Disclosure, banks CDS spreads and the European sovereign crisis

We investigate the impact of banks disclosure on the evolution of their CDS spreads during the European sovereign crisis. The disclosure of information helps investors in building expectations; disclosure may participate into the reduction of the information risk premium and may lead to a decrease of CDS spreads. We analyze the CDS spreads changes following the announcement of sovereign credit rating downgrades. We consider 16 dates in the period 2011-2013 and, for each one, we assess the cumulative abnormal CDS spread change (CASC). We build two disclosure indexes: one general and one specifically dedicated to sovereign exposure. We show that the bank exposure to sovereign risk has a positive impact on the CASC. Disclosure about sovereign exposure has a negative impact on CASC showing that information reduce risk premiums. However, the global disclosure increases the CASC; investors may disapprove the disclosure of too much abundant and broad information

The surface properties of milk fat globules govern their interactions with the caseins: Role of homogenization and pH probed by AFM force spectroscopy

The surface of milk fat globules consists of a biological membrane rich in polar lipids and glycoproteins. However, high shear stress applied upon homogenization disrupts the membrane and leads to the adsorption of casein micelles, as the major protein fraction of milk. These changes in the interface properties could affect the interactions between native or homogenized milk fat globules and the surrounding protein matrix, at neutral pH and upon acidification. In this study, macroscale rheometry, microscopic observations, nanoscale AFM-based force spectroscopy and physico-chemical analysis were combined to examine the interfacial composition and structure of milk fat globules and to evaluate their interactions with casein micelles. We showed that the surface properties of milk fat globules (biological membrane vs. caseins) and pH govern their interactions with casein micelles. The adhesion between individual fat globules and casein micelles was higher upon homogenization, especially at acid pH where the work of adhesion increased from 3.3 x 10-18 to 14 x 10-18 J for native and homogenized fat globules, respectively. Consequently, casein-coated homogenized fat globules yield stiffer milk acid gels. These findings cast light on the importance of colloidal particle’s surface properties and pH on their connectivity with the surrounding matrix, which modulates the bulk microstructure and rheological properties with potential functional consequences, such as milk lipid digestion

Development and validation of a dynamic system for monitoring in vitro food digestion

The best model for studying food digestion remains the Human himself. An alternative to in vivo assays is to use in vitro digestion system. The complexity is to perform a device able to mimic accurately the fate of the food occurring in the human digestive tract. The objective of this work was to develop a simple and rather cheap dynamic digestion system enabling the study of the disintegration occurring in the gastro-intestinal tract of neonate and to validate it towards in vivo data. Digestion of an infant formula was studied both in vitro and in vivo using the piglet model. The formula was adapted to the energy and protein requirements of piglets. Six piglets were slaughtered 30, 90 and 210 min after the meal intake. Effluents from the different compartments of the gut were collected at these 3 time points. In parallel, the same infant formula was digested using the in vitro dynamic digestion system. The device consists in two compartments i.e. stomach and small intestine, and is computer-controlled. Milk proteolysis was followed by SDS-PAGE and ELISA both in vivo and in vitro. The validation was assessed by comparing the kinetics of residual immunoreactivity of β-lactoglobulin and caseins. Results showed a good accordance between the 2 systems of digestion. A level of in vitro/in vivo correlation was established with a correlation coefficient of 0.987. Casein content decreased rapidly during the first 30 minutes of gastric digestion. In contrast, β-lactoglobulin remained much longer intact in the stomach (120 min after ingestion). Intestinal digestion resulted in rapid and drastic hydrolysis, no more intact proteins were detected. This validation on infant formula, using the piglet model, has confirmed that this in vitro dynamic digestion system is reliable

Development and validation of a dynamic system for monitoring in vitro food digestion

The best model for studying food digestion remains the Human himself. An alternative to in vivo assays is to use in vitro digestion system. The complexity is to perform a device able to mimic accurately the fate of the food occurring in the human digestive tract. The objective of this work was to develop a simple and rather cheap dynamic digestion system enabling the study of the disintegration occurring in the gastro-intestinal tract of neonate and to validate it towards in vivo data. Digestion of an infant formula was studied both in vitro and in vivo using the piglet model. The formula was adapted to the energy and protein requirements of piglets. Six piglets were slaughtered 30, 90 and 210 min after the meal intake. Effluents from the different compartments of the gut were collected at these 3 time points. In parallel, the same infant formula was digested using the in vitro dynamic digestion system. The device consists in two compartments i.e. stomach and small intestine, and is computer-controlled. Milk proteolysis was followed by SDS-PAGE and ELISA both in vivo and in vitro. The validation was assessed by comparing the kinetics of residual immunoreactivity of β-lactoglobulin and caseins. Results showed a good accordance between the 2 systems of digestion. A level of in vitro/in vivo correlation was established with a correlation coefficient of 0.987. Casein content decreased rapidly during the first 30 minutes of gastric digestion. In contrast, β-lactoglobulin remained much longer intact in the stomach (120 min after ingestion). Intestinal digestion resulted in rapid and drastic hydrolysis, no more intact proteins were detected. This validation on infant formula, using the piglet model, has confirmed that this in vitro dynamic digestion system is reliable

