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Arabinoxylan (AX) and arabinoxylo-oligosaccharides (AXOS) derived therefrom are emergent prebiotics with promising health promoting properties, likely linked to its capacity to foster beneficial species in the human gut. Bifidobacteria appear to be one taxa that is frequently promoted following AX or AXOS consumption, and that is known to establish metabolic cross-feeding networks with other beneficial commensal species. Therefore, probiotic bifidobacteria with the capability to metabolize AX-derived prebiotics represent interesting candidates to develop novel probiotic and synbiotic combinations with AX-based prebiotics. In this work we have deepen into the metabolic capabilities of bifidobacteria related to AX and AXOS metabolization through a combination of in silico an in vitro tools. Both approaches revealed that Bifidobacterium longum and, particularly, B. longum subsp. longum, appears as the better equipped to metabolize complex AX substrates, although other related subspecies such as B. longum subsp. infantis, also hold some machinery related to AXOS metabolization. This correlates to the growth profiles exhibited by representative strains of both subspecies in AX or AXOS enriched media. Based on these results, we formulated a differential carbohydrate free medium (CFM) supplemented with a combination of AX and AXOS that enabled to recover a wide diversity of Bifidobacterium species from complex fecal samples, while allowing easy discrimination of AX metabolising strains by the appearance of a precipitation halo. This new media represent an appealing alternative to isolate novel probiotic bifidobacteria, rapidly discriminating their capacity to metabolize structurally complex AX-derived prebiotics. This can be convenient to assist formulation of novel functional foods and supplements, including bifidobacterial species with capacity to metabolize AX-derived prebiotic ingredients.

The current public health framework promotes fiber increase and simple sugar decrease intakes as part of a healthy diet. This scenario has sparked the interest in the use of nondigestible or slowly digestible carbohydrates and low-calorie sweeteners. Nowadays, there is still insufficient information on physicochemical properties and structural features of nondigestible carbohydrates that prevent us from understanding the underlying causal mechanisms leading to health benefits. We describe recent findings about the role of fiber viscosity and distal small intestinal digestion of carbohydrates in gastric emptying, postprandial glycemic response, and weight management. Furthermore, the role of terpenoid glycosides, polyols, and rare sugars as simple sugar replacers, and how challenging it is to meet acceptable sensorial properties and desirable functionality in a single carbohydrate is also discussed.

El tomate (Lycopersicum esculentum L.) es uno de los vegetales con mayor producción mundial (200 millones de toneladas anuales). La industria de la transformación del tomate produce grandes cantidades de residuos tales como pieles y semillas. La necesidad de reducir la cantidad de estos residuos ha propiciado la aparición de nuevas estrategias para el aprovechamiento de éstos, pasando a ser considerados subproductos. Algunas de estas estrategias se centran en la obtención de compuestos funcionales de interés como pectinas, un grupo complejo de polisacáridos presente en la pared celular vegetal de frutas y vegetales. Están compuestas por tres dominios, el homogalacturonano, cadena lineal de ácido D-galacturónico (GalA), con enlaces ¿-(1,4), parcialmente metilesterificada en C-6; ramnogalacturonano I (RG-I), cadena de GalA y L-ramnosa, con enlaces ¿-(1, 2) y ¿-(1, 4) y ramificaciones de D-galactosa y/o L-arabinosa, unidas a la ramnosa; y RG-II, muy complejo, conservado y minoritario, constituido por una cadena de HG con ramificaciones formadas por 12 azúcares diferentes. Este trabajo se ha centrado en la optimización de la extracción de pectina a partir del residuo industrial pieles y semillas de tomate (PST) empleando la celulasa comercial Celluclast®1,5L, para llevar a cabo un diseño experimental (DisExp), posteriormente analizado mediante redes neuronales artificiales (ANN). Las variables independientes estudiadas en los 17 ensayos fueron Celluclast (45-250 U/g), tiempo de extracción (6-24 h) y concentración de sólidos (2-7%). Las variables dependientes fueron el rendimiento de extracción, el contenido en GalA y glucosa, considerado como impureza. Las pectinas extraídas fueron posteriormente caracterizadas determinando: masa molecular (HPSEC-ELSD), composición monomérica (GC-FID), y grado de metil esterificación (FT-IR). Las variables estudiadas en el DisExp presentaron los siguientes rangos de valores: rendimiento 3,0-6,4%, GalA 54,6-64,6% y glucosa 2,2-6,1%. En l

