Arabic gum, a new strategy for microbiological control in the dairy industry

The nutritional quality loss of food, usually is caused by microbial growth during different stages of production. Particularly in raw milk, the initial microbial content will affect the quality, shelf life and safety of processed milk and its derivatives. Traditionally, one of the strategies most used for reducing the risk of microbial contamination of raw milk, is storage under refrigeration immediately after to milking. However, this selectively favor the development of psychrotrophic microorganisms that can produce heat stable extracellular enzymes, causing alterations in the chemical composition and nutritional value of milk. In the last decade, the demand for minimally processed, easily prepared, and ready-to-eat fresh food products has grown globally, prompting the development of new methodologies as alternatives to thermal treatment. A growing trend is the addition of preservatives of natural sources, as a safe and healthy alternative to synthetics preservatives. The Arabic Gum (AG) is an edible biopolymer obtained as exudates of trees of Acacia, which is being widely used as a stabilizer, a thickener, and an emulsifier. However, to date, no antimicrobial activities studies have been conducted against psychrotrophics microorganisms. The aim of this work was to evaluate the effect of the addition of AG over the psychrotrophics bacterial growth, and viability. Several bacteria isolated from raw milk (Enterobacter spp.) were cultivated with different concentration of AG (0, 10, 20, 75, 100, 200, 400 M) during a period of 7 days at 4ºC and analyzed each 24 h. The bacterial growth in different conditions was evaluated by CFU counts, viability assays was performed using the LIVE/DEAD BacLight Bacterial Viability Kit (FACS), and metabolic activity was determined by colorimetric assay using tetrazolium salt (MTT). We observed that the addition of 200 and 400 M AG controlled proliferation of bacterial growth in more than a 50%, respect to the control condition and these effects were dose-dependent. In another hand, AG did not show significantly effect on the bacterial viability evaluated by the incorporation of propidium iodure. However using the tetrazolium salt as MTT we could determine that 75, 100, 200 and 400 M of AG were able to inhibit the metabolic activity of psychrotrophics bacterial growth significantly in all the assayed times. These data shown that AG had an important effect in the initial proliferation over psychrotrophic bacterial milk, which was maintained during analyzed times. Is important to hightlight that, for dairy factory the initial times are determinants to conserve the milk quality up to industrial processing, improving nutritional value in the final product. In base of these results, we can suggest that AG provides an additional beneficial effect to their usually technological use in food industry.Fil: Boiero, María Laura. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Gonzalez Estevez, Virginia. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Bachetti, R. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Morgante, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Porporatto, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Montenegto, Mariana. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Peer Reviewe

Evaluación comparativa por citometría de flujo y recuento en placa, de la actividad antimicrobiana de goma arábiga frente a microorganismos psicrótrofos

Una de las estrategias más aplicadas para la conservación de productos lácteos, es la refrigeración. Si bien el almacenamiento de leche a bajas temperaturas permite prolongar su vida útil, también favorece el desarrollo selectivo de microorganismos psicrótrofos (bacterias que crecen próximo a 0 °C) que producen enzimas hidrolíticas termorresistentes. Esto conduce a la pérdida de la calidad nutricional y organoléptica de la leche. La tendencia actual consiste en aplicar preservantes de origen natural, como una alternativa segura y saludable a los conservantes químicos. Goma arábiga (GA) es un biopolímero comestible obtenido del exudado de árboles Acacia Senegal y Seyal. Ésta se emplea comúnmente como agente espesante, estabilizante, emulsionante, en diversas industrias. Sin embargo, numerosos estudios indican que adicionalmente posee propiedades biológicas como antioxidante, contribución positiva sobre diferentes enfermedades, y actividad antimicrobiana. Es por ello que el objetivo del trabajo, fue evaluar la actividad antimicrobiana (AAM) de GA frente al desarrollo de microorganismos psicrótrofos aislados de leche cruda, almacenada a temperatura de refrigeración (4 °C), a través de la técnica de recuento en placa y comparar con la determinación de viabilidad por citometría de flujo (CMF). Los resultados obtenidos demostraron una relación entre los métodos de recuentos utilizados, indicando que GA, presenta AAM de sobre un microorganismo capaz de desarrollarse en leche, principalmente a altas concentraciones, aportando un efecto benéfico adicional a sus usos tecnológicos.Fil: Boiero, María Laura. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Gonzalez Estevez, Virginia. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Montenegro, Mariana. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Breser, L. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Bachetti, R. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Morgante, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Porporatto, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Peer Reviewe

A RG-II type polysaccharide purified from Aconitum coreanum and their anti-inflammatory activity

Korean mondshood root polysaccharides (KMPS) isolated from the root of Aconitum coreanum (Lévl.) Rapaics have shown anti-inflammatory activity, which is strongly influenced by their chemical structures and chain conformations. However, the mechanisms of the anti-inflammatory effect by these polysaccharides have yet to be elucidated. A RG-II polysaccharide (KMPS-2E, Mw 84.8 kDa) was isolated from KMPS and its chemical structure was characterized by FT-IR and NMR spectroscopy, gas chromatography–mass spectrometry and high-performance liquid chromatography. The backbone of KMPS-2E consisted of units of [→6) -β-D-Galp (1→3)-β-L-Rhap-(1→4)-β-D-GalpA-(1→3)-β-D-Galp-(1→] with the side chain →5)-β-D-Arap (1→3, 5)-β-D-Arap (1→ attached to the backbone through O-4 of (1→3,4)-L-Rhap. T-β-D-Galp is attached to the backbone through O-6 of (1→3,6)-β-D-Galp residues and T-β-D-Ara is connected to the end group of each chain. The anti-inflammatory effects of KMPS-2E and the underlying mechanisms using lipopolysaccharide (LPS) - stimulated RAW 264.7 macrophages and carrageenan-induced hind paw edema were investigated. KMPS-2E (50, 100 and 200 µg/mL) inhibits iNOS, TLR4, phospho-NF-κB–p65 expression, phosphor-IKK, phosphor-IκB-α expression as well as the degradation of IκB-α and the gene expression of inflammatory cytokines (TNF-α, IL-1β, iNOS and IL-6) mediated by the NF-κB signal pathways in macrophages. KMPS-2E also inhibited LPS-induced activation of NF-κB as assayed by electrophorectic mobility shift assay (EMSA) in a dose-dependent manner and it reduced NF-κB DNA binding affinity by 62.1% at 200µg/mL. In rats, KMPS-2E (200 mg/kg) can significantly inhibit carrageenan-induced paw edema as ibuprofen (200 mg/kg) within 3 h after a single oral dose. The results indicate that KMPS-2E is a promising herb-derived drug against acute inflammation