In vitro digestibility and fermentability of selected prebiotics and functional carbohydrates with prebiotic potential

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada. Fecha de lectura: 31-05-2019Esta tesis tiene embargado el acceso al texto completo hasta el 27-05-202

Obtención de pectooligosacáridos derivados de pectinas de cítricos y de manzana utilizando extractos enzimáticos comerciales

Póster presentado a las II Jornadas de Estudiantes de Máster en Química Agrícola y Nuevos Alimentos, celebradas en la Facultad de Ciencias de la Universidad Autónoma de Madrid del 30 de septiembre al 2 de octubre de 2015.Uno de los problemas de la industria transformadora de vegetales es la gestión y tratamiento los subproductos generados. Los subproductos pueden ser aprovechados para la obtención de ingredientes funcionales tales como las pectinas. Estos polisacáridos estructurales, presentes en la pared celular, son heteropolímeros constituidos por una cadena de ácido galacturónico (AGal) (homogalacturonano, HG), interrumpida por regiones ramificadas formadas por azúcares neutros, Ramnogalacturonano I y II (RG-I y RG-II). A partir de las pectinas pueden obtenerse pectooligosacáridos, POS, que pueden presentar propiedades funcionales que van a depender, en gran medida de sus características estructurales, es decir, grado de polimerización, grado de esterificación y composición en monosacáridos. Los POS pueden obtenerse por métodos físicos, químicos o enzimáticos, siendo estos últimos los mas utilizados.La presente investigación se ha realizado con financiación de los proyectos AGL2014-53445, ALIBIRD-CM S-2013/ABI-2728 e I-COOPB20099.Peer Reviewe

In vitro fermentation properties of pectins and enzymatic-modified pectins obtained from different renewable bioresources

The suitability of artichoke and sunflower by-products as renewable sources of pectic compounds with prebiotic potential was evaluated by studying their ability to modulate the human faecal microbiota in vitro. Bacterial populations and short-chain fatty acid (SCFA) production were measured. Reduction of the molecular weight of artichoke pectin resulted in greater stimulation of the growth of Bifidobacterium, Lactobacillus and Bacteroides/Prevotella, whilst this effect was observed only in Bacteroides/Prevotella for sunflower samples. In contrast, the degree of methylation did not have any impact on fermentability properties or SCFA production, regardless of the origin of pectic compounds. Although further in vivo studies should be conducted, either pectin or enzymatically-modified pectin from sunflower and artichoke by-products might be considered as prebiotic candidates for human consumption showing similar ability to promote the in vitro growth of beneficial gut bacteria as compared to well-recognized prebiotics such as inulin or fructo-oligosaccharides

Supplementation with the Symbiotic Formulation Prodefen® Increases Neuronal Nitric Oxide Synthase and Decreases Oxidative Stress in Superior Mesenteric Artery from Spontaneously Hypertensive Rats

In recent years, gut dysbiosis has been related to some peripheral vascular alterations linked to hypertension. In this work, we explore whether gut dysbiosis is related to vascular innervation dysfunction and altered nitric oxide (NO) production in the superior mesenteric artery, one of the main vascular beds involved in peripheral vascular resistance. For this purpose, we used spontaneously hypertensive rats, either treated or not with the commercial synbiotic formulation Prodefen® (108 colony forming units/day, 4 weeks). Prodefen® diminished systolic blood pressure and serum endotoxin, as well as the vasoconstriction elicited by electrical field stimulation (EFS), and enhanced acetic and butyric acid in fecal samples, and the vasodilation induced by the exogenous NO donor DEA-NO. Unspecific nitric oxide synthase (NOS) inhibitor L-NAME increased EFS-induced vasoconstriction more markedly in rats supplemented with Prodefen®. Both neuronal NO release and neuronal NOS activity were enhanced by Prodefen®, through a hyperactivation of protein kinase (PK)A, PKC and phosphatidylinositol 3 kinase-AKT signaling pathways. The superoxide anion scavenger tempol increased both NO release and DEA-NO vasodilation only in control animals. Prodefen® caused an increase in both nuclear erythroid related factor 2 and superoxide dismutase activities, consequently reducing both superoxide anion and peroxynitrite releases. In summary, Prodefen® could be an interesting non-pharmacological approach to ameliorate hypertensionThis research was funded by CiberCV (Grant number: CB16/11/00286), the Ministerio de Ciencia e Innovación (PID2020-116498RB-I00, and CDTI -Center for Industrial Technological Development-project PID 2020-FEDER Funds), and R+D projects for young researchers, Universidad Autónoma de Madrid-Comunidad de Madrid (SI1-PJI-2019-00321