The agri-food sector produces more than 50% of by-products from the food sector. Annually, 200,000 tons of tomato (Lycopersicum esculentum L.) are produced, of which 6% are considered wastes. Tomato Pulp (TP) constitutes 44% of the by-products of tomato processing [1,2]. In recent years, numerous strategies have been developed to use these by-products as a source for the extraction of pectin. However, as far as, we know they have not been used to obtain pectic oligosaccharides (POS). These compounds have interesting bioactivity. Several studies have shown that POS have the ability to reduce the adhesion of pathogenic bacteria, such as Escherichia coli, Salmonella Typhimurium and Listeria monocytogenes, to epithelial cells [4]. In general, POS are obtained from the depolymerization of pectin previously extracted from vegetal materials, commonly obtained from citrus, apple or artichoke, which leads to greater difficulties and costs in their scaling and industrial application [5]. It would therefore be of great interest to the industry to obtain them directly from the by-product, without pre-treatment or pre-extraction. The present work has focused on the optimization in obtaining POS directly from tomato pulp, a by-product from industrial tomato processing, using the commercial enzyme Rapidase fiber (DSM, Food & Beverage) used by the industry as a pulp viscosity modifier. For this aim, a factorial experimental design consisting of 17 assays with the independent variables: temperature (40 - 60 ºC), time (1.5 - 5 h) and enzyme dose (5 - 30 mg/g dry matter, DM). The reactions were performed without buffer (solids content 85 mg/mL). The data obtained from the analysis of the different assays showed that the molecular weight (Mw) distribution analysis, performed by HPSEC-ELSD, had 3 domains, of Mw (Da) and abundance (% quantified according to pullulan standards, 805-0.362 kDa) ranges: i) 1138-2240 Da, 6.9-13.2%, ii) 607-731 Da, 18.0-33.6% and iii) 118-124 Da, 59.1-73.7%. C

Tomato (Lycopersicum esculentum L.) is one of the world's most widely produced vegetables (200 million tonnes per year). The tomato processing industry produces large quantities of waste such as peels and seeds. The need to reduce the amount of these wastes has led to the emergence of new strategies for the utilisation of these wastes, which are now considered as by-products. Some of these strategies focus on obtaining functional compounds of interest such as pectins, a complex group of polysaccharides present in the plant cell wall of fruits and vegetables. They are composed of three domains, homogalacturonan, a linear chain of D-galacturonic acid (GalA), with ¿-(1,4) bonds, partially methylesterified at C-6; rhamnogalacturonan I (RG-I), a chain of GalA and L-rhamnose, with ¿-(1, 2) and ¿-(1, 4) bonds and branches of D-galactose and/or L-arabinose, linked to rhamnose; and RG-II, very complex, conserved and minority, consisting of a chain of HG with branches formed by 12 different sugars. This work has focused on the optimisation of the extraction of pectin from the industrial waste peels and seeds of tomato (PST) using the commercial cellulase Celluclast®1.5L, to carry out an experimental design (DisExp), subsequently analysed by means of artificial neural networks (ANN). The independent variables studied in the 17 trials were Celluclast (45-250 U/g), extraction time (6-24 h) and solids concentration (2-7%). The dependent variables were extraction yield, GalA and glucose content, considered as impurity. The extracted pectins were subsequently characterised by determining molecular mass (HPSEC-ELSD), monomer composition (GC-FID), and degree of methyl esterification (FT-IR). The variables studied in the DisExp presented the following ranges of values: yield 3.0-6.4%, GalA 54.6-64.6% and glucose 2.2-6.1%. In the modelling, the regression coefficients obtained by ANN were higher (R2 and R2adj > 0.87) than those presented by RSM (R2 and R2adj > 0.63). The optimal condit

Inflammatory bowel disease (IBD) is a public health challenge and the use of pectin for symptom amelioration is a promising option. In this work, sunflower pectin has been extracted without (CHP) and with assistance of ultrasound (USP) using sodium citrate as a food-grade extracting agent. At optimal conditions (64 °C, 23 min) the highest yield was obtained with ultrasound application (15.5 vs. 8.1 %). Both pectins were structurally characterized by 1H NMR, HPSEC-ELSD, FT-IR and GC-FID. Unlike CHP, USP showed a lower molecular weight, higher galacturonic acid, lower degree of methyl-esterification and, overall, higher viscosity. These characteristics could affect the anti-inflammatory activity of pectins, evaluated using DSS-induced IBD model mice. So, USP promoted the defence (ICAM-1) and repair of the gastrointestinal mucosa (TFF3, ZO-1) more effectively than CHP. These results demonstrate the potential amelioration of acute colitis in IBD mice through USP supplementation. Taking into account the biomarkers analysed, these results demonstrate, for the first time, the positive impact of sunflower pectin extracted by ultrasound under very soft conditions on inflammatory bowel disease that might open up new possibilities in the treatment of this serious pathology.

Brewer's spent grain (BSG), one of the largest by-products generated by brewing industries, holds a wealthy nutritional value due to its content in proteins and fibres. Although some initiatives have explored alternatives for leveraging the nutritional value of BSG, it mostly remains an underexploited source of valuable ingredients for human nutrition, being mainly dedicated to animal feed and landfilling. BSG is rich in hemicellulosic material, composed of arabinoxylans (AX), which have been postulated as emergent prebiotics, capable to confer health benefits through modulating the gut microbiome. In this work we comprehensively investigated in vitro the composition and gut microbiome modulatory potential of BSG and AX fractions on human microbiota of two population groups by means of fecal batch fermentations and 16S rRNA gene sequencing. The gut microbiome modulatory effects was influenced by the specific BSG/AX fraction; the population group (healthy or Crohn's disease (CD) patients) and by interindividual variation. For instance, Dorea and Eubacterium halli which include well-known fibre degrading, and health promoting bacteria, were only stimulated in fermentations of fractions with high arabinose and xylose contents. This work demonstrates diverse modulatory capacity of distinct AX fractions, diversifying alternative BSG valorization strategies through exploitation of novel prebiotics tailored to specific groups.