Reduction Of Ochratoxin A Research Articles

Kinetic study and optimization of ginger mediated ochratoxin A reduction: An eco-friendly approach including toxicity evaluation

Ochratoxin A (OTA) is a toxic secondary metabolite synthesized by certain fungal strains of Penicillium and Aspergillus and is characterized as a Group 2B carcinogen. OTA infiltrates food and feeds through diverse chains, posing health risks to humans and animals. Herein, seven distinct edible plant materials were screened for their OTA reduction activity. Amidst them, ginger juice in aqueous (2.5%, v/v) showed the highest OTA reduction (95.63%), following first-order reaction kinetics (R2 = 0.92) with 0.72 d−1 rate constant. OTA reduction activity of ginger juice was substantially compromised in the presence of salt (> 2.5%) and temperature (> 40 °C). The response surface methodology-based approach employing Box–Behnken experimental design revealed an integrated effect of temperature, pH, and salt concentrations on OTA reduction (27.44–100%) by ginger juice. In addition, heat treatment (100 °C) and dialysis (12–14 kDa cutoff) of ginger juice implied the inclusion of heat-stable small molecules in reducing OTA. Ginger-treated OTA ameliorated hepatocellular carcinoma (HepG2) cell viability and diminished reactive oxygen species (ROS) levels compared to native OTA. In zebrafish embryos, OTA-induced teratogenic effects, diminished hatching (22.91%), and elevated ROS levels leading to embryo mortality (75%), which was significantly reversed by OTA treated with ginger, underscoring the curtailed toxicity of OTA-converted products by ginger.

Efficiency of cold atmospheric plasma under ozone (O3) and nitrogen oxide (NOx) regimes on the degradation of aflatoxins and ochratoxin A in solid state and in spiked pistachio kernels

Mycotoxins are the primary contaminants in food that have a significant impact on global food safety and security. Cold atmospheric plasma (CAP) has demonstrated significant potential in reducing mycotoxins among innovative technologies. This study aimed to assess the effectiveness of a surface dielectric barrier discharge (SDBD) CAP system in reducing aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), and ochratoxin A (OTA). The distinctive feature of the device here used was the ability to operate at two different powers, resulting in two different plasma reactive species ambients: ozone (O3) and nitrogen oxides (NOx) regimes. CAP treatments exhibited a significant reduction of all investigated pure mycotoxins, which was regime, molecule chemical structure, distance from the source and time-dependent. In particular, O3 regime was more effective (AFB1 and AFG1 99%, AFB2 and AFG2 60%, OTA 70% reduction, respectively, at 60 min, 4 cm distance from the plasma source). As low-moisture foods pistachio kernels (Pistacia vera L. seeds) were selected to evaluate the matrix effect. As expected, the mycotoxins were reduced to a much lesser extent than pure molecules. Worthy of note was the 23% reduction of OTA. To our best knowledge, this is the first investigation about OTA degradation in pistachio food matrix by cold plasma. It should also be noted that the pistachios have been artificially contaminated with spots of a mixture of mycotoxins, to best represent a probable real contamination.

Efficacy of a multicomponent binding agent against combined exposure to zearalenone and ochratoxin A in weaned pigs.

The study aimed to evaluate the efficacy of a novel multicomponent substance against combined exposure to the mycotoxins zearalenone (ZEN) and ochratoxin A (OTA) in weaned piglets. In total, 60 piglets at the age of 28 days were equally allocated to four experimental groups (A-D), consisting of eight female and seven male piglets each (15 animals per group, for a total trial duration of 42 days). Animals from group A received typical weaner feed without mycotoxins or the test product [multicomponent mycotoxin detoxifying agent (MMDA)]. Group B animals received the same weaner feed contaminated with 0.992 mg ZEN/kg feed and 0.531 mg OTA/kg feed without the addition of the MMDA. Animals in group C received the same contaminated feed as group B with the addition of 1.5 g MMDA/kg feed, whereas group D received the same feed as group B with the inclusion of 3 g MMDA/kg feed. Clinical signs and performance parameters [body weight (BW), average daily weight gain (ADWG), and feed conversion ratio (FCR)] were evaluated, while mycotoxin residues were also assessed in the liver and kidney tissues. Findings showed improved FCR in the group that received the greatest dose of the test product (3 g MMDA/kg feed) compared to the group that received the lower dose (1.5 g MMDA/kg feed). A few hematological and biochemical parameters were slightly altered, predominantly within normal limits. The residue analysis demonstrated a reduction of OTA in liver samples, a-ZEL in the liver and total tested samples, and a total of ZEN and metabolite contents in all samples of the group that received the greatest MMDA dose in comparison to the group that received the toxins without the addition of the test product. Therefore, a positive effect of the MMDA at the greatest dosage regime on reducing bioavailability and tissue deposition of ZEN and OTA, with a particularly positive effect on FCR in weaned pigs, is suggested under concurrent ZEN and OTA exposure in vivo.

