Producción de hidrolizados proteicos a partir de subproductos pesqueros y agrícolas

Los residuos de la industria procesadora de pescado son materia prima con un gran potencial para la producción de hidrolizados de proteínas de pescado (HPP) con características funcionales que pueden ser utilizados no sólo como alimento para animales, sino también para el consumo humano (es decir, los aditivos alimentarios y nutracéuticos), que incluye la búsqueda de p éptidos biológicamente activos . La hidrólisis se lleva a cabo con mi croorganismos (fermentación). La fermentación se ve beneficiada al añadir un promotor, en este caso papaya (Carica papaya ) en es tado de madurez comercial, que produce proteasas y suplementa a los desechos de pescado con los nutrientes adecuados para el crecimiento microbiano , así como melaza que es un subproducto de la caña de azúcar. El procesamiento industrial de especies de pescado como el atún genera un porcentaje de subproductos entre el 60 y 70%. Los subproductos son considerados comúnmente como recursos de escaso valor en el mercado y entre ellos se encuentran las vísceras, las agallas, el músculo oscuro, la cabeza, los huesos y la piel. El alto contenido de proteína, las enzimas proteolíticas y la capacidad amortiguadora del sustrato fueron características importantes para tener una producción satisfactoria de hidrolizados proteicos obtenidos a partir de fermentació n láctica. Se determinó el consumo de azúcares, los cuales se relacionan directamente con la producción de ácido láctico (AL). La concentración máxima de AL generado, la constante de la tasa de acidificación y la tasa de máxima producción de ácido láctic o se estimaron con el modelo de Gompertz con datos de 5 días (120h) de fermentación y éstos fueron de 1.27 mmol A L /g, 0.142 h - 1 y 0.067 mmol AL /gh, respect ivamente. El grado más alto de hidrólisis proteica fue de 87.71% y fue alcanzado a las 120 h de fermentación. La actividad contra radicales libres fue evaluada mediante espectroscopía de resonancia paramagnética electrónica (EPR) basándose en la conversión del radical 2,2 - dif en il - 1 - picri lh i dra cil . La concentración de aminoácidos relacionados con la actividad antir r adicalaria (Val, Ile, Leu, Phe, Met, Pro, Tyr and His ) presentó un máximo a partir de las 72 h debido al incremento de la hidrólisis proteica. En este tiempo de fermentación se obtuvo la concentración más baja de hidrolizados proteicos capa ces de inhibir al radical en un 50% de su actividad, a cuál fue de 5.75 g prote ína /mg. La purificación de péptidos mostró fracciones con una alta concentración de aminoácidos hidrofóbicos, que están relacionados con la actividad contra radicales libres El procesamiento de subproductos de atún mediante la metodología propuesta resulta ser una fuente de hidrolizados proteicos de alto valor agregado debido a su actividad contra radicales libres, la estabilidad del proceso, el alto grado de hidrólisis y dige stibilidad, así como la inocuidad al no encontrarse la presencia de coliformes. Palabras clave: Thunnus albacares , antioxidante, biorefinación, hidrolizado proteico , Carica papaya.Fishery industry by - products are raw material with a wide potential to produce fish protein hydrolisates with functional properties that may lead their use not only for animal nourishment but for human consumption (i.e. food additives and nutraceuticals), which includes the search of biologically active peptides. Hydrolisis is carried by microbial fermentation, which gets benefit when it is promoted by the addition of papaya fruit ( Carica papaya ) in commercial ripeness as a source of proteases and nutrients for microbial growth, as well molasses as a carbon source (by - product of the sugar cane industry). Industrial processing of fish species like tuna generate a by - product percentage between 60 and 70%, are considered a low value material and consist mainly in viscera, gills, dark muscle, heads, bones and skin. High protein content, proteolytic enzymes and substrate buffer capacity were important characteristics for successful production of protein hydrolysates by fermentation of tuna by - products and papaya. The maximum lactic acid (LA) produced, acidification rate constant and maximum acid production rate were estimated by Gompertz model with experimental data of 5 d of fermentation to be 1.27 mmol LA /g, 0.142 h - 1 and 0.067 mmol LA /gh, respectively. The highe st protein degree of hydrolysis of 87.71% was achieved at 120 h of fermentation. The radical - scavenging activity in the protein hydrolysates was determined by electron paramagnetic resonance spectroscopy studies based on the conversion of 2,2 - diphenyl - 1 - pi crylhydrazil free - radical. The concentration of amino acids related to radical - scavenging activity; Val, Ile, Leu, Phe, Met, Pro, Tyr and His presented a maximum after 72 h of fermentation, due to increased protein hydrolysis. In addition, the lowest conce ntration of tuna protein hydrolysates, 5.75 g protein/mg, this inhibited 50% of radical activity. Purification of peptides shows a high concentration of hydrophobic amino acids, which are related to radical scavenging activity. T his process, which invo lves tuna by - products fermentation according to the method proposed , results to be a source of high quality protein hydrolysates because of the radical scavenging activity, process stability , high degree of hydrolysis and digestibility, as well safety due to the lack of presence of coliform bacteria . Key words: Thunnus albacares , antioxidant, radical scavenging, biorefinery, protein hydrolysate, Carica papaya

