Person:
Fernández Álvarez, Manuela

First Name

Manuela

Last Name

Fernández Álvarez

URI

https://hdl.handle.net/20.500.14352/80424

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Veterinaria

Department

Farmacia Galénica y Tecnología Alimentaria

Area

Tecnología de los Alimentos

Identifiers

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Now showing 1 - 10 of 23

Volatile N-nitrosamines in Spanish commercial meat products and in fermented sausages prepared with different ingoing amounts of nitrate and nitrite
(Heliyon, 2024) Fernández Hospital, Xavier; Fernández Álvarez, Manuela; Morales Gómez, Paloma; Alba Rubio, Claudio; Haza Duaso, Ana Isabel; Hierro Paredes, Eva
Spanish commercial dry fermented sausages and dry hams, manufactured with and without nitrate and/or nitrite have been screened for volatile N-nitrosamine (VNA) content. VNAs have been also quantified in experimental fermented sausages prepared with known ingoing amounts of curing salts. Solid phase microextraction followed by tandem quadrupole gas chromatography/mass spectrometry (GC-QQQ-MS) analysis allowed the identification and quantification of 8 VNAs, 5 of which were detected in the samples. The highest concentration of VNAs found in the commercial products was 5.4 μg/kg. The most frequently detected VNAs were N-nitrosodiphenylamine and N-nitrosopyrrolidine. Principal component analysis and cluster analysis did not show correlation between the content of VNAs and the use of nitrate/nitrite in the formula. In the experimental sausages N-nitrosodiphenylamine and N-nitrosopyrrolidine were only detected (0.55 μg/kg total concentration) when 150 mg/kg of both nitrate and nitrite were added to the formula without any antioxidant. The levels of VNAs detected in this study are similar to those reported in the literature in different fermented meat products and dry hams.
Differential Apoptotic Effects of Bee Product Mixtures on Normal and Cancer Hepatic Cells
(Antioxidants, 2023) Sánchez Martín, Vanesa; Morales Gómez, Paloma; Iriondo De Hond, Amaia; Fernández Hospital, Xavier; Fernández Álvarez, Manuela; Hierro Paredes, Eva; Haza Duaso, Ana Isabel; Gan, Ren-You
Most effective anticancer drugs normally generate considerable cytotoxicity in normal cells; therefore, the preferential activation of apoptosis in cancer cells and the reduction of toxicity in normal cells is a great challenge in cancer research. Natural products with selective anticancer properties used as complementary medicine can help to achieve this goal. The aim of the present study was to analyze the effect of the addition of bee products [propolis (PR) or royal jelly (RJ) or propolis and royal jelly (PR+RJ), 2–10%] to thyme (TH) and chestnut honeys (CH) on the differential anticancer properties, mainly the cytotoxic and pro-apoptotic effects, in normal and cancer hepatic cells. The cytotoxic effects of samples were analyzed using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay (0–250 mg/mL) and the effects on apoptosis were analyzed using cell cycle analysis, TdT-dUTP terminal nick-end labeling (TUNEL) assay, DR5 (Death Receptor 5) and BAX (BCL-2-Associated X) activation, and caspases 8, 9, and 3 activities. Both honey samples alone and honey mixtures had no or very little apoptotic effect on normal cells. Antioxidant honey mixtures enhanced the apoptotic capacity of the corresponding honey alone via both extrinsic and intrinsic pathways. Of all the samples, chestnut honey enriched with 10% royal jelly and 10% propolis (sample 14, CH+10RJ+10PR) showed the highest apoptotic effect on tumor liver cells. The enrichment of monofloral honey with bee products could be used together with conventional anticancer treatments as a dietary supplement without side effects. On the other hand, it could be included in the diet as a natural sweetener with high added value.
Bee products as an alternative for the preservation of nitrate and nitrite-reduced dry fermented sausages
(Food Bioscience, 2024) Fernández Hospital, Xavier; Hierro Paredes, Eva; Martín Cabrejas, Izaskun; Caballero, Natalia; Jiménez Begoña; Sánchez Martín, Vanesa; Morales Gómez, Paloma; Haza Duaso, Ana Isabel; Fernández Álvarez, Manuela