Surveillance of ochratoxin A in cocoa beans from cocoa-growing regions of Ghana

Cocoa is one of the agricultural commodities which is highly susceptible to mycotoxin contamination. During two crop/harvest seasons, the occurrence and distribution of ochratoxin A (OTA) in viable commercial cocoa beans were investigated. The cocoa bean samples were collected randomly from farmers across cocoa-growing regions of Ghana. OTA concentrations in the samples were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods following purification on immunoaffinity solid phase column. The result showed that 21.7% of all samples analyzed were contaminated with OTA at concentrations ranging from 0.01 μg/kg to 12.36 μg/kg. The Western South region had the highest occurrence of OTA-positive samples at 32.5%, followed by the Western North region at 28.75%, the Eastern and Volta regions at 25% each, Brong Ahafo (16.25%), Central (15%) and the Ashanti region at 11.25%. However, 0.9% and 3.5% of the total OTA-positive samples exceeded the OTA maximum limits of 10 μg/kg for cocoa beans and 3 μg/kg for cocoa powder, set by the Brazilian National Health Surveillance Agency and the European Commission, respectively. During the Main and Light crop seasons, the highest concentrations of OTA were detected in the Western North region, reaching up to 12.36 μg/kg and 3.45 μg/kg, respectively. OTA concentrations between the cocoa-growing regions in the Main crop season were not significantly different (p > 0.05), however, the Light crop season indicated a significant difference (p < 0.05). There was a significant difference (p < 0.05) between the two crop seasons. The need for regular monitoring and careful adherence to agronomic strategies such as good agricultural practices (GAPs), recommended code of practices (COPs) and good manufacturing practices (GMPs) for the prevention and reduction of OTA throughout the cocoa value chain cannot be overemphasized.

Removal of Ochratoxin A from Grape Juice by Clarification: A Response Surface Methodology Study.

This study achieved maximum removal of ochratoxin A (OTA) during the grape juice clarification process with minimal reduction in antioxidant compounds (phenolic acid, flavonoids, and antioxidant capacity by FRAP) by the RSM method. Independent variables included three types of clarifiers—gelatin, bentonite, and diatomite (diatomaceous earth)—at a concentration level of 0.25–0.75% and clarification time of 1–3 h. OTA was measured by high-performance liquid chromatography with fluorescence detection. Clarifying agent concentration and clarification time affected the reduction amount of OTA and antioxidant compounds in grape juice. There was a direct linear correlation between the reduction amounts of OTA and antioxidant compounds and capacity with the concentration of bentonite, gelatin, and diatomite, and the clarification time. The reduction amount of OTA and antioxidant capacity followed the linear mode. However, the decreased phenolic acid and flavonoid values followed the quadratic model. The study results showed that if the concentrations of bentonite, gelatin, and diatomite and clarification time were 0.45, 0.62, 0.25%, and 1 h, respectively, the maximum amount of OTA reduction (41.67%) occurred. Furthermore, the phenolic acid, flavonoid, and antioxidant activity decrease amounts were at their lowest levels, i.e., 23.86, 7.20, and 17.27%, respectively.