Estudio fisicoquímico comparativo de coacervados complejos obtenidos a partir de mezclas binarias y ternarias de biopolímeros

Food industry has challenged researchers to develop new biomaterials capable to improve product features as microencapsulation matrix, shell life extension by formulation stabilization, to improve rheological properties that ameliorate industrial processes, to endow new outstanding properties to formulations or enhancing a better sensorial experience to consumers, fat substitution or substances that result harmful in small or excessive amounts that participate in an active way in rheological properties of some food. Complex formation by electrostatic interactions between its components results important due to the efficiency in rheological properties compared with individual biopolymers on mixtures of them. Coacervation phenomenon consists in complex formation between opposite charged biopolymers resulting electrostatically neutral. The aim of this work is to obtain and characterize complex coacervates obtained from binary and ternary biopolymer mixtures: arabic and mesquite gum (GA, GM) as polyanions and chitosan (Q) and whey protein isolate (WPI) as polycathions. to probe that coacervates from ternary mixtures present different features than those obtained from binary mixtures, due to favorable interactions between its components, which impact on their rheological behavior. Optimal conditions where zeta potential minimal difference occurs between polyanionic and polycathionic biopolymers involved in coacervation were evaluated at pH values between 3.5 and 5.5. To determine amount of functional groups that react in biopolymer solution, a miliequivalent rate was made, taking account how many from NaOH are necessary to titrate a mass fraction of biopolymer solutions. Rheological parameters determined to coacervates were oscillation and flow tests in a rotational rheometer. Highest yieldings are related to binary coacervates with mesquite gum in both polycathions (more than 70%) followed by binary treatment of gum Arabic with both polycathions (up to 50% with chitosan and over 50% with WPI). The other ternary treatments have a similar behavior, over 40% with chitosan and over 60% with WPI. The lowest treatment yielding is ternary coacervate 75%GM-25%GA even for chitosan (30%) as for WPI (40%). Some favorable or unfavorable facts about interaction between component interactions are explained about polyelectrolytic behavior of macromolecules in solution. Binary and ternary coacervates obtained from treatments with chitosan as polycathion and ternary coacervates with WPI as polycathion presented predominantly viscous characteristics and weak gel behavior. Every treatment presented a shear-thinning behavior, fitting to Carreau model with high correlation coefficients. No evidence about synergy between GA and GM was found in binary and ternary treatments of Chitosan and WPI as polycathion. Due to WPI as a low cost material, coacervates obtained from it could be used potentially as stabilizers and as a matrix to contain high added value products in food formulations. Coacervates with chitosan as polycathion could be used potentially as stabilizers and as a matrix to contain high added value products in healthcare formulations.La industria alimentaria ha puesto el reto a los investigadores para que desarrollen nuevos biomateriales que puedan mejorar las características de sus productos, tanto para prolongar la vida de anaquel al estabilizar formulaciones, para mejorar las propiedades reológicas que repercutan en mejorar los procesos de fabricación, brindar nuevas propiedades favorables a las formulaciones o mejorar la experiencia