Structural and Physicochemical Properties of Starch from Rejected Chestnut: Hydrothermal and High-Pressure Processing Dependence.

The quality standards for the export of chestnuts generate large quantities of rejected fruits, which require novel processing technologies for their safe industrial utilization. This study aimed to investigate the impact of high-pressure processing (HPP) and hydrothermal treatments (HT) on the physicochemical properties of rejected chestnut starch. Chestnuts were treated by HPP at 400, 500, and 600 MPa for 5 min and HT at 50 °C for 45 min. In general, all HPP treatments did not induce starch gelatinization, and their granules preserved the integrity and Maltese-cross. Moreover, starch granules' size and resistant starch content increased with the intensity of pressure. Native and HT chestnut starches were the most susceptible to digestion. HPP treatments did not affect the C-type crystalline pattern of native starch, but the crystalline region was gradually modified to become amorphous. HPP-600 MPa treated starch showed modified pasting properties and exhibited the highest values of peak viscosity. This study demonstrates for the first time that after HPP-600 MPa treatment, a novel chestnut starch gel structure is obtained. Moreover, HPP treatments could increase the slow-digesting starch, which benefits the development of healthier products. HPP can be considered an interesting technology to obtain added-value starch from rejected chestnut fruits.

Brazilian Table Olives: A Source of Lactic Acid Bacteria with Antimycotoxigenic and Antifungal Activity.

Food and feed contamination by fungi, especially by toxigenic ones, is a global concern because it can pose serious health problems when the production of mycotoxins is involved. Lactic acid bacteria (LAB), well-known for fermenting foods, have been gaining attention for their antifungal and anti-mycotoxin properties. This work tested 14 LAB strains isolated from naturally fermented Brazilian table olives for growth inhibition of Aspergillus flavus, Aspergillus carbonarius, Penicillium nordicum, and Penicillium expansum. The strains Lacticaseibacillus paracasei subsp. paracasei CCMA 1764, Levilactobacillus brevis CCMA 1762, and Lactiplantibacillus pentosus CCMA 1768 showed the strongest antifungal activity, being more active against P. expansum. Aflatoxin B1 (AFB1), ochratoxin A (OTA), and patulin (PAT) production was reduced essentially by mycelia growth inhibition. The main organic acids detected in the cell free supernatant (CFS) were lactic and acetic acids. Tested LAB exhibited adsorption capacity against AFB1 (48-51%), OTA (28-33%), and PAT (23-24%). AFB1 was converted into aflatoxin B2a (AFB2a) by lactic and acetic acids produced by the strain CCMA 1764. A similar conversion was observed in solutions of these organic acids (0.1 M). These findings demonstrate the potential of isolated LAB strains as natural agents to control toxigenic fungi and their mycotoxins in fermented products, such as table olives.

Detoxification of ochratoxin A and zearalenone by Pleurotus ostreatus during in vitro gastrointestinal digestion.

Powdered Pleurotusostreatus (PO) was tested for the detoxification of ochratoxin A (OTA) and zearalenone (ZEN) through in vitro gastrointestinal digestion in the absence and presence of ground feed and cornmeal. Ochratoxin α was detected in the chromatograms after OTA elimination, suggesting the presence of an OTA-hydrolytic enzyme in the PO, whereas ZEN was adsorbed by PO. OTA was totally eliminated at pH 5 and 7, while ZEN was better adsorbed at pH 3. In simulated gastrointestinal conditions conducted without feed matrices, PO eliminated OTA by 85% and ZEN by 23% at the end of the intestinal phase. When digestions were conducted with ground feed and cornmeal, PO eliminated OTA by 13 and 34%, and ZEN by 20 and 2%, respectively. PO demonstrated great potential for OTA detoxification, but the feed matrices adsorbed the mycotoxins, reducing their bioaccessibility considerably in the oral and gastric phases and negatively influencing PO detoxification capacity.