Varied reduction of ochratoxin A in brown and white rice during roasting

Ochratoxin A (OTA) is a possible human carcinogen commonly found in various agricultural commodities worldwide. While this potent nephrotoxin tends to survive common food processes and contaminate food products, certain process with higher temperature treatments may reduce OTA contents. Roasting has been suggested as a possible method to reduce OTA in coffee beans with up to 90% reduction, which may be applied to other food commodities. In this study, the possible influence of fibres on the reduction of OTA was investigated with brown and white rice with 2.2 and 6.7% of total dietary fibre content, respectively, roasting at two different temperatures (160 and 200 °C) for up to 30 min. The results showed that the rate and extent of OTA reduction were dependent on time, temperature, and rice type; greater than 60% of OTA reduction were achieved at 200 °C for 30 min for white rice and 37% for brown rice at the same conditions. No significant differences in reduction were observed between the samples roasted at 160 °C for 30 min and 200 °C for 15 min for both the white and brown rice, while white rice roasted at 160 °C for 15 min during roasting may be affected by the presence of fibre and/or fat in the cereal grains.

The fate of ochratoxin A during grape vinegar production

ABSTRACT Vinegar is used as one of the best seasoning and preservatives in foodstuffs worldwide; however, it might be contaminated with mycotoxins like ochratoxin A (OTA). This study aimed to investigate the fate of OTA during unit operations utilised for vinegar production, including washing, juicing, alcoholic fermentation, acetic fermentation, and pasteurisation. Results showed that all unit operations used in vinegar production led to OTA reduction. The highest (40.43%) and lowest (9.63%) reduction values of OTA were obtained during alcoholic fermentation and washing stages, respectively. Juicing, acetic fermentation, and pasteurisation stages reduced 18.86%, 35.97%, and 11.28% of OTA content, respectively. The average overall reduction of OTA during grape vinegar was 75.19%, which can play an influential role in reducing the risks of this mycotoxin.

Proteomic analyses reveal mechanisms of action of biocontrol agents on ochratoxin A repression in Penicillium nordicum

Penicillium nordicum is among the main ochratoxin A (OTA) producers in dry-cured fermented sausages. Recent strategies to prevent its development on the surface of these products include the substitution of synthetic antifungals, such as potassium sorbate, by natural compounds. However, the mechanisms of action of the latter are still unclear. The Proteomic analysis is a useful tool to elucidate the basis of the antifungal compound effects on moulds. Therefore, the aim of this study was to evaluate the efficiency of biocontrol agents on the OTA repression in P. nordicum and its relation to proteome changes. Seven different combinations of rosemary leaves, rosemary essential oil, acorn shell extract and the yeast Debaryomyces hansenii have been tested as biocontrol agents against two ochratoxigenic P. nordicum strains on a dry-cured fermented sausage-based medium. The rosemary essential oil and the combination of rosemary leaves with D. hansenii provoked significant inhibition of OTA production in both moulds (p ≤ 0.05). The acorn shell extract and D. hansenii individually decreased OTA only in one of the mould strains. The Proteomic analyses revealed that rosemary essential oil reduced the abundance of proteins involved in the polyketide synthase enoylreductase domain in both moulds, which would explain the OTA reduction. However, the combination of rosemary leaves with D. hansenii showed inter-strain differences, reducing the abundance of proteins related to the cell wall integrity and to the purine pathway, depending on the tested mould. In conclusion, rosemary essential oil and the combination of rosemary leaves with D. hansenii can be proposed as efficient biocontrol agents against ochratoxigenic P. nordicum on dry-cured fermented sausages, although some inter-strain differences at proteome level were found regarding the mechanism of action involved in the reported OTA repression.

Reduction of Ochratoxin A during the Preparation of Porridge with Sodium Bicarbonate and Fructose.

