Seleenilisä säilörehuun säilöntäaineen mukana

Kotieläinten riittävästä seleeninsaannista joudutaan huolehtimaan tilakohtaisesti, sillä Suomen maaperässä on niukasti seleeniä. Läheskään aina rehuja ei ole tuotettu lannoitteilla, joihin seleeniä on lisätty eikä kotieläintuottaja pysty aina suoraan vaikuttamaan ostamansa rehun lannoituskäytäntöön. Vaikka suoranaiset seleeninpuutosoireet ovat nykyisin tiloilla harvinaisia, seleenilisien käyttöön motivoivat tutkimustulokset riittävän seleeninsaannin terveyttä edistävistä vaikutuksista. Ruokinnassa seleenin lisäämisen erityinen haaste on oikean annostuksen varmistaminen, sillä liian suuri seleeniannos johtaa helposti myrkytyksiin. Erityisen haasteellista optimaalisen seleenilisän antaminen on eläinryhmille, jotka saavat lähes ainoastaan säilörehua, kuten hiehot ja ummessa olevat lehmät. Säilörehun säilöntäaine annostellaan suuttimilla rehuvirtaan korjuukoneessa. Annostelun tasaisuus on tärkeää säilönnän onnistumisen kannalta. Säilöntäaineen annostelun yhteydessä on mahdollista lisätä rehuun myös seleeniä, sillä seleeninlisäysmäärä on niin pieni, että se voidaan lisätä happosäilöntäaineeseen lopputuotteen annostelusuositusta muuttamatta. Seleenin lisääminen säilöntäaineeseen voidaan tehdä tehdasolosuhteissa valvotusti ja turvallisesti. Säilöntäkokeessa todennettiin, että säilöntäaineeseen (AIV Ässä, Kemira Oyj) lisätty natriumselenaatti säilyy rehussa. Säilöttävä nurmi oli timoteinurminatakasvuston toinen sato, jota oli kyseisellä kasvukaudella lannoitettu seleenittömällä väkilannoitteella. Kasvusto niitettiin niittomurskaimella ja korjattiin tarkkuussilppurilla ilman säilöntäainetta. Säilöntäainekäsittelyt (Ässä + selenaatti 0,05 %; Ässä + selenaatti 0,005 %; Ässä + selenaatti 0,001 %; vesi + selenaatti 0,005 %; ei säilöntäainetta) lisättiin rehueriin laboratoriossa ja kutakin käsittelyä kohden rehua säilöttiin kolmeen 12 l siiloon. Siilot avattiin 107 päivän säilöntäjakson jälkeen. Säilöntäaineessa annosteltu natriumselenaatti säilyi rehuissa säilöntäprosessin ajan. Seleenin muuttumista orgaaniseen muotoon ei havaittu. Tulosten perusteella natriumselenaatti ei vaikuttanut säilöntätulokseen, mutta AIV Ässä rajoitti käymistä ja valkuaisen hajoamista säilönnän aikana ilman säilöntäainetta säilöttyihin rehuihin verrattuna. Säilörehun säilöntäaineeseen lisättävän seleenin määrää rajaavat tuotteen käyttösuositus ja nurmirehun seleenipitoisuus, sillä rehun seleenipitoisuus ei saa ylittää sallittua pitoisuutta (0,5 mg/kg rehussa, jonka kosteus on 12 %, MMM 43/2005). Nämä rajat huomioiden säilöntäaineeseen voidaan lisätä seleeniä määrä, joka varmistaa ummessa olevan lehmän riittävän seleenin saannin säilörehusta myös tilanteessa, jossa nurmi ei ole saanut seleenilannoitusta

Biotransformation of Selenium by Lactic Acid Bacteria: Formation of Seleno-Nanoparticles and Seleno-Amino Acids