Lipid-based nanostructures as a strategy to enhance curcumin bioaccessibility: Behavior under digestion and cytotoxicity assessment.

The aim of this study was to evaluate the behavior of different lipid-based nanostructures during in vitro digestion, in particular on curcumin's bioaccessibility, and to access their potential toxicity. Solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and nanoemulsions (NE) were submitted to harmonized static in vitro digestion and their cytotoxicity and cellular transport were evaluated using Caco-2 cell line. NE presented the highest curcumin's bioaccessibility followed by NLC and SLN, 71.1%, 63.7% and 53.3%, respectively. Free fatty acids percentage increased in the following order: NLC ≤ NE < SLN. Non-digested nanostructures and excipients presented no cytotoxicity; however, digested NE and NLC presented cytotoxicity due to MCT oil, which presented cytotoxicity after digestion. The apparent permeability coefficient of NLC was higher than SLN and NE. These results showed that lipid-based nanostructures' physical state and composition have a high influence on particles' behavior during digestion, and on their cytotoxicity/intestinal permeability, and highlights the importance of conducting cytotoxicity assessments after in vitro digestion. This work contributes to a better understanding of the behavior of lipid-based nanostructures under digestion/adsorption, and this knowledge will be useful in design of nanostructures that afford both safety and an increased bioactive compounds' bioavailability.

Nanoemulsions for Enhancement of Curcumin Bioavailability and Their Safety Evaluation: Effect of Emulsifier Type.

This work aimed at evaluating the effects of different emulsifiers on curcumin-loaded nanoemulsions' behavior during digestion, its safety and absorption, to develop nanoemulsions that provide safety and improved curcumin functionality. Nanoemulsions (NEs) were produced using two bio-based (lecithin (LEC) and rhamnolipids (RHAM)) and one synthetic (Tween®80 (TWE)) emulsifier at similar concentrations. Different NEs were subjected to in vitro digestion. The cytotoxicity and permeability tests were performed in Caco-2 cells. NE_TWE were stable during all phases of in vitro digestion, whereas NE_LEC and NE_RHAM were found to be unstable from the gastric phase. NE_TWE showed 100% of free fatty acids released, followed by NE_RHAM and NE_LEC. Curcumin's bioaccessibility and stability increased in the following order: NE_LEC > NE_RHAM > NE_TWE. NE_LEC and NE_TWE did not show cytotoxic effects in any of the concentrations tested, while NE_RHAM presented high cytotoxicity in all concentrations tested. The apparent permeability coefficients were determined for NE_LEC and NE_TWE; however, the results were not statistically different. These results showed that the emulsifier used has a high impact on nanoemulsions' behavior under the digestion process and on their cytotoxicity. This work contributed to the state-of-the-art's progress on the development of safer curcumin delivery systems with improved functionality, particularly regarding the proper selection of ingredients to produce said systems.

Rhamnolipids inhibit aflatoxins production in Aspergillus flavus by causing structural damages in the fungal hyphae and down-regulating the expression of their biosynthetic genes.

Aflatoxins are hepatotoxic and carcinogenic fungal secondary metabolites that usually contaminate crops and represent a serious health hazard for humans and animals worldwide. In this work, the effect of rhamnolipids (RLs) produced by Pseudomonas aeruginosa #112 on the growth and aflatoxins production by Aspergillus flavus MUM 17.14 was studied in vitro. At concentrations between 45 and 1500 mg/L, RLs reduced the mycelial growth of A. flavus by 23-40% and the production of aflatoxins by 93.9-99.5%. Purified mono-RLs and di-RLs exhibited a similar inhibitory activity on fungal growth. However, the RL mixture had a stronger inhibitory effect on aflatoxins production at concentrations up to 190 mg/L, probably due to a synergistic effect resulting from the combination of both congeners. Using transmission electron microscopy, it was demonstrated that RLs damaged the cell wall and the cytoplasmic membrane of the fungus, leading to the loss of intracellular content. This disruptive phenomenon explains the growth inhibition observed. Furthermore, RLs down-regulated the expression of genes aflC, aflE, aflP and aflQ involved in the aflatoxins biosynthetic pathway (6.4, 44.3, 38.1 and 2.0-fold, respectively), which is in agreement with the almost complete inhibition of aflatoxins production. Overall, the results herein gathered demonstrate for the first time that RLs could be used against aflatoxigenic fungi to attenuate the production of aflatoxins, and unraveled some of their mechanisms of action.