Ochratoxin A (OTA) is a potential human carcinogen that poses a significant concern in food safety and public health. OTA has been found in a wide variety of agricultural commodities, including cereal grains. This study investigated the reduction of OTA during the preparation of rice- and oat-based porridge by a simulated indirect steam process. The effects of sodium bicarbonate (NaHCO3) and fructose on the reduction of OTA were also investigated. During the processing, OTA in rice- and oat-porridge was decreased by 59% and 14%, respectively, from initial OTA artificially added at 20 μg/kg (dry weight basis). When 0.5% and 1% of sodium bicarbonate were added to rice porridge, increased reduction of OTA was observed as 78% and 68%, respectively. The same amounts of added sodium bicarbonate also further reduced OTA in oat porridge to 58% and 72%, respectively. In addition, increased reduction of OTA in the presence of fructose was observed. A combination of the two, i.e., 0.5% sodium bicarbonate and 0.5% fructose, resulted in a 79% and 67% reduction in rice porridge and oat porridge, respectively. These results indicate that indirect steaming may effectively reduce OTA in preparation of porridge-type products, particularly when sodium bicarbonate and/or fructose are added.

Efficiency of Hydroxycinnamic Phenolic Acids to Inhibit the Production of Ochratoxin A by Aspergillus westerdijkiae and Penicillium verrucosum.

Ochratoxin A (OTA) is one of the worldwide most important mycotoxins in terms of health and agroeconomic consequences. With the aim to promote the use of phytochemicals as alternatives to synthetic fungicides, the effect of hydroxycinnamic acids on the fungal growth and OTA yield by two major OTA-producing species was investigated. After a first step dedicated to the definition of most suitable culture conditions, the impact of 0.5 mM ferulic (FER), p-coumaric (COUM), caffeic and chlorogenic acids was evaluated on Aspergillus westerdijkiae and Penicillium verrucosum. Whereas no fungal growth reduction was observed regardless of the phenolic acid and fungal isolate, our results demonstrated the capacity of FER and COUM to inhibit OTA production. The most efficient compound was FER that led to a 70% reduction of OTA yielded by P. verrucosum and, although not statistically significant, a 35% inhibition of OTA produced by A. westerdijkiae. To further investigate the bioactivity of FER and COUM, their metabolic fate was characterized in fungal broths. The capacity of P. verrucosum to metabolize FER and COUM through a C2-clivage type degradation was demonstrated. Overall, our data support the potential use of FER to prevent OTA contamination and reduce the use of synthetic pesticides.

Isolation of a Novel Kluyveromyces marxianus Strain QKM-4 and Evidence of Its Volatilome Production and Binding Potentialities in the Biocontrol of Toxigenic Fungi and Their Mycotoxins

To overcome the economic losses associated with fungi and their toxic metabolites, environmentally safe and efficient approaches are needed. To this end, biological control using yeasts and safe bacterial strains and their products are being explored to replace synthetic fungicides. In the present study, the biocontrol effect of a yeast strain of Kluyveromyces marxianus, QKM-4, against the growth and mycotoxin synthesis potential of key toxigenic fungi was evaluated. In vitro assays were performed to find the application of yeast volatile organic compounds (VOCs) against fungal contamination on important agricultural commodities. The removal of ochratoxin A (OTA) and deoxynivalenol (DON) by living and heat-inactivated yeast cells was also explored. VOCs produced by strain QKM-4 were able to significantly limit the fungal growth of 17 fungal species belonging to genera Aspergillus, Penicillium, and Fusarium. Yeast VOCs were able to reduce OTA biosynthesis potential of Penicillium verrucosum and Aspergillus carbonarius by 99.6 and 98.7%, respectively. In vivo application of QKM-4 VOCs against Fusarium oxysporum and A. carbonarius infection on tomatoes and grapes, respectively, determined a complete inhibition of fungal spore germination. GC/MS-based analysis of yeast VOCs identified long-chain alkanes, including nonadecane, eicosane, docosane, heptacosane, hexatriacontane, and tetracosane. In vitro testing of the mycotoxin-binding potential of the living and heat-inactivated QKM-4 cells showed a reduction of OTA and DON up to 58 and 49%, respectively, from artificially contaminated buffers. Our findings clearly demonstrate the strong antifungal potential of K. marxianus QKM-4 and propose this strain as a strong candidate for application in agriculture to safeguard food and feed products.

