Catalytic oxidation of concentrated orange oil phase by synthetic metallic complexes biomimetic to MMO enzyme

BACKGROUND: This paper reports the catalytic oxidation of the concentrated orange oil phase using the complexes [Fe^III(BMPP)Cl(µ‐O)Fe^IIICl₃], [Cu^II(BTMEA)₂Cl]Cl and [Co^II(BMPP)]Cl₂ biomimetic to methane monooxygenase enzyme as catalysts and hydrogen peroxide as oxidant. RESULTS: The reaction products of oil oxidation, mainly nootkatone, were identified by gas chromatography/mass spectrometry. A screening of catalysts was performed through a full 2³ experimental design, varying the temperature from 30 to 70 °C, the catalyst concentration from 7.0 × 10^?4 to 1.5 × 10^?3 mol L^?1 and the oxidant/substrate molar ratio from 1:1 to 3:1. The results of reaction kinetics employing the most promising catalysts showed that conversions to nootkatone of up to 8% were achieved after 16 h at 70 °C. CONCLUSION: The results obtained in this study in terms of nootkatone production should be considered encouraging, since a real, industrially collected, raw material, instead of pure valencene, was employed in the reaction experiments, with a final content about ten times that present in the original concentrated oil. Copyright © 2010 Society of Chemical Industry     

Photochemical Degradation of Disazo Dyes,R-Salt Derivatives,on Dyed Cotton

Direct disazo dyes, R-salt derivatives, were synthesized and examined. The dyes were prepared by coupling of appropriate components with tetrazotized diacyl derivatives of aromatic diamines. Derivatives of dicarboxylic acids with the general formula HOOC―(CH₂)_n―COOH (n = 0 ÷ 4) were used as acylating agents. Photochemical degradation rates of dyes on dyed cotton fabric were studied. Compositions of azo-hydrazone tautomers, their aggregates, and their decay rates in UV-Vis light were determined. It was assumed that the length of aliphatic chain in the molecule affects the rate of its photochemical degradation T_1/2, tautomeric composition, and dyes aggregation in azo and hydrazo forms.     

Quantification of character-impact odour compounds of roasted beef

Beef was roasted for 7 min in frying pans made of glass (A) or of stainless steel (B). The lower temperature in A yielded a more roasty-sweet flavour and the higher temperature in B a roasty-harsh, more caramellike flavour. Using stable isotope dilution assays the concentration levels of the odour compounds 4-hydroxy-2,5-dimethyl-3(2H)-furanone (I), 2-acetyl-2-thiazoline (II), 2-ethyl-3,5-dimethylpyrazine (III), 2,3-diethyl-5-methylpyrazine (IV), guaiacol (V) and methional (VI) were determined in samples A and B. The data obtained were divided by the corresponding odour thresholds which were evaluated nasally and retronasally. The results indicated that the flavour differences of A and B were preferentially caused by differences in the concentration levels of odorantsI, II, IV, andVI.

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Quantitative Analyse charakteristischer Geruchsstoffe von gebratenem Rindfleisch

Zusammenfassung Rindfleisch wurde 7 min in Pfannen aus Glas (A) und rostfreiem Stahl (B) gebraten. Die niedrigere Temperatur in A führte zu einem stärker röstig-süßen Aroma und die höhere Temperatur in B zu einem röstig-herben, stärker caramelartigen Aroma. Die Konzentrationen der Geruchsstoffe 4-Hydroxy-2,5-dimethyl-3(2H)-furanon (I), 2-Acetyl-2-thiazolin (II), 2-Ethyl-3,5-dimethyl-pyrazin (III), 2,3-Diethyl-5-methylpyrazin (IV), Guajacol (V) und Methional (VI) wurden in den Proben A und B mit Hilfe von Isotopenverdünnungsanalysen bestimmt. Die erhaltenen Werte wurden dividiert durch die entsprechenden nasal und retronasal ermittelten Geruchsschwellen. Die Ergebnisse zeigten, daß die Aromaunterschiede von A und B in erster Linie auf Unterschiede in den Konzentrationen der GeruchsstoffeI,II, IV undVI beruhen.

