Influence of raw milk microflora and starter cultures in cheese on protein hydrolysis and peptide generation during digestion

Do bacterial strains in cheese have an impact on the protein hydrolysis during human digestion, and if so, does a higher microbial diversity lead to the generation of a higher number of different peptides after digestion?Cheese bacteria are responsible for the hydrolysis of proteins already during cheese ripening. These bacterial cultures are introduced at different steps of the cheese manufacturing process. First, the raw milk flora that is dependent on the milk heat treatment before the cheese manufacturing process, is a major source of a variety of bacteria. Second, starter cultures, needed for a successful acidification of the cheese curd are added to prevent side fermentations. Third, addition of cultures is made for improving flavor or accelerating the ripening process, depending on the type of cheese. Because of bacterial proteolytic activity, proteins in cheese are partially hydrolyzed, depending on the ripening time and are further digested by gastric and pancreatic proteases, after consumption, to the level of small peptides and free amino acids. In order to elucidate possible differences in proteolysis depending on the presence of different bacteria, Swiss Raclette cheeses were produced either from raw or pasteurized milk with or without addition of a proteolytic bacterial strains (Lactobacillus helveticus) and ripened during 120 days.The microbial diversity and the relative abundance of specific strains in the different cheeses was assessed after 24 hours, 80 and 120 days of cheese ripening by sequencing the hypervariable regions V1-V2 of the 16S rRNA genes. Moreover, protein hydrolysis in the different cheeses was analyzed with gel electrophoresis, mass spectrometry, and HPLC after in vitro digestion, applying a static (Infogest) and a dynamic (DIDGI®) oro-gastrointestinal in vitro digestion protocol. In order to gain information on the influence of bacterial strains on protein hydrolysis, the 16s meta-genomic and 16s meta-transcriptomic results were correlated with protein and peptide patterns

Understanding the gastrointestinal tract of the elderly to develop dietary solutions that prevent malnutrition

Although the prevalence of malnutrition in the old age is increasing worldwide a synthetic understanding of the impact of aging on the intake, digestion, and absorption of nutrients is still lacking. This review article aims at filling the gap in knowledge between the functional decline of the aging gastrointestinal tract (GIT) and the consequences of malnutrition on the health status of elderly. Changes in the aging GIT include the mechanical disintegration of food, gastrointestinal motor function, food transit, chemical food digestion, and functionality of the intestinal wall. These alterations progressively decrease the ability of the GIT to provide the aging organism with adequate levels of nutrients, what contributes to the development of malnutrition. Malnutrition, in turn, increases the risks for the development of a range of pathologies associated with most organ systems, in particular the nervous-, muscoskeletal-, cardiovascular-, immune-, and skin systems. In addition to psychological, economics, and societal factors, dietary solutions preventing malnutrition should thus propose dietary guidelines and food products that integrate knowledge on the functionality of the aging GIT and the nutritional status of the elderly. Achieving this goal will request the identification, validation, and correlative analysis of biomarkers of food intake, nutrient bioavailability, and malnutrition.info:eu-repo/semantics/publishedVersio

Dairy products and inflammation: a review of the clinical evidence

Inflammation is a major biological process regulating the interaction between organisms and the environment, including the diet. Because of the increase in chronic inflammatory diseases, and in light of the immune-regulatory properties of breastfeeding, the ability of dairy products to modulate inflammatory processes in humans is an important but unresolved issue. Here, we report a systematic review of 52 clinical trials investigating inflammatory markers in relation to the consumption of dairy products. An inflammatory score (IS) was defined to quantitatively evaluate this interaction. The IS was significantly positive for the entire data set, indicating an anti-inflammatory activity in humans. When the subjects were stratified according to their health status, the IS was strongly indicative of an anti-inflammatory activity in subjects with metabolic disorders and of a pro-inflammatory activity in subjects allergic to bovine milk. Stratifying the data by product categories associated both low-fat and high-fat products, as well as fermented products, with an anti-inflammatory activity. Remarkably, the literature is characterized by a large gap in knowledge on bioavailability of bioactive nutrients. Future research should thus better combine food and nutritional sciences to adequately follow the fate of these nutrients along the gastrointestinal and metabolic axes.info:eu-repo/semantics/publishedVersio

Serum Metabolites Responding in a Dose-Dependent Manner to the Intake of a High-Fat Meal in Normal Weight Healthy Men Are Associated with Obesity

