isotherm shape. Some ion-exchange resins showed a favourable behaviour and have good potential as alternative adsorbents.     

Comparing the impact of bentonite addition for both must clarification and wine fining on the chemical profile of wine from Chambave Muscat grapes

The impact of bentonite fining is generally studied on final wines, and few studies have evaluated it throughout the winemaking process. This work studied the fate of proteins and terpenols, the main targets of bentonite addition, during the processing of Chambave Muscat aromatic grapes. The experimental trials were performed in two vintages (2006 and 2007) and included the following processes: bentonite addition to must only (100 g hL^?1 in both vintages), fining of wine only (100 g hL^?1 in both vintages), double bentonite treatment on must and wine (200 and 150 g hL^?1 in 2006 and in 2007, respectively) and no treatment (control). The results demonstrated that the treatment allowing the best removal of protein was the addition of bentonite to must only. Moreover, a lower removal of free terpenols was observed in samples from double treatment compared with wines fined with bentonite only after alcoholic fermentation.     

Effects of Fining Agents on Antioxidant Capacity of Red Wines

The antioxidant capacity of wine depends not only on the grape variety but also on the wine processing steps. The aim of this study was to determine the effects of different fining agents, used at different concentrations, on the antioxidant status of fined wines. The results demonstrated that the use of a combination of gelatin and Kieselsol led to the highest total phenol value (3,491 mg/L GAE) and antioxidant activities (29%) among the tested fining agents. Wines were mostly negatively affected by the use of egg white as an agent and led to the lowest value of total phenol (3,038 mg/L GAE) and the lowest rate of antioxidant activity (26%). Significant differences (p<0.05) were determined between gelatin, egg white, and the control groups. The results of the grouping of analyzed parameters in n‐dimensional space, with different fining agents at different concentrations, demonstrated the importance of a low concentration of fining agents for high antioxidant activity and total phenols.