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Presented in part at the symposium Flavour Precursors, University of Würzburg, Sept. 30th to Oct. 2nd, 1992     

铁改性腈纶纤维催化剂在偶氮染料降解反应中的应用

使用水合肼和盐酸羟胺对腈纶纤维进行表面改性,然后将其与铁离子反应制得铁改性腈纶纤维催化剂（PAN-Fe）。在过氧化氢存在条件下将PAN-Fe催化剂应用于2种水溶性阴离子偶氮染料的光催化氧化降解反应中,考察了催化剂添加量、催化剂表面铁离子含量、染料浓度和pH值对染料降解反应的影响。结果表明,尽管PAN-Fe催化剂在暗态能催化染料降解反应,但是光辐射可促进其催化作用的提高;催化剂添加量及其表面铁离子含量的增加能够明显提高染料的脱色率。在PAN-Fe催化剂存在下染料降解反应可在碱性条件下进行,但是染料浓度的增加会使其脱色率降低。     

Cis selectivity of mixed catalyst systems in canola oil hydrogenation

Two mixed catalyst systems were investigated for their suitability to produce partially hydrogenated canola oils with low levels of trans fatty acids. Each system included a homogeneous catalyst paired with a heterogeneous catalyst. Cl₂(CO)₂(PPh₃)₂Ru(II) was combined with Ni, while methyl benzoate chromium tricarbonyl [MeBeCr(CO)₃] was paired with Pd. The effect of changing the catalysts’ molar ratios and the reaction conditions on activity, specific isomerization index, linoleate and linolenate selectivities and fatty acid compositions was evaluated in an effort to identify synergies related to differences in the hydrogenation reaction mechanisms of the two components. Only the Ru and Ni combination proved to be advantageous. At 110 °C and 5.2 MPa, the activities of the Ni/Ru mixtures were higher than the activities of the catalysts used individually, and low levels of trans isomers (∼9%), characteristic of the Ru catalyst, were observed.     

The use of hydrogen peroxide for the digestion and determination of total nitrogen in chickpea (Cicer arietinum L.) and pigeonpea (Cajanus cajan L.)

The use of hydrogen peroxide as an alternative to catalysts in the determination of nitrogen in plant materials has been investigated. Nitrogen determination in leaf, stem and seed samples of chickpea and pigeonpea was carried out by three digestion procedures, using hydrogen peroxide (H₂O₂ digestion) without a catalyst, and with mercury or selenium as catalysts (catalyst digestions). The nitrogen values obtained by the three digestion procedures did not differ significantly from each other when examined by microKjeldahl (MKJ) using mercury as a catalyst, and by a Technicon auto analyser (TAA) using selenium as catalyst. The gradual addition of H₂O₂, as recommended previously, was found to be unnecessary. In view of the cost and health hazards implicated with the use of mercury and selenium for digestion, the procedure based on H₂O₂ digestion is preferable for large scale N determinations in plant tissue and seed samples of these pulse crops. The results sugest that the H₂O₂ digestion technique can be conveniently adapted for total N analysis in plant tissues and grain samples by either TAA or MKJ method.     

Interregional and interannual variability of ethanol site-specific deuterium content in Italian wines

The site-specific natural isotope fractionationnuclear magnetic resonance (SNIF-NMR)²H analysis is at present the reference method for determining the origin of ethanol and has been successfully applied for analysing all grape products. The method has also been used to identify the origin of wines and the aim of this study was to verify this application. In all, 3309 samples belonging to the Italian wines data bank were analysed from all 20 Italian regions to study the possibilities of determining and controlling the exact origin and year of the product. The dependency of the deuterium/hydrogen ratio of the methyl site (D/H_I) with latitude was confirmed but this was not the case for the D/H ratio of the methylene site (D/H_II) and the parameter R [2(D/H_II)/(D/H_I)] did not add any additional information. The frequency distribution of the NMR parameters follows a regular North-South gradient but they are not sufficiently different in each region to allow unique characterisation. The lack of effectiveness of the method, when applied to identification, depends on interannual and interregional variability. As a consequence, all but some very different regions overlap. The SNIF-NMR method is particularly suitable for detecting simple adulterations but, in the Italian situation, seems not to be so useful for solving problems of geographical origin. For this, it could be helpful to use other isotopic parameters and to ameliorate the sampling technique, to improve the effectiveness of the method.