Valorisation of rejected unripe plantain fruits of Musa AAB Simmonds: from nutritional characterisation to the conceptual process design for prebiotic production.

The increasing consumption of plantain fruits with specific quality standards generates high agricultural waste. This work aimed at valorising the rejected unripe pulp of Dominico-Hartón plantain fruits (Musa AAB Simmonds). The pulp was characterised physico-chemically, thermally and functionally. The data gathered experimentally and collected from different databases were used to design a production process of isomalto-oligosaccharides (IMO) syrup. The plantain flour contains high levels of starch (87 ± 2%) and amylose (31.2 ± 0.8%). The flour showed stability at high temperatures (pasting temperature of 79.26 ± 0.02 °C), allowing its use in high temperature processes. In vitro gastrointestinal digestion of the plantain flour showed that when cooked, the glycemic index of the flour increased from 47.7 ± 2.2 to 84.2 ± 1.8, while its resistant starch content only slightly decreased from 71.7 ± 1% to 52.6 ± 2%, suggesting that this type of flour preserves high content of dietary fibre after digestion. The conceptual process design showed that 24.48 g of IMO are theoretically obtained from 53.24 g of plantain flour maltose. These results suggest that the rejected plantain pulp holds high potential as an ingredient for the production of prebiotic compounds such as IMO.

Curcumin encapsulation in nanostructures for cancer therapy: A 10-year overview.

Curcumin (CUR) is a phenolic compound present in some herbs, including Curcuma longa Linn. (turmeric rhizome), with a high bioactive capacity and characteristic yellow color. It is mainly used as a spice, although it has been found that CUR has interesting pharmaceutical properties, acting as a natural antioxidant, anti-inflammatory, antimicrobial, and antitumoral agent. Nonetheless, CUR is a hydrophobic compound with low water solubility, poor chemical stability, and fast metabolism, limiting its use as a pharmacological compound. Smart drug delivery systems (DDS) have been used to overcome its low bioavailability and improve its stability. The current work overviews the literature from the past 10 years on the encapsulation of CUR in nanostructured systems, such as micelles, liposomes, niosomes, nanoemulsions, hydrogels, and nanocomplexes, emphasizing its use and ability in cancer therapy. The studies highlighted in this review have shown that these nanoformulations achieved higher solubility, improved tumor cytotoxicity, prolonged CUR release, and reduced side effects, among other interesting advantages.

Elimination of Aflatoxins B1 and B2 in White and Red Wines by Bentonite Fining. Efficiency and Impact on Wine Quality.

Aflatoxins B1 and B2 are two highly toxic mycotoxins that have been sometimes found in wines. Currently, no technological solution is available to reduce or eliminate aflatoxins from wines when they are present. Therefore, this work aims to study the efficiency of already approved wine fining agents like activated carbon, potassium caseinate, chitosan, and bentonite for aflatoxins B1 and B2 removal from white and red wines. It was observed that the fining agents' efficiency in removing aflatoxins was dependent on the wine matrix, being higher in white than in red wine. Bentonite was the most efficient fining agent, removing both aflatoxins (10 µg/L total) from the white wine and 100% of aflatoxin B1 and 82% of aflatoxin B2 from red wine. The impact of bentonite on white wine chromatic characteristics was low (color difference, ΔE* = 1.35). For red wine, bentonite addition caused a higher impact on wine' chromatic characteristics (ΔE* = 4.80) due to the decrease in total anthocyanins, although this decrease was only 1.5 points of color intensity. Considering the high efficiency of bentonite in aflatoxins B1 and B2 removal and despite the impact on red wine color, bentonite is a very good technological solution for aflatoxin removal in white and red wines.