Glicosil hidrolasas de Lactiplantibacillus plantarum WCFS1

Resumen del trabajo presentado a la 15ª Reunión de la Red Española de Bacterias Lácticas: Bacterias Lácticas en Alimentación y Salud. Valencia, 26 y 27 de mayo de 2022.AGL2017-84614-C2-1-R y AGL2017-84614-C2-2-RPeer reviewe

In vitro digestibility and fermentability of selected prebiotics and functional carbohydrates with prebiotic potential

Thesis submitted in fulfilment of the requirements for the degree of doctor at Autónoma University of Madrid (UAM) Madrid, 2019.[EN]: The regulation of microbiota through the use of prebiotics has been widely studied in the last decades, due to its high correlation with human health and several diseases. In this sense, there are a huge number of reports regarding the beneficial effects of these compounds on gut microorganisms, however, scarce efforts have been made towards their previous passage through gastrointestinal digestion. In a first part of this PhD Thesis, the digestibility of several recognised prebiotics has been studied and results are presented in the first three chapters. A more efficient and reliable in vitro method based on the use of rat small intestinal extract has been proposed for carbohydrate digestion overcoming the limitations of general standardised models for gastrointestinal digestion which overlook the critical role of the small intestine mucosal carbohydrases. Likewise, considering the high physiological and anatomical similarity of the pig and human digestive tracts, the isolation of brush border membrane vesicles of the pig small intestine has been carried out in order to, subsequently, assess the intestinal digestibility of a series of commercial galactooligosaccharides differing in the predominant glycosidic linkage, as well as that of novel lactulose-derived galactooligosaccharides. In this sense, to a greater or lesser extent, all carbohydrates tested presented degradation rates by small intestinal enzymes. Crucial structure-function relationship was found by determining the key role of structural features (glycosidic linkage or monosaccharides composition) on their resistance to degradation, increasing therefore essential knowledge towards the eventual development of new customized prebiotics. On the other hand, interest towards the production and obtainment of prebiotics using more sustainable methods has also raised a great interest. Therefore, in a second part of this dissertation, the prebiotic potential of pectic compounds obtained from agricultural by-products of artichoke, sunflower and citrus products was evaluated. A high prebiotic effect similar to well-recognized prebiotics was revealed after the in vitro fermentation study. Moreover, structure-function relationships were also found by elucidating the effect of the structural features (molecular weight, methylation degree, monosaccharide composition) on their ability to grow beneficial bacteria. Findings in this part of the thesis provided evidence on the prebiotic potential of theses substrates and may enhance the use of waste agricultural by-products as a renewable source of bioactive compounds.[ES]: La modulación de la microbiota intestinal a través del uso de prebióticos ha sido ampliamente estudiada en las últimas décadas debido a su relación con la salud humana. Existen numerosos estudios acerca de los efectos beneficiosos de estos prebióticos sobre la microbiota intestinal, sin embargo, el conocimiento actual sobre su paso previo por el tracto gastrointestinal superior y, más concretamente, sobre los posibles cambios estructurales durante el proceso de digestión gastrointestinal es muy limitado, dando por hecho su total resistencia . En ese sentido, una primera parte de esta tesis doctoral está enfocada en el estudio de la digestibilidad de distintos carbohidratos prebióticos reconocidos (Capítulos 1-3). Se ha propuesto un método in vitro fiable y eficaz, basado en la utilización de extractos intestinales de rata, para evaluar la digestión de estos carbohidratos que solventaría importantes limitaciones que presentan los métodos actualmente en uso y que ignoran el papel clave de las carbohidrasas expresadas en la mucosa intestinal. Asimismo, y dado que el cerdo es un mamífero fisiológicamente más similar a la especie humana que la rata, se ha procedido al aislamiento de vesículas del epitelio intestinal de cerdos para, posteriormente, evaluar la digestibilidad intestinal de galactooligosacáridos comerciales caracterizados por diferentes enlaces glicosídicos, así como de nuevos galactooligosacáridos derivados de lactulosa. Los resultados de esta primera parte resaltan la idoneidad del empleo de estos extractos para la simulación de la digestibilidad intestinal de carbohidratos. Se ha observado una degradación, en mayor o menor medida, de los prebióticos analizados tras el tratamiento con las enzimas intestinales y, además, se han establecido correlaciones importantes entre la estructura química de estos compuestos (composición monomérica, tamaño molecular o enlace glicosídico) y su resistencia a la degradación durante la digestión intestinal. Por otro lado, y debido al interés creciente hacia el desarrollo de nuevas estrategias sostenibles para la obtención de prebióticos emergentes, la segunda parte de esta tesis se ha centrado en la evaluación del potencial prebiótico de sustratos alternativos, como son los compuestos pécticos, obtenidos a partir de subproductos de la industria agrícola de alcachofa, girasol y cítricos. Para ello, se han utilizado modelos de fermentación in vitro estáticos y dinámicos que suponen un avance debido a la posibilidad de simular las diferentes etapas gastrointestinales en un entorno fisiológicamente más relevante. En general, se observó una alta actividad prebiótica en los sustratos analizados, siendo similar a la de prebióticos reconocidos. Además, ha sido posible correlacionar determinadas características estructurales (tamaño molecular, grado de metilación y composición de monosacáridos) con su capacidad para promover el crecimiento de bacterias beneficiosas. De este modo, los resultados obtenidos en esta parte aportan evidencias sobre el potencial prebiótico de estos sustratos y apuntan hacia la potencial utilización de determinados subproductos agrícolas como fuentes sostenibles para la obtención de compuestos bioactivos.AGL2014-53445-RPeer reviewe