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Regionale und jährliche Variabilität des Ethanolgebundenen Deuteriumgehaltes italienischer Weine

Zusammenfassung Die SNIF-NMR²H-Analytik wird derzeit als Referenzmethode zur Bestimmung der Herkunft des Ethanols bei Produkten aus Weintrauben erfolgreich angewandt. Die Methode wird auch zur Ermittlung der geographischen Herkunft von Wein eingesetzt. Ziel der vorliegenden Arbeit war es, die Brauchbarkeit dieser Analysenmethode zur Bestimmung des geographischen Ursprungs italienischer Weine zu überprüfen. Dazu wurden Analysenergebnisse von 3309 Weinen aus allen 20 Weinbaugebieten Italiens im Rahmen einer Datenbank des D/H-Verhältnisses gesammelt. Während für die D/H_I-Werte eine deutliche Abhängigkeit von der geographischen Breite bestätigt werden konnte, zeigten die D/H_II-Werte keinen derartigen Zusammenhang. Auch der Parameter R erbrachte keine weiteren Informationen. Die Häufigkeits-Verteilung der NMR-Werte folgt deutlich einem Nord-Süd-Gradienten, aber sie sind nicht in jeder Region so unterschiedlich, daß eine signifikante Differenzierung möglich ist. Dies resultiert aus den jahrgangs- und gebietsabhängigen Schwankungen. Die SNIF-NMR Methode ist zur Aufklärung bestimmter Verfälschungen (Zuckerzusatz) gut geeignet, bei italienischen Weinen ist jedoch mit dieser Methode das Problem der Bestimmung der geographischen Herkunft nicht lösbar. Durch Messung weiterer stabiler Isotopen sowie durch eine Verbesserung der Probennahme kann eine Erhöhung der Effizienz zum Nachweis der geographischen Herkunft erzielt werden.

     

Cure properties and adhesive performances of cure-accelerated phenol-urea-formaldehyde resins

The cure properties of cure-accelerated phenol-urea-formaldehyde (PUF) resins with different catalysts [calcium oxide (CaO), sodium carbonate (Na₂CO₃), zinc oxide (ZnO), and magnesium oxide (MgO)] were investigated by gelation test and differential scanning calorimetry (DSC) analysis. The results indicated that catalysts such as Na₂CO₃, ZnO, and MgO were capable of increasing the curing rate and decreasing the curing temperature of PUF resins, however, the CaO inhibited the cure reaction. The formation of methylene bridges was considered to be the main reaction during curing. For the ZnO- and MgO-accelerated PUF resins, the addition reaction of formaldehyde with free phenolic site may act as subsidiary reaction. The activation energies (E _a ) of cure-accelerated PUF resins other than CaO-acceleration were much lower than the control resin. The effects of catalysts and hot press temperature on adhesive performances of PUF resins were also discussed by plywood test. The PUF resins with Na₂CO₃, ZnO, and MgO had higher wet shear strength than the control resin. Hot press temperature had a strong influence on the wet shear strength as well as the catalysts. Among the catalysts, MgO had more significant improving effect on both the curing process and the wet shear strength of PUF resin.     

Synthesis and spectral characterization of some new azo benzothiazole derivative and relative compounds

A series of azo benzothiazole derivatives (2a–m) were prepared by coupling of the appropriate arylamine diazonium salts with 2-(benzo[d]thiazole-2-yl)-3-oxo-pentadinitriles (1). Also, the cyclization of azo derivatives (2d, 2h) with malononitrile in refluxing DMF afforded pyridazine carbonitrile derivatives (3a,b). Moreover, the azo derivatives (2a–m) underwent cyclization on refluxing in DMF to afford pyridazine derivatives (6a–m). All the newly synthesized compounds were characterized by both analytical and spectral analyses. Dyeing performance of the synthesized dyes on polyester fibers has been assessed. Most of the dyes showed good affinity to polyester fibers. No details regarding the synthesis and dyeing performance of such dyes are reported before in the literature.     

Distribution of deoxynivalenol and 3‐acetyldeoxynivalenol in naturally contaminated and Fusarium culmorum infected triticale samples

Eight triticale genotypes, naturally contaminated (C) and collected from heads inoculated with two separate isolates Fusarium culmorum (I₁ and I₂) kernels were analysed for accumulation ofFusarium toxins. Triticale kernels were contaminated with deoxynivalenol (DON) and 3‐acetyldeoxynivalenol (3‐AcDON). Statistical analysis revealed significant differences between naturally contaminated samples (C) and those inoculated with isolate I₁ and I₂. The following accumulation of toxins in kernels (mean mg/kg) was found: C, I₁, I₂ – DON 0.06, 14.45, 8.09; 3‐AcDON – 0.01, 0.20, 0.49. Distribution of DON and 3‐AcDON was studied in four size fractions of kernels (> 2.8 mm; ≤ 2.8–2.5 mm, < 2.5–2.2 mm and < 2.2 mm).The highest concentration of DON and 3‐AcDON was found in the smallest fraction of damaged kernels. The percentage distribution of DON and 3‐AcDON in fraction < 2.2 mm was (C) 66%, 77%, (I₁) 38%, 27%, (I₂) 46%, 40%; and in fraction < 2.5 mm: (C) 85%, 94%, (I₁) 57%, 51%, (I₂) 80%, 76%. The naturally contaminated kernel fraction < 2.2 mm (although only 2% of all) contained 33% DON and 59% 3‐AcDON, for more toxigenic isolate I₁ 10%, 15%, 14%, less toxigenic isolate I₂ 4%, 13%, 11%, respectively, calculated on dry matter basis. No significant correlation between examined characteristics was found for either I₁ or I₂ isolate. The biosynthesis mechanism of toxic metabolites was to approximate (significantly correlated) to pair objects C/I₂.     