Effect of Gamma-Radiation on Zearalenone-Degradation, Cytotoxicity and Estrogenicity.

Zearalenone (ZEA) is produced in cereals by different species of Fusarium, being a non-steroidal estrogenic mycotoxin. Despite having a low acute toxicity, ZEA strongly interferes with estrogen receptors. Gamma-radiation has been investigated to eliminate mycotoxins from food and feed, showing promising results. The present study aims to investigate the gamma-radiation effect on ZEA at different moisture conditions and to evaluate the cytotoxicity and estrogenicity of the irradiated ZEA. Different concentrations of dehydrated ZEA and aqueous solutions of ZEA were exposed to gamma-radiation doses ranging from 0.4 to 8.6 kGy and the mycotoxin concentration determined after exposure by high performance liquid chromatography (HPLC) with fluorescence detection. Following this, the cytotoxicity of irradiated samples was assessed in HepG2 cells, by measuring alterations of metabolic activity, plasma membrane integrity and lysosomal function, and their estrogenicity by measuring luciferase activity in HeLa 9903 cells. Gamma-radiation was found to be effective in reducing ZEA, with significant increases in degradation with increased moisture content. Furthermore, a reduction of cytotoxicity with irradiation was observed. ZEA estrogenicity was also increasingly reduced with increasing radiation doses, but mainly in aqueous solutions. These results suggest reduction of ZEA levels and of its toxicity in food and feed commodities may be achieved by irradiation.

Mycobiota and mycotoxins in Portuguese pork, goat and sheep dry-cured hams.

The objectives of the present work were to survey, for the first time, the contamination of Portuguese fresh and dry-cured meat products with ochratoxin A (OTA) and aflatoxin B1 (AFB1), and to determine the fungi potentially responsible for this contamination. A total of 128 samples including pork fresh legs, dry-cured legs and shoulders, as well as goat and sheep dry-cured legs were analysed. Mycological analysis of these samples yielded a total of 630 fungal isolates. Penicillium sp. was the dominant fungal genus in all products (66% of all isolates). Penicillium nordicum and Aspergillus westerdijkiae were only rarely isolated from pork ham samples. In fresh pork meat, 40% of the samples were contaminated with OTA at levels below 1 µg/kg. In pork dry-cured legs with 20 to 25 months of ripening, 43% of the samples showed detectable contamination, while 18% of the shoulder hams were contaminated. OTA was not detected in any of the goat and sheep samples. OTA contamination does not seem to be a risk in small-piece and short-ripe products like goat and sheep legs, but affects longer ripe products like pork legs and shoulders. Although aflatoxigenic fungi were identified, AFB1 was not detected in any sample, and it should not be considered a risk in dry-cured hams.

BSA-based sample clean-up columns for ochratoxin A determination in wine: Method development and validation.

Analytical chromatographic techniques for mycotoxins control are well established, but they often depend on costly immunoaffinity sample clean-up. Serum albumins, particularly that from bovine origin (BSA), have stable binding affinity towards some mycotoxins, and can be cheaper alternative receptors for sample clean-up due to their wide availability. Thus, this work used BSA immobilized in agarose beads as a novel solid-phase extraction method for quantification of ochratoxin A (OTA) in wine. Constructed BSA-agarose columns could extract OTA efficiently from red wine after its dilution (4-fold) in 0.1 M Tris pH 8.0. The method was linear (R2 = 0.9999) in the OTA concentration range studied (0.05 to 3.0 µg L-1), with recovery rates above 98%. It also showed low detection (0.017 µg L-1) and quantification (0.051 µg L-1) limits. The efficacy of the BSA-based method was further validated by direct comparison with commercial immunoaffinity columns. Portuguese wines analyzed by both methods had agreeing results.