Food regulations are becoming increasingly restrictive on the use of nitrate and nitrite as additives in meat products, so different alternatives are being investigated to replace their functions. In this study, we tested the antioxidant activity of mixtures of bee products to partially replace nitrate and nitrite in dry fermented sausages. Two combinations of chestnut honey, propolis and royal jelly were added to sausages at 2% concentration, together with 0 and 75 mg/kg of nitrate and nitrite. TBARs and volatile profile analysis revealed a lower intensity of oxidation phenomena in sausages prepared with bee products, but these differences were not perceived by the tasters in the sensory analysis. Only instrumental differences in the a* colour parameter were observed when nitrate and nitrite were not used in the formulation. The addition of bee products did not affect the typical microbiota (lactic acid bacteria and gram-positive catalase-positive cocci) of sausages. The combination of 2% bee products and 75 mg/kg of nitrate and nitrite may be useful to obtain dry fermented sausages with a sensory quality and oxidation stability similar to a standard product containing the maximum amounts of these additives allowed in the European Union (150 mg/kg each).
Protective Effect of Thyme and Chestnut Honeys Enriched with Bee Products against Benzo(a)pyrene-Induced DNA Damage
(International Journal of Environmental Research and Public Health, 2022) Sánchez Martín, Vanesa; Haza Duaso, Ana Isabel; Iriondo De Hond, Amaia; Del Castillo, María Dolores; Fernández Hospital, Xavier; Fernández Álvarez, Manuela; Hierro Paredes, Eva; Morales Gómez, Paloma; Tchounwou, Paul B.
The aim of the present study was to validate the cytotoxicity, genotoxicity, and preventive potential against benzo(a)pyrene (BaP)-induced DNA damage of nine samples of thyme and chestnut honeys enriched with bee products (royal jelly and propolis, 2–10%). Cell viability was determined by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay (0–250 mg/mL) to select nontoxic concentrations, and DNA damage (0.1–10 μg/mL) was evaluated by the alkaline single-cell gel electrophoresis or comet assay. Treatment with honey samples or royal jelly and propolis did not affect the viability of HepG2 cells up to 100 and 50 mg/mL, respectively. Treatment with 100 μM BaP significantly increased (p ≤ 0.001) the levels of the DNA strand breaks. None of the tested concentrations (0.1–10 μg/mL) of the honey samples (thyme and chestnut), royal jelly, and propolis caused DNA damage per se. All tested samples at all the concentrations used decreased the genotoxic effect of BaP. In addition, all mixtures of thyme or chestnut honeys with royal jelly or propolis showed a greater protective effect against BaP than the samples alone, being the thyme and chestnut honey samples enriched with 10% royal jelly and 10% propolis the most effective (70.4% and 69.4%, respectively). The observed protective effect may be associated with the phenolic content and antioxidant capacity of the studied samples. In conclusion, the thyme and chestnut honey samples enriched with bee products present potential as natural chemoprotective agents against the chemical carcinogen BaP.
Potential of selected bacteriocinogenic lactic acid bacteria to control Listeria monocytogenes in nitrite-reduced fermented sausages
(Food Control, 2023) Caballero, Natalia; Jiménez, Begoña; Haza Duaso, Ana Isabel; Hierro Paredes, Eva; Fernández Hospital, Xavier; Fernández Álvarez, Manuela; Sánchez Martín, Vanesa; Morales Gómez, Paloma
The antilisterial activity of four strains of bacteriocinogenic lactic acid bacteria has been tested in vitro and in a meat model, as an alternative to reduce nitrite added to fermented sausages. Cell-free supernatants were obtained after bacterial growth under monoculture and coculture conditions, both at 32 °C/16 h and 22 °C/72 h. After being adjusted to different pH, supernatants were assayed for inhibition of Listeria monocytogenes inoculated on tryptone soya broth added with 0.8% bacteriological agar. The highest inhibition was observed for Pediococcus acidilactici MP14 and the commercial starter P. acidilactici B-LC-20, especially when they were grown in coculture with Staphylococcus spp. meat starters. Lactococcus lactis MP11 showed lower antilisterial activity, and it was dependant on pH. In a fermented sausage model prepared without and with 50% of the maximum level of sodium nitrite allowed by the European Union (i.e. 75 mg/kg) both pediococci confirmed the activity observed in vitro, and reduced Listeria numbers by 1.3–1.4 log cfu/g in the absence of nitrite and 0.8 log cfu/g in its presence. Therefore P. acidilactici MP14, which had been isolated from an artisanal fermented sausage, has shown potential interest for biopreservation applications that must be confirmed in studies under real sausage manufacture conditions.