An optimised low-salinity seawater decolourising method produces decolourised seaweed (Kappaphycuz alvarezii) as semi-refined carrageenan raw material:

Semi-refined carrageenan (SRC) production from decolourised Kappaphycuz alvarezii treated by chemicals (CaCO₃) drives the search for ‘greener’ decolourisation methods to sustainably supply cheaper and energy efficient products. Therefore, a decolourisation method of low-salinity seawater (LSS) (3, 9 and 15 g/L) was investigated to replace CaCO₃. In addition, decolourised seaweed colour powder (DSP) and SRC colour, yield, viscosity and gel strength were used to screen the salinity treatments. SRC prepared from LSS (3 g/L) treatment demonstrated similar colour and physical properties to CaCO₃ treatments, which indicated low-salinity seawater (3 g/L) could replace CaCO₃ as a decolourising agent. Moreover, purity of SRC (3 g/L salinity) were confirmed by x-ray diffraction (XRD), scanning electron microscopy-energy-dispersive x-ray (SEM-EDX), and its functional group by fourier transform infrared (FTIR). In this study, waste seawater from LSS (3 g/L) exhibited radical scavenging properties. This decolourising method could be easily adopted by smallholder seaweed farmers in low- and middle-income countries.     

Selective adsorption and separation of illegal cationic dyes from foodstuffs with anionic polyelectrolyte functionalised metal-organic frameworks

ABSTRACT

A novel adsorbent, poly(sodium 4–styrenesulfonate) modified MIL-101(Cr)–NH₂, was successfully prepared. Owing to its high surface area and degree of negative surface charge, it enables effective adsorption and separation of illegal cationic dyes, such as rhodamine B, pararosaniline, and auramine O, from foodstuffs prior to high performance liquid chromatography analysis. Under optimised conditions, good linearity was obtained over 1.0–80.0 or 1.0–120 ng mL^?1 with a correlation coefficient (R²) > 0.999. Limits of detection and limits of quantification of the three dyes were 0.28–0.65 and 0.94–2.13 μg kg^?1, respectively. The recoveries of the three dyes in shrimp powder, chili powder, tofu sheets, and tomato sauce were in the range of 86.8–119.3%, suggesting that the developed method is a promising tool for accurate quantification of the three dyes at trace levels in foodstuffs.     

Preparation and characterization of electrically semi-conductive polyfuran-coated poly(ethylene terephthalate) fibers

One of the most important textile materials, poly(ethylene terephthalate) (PET) fiber, was coated with a semi-conductive polyfuran (PFu) by in situ oxidative polymerization using FeCl₃ oxidant in solvent mixture of acetonitrile–chloroform. The effects of polymerization conditions such as volume ratios of acetonitrile/chloroform, monomer concentration, and oxidant/monomer mol ratio were investigated on PFu content (%) of the composites. It was observed that pretreatment of PET in dichloromethane increased PFu content and its coating continuity before polymerization. The highest PFu content (12.0%) was obtained using FeCl₃/furan mol ratios of 3.5 in acetonitrile/chloroform mixture (5/1). The density values of the composites with different PFu contents were measured. Composite fibers were also subjected to doping processes with HCl and I₂ vapors, separately, and it was observed that the surface resistivity of PFu/PET (10¹² Ω/cm²) reached to 53 Ω/cm² after doping with I₂. The structural, thermal, and morphological characterization was performed with FTIR, XRD, TGA, and SEM, respectively.     