In vitro adsorption of aflatoxin B1, ochratoxin A, and zearalenone by micronized grape stems and olive pomace in buffer solutions.

This work characterizes the adsorption of aflatoxin B1 (AFB1), ochratoxin A (OTA), and zearalenone (ZEN) by dry micronized olive pomace (OliPom) and grape stems (GrapStem). Their performance was compared with that of three other materials, activated carbon (ActCarb), bentonite (Bent), and a commercial product (ComProd). Experiments were conducted in vitro at several pH values using buffer solutions. For OTA and ZEA, the strongest adsorbent was ActCarb, with 5 mg/mL being sufficient to bind > 99% of all the mycotoxins. For AFB1, ComProd and Bent were the most effective adsorbents, as 0.5 mg/mL bound > 95% of this mycotoxin. Among the two agro by-products, GrapStem was the strongest binder, with 10 mg/mL being sufficient to bind at least 90% of all the mycotoxins (except OTA at pH 7). OliPom was the least efficient material, but at a concentration of 30 mg/mL, its performance was similar to GrapStem. Adsorption isotherms were calculated, and ActCarb showed the maximum adsorption capacity (Qmax), with values that ranged from 19 to 24 µg/mg for pH 2 and from 17 to 20 µg/mg for pH 7. ComProd, Bent, and GrapStem showed more similar Qmax between them (1.4-4.4 µg/mg for pH 2 and 0.5-4.8 µg/mg for pH 7).

Antifungal effect of organic acids from lactic acid bacteria on Penicillium nordicum.

The control of fungal contamination is particularly important to avoid both spoilage of food and feed products and the occurrence of toxic compounds, known as mycotoxins. Some lactic acid bacteria (LAB) strains have shown the capacity to inhibit fungal growth and the production of mycotoxins. In this work, cell-free supernatants (CFS) of Lactobacillus plantarum UM55 and Lactobacillus buchneri UTAD104 were tested against Penicillium nordicum radial growth and OTA production. When CFS of these strains were used, the radial growth of the fungus was inhibited by less than 20%, but the production of OTA was reduced by approx. 60%. These antifungal effects resulted from organic acids produced by LAB. The CFS of L. plantarum UM55 contained lactic acid, phenyllactic acid (PLA), hydroxyphenyllactic acid (OH-PLA) and indole lactic acid (ILA), while L. buchneri UTAD104 CFS contained acetic acid, lactic acid and PLA. These organic acids were further tested individually for their inhibitory capacity. Calculation of the inhibitory concentrations (ICs) showed that acetic acid, ILA and PLA were the most effective in inhibiting P. nordicum growth and OTA production. When the inhibitory activity of LAB cells incorporated into the culture medium was tested, L. buchneri UTAD104 inhibited the production of OTA entirely in all conditions tested, but fungal growth was only inhibited completely by the highest concentrations of cells. Acetic acid production was primarily responsible for this effect. In conclusion, the ability of LAB to inhibit mycotoxigenic fungi depends on strain capability to produce specific organic acids, and those acids may differ from strain to strain. Also, the use of LAB cells, especially from L. buchneri, in food products prone to contamination with P. nordicum (e.g. dry-cured meats and cheeses) may be an alternative solution to control fungal growth and OTA production.

Edible Films and Coatings as Carriers of Living Microorganisms: A New Strategy Towards Biopreservation and Healthier Foods.