Effect of thermal processing and traditional flavouring mixture on mycotoxin reduction in pistachio

The effect of heating (roasting and microwave radiation heating) along with a traditional pistachio flavouring mixture (containing verjuice, thyme extract, and sodium chloride) was investigated on reducing aflatoxins (AFs) and ochratoxin A (OTA) in pistachios. The naturally and artificially contaminated samples were soaked in the flavouring mixture (for 5, 10 and 24 h) and then subjected to roasting (at 120 and 150 °C for 50 min) and heating by microwave radiation (6 and 10 min). The residual mycotoxins were determined by high-performance liquid chromatography. The results showed that all treatments were able to reduce mycotoxin content (aflatoxin B1, B2, G1, G2 and OTA) significantly (P&lt;0.05), up to 85.7±2.5% (during roasting) and up to 72.5±2.6% (during heating by microwave radiation). The highest reduction of AFs and OTA (ranging from 51.7±2.3 to 85.7±2.5%) was found when the contaminated (naturally and artificially) samples were soaked in the traditional mixture for 24 h and roasted at 150 °C. It could be concluded that the traditional flavouring method in combination with the roasting process or heating by microwave radiation could be applied as a useful and safe method for mycotoxin degradation in pistachio. Although, complete elimination of mycotoxins was not achieved, the method reduced mycotoxins more than 60% without adverse effect on the taste and appearance of pistachios.

Stability of ochratoxin A in oats during roasting with reducing sugars

Ochratoxin A (OTA) is a possible human carcinogen commonly occurring in many agricultural commodities, particularly in oats and their processed products. Due to its heat stability, OTA has been found in thermally processed food products including breakfast cereals and cereal grains. In this study, the reduction of OTA during roasting of oats was investigated under conditions similar to the industrial applications including addition of sugars. Oat grains were conditioned to achieve a uniform moisture content (16% wet weight basis, wb) and OTA (100 μg/kg wb). Then, the grains were roasted at 120 °C and 180 °C for 30 min and 60 min, respectively. The concentration of OTA in roasted oat-based cereals was decreased by 2–18% with increasing roasting temperature and time. The reduction of OTA was greater when oat grains were roasted with reducing sugars, i.e., glucose (11%) and fructose (15%), compared with oat-based cereal samples with no added sugar (10%). In addition, previously identified degradation products of OTA such as OTA isomer, OTα, and OTα amide were not formed during roasting. These results indicate that increased reduction of OTA in oats can be achieved by roasting with sugars, which can be readily applicable in commercial production of oat-based snack foods.

Effects of baking soda and fructose in reduction of ochratoxin A in rice and oat porridge during retorting process

Ochratoxin A (OTA) is a possible human carcinogen found in a wide range of foods and agricultural commodities worldwide. This potent nephrotoxin is of concern because of its thermal stability under most conditions used during food processing and high incidence and concentration in oat-based baby foods. In this study, the effects of added baking soda (0.5% and 1%; w/w), fructose (0.5% and 5%; w/w), or combination of both (baking soda 0.5% + fructose 0.5%; w/w) on the stability of OTA during retorting of porridge type products made of oat flour or rice flour (10% solid content; w/v) were investigated using a laboratory scale horizontal steam retort. The reduction of OTA after retort was 17.2% in oat porridge and 53.8% in rice porridge, while addition of baking soda resulted in greater reduction of OTA. In retorted oat porridge, reduction of OTA was 30.3% and 47.9% with 0.5% and 1.0% of added baking soda, respectively. The reduction of OTA in retorted rice porridge reached 55.5% and 66.4% with 0.5% and 1% baking soda, respectively. Addition of fructose resulted in greater reduction of OTA in oat porridge (35.5–40.8%) but not in rice porridge. The reduction of OTA in retorted rice and oat porridges with combination 0.5% baking soda and 0.5% fructose were 35.8% and 39.8%, respectively. These results suggest that OTA may be reduced significantly by retorting of oat and rice porridge. In addition, added baking soda may contribute to the reduction of OTA in rice and oat porridges while added fructose may facilitate OTA reduction in oat porridge.