Separation and structure analysis of trisaccharide isomers produced from lactose by Lactobacillus bulgaricus L3 β-galactosidase

Using lactose as the substrate, galacto-oligosaccharides containing β-d-galactose residues were synthesised with β-galactosidase from Lactobacillus bulgaricus L3. The reaction mixture was fermented by yeast cells to consume the monosaccharides and disaccharides, and then it was fully acetylated in the presence of acetic anhydride under I₂ catalysis. Column chromatography of the resulting products, using ethyl acetate: petroleum ether as the eluent, generated two isomers of trisaccharide derivatives (I and II) in gram scale for the first time. Their structure characteristics were investigated by ESI-MS and NMR spectra. They were identified as (2,3,4,6-tetra-O-acetyl-d-galactopyranosyl)-β-(1 → 6)-(2,3,4-tri-O-acetyl-d-galactopyranosyl)-β-(1 → 4)-1,2,3,6-tetra-O-acetyl-α-d-glucopyranose (I) and (2,3,4,6-tetra-O-acetyl-d-galactopyranosyl)-β-(1 → 3)-(2,4,6-tri-O-acetyl-d-galactopyranosyl)-β-(1 → 4)-1,2,3,6-tetra-O-acetyl-α-d-glucopyranose (II), respectively. ESI-MS analysis of both deacetylated products of the two trisaccharide derivatives I and II revealed molecular ion peaks of free trisaccharides, which were structurally identified as Gal-β-(1 → 6)-Gal-β-(1 → 4)-Glc and Gal-β-(1 → 3)-Gal-β-(1 → 4)-Glc, respectively.     

Examination of Dyeing Properties of the Dyed Cotton Fabrics with Barberry (Berberis vulgaris L.)

ABSTRACT

In this study, it was aimed at investing the cotton fabrics dyed with different percentages of the roots of barberry (Berberis vulgaris L.) via gall oak (Quercus infectoria Olivier; 10% and 20%) and aluminum sulfate (Al₂(SO₄)₃; 6%) mordants. The dyeing process was performed with the roots of barberry in the range of 10–100%. A reversed phase high performance liquid chromatography with diode array detection method was utilized for the identification of dyes present in the sample extracts. Natural yellow-dyed cotton samples were studied calorimetrically and their color coordinates L*, a*, b*, C*, h, K/S, and ?E* values were given.     

Structural changes in squid (Loligo japonica) collagen after modification by formaldehyde

BACKGROUND: Formaldehyde (FA) has been suggested to cause changes in texture and functional properties in some marine species. It was therefore hypothesised that FA may affect collagen, a fundamental constituent of the extracellular matrix in squid. RESULTS: Two types of collagen, I and V, were isolated by pepsin digestion and differential salt precipitation. Type V collagen contained higher proportions of isoleucine, leucine, and lysine and lower proportions of alanine and hydroxyproline. The effects of FA on pepsin‐solubilised squid collagen were examined by differential scanning calorimetry and Raman spectroscopy. The squid collagen showed a transition temperature (T_m1) of 37.2 ± 0.2 °C, which was significantly reduced in the presence of 2 and 10 mmol L^?1 FA. In the presence of 1, 2 and 10 mmol L^?1 FA an additional peak (T_m2) was also observed at 77.7 ± 0.1, 78.4 ± 0.1 and 62.7 ± 0.2 °C respectively, suggesting FA–collagen interactions. Treatment with 2 mmol L^?1 FA increased the I₉₄₀/I₁₀₀₅ ratio from 1.09 to 1.66 and shifted the 990 and 1245 cm^?1 bands. The tyrosine doublet ratio (I₈₅₀/I₈₃₀) was also increased about threefold, suggesting that α helix, β sheet type and random coil structures were changed by FA. CONCLUSION: The secondary structure of squid collagen can be affected by FA through hydrophobic interactions. Copyright © 2008 Society of Chemical Industry     

Investigation of dyes degradation intermediates with <Emphasis Type="Italic">Scytalidium thermophilum</Emphasis> laccase

Scytalidium thermophilum laccase was able to successfully decolourise Congo Red, Bromo-Cresol Green, Malachite Green, Phenol Red and Indigo Carmine under optimised conditions. The cited dyes belonging to three different classes were named azo, triarylmethane and indigoid. The decolourisation rates were 100, 95, 76, 57 and 22 mg h⁻¹ U⁻¹ for Indigo Carmine, Malachite Green, Bromo-Cresol Green, Congo Red and Phenol Red, respectively. The degradation products were characterised by UV–vis and FT-IR techniques, and their cytotoxicity was monitored. UV–visible absorption spectra and FT-IR analysis showed a complete degradation of Congo Red, Bromo-Cresol Green and Malachite Green, a partial degradation of Phenol Red and a transformation of Indigo Carmine. Toxicity study revealed that most of the treated dyes were less toxic than those before treatment, especially for Malachite Green. In fact, Scytalidium thermophilum laccase degraded Malachite Green into non-toxic products. Scytalidium thermophilum laccase constitutes a powerful tool for effective bioremediation of rich-dye textile effluents and was, therefore, found worthy of investigation for potential applications in restoration work and other biotechnological uses.     