Use of Lactococcus lactis subsp. cremoris NCDO 763 and -ketoglutarate to improve the sensory quality of dry fermented sausages.
(Meat Science, 2004) Bruna, Jose María; Ordóñez, Juan Antonio; de la Hoz, Lorenzo; Herranz Hernández, María Beatriz; Fernández Álvarez, Manuela; Hierro Paredes, Eva
The aim of the present work was to enhance the degradation of free amino acids in dry fermented sausages as precursors of volatile compounds responsible for the ripened flavour. For this purpose, Lactococcus lactis subsp. cremoris NCDO 763, its intracellular cell free extract (ICFE) and α-ketoglutarate were added to sausages. Papain was also used to increase the amount of free amino acids. When L. lactis was inoculated in sausages, an increase in the proteolytic phenomena was observed. The addition of α-ketoglutarate increased transamination phenomena in batches where it was added. The enhancement of these phenomena determined a noticeable rise in the content of glutamic acid (the main final product in transamination reactions) and a decrease, among other amino acids, of valine and leucine, with the formation of high amounts of their derivatives 2-methylpropanal and 3-methylbutanal. These aldehydes are responsible for the ripened flavour of dry fermented sausages. Sensory analysis showed an improvement of odour and flavour when L. lactis and α-ketoglutarate were combined. On the other hand, the intracellular cell free extract of L. lactis did not show any important activity in relation to amino acid breakdown even when used together with α-ketoglutarate and/or papain.
Project number: 236
Desarrollo de una práctica integral sobre el diseño, elaboración y comercialización de un alimento obtenido por fermentación a escala semi-industrial
(2020) Fernández Álvarez, Manuela; Gilabert Santos, Juan Antonio; García De Fernando Minguillón, Gonzalo Doroteo; Selgas Cortecero, María Dolores; Fernández Álvarez, Leonides; Cabeza Briales, María Concepción; Orgaz Martín, Belén; Guerrero Moreno, Andrés; Lucas López, Juan Raúl; Marty Poncini, Lorena; Estebas Elizo, Víctor Juan
Este documento contiene la memoria final del proyecto de innovación docente "Desarrollo de una práctica integral sobre el diseño, elaboración y comercialización de un alimento obtenido por fermentación a escala semi-industrial", llevado a cabo en el curso 2018-19. En la memoria se describen los resultados obtenidos en el desarrollo de este proyecto, cuyo objetivo ha sido implementar una práctica para que los estudiantes del Grado en Ciencia y Tecnología de los Alimentos llevaran a cabo el diseño y la elaboración de cerveza en condiciones similares a las reales en la industria alimentaria. El proyecto se ha incluido dentro de las actividades de la asignatura optativa "Tecnología Enológica y de Otras Bebidas Alcohólicas", que se imparte en el cuarto curso del Grado.
Efecto de la adición de lipasa pancreática en la maduración de embutidos crudos curados
(2002) Fernández Álvarez, Manuela; Ordóñez Pereda, Juan Antonio; Hoz Perales, Lorenzo de la
Se ha estudiado el efecto de la adición de distintas cantidades de lipasa pancreática en la maduración de embutidos crudos curados. Según los resultados obtenidos, esta enzima no modifico las características microbiológicas y fisico-químicas generales de los embutidos, aunque se observo una lipolisis mas intensa que en embutidos convencionales, que determino una mayor acumulación de diglicéridos y de ácidos grasos libres, principalmente oleico y linoleico. Estos ácidos grasos son los principales precursores de compuestos aromáticos y sapidos. No se aprecio efecto sobre la composición de ácidos grasos de cadena corta. En todos los embutidos elaborados con lipasa se observo un contenido de carbonilos mayor que el registrado en embutidos convencionales, siendo el hexanal el componente mayoritario. El análisis sensorial reflejo diferencias positivas (p<0,01) entre los embutidos controles y los elaborados con 60 y 90 unidades de lipasa pancreática, siendo la característica sensorial mejor evaluada el sabor y aroma. Aunque los resultados no son totalmente concluyentes, estas investigaciones pretenden ser el punto de partida en la utilización de lipasas para acelerar el proceso madurativo de los embutidos