Transformation of Ochratoxin A by Microorganisms Isolated from Tempranillo Grapes in Wine Systems

Mycotoxins are toxic metabolites produced by various genera of fungi. Fungi belonging to species of the genera Aspergillus and Penicillium are the main source of ochratoxin A (OTA) in wine. The reduction of OTA in must and wine has been studied using physical, chemical, and biological technologies. In this paper, we report on the capacity of different cultures isolated from Tempranillo winegrapes contaminated with fungus to degrade OTA in tryptic soy broth (TSB) medium at pH 3.5 and 6.5. We studied the interaction between OTA and four isolates during alcoholic fermentation of red wine. This study showed that microorganism isolates reduced the content of OTA in TSB medium and in the wine experiment system. The bacterium Lactobacillus rhamnosus exhibited the greatest mean reduction of OTA in TSB medium at both pH values (55%). During the wine fermentation, the yeast Metschnikowia pulcherrima showed the most reduction of OTA (34%). Liquid chromatography with tandem mass spectrometry was used to identify OTA degradation products, particularly α-OTA (m/z = 257) and the sodium adduct of α-OTA with the loss of the coumarin group (m/z = 170). The presence of OTA in must and wines is a problem for food safety. The use of lactic acid bacteria and yeasts during the winemaking process presents an interesting practical solution.

Transcriptome analysis of non-ochratoxigenic Aspergillus carbonarius strains and interactions between some black aspergilli species

Aspergillus carbonarius consistently produces large amounts of ochratoxin A (OTA), a mycotoxin with nephrotoxic effects on animals and humans. In the present study, we analyzed the transcriptional changes associated to OTA production in three atypical non-ochratoxigenic strains of A. carbonarius. In addition, in vitro interactions between ochratoxigenic strains of A. carbonarius and A. niger and non-ochratoxigenic strains of A. carbonarius and A. tubingensis were studied in order to evaluate their potential for controlling OTA production. RNA-seq analysis revealed that there are 696 differentially expressed genes identified in the three non-OTA-producing strains, including 280 up-regulated and 333 down-regulated genes. A functional and gene ontology enrichment analysis revealed that the processes related to metabolic and oxidation processes, associated with functions such as oxidoreductase and hydrolase activity were down regulated. All the genes related with OTA biosynthesis in A. carbonarius were the most down-regulated genes in non-ochratoxigenic strains. We also showed that these strains possess a deleterious mutation in the AcOTApks gene required for OTA biosynthesis. Moreover, one of these strains gave the best control of OTA production resulting in an OTA reduction of 98–100% in co-inoculation with an ochratoxigenic strain of A. niger and an OTA reduction of 79–89% with an ochratoxigenic strain of A. carbonarius. Results of this study provided novel insights into the knowledge of the OTA biosynthetic pathway in these non-ochratoxigenic wild strains, and showed the biocontrol potential of these strains.

Assessment of processing impacts and type of clarifier on the concentration of ochratoxin A in pekmez as a conventional grape-based product

Pekmez can be considered as one of the most favored traditional grape's products, however, it can be contaminated with ochratoxin A (OTA). In this regard, for the first time, the effects of unit operations including washing, juicing (crushing and pressing), clarification with the aid of various clarifier (bentonite, white soil, and gelation) and boiling on the concentration of OTA in artificially spiked pekmez samples were investigated. According to findings, all unit operations utilized in pekmez production led to OTA reduction while the range - mean of OTA reduction in washing, juicing (crushing and pressing), clarification and boiling stages were recorded as 7.36–16.53%-12.19 ± 4.60%, 2.51–8.32%-6.13 ± 3.16%, 4.24–16.55%-16.38 ± 10.25%, and 1.54–37.43%-10.44 ± 3.85%, respectively. Among the clarifiers used, the highest (23.76 ± 7.90%) and lowest (11.48 ± 9.37%) mean reduction of OTA was attributed to gelatin and bentonite, respectively. Therefore, the utilization of gelatin could remove higher levels of OTA. Generally speaking, the OTA overall reduction range and mean during the pekmez production process was 25.84–54.67 and 37.52 ± 6.54%, respectively, which depended on the initial concentration of OTA and unit operations, the type and concentration of clarifier. The optimum condition of OTA reduction was obtained in samples containing initial OTA content of 5 μg kg−1 which were clarified with 3% of gelatin.