Selenium (Se) is an essential micronutrient for the majority of living organisms, and it has been identified as selenocysteine in the active site of several selenoproteins such as glutathione peroxidase, thioredoxin reductase, and deiodinases. Se deficiency in humans is associated with viral infections, thyroid dysfunction, different types of cancer, and aging. In several European countries as well as in Argentina, Se intake is below the recommended dietary Intake (RDI). Some lactic acid bacteria (LAB) can accumulate and bio-transform selenite (toxic) into Se-nanoparticles (SeNPs) and Se-amino acids (non-toxic). The microbial growth, Se metabolite distribution, and the glutathione reductase (involved in selenite reduction) activity of Se-enriched LAB were studied in this work. The ninety-six assayed strains, belonging to the genera Lactococcus, Weissella, Leuconostoc, Lactobacillus, Enterococcus, and Fructobacillus could grow in the presence of 5 ppm sodium selenite. From the total, eight strains could remove more than 80% of the added Se from the culture medium. These bacteria accumulated intracellularly between 1.2 and 2.5 ppm of the added Se, from which F. tropaeoli CRL 2034 contained the highest intracellular amount. These strains produced only the seleno-amino acid SeCys as observed by LC-ICP-MS and confirmed by LC-ESI-MS/MS. The intracellular SeCys concentrations were between 0.015 and 0.880 ppm; Lb. brevis CRL 2051 (0.873 ppm), Lb. plantarum CRL 2030 (0.867 ppm), and F. tropaeoli CRL 2034 (0.625 ppm) were the strains that showed the highest concentrations. Glutathione reductase activity values were higher when the strains were grown in the presence of Se except for the F. tropaeoli CRL 2034 strain, which showed an opposite behavior. The cellular morphology of the strains was not affected by the presence of Se in the culture medium; interestingly, all the strains were able to form spherical SeNPs as determined by transmission electron microscopy (TEM). Only two Enterococcus strains produced the volatile Se compounds dimethyl-diselenide identified by GC-MS. Our results show that Lb. brevis CRL 2051, Lb. plantarum CRL 2030, and F. tropaeoli CRL 2034 could be used for the development of nutraceuticals or as starter cultures for the bio-enrichment of fermented fruit beverages with SeCys and SeNPs.Fil: Martínez, Fernando Gabriel. Universidad Complutense de Madrid. Facultad de Ciencias Químicas. Departamento de Química Analítica; . Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Moreno Martin, Gustavo. Universidad Complutense de Madrid. Facultad de Ciencias Químicas. Departamento de Química Analítica;Fil: Pescuma, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Madrid Albarrán, Yolanda. Universidad Complutense de Madrid. Facultad de Ciencias Químicas. Departamento de Química Analítica;Fil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Functional fermented beberages enriched in seleno-amino acids and seleno-nanoparticles

Selenium (Se) is an essential micronutrient for human health, which is found as selenocysteine (SeCys) in the active site of Se-dependent enzymes involved in the response to oxidative stress and in thyroid functions. The main inorganic Se forms, selenite and selenate are toxic. Some lactic acid bacteria (LAB) can reduce Se salts into seleno-nanoparticles (SeNPs) and seleno-amino acids, which are non-toxic and highly bioavailable forms. In several European countries, as well as in Argentina, Se intake is below the recommended dietary intake (RDI). Se-enrichment of foods is an attractive strategy to increase its ingestion. We aimed to formulate a fermented fruit juice-milk beverage (FJMB) bio-enriched in Se. The fruit-origin strains Fructobacillus tropaeoli CRL 2034 and Levilactobacillus brevis CRL 2051 were grown with or without 5 mg/L of Se prior to co-inoculation (1% of each strain) in the FJMB and were incubated 14 h at 30 °C. The survival of the strains under storage conditions (6 °C, 52 days), and after digestion [using an in vitro gastrointestinal system (GIS)] was analyzed. The strains grew (up to 8.6 U log each) and acidified FJMB reaching a final pH of 4.6. Sugar metabolism and organic acid production were similar for control and selenized cells (RP-HPLC); while mannitol production by selenized cells of the Fructobacillus was lower (0.18 ± 0.03) than control cells. The studied strains could not degrade the proteins present in the FJMB (SDS-PAGE). Selenized cells increased the beverage total Se concentration (ICP-MS, 84.9 ± 4.5 μg/L) and biotransformed selenite into SeCys (39.1 ± 0.4 μg/L) and SeMet (6.1 ± 0.1 μg/L) as detected by LC-ICP-MS. Moreover, SEM images of the fermented FJMB revealed the presence of SeNPs attached to the cell surface of both strains. Interestingly, microbial resistance at the end of the shelf life was greater (between 0.5 and 0.7 U log) for selenized than non-selenized cells. However, no differences were observed in the sugar and organic acid concentrations between treated and non-treated cells and a lower (0.29 ± 0.04 g/L) mannitol production was detected at 28 day incubation by the treated strains. After GIS digestion, a decrease in the cell counts of F. tropaeoli and L. brevis (1.60 and 0.80 U log, respectively) was observed. Interestingly, 64.3 ± 3.3 μg total Se/L partly as SeCys (25.8 ± 2.3 μg/L) and SeMet (2.4 ± 0.2 μg/L) were found in the FJMB supernatant after intestinal digestion, highlighting the bioaccessibility of these compounds. Remarkably, 250 mL of the FJMB could cover 64% of the Se RDI (25 μg/day), from which 28% is composed by seleno-amino acids. Our results suggest that selenized cells of F. tropaeoli CRL 2034 and L. brevis CRL 2051 could be used for formulating functional Se-enriched beverages to improve this micronutrient intake in humans.Fil: Martínez, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Complutense de Madrid. Facultad de Ciencias Químicas; EspañaFil: Moreno Martin, Gustavo. Universidad Complutense de Madrid. Facultad de Ciencias Químicas; EspañaFil: Madrid Albarrán, Yolanda. Universidad Complutense de Madrid. Facultad de Ciencias Químicas; EspañaFil: Ordoñez, Omar Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Pescuma, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaLVI Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; XV Annual Meeting of the Argentinean Society for General MicrobiologyVirtualArgentinaSociedad Argentina de Investigación en Bioquímica y Biología MolecularSociedad Argentina de Microbiología Genera