sensorial de los consumidores; de sustitución de grasas u otro tipo de sustancias que resultan nocivas para algunas personas al ingerirlas en exceso o en pequeñas proporciones y que participan activamente en las propiedades reológicas de algunos alimentos. Dicho esto, se ha investigado el comportamiento de los complejos de biopolímeros. Resulta interesante la formación de complejos mediante interacciones electrostáticas entre sus componentes, debido a que sus propiedades reológicas resultan ser mucho más eficientes que las de los biopolímeros de manera individual o en mezclas. El fenómeno de la coacervación forma complejos de polielectrolitos de cargas opuestas que son electrostáticamente neutros. El objetivo de este trabajo es la obtención y caracterización de coacervados complejos a partir de mezclas binarias y ternarias de biopolímeros (goma arábiga (GA) y goma de mezquite (GM) como polianiones, quitosano (Q) y aislado de proteína de suero de leche (WPI), buscando probar que los coacervados obtenidos a partir de mezclas ternarias de biopolímeros presentan diferentes características fisicoquímicas que los coacervados obtenidos a partir de mezclas secundarias debidas a las interacciones favorables que ocurren entre sus componentes, las cuales influyen en su comportamiento reológico. Se evaluaron las condiciones en las que ocurre la mínima diferencia entre los valores de potencial zeta de los biopolímeros polianiónicos y policatiónicos que forman parte de los coacervados, esto fue a valores de pH entre 3.5 y 5.5. Se hizo una relación de los miliequivalentes necesarios para titular una porción másica de biopolímeros en solución. Se evaluó el rendimiento de coacervación de todos los tratamientos. Los parámetros reológicos que fueron determinados a los coacervados consisten en pruebas de oscilación y amplitud en un reómetro rotacional. Los rendimientos más altos son los que se relacionan con los coacervados binarios con goma de mezquite en ambos policationes (superiores al 70%), seguidos por el tratamiento binario de goma arábiga para ambos policationes (cercano al 50% en quitosano y superior al 50% en WPI). Los demás tratamientos ternarios tienen un comportamiento similar, superior al 40% con los de quitosano y superiores al 60% con los de WPI. El tratamiento con el rendimiento más bajo es el coacervado ternario 75%GM-25%GA tanto para quitosano (30%) como para WPI (40%). Algunas cuestiones favorables o desfavorables respecto a la interacción de los componentes de los coacervados se pueden explicar con respecto al comportamiento polielectrolítico de las macromoléculas en solución. Los coacervados binarios y ternarios de los tratamientos con quitosano como policatión y los coacervados ternarios de WPI como policatión presentaron características predominantemente viscosas y comportamiento de gel débil. Los coacervados binarios de WPI como policatión presentaron características predominantemente elásticas y comportamiento de gel débil también. Todos los tratamientos presentaron un carácter reoadelgazante, ajustándose al modelo de Carreau con altos coeficientes de correlación. No se observa evidencia de sinergia entre GA y GM tanto en tratamientos binarios y ternarios de Quitosano y WPI como policatión. Por el ccosto bajo que representa utilizar WPI como materia prima, los coacervados obtenidos a partir de este policatión tienen potencial de utilizarse como estabilizantes y como matriz para contener compuestos de alto valor agregado en formulaciones alimenticias. Los coacervados con quitosano como policatión pueden aplicarse como estabilizante y como matriz contenedora de compuestos de alto valor agregado en formulaciones para el cuidado de la salud