Effect of Aspergillus carbonarius on ochratoxin a levels, volatile profile and antioxidant activity of the grapes and respective wines

Aspergillus carbonarius can produce a possibly carcinogenic mycotoxin named ochratoxin A (OTA). The metabolism of this fungus can also impact grape and wine quality as it influences the volatile and phenolic profiles, which are related to aroma and antioxidant activity, respectively. The objective of this study was to evaluate the effect of A. carbonarius on OTA levels and for the first time on volatile profile and antioxidant activity of grapes and their respective wines. Cabernet Sauvignon (CS, red) grapes presented higher susceptibility to A. carbonarius than Moscato Italico (MI, white) grapes and OTA levels in their respective musts were in accordance with this same trend. However, vinification of red grapes resulted in 67% reduction of OTA, while the reduction observed with white wines was 45%. The presence of acids (hexanoic, octanoic, nonanoic and decanoic, fatty odor) was found to be an indicative of the fungus incidence in grapes. These acids were precursors of esters that might impart negative aroma (methyl nonanoate and isoamyl octanoate, fatty odor) or provide desirable fruity characteristics (ethyl hexanoate, ethyl octanoate and methyl octanoate) for wine. In addition, terpenes were detected only in wines produced with grapes (CS and MI) inoculated with A. carbonarius. The presence of A. carbonarius increased the antioxidant activity of CS grapes. For MI grapes and both wines (CS and MI) no differences were verified in the antioxidant activity of the samples affected or not affected by this fungus. Although A. carbonarius occurrence has shown no influence on the antioxidant activity of wines, it produced OTA and has negatively influenced the wine odor profile, due to the production of some volatiles that impart a deleterious effect on wine aroma.

Efficient, safe, renewable, and industrially feasible strategy employing Bacillus subtilis with alginate bead composite for the reduction of ochratoxin A from wine

Abstract In this study, environment-friendly cost-effective, non-toxic, and reusable strategy was developed using Bacillus subtilis (a GRAS-grade bacterium, isolated from the Korean traditional food, Kimchi) immobilized in edible alginate bead composite for the reduction of ochratoxin A (OTA) toxin from red wine. Initially, B. subtilis-immobilized sodium alginate beads reduced 90% of the OTA from the culture medium (pH 3 and 25% NaCl), and the reduction in the OTA content increased as the pH decreased and the NaCl concentration increased. Additionally, the immobilized sodium alginate beads when added to red wine spiked with OTA, resulted in OTA reduction by 78.50 ± 0.49% after 1 h. Free Bacillus subtilis cells showed OTA reduction by 81.70 ± 1.91% but required higher number of cells, thus was not a cost effective approach. Furthermore, simple cleaning the beads with ethanol allowed them to be reused and renewed at least 10–20 times with a significant OTA reduction ability. These findings suggest the potential application of B. subtilis-immobilized alginate beads in OTA reduction from red wine samples, and the strategy could be applied for other types of liquid foods.

Ochratoxin A reduction by peroxidase in a model system and grape juice.

This study aimed at evaluating the potential of the peroxidase (PO) enzyme to reduce ochratoxin A (OTA) levels and its application to grape juice. Both commercial PO and PO extracted from rice bran were evaluated, respectively, regarding their activity towards OTA in a model system. The affinity between PO and OTA was verified by the Michaelis-Menton constant and the maximum velocity parameters, resulting in 0.27μM and 0.015μMmin-1 for the commercial enzyme, and 6.5μM and 0.031μMmin-1 for PO extracted from rice bran, respectively. The lowest residual OTA levels occurred when 0.063UmL-1 of the enzyme was applied. Under these conditions, the OTA reduction was 41% in 5h for the commercial enzyme, and 59% in 24h, for PO extracted from rice bran. When the extracted PO, with the activity of 0.063UmL-1, was applied to whole grape juice, the OTA levels decreased to 17%, at 24h. The capacity shown by PO for reducing OTA levels was confirmed in whole white grape juice, as a model system. This study may assist the wine industry to offer healthier products and add value to rice bran. Graphical abstract.