Peptidomic data in porcine duodenal effluents after oral administration of micellar casein.

The data in this article are related to the research publication "Digestion of micellar casein in duodenum cannulated pigs. Correlation between in vitro simulated gastric digestion and in vivo data" (Miralles et al., Food Chemistry, 2021, 343, 128428). Pig duodenum effluents were collected with a T-shaped cannula 15 min before and during digestion over 150 min after casein intake. The casein degradation profile of individual pigs during digestion is presented. All identified peptide sequences at different digestion times for six subjects are provided. The peptide profile of digests in the form of heat maps is shown for αs1-, αs2-, ß- and κ-casein. The sum of amino acids belonging to peptides released from ß- and αs1-casein has been used to determine correlation coefficients and range the inter-individual variability. Finally, the global amino acid composition, isoelectric point and sequence length of all released peptides has been determined.

Digestion of micellar casein in duodenum cannulated pigs. Correlation between in vitro simulated gastric digestion and in vivo data.

Correlation and validation of the results of simulated gastrointestinal digestion of food compounds towards in vivo data is essential. The objective of this work was to monitor the digestion of milk micellar casein in the porcine upper intestinal tract and to match the outcome with the gastric in vitro digestion following the Infogest harmonized protocol. In pig duodenum, small amounts of intact caseins were present in all samples, while caseins were observed up to 60 min of gastric in vitro digestion. The peptide profile generated after in vitro and in vivo digestion showed clear similarities with specific overrepresented regions rich in proline and other hydrophobic residues. The statistical comparison of the in vivo and in vitro peptidome resulted in satisfactory correlation coefficients, up to 0.8. Therefore, the in vitro protocol used was a robust and simple model that provides a similar peptide profile than that found in porcine duodenum.

A methodology for monitoring globular milk protein changes induced by ultrafiltration: a dual structural and functional approach.

Understanding filtration mechanisms at a molecular level is important for predicting structural and functional properties of globular milk proteins after membrane operations. This stage is thus highly decisive for the further development of membrane separations as an efficient alternative to chromatographic processes for the fractionation of milk proteins. In this study, we proposed an original and complete analytical package for the examination of the putative effect of filtration at both macroscopic and molecular levels. We then investigated the pertinence of this analytical package during ultrafiltration (UF) of globular milk proteins in both dead-end and crossflow modes. Reverse-phase HPLC combined with statistical computing was shown to be relevant for the assessment of even slight physically induced modifications. Adaptations of circular dichroism and solubility measurements, regarding their respective dependence on temperature and pH, were also useful for an accurate evaluation of functional modifications. At last, immunochemistry was proven to be a pertinent tool for the specific detection of modifications affecting a targeted protein, even in mixed solutions. Moreover, results obtained by such methods were shown to be coherent with data obtained from classical techniques such as fluorescence. For beta-lactoglobulin, some physically induced modifications were noticed in the permeate because of shear stress inside membrane pores. In the case of alpha-lactalbumin dead-end UF, permeation was shown to affect protein characteristics because of an increase in the relative calcium content responsible for a conformational transition from the apo-form to the holo-form of the protein. Finally, during crossflow UF with limited transmission of BSA, observations were coherent with a partial aggregation because of the circulation of proteins in the filtration pilot. Such a hypothesis corroborates results previously mentioned in the literature.