Although the composition of the human blood metabolome is influenced both by the health status of the organism and its dietary behavior, the interaction between these two factors has been poorly characterized. This study makes use of a previously published randomized controlled crossover acute intervention to investigate whether the blood metabolome of 15 healthy normal weight (NW) and 17 obese (OB) men having ingested three doses (500, 1000, 1500 kcal) of a high-fat (HF) meal can be used to identify metabolites differentiating these two groups. Among the 1024 features showing a postprandial response, measured between 0 h and 6 h, in the NW group, 135 were dose-dependent. Among these 135 features, 52 had fasting values that were significantly different between NW and OB men, and, strikingly, they were all significantly higher in OB men. A subset of the 52 features was identified as amino acids (e.g., branched-chain amino acids) and amino acid derivatives. As the fasting concentration of most of these metabolites has already been associated with metabolic dysfunction, we propose that challenging normal weight healthy subjects with increasing caloric doses of test meals might allow for the identification of new fasting markers associated with obesity

RAMÓN, PEDRO [Material gráfico]

SRA. DECopia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Image thresholding techniques for localization of sub-resolution fluorescent biomarkers

In this article, we explore adaptive global and local segmentation techniques for a lab-on-chip nutrition monitoring system (NutriChip). The experimental setup consists of Caco-2 intestinal cells that can be artificially stimulated to trigger an immune response. The eventual response is optically monitored using immunofluoresence techniques targeting toll-like receptor 2 (TLR2). Two problems of interest need to be addressed by means of image processing. First, a new cell sample must be properly classified as stimulated or not. Second, the location of the stained TLR2 must be recovered in case the sample has been stimulated. The algorithmic approach to solving these problems is based on the ability of a segmentation technique to properly segment fluorescent spots. The sample classification is based on the amount and intensity of the segmented pixels, while the various segmenting blobs provide an approximate localization of TLR2. A novel local thresholding algorithm and three well-known spot segmentation techniques are compared in this study. Quantitative assessment of these techniques based on real and synthesized data demonstrates the improved segmentation capabilities of the proposed algorithm

The NutriChip project - translating technology into nutritional knowledge

Advances in food transformation have dramatically increased the diversity of products on the market and, consequently, exposed consumers to a complex spectrum of bioactive nutrients whose potential risks and benefits have mostly not been confidently demonstrated. Therefore, tools are needed to efficiently screen products for selected physiological properties before they enter the market. NutriChip is an interdisciplinary modular project funded by the Swiss programme Nano-Tera, which groups scientists from several areas of research with the aim of developing analytical strategies that will enable functional screening of foods. The project focuses on postprandial inflammatory stress, which potentially contributes to the development of chronic inflammatory diseases. The first module of the NutriChip project is composed of three in vitro biochemical steps that mimic the digestion process, intestinal absorption, and subsequent modulation of immune cells by the bioavailable nutrients. The second module is a miniaturised form of the first module (gut-on-a-chip) that integrates a microfluidic-based cell co-culture system and super-resolution imaging technologies to provide a physiologically relevant fluid flow environment and allows sensitive real-time analysis of the products screened in vitro. The third module aims at validating the in vitro screening model by assessing the nutritional properties of selected food products in humans. Because of the immunomodulatory properties of milk as well as its amenability to technological transformation, dairy products have been selected as model foods. The NutriChip project reflects the opening of food and nutrition sciences to state-of-the-art technologies, a key step in the translation of transdisciplinary knowledge into nutritional advic

Biomarker of food intake for assessing the consumption of dairy and egg products

Foods of animal origin constitute one of the predominant food groups consumed in Western diets. They play an essential role in human nutrition as they represent an excellent source of high quality proteins, vitamins, minerals and fats. Foods of animal origin are highly diverse (e.g. meat, fish, dairy products and eggs) and their associations with a range of nutritional and health outcomes are therefore heterogeneous. Such associations are also often weak or debated due to the difficulty in establishing correct assessments of dietary intake. Therefore, in order to better characterize associations between the consumption of specific foods of animal origin and health outcomes, it is important to identify reliable biomarkers of food intake (BFIs). BFIs provide a more accurate measure of intake and are independent of the memory and sincerity of the subjects as well as of their knowledge about the consumed foods. To date, only a very limited number of compounds have been proposed as biomarkers of the intake of foods of animal origin and further studies are necessary to validate them and to discover new candidate BFIs. We have, therefore, conducted a systematic search of the scientific literature to evaluate the current status of potential BFIs for each category of foods of animal origin commonly consumed in Europe. This review reports on candidate biomarkers for dairy products and eggs intake, while biomarkers for fish and meat intake will be published separately. Remarkably, validated BFIs for dairy products and eggs are not available. A series of challenges hinders their identification and validation, in particular the heterogeneous composition of each food within a product category and the lack of specificity of the markers identified so far. Untargeted metabolomic strategies may allow the identification of novel food biomarkers, that, when taken separately or in combination, could be used to assess the intake of dairy products and eggs