Development and validation of a dynamic system for monitoring in vitro food digestion

The best model for studying food digestion remains the Human himself. An alternative to in vivo assays is to use in vitro digestion system. The complexity is to perform a device able to mimic accurately the fate of the food occurring in the human digestive tract. The objective of this work was to develop a simple and rather cheap dynamic digestion system enabling the study of the disintegration occurring in the gastro-intestinal tract of neonate and to validate it towards in vivo data. Digestion of an infant formula was studied both in vitro and in vivo using the piglet model. The formula was adapted to the energy and protein requirements of piglets. Six piglets were slaughtered 30, 90 and 210 min after the meal intake. Effluents from the different compartments of the gut were collected at these 3 time points. In parallel, the same infant formula was digested using the in vitro dynamic digestion system. The device consists in two compartments i.e. stomach and small intestine, and is computer-controlled. Milk proteolysis was followed by SDS-PAGE and ELISA both in vivo and in vitro. The validation was assessed by comparing the kinetics of residual immunoreactivity of β-lactoglobulin and caseins. Results showed a good accordance between the 2 systems of digestion. A level of in vitro/in vivo correlation was established with a correlation coefficient of 0.987. Casein content decreased rapidly during the first 30 minutes of gastric digestion. In contrast, β-lactoglobulin remained much longer intact in the stomach (120 min after ingestion). Intestinal digestion resulted in rapid and drastic hydrolysis, no more intact proteins were detected. This validation on infant formula, using the piglet model, has confirmed that this in vitro dynamic digestion system is reliable

Development of an in vitro dynamic digestion system to study food digestion

The best model for studying food digestion remains the Human himself. However, getting ethical agreement to perform such experiments on human is difficult. Developing in vitro digestion tools appears as a crucial step for monitoring the behaviour and the kinetics of hydrolysis of the food during the different phases of the digestion process. The objective of this work was to develop a simple and rather cheap dynamic digestion system enabling the study of the disintegration occurring in in the gastro-intestinal tract. The device consists in two compartments i.e. stomach and small intestine and is controlled by the STORM (STOmach Regulation and Monitoring) software. This digestion system simulates the GI physiological states as follows: i) flow of secretions and enzymes in physiological amounts (pepsin, lipase, bile, pancreatin), ii) appropriate pH (acidification curve in the stomach) and neutralization of the pH in the intestine, iii) mixing in each compartments, iv) physiological transit time for the gastric and intestinal step of digestion. The differents functions are monitored by the sofware and are saved all along the digestion process. Relevant physiological parameters are essential to simulate as close as possible the human GI tract. To achieve this aim, an exhaustive analysis of the data from the literature has been realized in order to adjust the parameters of the digestion model, and the key parameters such as gastric acidification curve, gastro-intestinal emptying rate and enzymes flow have been modelled as a function of the stage of life (infants vs adults). Validation of this model by a comparison of the kinetics of proteolysis of an infant formula observed either in an animal model (piglets) or in the in vitro model is currently under investigation. This model offers numerous advantages as compared to in vitro static models. Despite this, the model should be improved by (1) making the stirring conditions more physiologically relevant, (2) adding a dialysis membrane to mimic nutrients absorption in the intestinal compartment

Flavored yogurt complex viscosity influences real-time aroma release in the mouth and sensory properties

International audienceThe influence of flavored yogurt texture on aroma perception and in-nose aroma release measured by atmospheric pressure chemical ionization mass spectrometry analysis was investigated. The study was carried out on six yogurts varied by protein composition and mechanical treatment. For the same matrix composition, the complex viscosity of yogurts influenced in-nose release and perception. After swallowing, aroma release and intensity of olfactory perception were stronger in low-viscosity yogurts than in high-viscosity yogurts. Moreover, the protein composition influenced aroma release only when yogurts exhibited wide variations of complex viscosity and consequently texture. In mouth, aroma release and perception were influenced more by yogurt mechanical treatment than by protein composition. On the basis of mass transfer analysis, the main physical mechanism which could explain the difference in aroma release would be the surface exchange area developed in the mouth and in the throat

Validation of a new in vitro dynamic system to simulate infant digestion

This work was funded by the Institut National de la RechercheAgronomique (INRA) France. The authors are involved in the Foodand Agriculture COST (European Cooperation in Science and Technology)Action FA1005 ‘Improving health properties of food bysharing our knowledge on the digestive process (INFOGEST)Understanding the mechanisms of infant formula disintegration in the infant gastrointestinal tract is akey step for developing new formulas with health benefits for the neonate. For ethical reasons, the accessto in vivo data obtained on infants is limited. The use of animal models can be an alternative but theseexperiments are labour intensive, expensive and results obtained show high inter-individual variability,making their interpretation difficult. The aim of this work was to develop a simple in vitro dynamic gastrointestinaldigestion system, for studying infant formula digestion, and to validate it by comparing thekinetics of proteolysis obtained in vitro with in vivo data collected from piglets. Results showed a goodcorrelation between in vitro and in vivo data and confirmed the rapid hydrolysis of caseins in gastric conditions,whereas whey proteins appeared more resistant to digestion