Simultaneous Determination of Aflatoxins B1, B2, G1 and G2 IN Commercial Rices Using Immunoaffinity Column Clean-UP and HPLC-MS/MS

Rice is frequently contaminated with aflatoxins, that are highly toxic fungal substances and strongly involved on hepatic cancer. In this work, different extraction and clean-up methods were evaluated for the simultaneous extraction and clean-up of aflatoxins B1, B2, G1 and G2 from rice. Favourable results were obtained by using methanol – water (80:20, v/v) extraction followed by immunoaffinity columns for clean-up, with recoveries of 86–92%, standard deviations between 5 and 11%, LOD ranged between 0.09 and 0.32 µg/kg, and LOQ between 0.31 and 1.06 µg/kg. Method validation and sample analysis were performed by using HPLC-MS/MS. Nine rice samples from different origin, varieties and specific characteristics, acquired in Spanish supermarkets were analysed. In two basmati samples from the same batch aflatoxin B1 was detected at (1.62 ± 0.08) µg/kg and (0.77 ± 0.03) µg/kg, both lower than the levels established by European Regulation for aflatoxin B1 in cereals

Screening the extraction process of phenolic compounds from pressed grape seed residue: Towards an integrated and sustainable management of viticultural waste

The integrated valorisation of waste from the food chain to obtain value-added compounds with biological functionality will facilitate the transition to the era of a sustainable bioeconomy. To this end, an efficient matrix solid-phase dispersion (MSPD) extraction method was developed and optimized, using experimental factorial design and response surface methodology, for polyphenols recovery from pressed grape seeds obtained after the extraction of essential oils by cold pressing. Gallic, dihydroxybenzoic, p-coumaric and trans-ferulic acid, naringin, resveratrol, quercetin and kaempferol were quantified at 2.1–295 μg g−1 by capillary liquid chromatography coupled to a diode array detector and a mass analyser (cLC-DAD-MS). Furthermore, total antioxidant activity, free radical scavenging and lipid peroxidation suppression, together with the inhibition of beta-amyloid (Αβ42) protein aggregation, considered one of the main pathological effects of Alzheimer's disease, were evaluated. Potent lipid peroxidation inhibition (IC50 0.238 ± 0.003 ng g−1) was observed, along with the reduction of Αβ42 fibril width (9.4–54.8%) and aggregation. The results presented proved that the MSPD extraction method could be considered as an efficient and sustainable methodology to produce phenolic-rich extracts that may serve as an alternative antioxidant and neuroprotective ingredient for the food or pharmaceutical formulations, leading to the cascade valorisation of winery by-products

Curso abierto de ayuda para la elaboración del Trabajo Fin de Grado en los Grados en Química e Ingeniería Química

Este proyecto llevará a cabo el desarrollo de un curso abierto que sirva a los estudiantes como guía de ayuda a la hora de elaborar su Trabajo Fin de Grado (TFG) en los Grados de Química e Ingeniería Química. Se incluirá una descripción de herramientas que los estudiantes puedan emplear en el desarrollo de sus TFG. Éstas serán seleccionadas de acuerdo con la experiencia de los miembros del Grupo y en función de las necesidades de los estudiantes. El curso resultante se editará para libre acceso a través del portal iTunes U, de ámbito internacional, convirtiéndose en el primer curso UCM ofertado en esta plataforma (tras consulta y aprobación del Vicerrectorado de Innovación; de no ser así, se alojará en alguna otra plataforma de amplia difusión). Se aprovechará la accesibilidad ofertada a los estudiantes por iTunes U para poner a su disposición el material elaborado logrando una gran difusión, incrementándose la visibilidad internacional de la UCM. El material de ayuda elaborado para el curso se presentará tanto en español como en inglés, para facilitar su uso por alumnos visitantes de la UCM, favoreciendo la movilidad de los estudiantes en el marco del EEES. Este material también se adaptará para poder ser empleado de forma directa, totalmente o en forma de módulos, en el Campus Virtual UCM

Diseño y preparación de un laboratorio virtual de Química Analítica: Técnicas instrumentales de análisis