Red quasars not so dusty

Webster et al (1995) claimed that up to 80% of QSOs may be obscured by dust. They inferred the presence of this dust from the remarkably broad range of B-K optical-infrared colours of a sample of flat-spectrum PKS radio QSOs. If such dust is typical of QSOs, it will have rendered invisible most of those which would otherwise been have detected by optical surveys. We used the William Herschel Telescope on La Palma to obtain K infrared images of 54 B3 radio quasars selected at low frequency (mainly steep-spectrum), and we find that although several have very red optical-infrared colours, most of these can be attributed to an excess of light in K rather than a dust-induced deficit in B. We present evidence that some of the infrared excess comes from the light of stars in the host galaxy (some, as previously suggested, comes from synchrotron radiation associated with flat-spectrum radio sources). The B-K colours of the B3 QSOs provide no evidence for a large reddened population. Either the Webster et al QSOs are atypical in having such large extinctions, or their reddening is not due to dust; either way, the broad range of their B-K colours does not provide evidence that a large fraction of QSOs has been missed from optical surveys.Comment: 16 pages TeX file + 2 PostScript figures. Accepted in MNRA

K-band imaging of 52 B3-VLA quasars: Nucleus and host properties

We present K-band imaging and photometry of a sample of 52 radio loud quasars (RQs) selected from the B3 survey with flux densities above 0.5 Jy at 408 MHz. The optical completeness of the sample is 90% and the quasars cover the redshift range 0.4 - 2.3. For ~57% of the sources for which the quality of the images allowed a detailed morphological study (16/28) resolved extended emission was detected around the QSO, and its K flux was measured. Interpreting this ``fuzz'' as starlight emission from the host galaxy, its location on the K-z plane at z<1 is consistent with radio quasars being hosted by galaxies similar to radio galaxies (RGs) or giant ellipticals (gEs). At higher redshifts the detected host galaxies of RQs are more luminous than typical RGs and gEs, although some weak detections or upper limits are consistent with a similar fraction of RQs being hosted by galaxies with the expected luminosities for RGs or gEs. We found a significant correlation between radio power and nuclear infrared luminosity indicating a direct link between the radio synchrotron emission and the nuclear emission in K. This correlation is more tight for the steep-spectrum sources (99.97% significance). In addition, a trend is found between radio power and infrared luminosity of the host galaxy (or mass), in the sense that the most powerful quasars inhabit the most luminous galaxies.Comment: tar gzipped file including 1 LaTeX file, 4 latex tables, and 13 PostScript figures. Accepted in AJ (April 1998

Essential and checkpoint functions of budding yeast ATM and ATR during meiotic prophase are facilitated by differential phosphorylation of a meiotic adaptor protein, Hop1

A hallmark of the conserved ATM/ATR signalling is its ability to mediate a wide range of functions utilizing only a limited number of adaptors and effector kinases. During meiosis, Tel1 and Mec1, the budding yeast ATM and ATR, respectively, rely on a meiotic adaptor protein Hop1, a 53BP1/Rad9 functional analog, and its associated kinase Mek1, a CHK2/Rad53-paralog, to mediate multiple functions: control of the formation and repair of programmed meiotic DNA double strand breaks, enforcement of inter-homolog bias, regulation of meiotic progression, and implementation of checkpoint responses. Here, we present evidence that the multi-functionality of the Tel1/Mec1-to-Hop1/Mek1 signalling depends on stepwise activation of Mek1 that is mediated by Tel1/Mec1 phosphorylation of two specific residues within Hop1: phosphorylation at the threonine 318 (T318) ensures the transient basal level Mek1 activation required for viable spore formation during unperturbed meiosis. Phosphorylation at the serine 298 (S298) promotes stable Hop1-Mek1 interaction on chromosomes following the initial phospho-T318 mediated Mek1 recruitment. In the absence of Dmc1, the phospho-S298 also promotes Mek1 hyper-activation necessary for implementing meiotic checkpoint arrest. Taking these observations together, we propose that the Hop1 phospho-T318 and phospho-S298 constitute key components of the Tel1/Mec1- based meiotic recombination surveillance (MRS) network and facilitate effective coupling of meiotic recombination and progression during both unperturbed and challenged meiosis

Unravelling the immunomodulatory role of apple phenolic rich extracts on human THP-1- derived macrophages using multiplatform metabolomics

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGApples represent a significant source of dietary phenolic compounds with evidenced anti-inflammatory and immunomodulatory activities. Nevertheless, the effect of the whole apple matrix on human macrophages is unknown. In this context, our study attempts to evaluate the effect of apple-derived phenolic compounds-rich extracts (pulp, peel and leaf) on IL-1β production in THP-1-differentiated macrophages and derived metabolic alterations through untargeted metabolomics. Our results have showed that apple pulp treatment inhibited the release of the pro-inflammatory cytokine IL-1β induced by LPS in THP-1 macrophages by ELISA analysis. Metabolomics demonstrate that different proportions of phenolic compounds led to differential alterations in the metabolism of THP-1 macrophages. Indeed, apple extracts promoted alterations in lipid, carbohydrate, amino acid and vitamins as well as cofactors metabolism. Specifically, leaf extracts were characterized by alteration of galactose metabolism while the extracts derived from the fruit showed predominant alterations in lipids metabolism. All extracts mimicked the response observed under normal conditions in LPS-stimulated macrophages, inhibiting LPS response. Thus, the phenolic enriched extracts from apples will be a good source of natural compounds with a beneficial effect against inflammation, and they may be applied as a food supplement and/or functional ingredient for the treatment of inflammatory diseasesFondo Europeo de Desarrollo Regional (FEDER) | Ref. 0377_IBERPHENOL_6_EFundação para a Ciência e a Tecnologia | Ref. UIDB/50006/2020Fundação para a Ciência e a Tecnologia | Ref. PTDC/SAU-NUT/30448/2017Fundação para a Ciência e a Tecnologia | Ref. SFRH/BPD/86173/201