Project number: 146
Estrategias colaborativas de integración de recursos docentes en línea para la mejora del proceso de enseñanza/aprendizaje del Grado en Veterinaria entre las facultades españolas donde se imparte dicha titulación
(2021) Gagete Camargo, María Victoria; García-Cuevas Roque, María Carmen; Martínez Martín, Cesar; Arias Álvarez, María; Cabeza Briales, María Concepción; Castro Madrigal, Teresa; Cambero Rodríguez, María Isabel; Fernández Álvarez, Manuela; Martínez De Merlo, Elena; Pérez Cabal, María De Los Ángeles; Pérez Sen, Raquel; Serres Dalmau, María Consolacion; Díez Martín, Amalia
La emergencia sanitaria por la pandemia COVID-19 afectó al desarrollo académico del Curso 2019-20 de tal manera que, en un periodo de tiempo escaso, las Universidades tuvieron que virar de forma urgente hacia un modelo de enseñanza-aprendizaje a distancia. Todos los planes de estudio cuidadosamente construidos cambiaron de repente hacia una docencia y una evaluación que se tuvo que desarrollar completamente en línea. La evolución de la pandemia impidió la vuelta a una enseñanza presencial completa para el Curso 2020-21 y nos obligó a plantear la docencia en un nuevo escenario semipresencial en donde el uso de herramientas virtuales para la adquisición de competencias de los estudiantes es necesario. El proyecto pretende compartir experiencias docentes y metodologías didácticas innovadoras desarrolladas por profesorado del Grado en Veterinaria que faciliten la docencia ante distintas eventualidades. Este proyecto brinda una gran oportunidad al profesorado, que tuvo que enfrentarse a una situación académica sin precedentes, para reflexionar, y detectar las debilidades del material docente que se preparó con urgencia y mejorarlas.
Formation of Listeria monocytogenes persister cells in the produce-processing environment
(International Journal of Food Microbiology, 2023) Li, Xiran; Fernández Hospital, Xavier; Hierro Paredes, Eva; Fernández Álvarez, Manuela; Sheng, Lina; Wang, Luxin
Persisters are a subpopulation of growth-arrested cells that possess transient tolerance to lethal doses of antibiotics and can revert to an active state under the right conditions. Persister cells are considered as a public health concern. This study examined the formation of persisters by Listeria monocytogenes (LM) in an environment simulating a processing plant for leafy green production. Three LM strains isolated from California produce-processing plants and packinghouses with the strongest adherence abilities were used for this study. The impact of the cells' physiological status, density, and nutrient availability on the formation of persisters was also determined. Gentamicin at a dose of 100 mg/L was used for the isolation and screening of LM persisters. Results showed that the physiological status differences brought by culture preparation methods (plate-grown vs. broth-grown) did not impact persister formation (P > 0.05). Instead, higher persister ratios were found when cell density increased (P < 0.05). The formation of LM persister cells under simulated packinghouse conditions was tested by artificially inoculating stainless steel coupons with LM suspending in media with decreasing nutrient levels: brain heart infusion broth (1366 mg/L O2), produce-washing water with various organic loads (1332 mg/L O2 and 652 mg/L O2, respectively), as well as sterile Milli-Q water. LM survived in all suspensions at 4 °C with 85 % relative humidity for 7 days, with strain 483 producing the most persister cells (4.36 ± 0.294 Log CFU/coupon) on average. Although persister cell levels of LM 480 and 485 were reasonably steady in nutrient-rich media (i.e., BHI and HCOD), they declined in nutrient-poor media (i.e., LCOD and sterile Milli-Q water) over time. Persister populations decreased along with total viable cells, demonstrating the impact of available nutrients on the formation of persisters. The chlorine sensitivity of LM persister cells was evaluated and compared with regular LM cells. Results showed that, despite their increased tolerance to the antibiotic gentamicin, LM persisters were more susceptible to chlorine treatments (100 mg/L for 2 min) than regular cells.