La reciente pandemia del COVID-19 ha supuesto un cambio excepcional y drástico de la concepción tradicional del aprendizaje, tanto para los estudiantes como para los docentes. Ante esta situación se requiere no sólo acciones que faciliten la adaptación de los estudiantes y profesores a las plataformas educativas en línea, sino también a que éstas se conviertan en auténticas herramientas para potenciar y mejorar de forma significativa el aprendizaje del alumno. El presente proyecto de Innovación Educativa y Mejora de la Calidad Docente pretende mejorar la calidad del aprendizaje de varias asignaturas de los Grados de Química e Ingeniería Química que llevan asociado un Laboratorio de Técnicas Instrumentales. Tradicionalmente esa docencia práctica ha sido presencial, pero la situación excepcional surgida con la pandemia en el curso 2019/2020, ha demostrado que disponer de unas prácticas virtualizadas es de gran ayuda para facilitar el aprendizaje de los alumnos y facilitar una transferencia del conocimiento constructivo y colaborativo. Desde hace años, el personal docente e investigador (PDI), personal de administración y servicios (PAS) y los estudiantes de la UCM, disponemos de la plataforma de enseñanza online Moodle (Campus Virtual, CV). Sin embargo, la pandemia que vivimos ha evidenciado la brecha digital en lo referente a cómo usar Moodle y, por ende, la utilización de las Tecnologías de Información y Comunicación (TICs) como facilitadoras didácticas. A pesar de nuestras limitaciones, tanto profesores como estudiantes, hemos desarrollado una enorme capacidad resiliente, lo que permitió, durante el pasado mes de mayo, la puesta en marcha de los primeros laboratorios en línea en el Departamento de Química Analítica de la UCM. Fruto de esta experiencia, así como de la situación actual de incertidumbre para el curso próximo, algunos profesores, estudiantes y PAS del departamento hemos decidido adelantarnos a un escenario futuro en el que se contemple nuevamente la impartición de Docencia Experimental en línea y solicitar el presente proyecto de Innovación Educativa y Mejora de la Calidad Docente

Exploring the Behavior and Metabolic Transformations of SeNPs in Exposed Lactic Acid Bacteria. Effect of Nanoparticles Coating Agent

The behavior and transformation of selenium nanoparticles (SeNPs) in living systems such as microorganisms is largely unknown. To address this knowledge gap, we examined the effect of three types of SeNP suspensions toward Lactobacillus delbrueckii subsp. bulgaricus LB-12 using a variety of techniques. SeNPs were synthesized using three types of coating agents (chitosan (CS-SeNPs), hydroxyethyl cellulose (HEC-SeNPs) and a non-ionic surfactant, surfynol (ethoxylated-SeNPs)). Morphologies of SeNPs were all spherical. Transmission electron microscopy (TEM) was used to locate SeNPs in the bacteria. High performance liquid chromatography (HPLC) on line coupled to inductively coupled plasma mass spectrometry (ICP-MS) was applied to evaluate SeNP transformation by bacteria. Finally, flow cytometry employing the live/dead test and optical density measurements at 600 nm (OD600) were used for evaluating the percentages of bacteria viability when supplementing with SeNPs. Negligible damage was detected by flow cytometry when bacteria were exposed to HEC-SeNPs or CS-SeNPs at a level of 10 μg Se mL−1. In contrast, ethoxylated-SeNPs were found to be the most harmful nanoparticles toward bacteria. CS-SeNPs passed through the membrane without causing damage. Once inside, SeNPs were metabolically transformed to organic selenium compounds. Results evidenced the importance of capping agents when establishing the true behavior of NPs

Volatile organo-selenium speciation in biological matter by solid phase microextraction–moderate temperature multicapillary gas chromatography with microwave induced plasma atomic emission spectrometry detection

Microwave induced plasma atomic emission spectrometry (MIP-AES) in combination with multicapillary (MC) gas chromatography could be proven to be useful for element specific detection of volatile species. Solid phase microextraction (SPME) was used for preconcentration and sample-matrix separation. The fiber desorption unit as well as the heating control for the MCcolumn were in-house developed and multicapillary column was operated at moderate temperatures (30–100 ◦C). The method was optimized for organo-selenium species (dimethylselenide (DMSe), diethylselenide (DEtSe) and dimethyldiselenide (DMDSe)), using a chemometric approach. Stationary phases for the separation column were optimized using a conventional GC and contrasted with the results obtained with the MC. Application was focussed on selenium accumulating biological matter, such as lupine, yeast, Indian mustard and garlic. These samples were grown in hydroponic solution containing inorganic selenium (Na2SeO3 and Na2SeO4). SPME sampling was carried out in fixed volume flow boxes in headspace above the living plants and in vials using treated samples. Results demonstrate inorganic selenium transformation into volatile organic species during metabolism. Separation is fast, a chromatogram can be obtained in less than 3 min and detection limits were at sub-ppb level for all investigated species. The system is independent from the use of a conventional gas chromatographic oven and can be used as a versatile alternative to highly cost intensive methods such as GC–ICP-MS