Edible films and coatings have been extensively studied in recent years due to their unique properties and advantages over more traditional conservation techniques. Edible films and coatings improve shelf life and food quality, by providing a protective barrier against physical and mechanical damage, and by creating a controlled atmosphere and acting as a semipermeable barrier for gases, vapor, and water. Edible films and coatings are produced using naturally derived materials, such as polysaccharides, proteins, and lipids, or a mixture of these materials. These films and coatings also offer the possibility of incorporating different functional ingredients such as nutraceuticals, antioxidants, antimicrobials, flavoring, and coloring agents. Films and coatings are also able to incorporate living microorganisms. In the last decade, several works reported the incorporation of bacteria to confer probiotic or antimicrobial properties to these films and coatings. The incorporation of probiotic bacteria in films and coatings allows them to reach the consumers' gut in adequate amounts to confer health benefits to the host, thus creating an added value to the food product. Also, other microorganisms, either bacteria or yeast, can be incorporated into edible films in a biocontrol approach to extend the shelf life of food products. The incorporation of yeasts in films and coatings has been suggested primarily for the control of the postharvest disease. This work provides a comprehensive review of the use of edible films and coatings for the incorporation of living microorganisms, aiming at the biopreservation and probiotic ability of food products.

Anti-aflatoxigenic effect of organic acids produced by Lactobacillus plantarum.

Lactic acid bacteria (LAB), which are commonly used in the production of fermented foods, have been gaining attention for their antifungal and antimycotoxin properties. In this work, the strain Lactobacillus plantarum UM55 was selected among other LAB for inhibiting the growth of Aspergillus flavus. Further, it is shown that cell-free supernatant (CFS) of this strain inhibits the production of aflatoxins (AFLs) by 91%. This inhibition was dependent on CFS pH, increased with increasing concentrations of CFS, and was independent of fungal growth, which was inhibited only by 32%. CFS was also effective in inhibiting the growth and AFLs production in A. parasiticus, A. arachidicola, A. nomius and A. minisclerotigenes. Further, L. plantarum UM55 CFS was analysed for the presence of organic acids and the main differences compared to controls were found in the levels of lactic acid, phenyllactic acid (PLA), hydroxyphenyllactic acid (OH-PLA), and indole lactic acid (ILA). These compounds were individually tested against A. flavus, with all of the compounds showing an inhibiting effect on fungal growth and AFLs production. PLA showed the stronger effects, and the obtained IC90 for the inhibition of growth and AFLs was of 11.9 and 0.87mg/mL, respectively. AFLs IC90 for ILA, OH-PLA and lactic acid were of 1.47, 1.80, and 3.92mg/mL, respectively. The antiaflatoxigenic properties of LAB depend on strain's capability to produce lactic acid, PLA, OH-PLA and ILA.

Gamma irradiation effects on ochratoxin A: Degradation, cytotoxicity and application in food.

Ochratoxin A (OTA) is one of the main mycotoxins that can be found in food. The use of gamma radiation is a technique for preserving food that may exert some effects on mycotoxins. OTA was irradiated in its dry form, in aqueous and in methanolic solutions, and in wheat flour, grape juice and wine. Additionally, the toxicity of OTA irradiated in water was tested. In aqueous solutions, more than 90% of the OTA was degraded by γ-radiation doses ≥2.5kGy, and a 2-fold reduction in OTA cytotoxicity was observed. In food matrices, the elimination of OTA by γ-radiation was found more difficult, as radiation doses of 30kGy eliminate at most 24% of the OTA. Higher moisture content of food matrices did not substantially increase OTA elimination. It is concluded that OTA is very sensitive to irradiation in water solutions but resistant in its dry form and in food matrices.

ß-galactosidase from Aspergillus lacticoffeatus: A promising biocatalyst for the synthesis of novel prebiotics.