Dyeing of silk fabric with natural dyes extracted from cochineal (Dactylopius coccus Costa) and gall oak (Quercus infectoria Olivier)

Silk fabric samples were mordanted with alum [KAl(SO₄)₂.12H₂O]. Then, the samples were dyed with cochineal (Dactylopius coccus Costa) and gall oak (Quercus infectoria Olivier) shellac extracts. Optimum dyeing parameters were determined by using different concentrations of these natural colorants. All the dyed samples were cut into two equal pieces. One group of the parts were post-mordanted with FeSO₄. A reserved-phase high-performance liquid chromatography (RP-HPLC) with the diode-array detection (DAD) method was utilized for the identification of the components of dyes present in the all dyed and post-mordanted samples. The color coordinates and fastness values of washing, perspiration, rubbing, and light were investigated and compared with each other. Using a mixture of these natural dyes enhanced the exhaustion of the dye and good color fastness test results were achieved.     

Concurrent dyeing and finishing of cotton with natural colour and citric acid in the presence of NaH2PO4 as catalyst under thermal treatment

Cotton fabric was simultaneously modified and dyed with citric acid and Camellia sinensis, and citric acid and Punica granatum in the presence of sodium di‐hydrogen phosphate (NaH₂PO₄) as the catalyst using a pad–dry–cure technique. Treatment with 10% citric acid, 15% NaH₂PO₄ and any of the above‐mentioned dyes at 100% wet pick‐up, followed by drying at 95°C for 5 min and curing of the dried fabric at 140°C for 5 min produced most balanced improvements in respect of the depth of shade, wrinkle recovery and colour fastness to light, wash and rubbing with retention of more than 70% of the original strength. Infrared analysis of the dyed cotton fabric indicated that the treatment of cotton with citric acid and either Camellia sinensis or Punica granatum under the influence of an esterification catalyst led to the esterification of carboxyl groups of citric acid and of hydroxyl groups of cotton cellulose and with that of both the dyes. The said process also led to some degree of cross‐linking of polymeric chains of cotton.     

Pediococcus acidolactici and Pediococcus pentosaceus isolated from a rainbow trout ecosystem have probiotic and ABF1 adsorbing/degrading abilities in vitro

ABSTRACT

Probiotics are being used in biological control of bacterial pathogens, as an alternative to antibiotics, to improve health and production parameters in fish farming. Fish farming production is severely affected by aflatoxins (AFs), which are a significant problem in aquaculture systems. Aflatoxins exert substantial impact on production, causing disease with high mortality and a gradual decline of reared fish stock quality. Some aspects of aflatoxicosis in fish, particularly its effects on the gastrointestinal tract, have not been well documented. The aim of the present study was to evaluate probiotic properties of lactic acid bacterial (LAB) strains isolated from rainbow trout intestine and feed. Moreover, AFB₁-binding and/or degrading abilities were also evaluated to assess their use in the formulation of feed additives. Growth at pH 2, the ability to co-aggregate with bacterial pathogens, inhibition of bacterial pathogens, and determination of the inhibitory mechanism were tested. Aflatoxin B₁ (AFB₁) adsorption and degradation ability were also tested. All strains were able to maintain viable (10⁷ cells ml^–1) at pH 2. Pediococcus acidilactici RC001 and RC008 showed the strongest antimicrobial activity, inhibiting all the pathogens tested. The strains produced antimicrobial compounds of different nature, being affected by different treatments (catalase, NaOH and heating), which indicated that they could be H₂O_2, organic acids or proteins. All LAB strains tested showed the ability to coaggregate pathogenic bacteria, showing inhibition percentages above 40%. Pediococcus acidilactici RC003 was the one with the highest adsorption capacity and all LAB strains were able to degrade AFB₁ with percentages higher than 15%, showing significant differences with respect to the control. The ability of some of the LAB strains isolated in the present work to compete with pathogens, together with stability against bile and gastric pH, reduction of bioavailability and degradation of AFB₁, may indicate the potential of LAB for use in rainbow trout culture.