Obtención de pectinas de calidad premium a partir de subproductos de la industria elaboradora de zumo de naranja

Peer reviewe

Green technologies for sustainable food production and preservation: Ultrasounds

Overcoming challenges related to food security and sustainability represent one of the major concerns for worldwide governments, industry, science and consumers. A wide range of sustainability challenges is persistent throughout the agri-food supply chain. We cannot continue with the traditional processing methods that contribute to damaging the environment without paying attention to the increase in poverty and lack of foods. There are different ways to reduce environmental footprint such as the application of ecofriendly methods, the reduction of food waste and the use of sustainable ingredients. In this sense, alternatives such as ultrasound (US) present new opportunities. US may be considered as a green technology due to its ecofriendly character, non-toxic behavior and low consumption of energy. In this chapter, we have summarized the benefits of high-intensity US for several applications, paying special attention to its use as a preservation technique and for the acquisition of functional ingredients. It is noteworthy that there is an exhaustive compilation of studies on the usefulness of US as a sustainable technology in the treatment of waste and/or the attainment of biofuels. Although more investigations should be carried out on the scale-up of US for the preservation and processing of foods, there is enough scientific evidence that should encourage us to invest in this sustainable technology.Peer reviewe

Valorization of Grape Pomace as a Renewable Source of Techno-Functional and Antioxidant Pectins

The food industry’s increasing demand for new functional ingredients that meet both organoleptic and healthy requirements has driven the exploration of new sources of functional ingredients in agro-industrial by-products. The aim of this work was to valorize grape pomace (Vitis vinifera L. garnacha) as a source of pectins using food-grade extracting agents. Obtained pectins were evaluated for monomeric composition, methyl esterification, molecular weight, water retention, oil-holding capacity, and antioxidant properties. The relatively soft extraction conditions used permitted obtaining low methoxyl pectin (10–42%) enriched in homogalacturonan (38–45%) or rhamnogalacturonan (33–41%) with different branching degrees, molecular weight, and fewer impurities than those found in the scarce previous literature. The relationship between structure and functionality was studied. Among the different pectins obtained, the sample derived from the extraction with sodium citrate could resume the best characteristics, such as pectin purity and higher water retention and oil holding capacity. These results underscore the relevance of grape pomace as a viable alternative source of pectin

Bringing the digestibility of prebiotics into focus: update of carbohydrate digestion models

Oro-gastrointestinal digestion of dietary carbohydrates involves up to six different carbohydrases in a multistage process. Enzymes from the small intestinal brush border membrane play a major role in the digestibility of these substrates. However, to date, the inclusion of these small intestinal enzymes has been dismissed in most in vitro studies carried out, despite their importance in the degradation of carbohydrates. Several in vitro and in vivo studies have demonstrated the capability of brush border enzymes to degrade certain “non-digestible” carbohydrates to a different extent depending on their structural composition (monomeric composition, glycosidic linkage, etc.). In this sense, considering the available evidence, mucosal disaccharidases embedded in the small intestinal brush border membrane vesicles must be considered in addition to α-amylases; therefore, new approaches for the evaluation of the digestibility of carbohydrates have been recently reported. These new methods based on the utilization of the small intestinal enzymes present in the brush border membrane aim to fulfill the final and key step of the digestion of carbohydrates in the small intestine. Here, rat small intestinal extract enzymes as well as brush border membrane vesicles from pig have emerged as very reliable and useful tools to evaluate carbohydrate digestion. Thus, this review aims to go briefly through the most relevant digestion methods for carbohydrates that are currently available and to highlight the new improved methods, which include mammalian intestinal enzymes, and their current use in the evaluation of the digestibility of prebiotics.This work has been funded by the Ministry of Economy and Competitiveness (MINECO) of Spain with Projects AGL2017-84614-C2-1-R.Peer reviewe