ß-galactosidase (EC 3.2.1.23) are interesting enzymes able to catalyze lactose hydrolysis and transfer reactions to produce lactose-based prebiotics with potential application in the pharmaceutical and food industry. In this work, Aspergillus lacticoffeatus is described, for the first time, as an effective ß-galactosidase producer. The extracellular enzyme production was evaluated in synthetic and alternative media containing cheese whey and corn steep liquor. Although ß-galactosidase production occurred in all media (expect for the one composed solely by cheese whey), the highest enzymatic activity values (460U/mL) were obtained for the synthetic medium. Ochratoxin A production in synthetic medium was also evaluated and 9days of fermentation was identified as a suitable fermentation time to obtain a crude extract enzyme with mycotoxin concentration below the legal comparable value established for wine and grape juices (2ng/mL). The optimal pH and temperature for the crude extract enzyme was found in the range of 3.5-4.5 and 50-60°C, respectively. The ß-galactosidase activity was reduced in the presence of Ba2+, Fe2+, Li+, K+ and galactose, while additives (except for ascorbic acid) and detergents exhibited a positive effect on enzymatic activity. This enzyme was able to catalyze the synthesis of prebiotics, namely lactulose (2.5g/L) and a galacto-oligosaccharide (trisaccharide, 6.3g/L), either when whole cells or crude enzyme was used as biocatalyst. The lactulose production using fungal whole cells is herein reported for the first time. Additionally, A. lacticoffeatus was also found to produce an enzyme with fructosyltransferase activity and other prebiotics, namely fructo-oligosaccharide 1-kestose (2.4g/L).

Optimization of lipase production by solid-state fermentation of olive pomace: from flask to laboratory-scale packed-bed bioreactor.

Lipases are versatile catalysts with many applications and can be produced by solid-state fermentation (SSF) using agro-industrial wastes. The aim of this work was to maximize the production of Aspergillus ibericus lipase under SSF of olive pomace (OP) and wheat bran (WB), evaluating the effect on lipase production of C/N ratio, lipids, phenols, content of sugars of substrates and nitrogen source addition. Moreover, the implementation of the SSF process in a packed-bed bioreactor and the improvement of lipase extraction conditions were assessed. Low C/N ratios and high content of lipids led to maximum lipase production. Optimum SSF conditions were achieved with a C/N mass ratio of 25.2 and 10.2% (w/w) lipids in substrate, by the mixture of OP:WB (1:1) and supplemented with 1.33% (w/w) (NH4)2SO4. Studies in a packed-bed bioreactor showed that the lower aeration rates tested prevented substrate dehydration, improving lipase production. In this work, the important role of Triton X-100 on lipase extraction from the fermented solid substrate has been shown. A final lipase activity of 223 ± 5 U g-1 (dry basis) was obtained after 7 days of fermentation.

Adsorption of aflatoxin B1, zearalenone and ochratoxin A by microorganisms isolated from Kefir grains.

A strategy to reduce the deleterious effects of mycotoxins is to use dietary supplements that contain microorganisms that bind mycotoxins and decrease their gastrointestinal absorption. Novel strains were isolated from a Kefir culture and assessed for their mycotoxin adsorption and biotransformation ability. The most active strains were identified using DNA sequencing, and the stability of microorganism/mycotoxin complexes was evaluated using buffer solutions to simulate the pH conditions in the gastrointestinal tract. Our results showed that the microorganism consortium of Kefir grains adsorbed 82 to 100% of aflatoxin B1 (AFB1), zearalenone (ZEA) and ochratoxin A (OTA) when cultivated in milk. The main strains that were capable of mycotoxin adsorption were identified as Lactobacillus kefiri, Kazachstania servazzii and Acetobacter syzygii. The strain L. kefiri KFLM3 was the most active, adsorbing 80 to 100% of the studied mycotoxins when cultivated in milk. Nonetheless, the strain K. servazzii KFGY7 retained more mycotoxin after the desorption experiments (65, 69 and 67% for AFB1, OTA and ZEA, respectively). These findings suggest that Kefir consumption may help to reduce gastrointestinal absorption of these mycotoxins and consequently reduce their toxic effects. The isolated strains may be of interest for the development of fermented dairy products for human consumption that have a new probiotic characteristic, the adsorption of mycotoxins.