Standardization of in vitro digestibility and DIAAS method based on the static INFOGEST protocol

Background: The FAO recommends the digestible indispensable amino acid score (DIAAS) as the measure for protein quality, for which the true ileal digestibility needs to be assessed in humans or pigs. However, due to high costs and ethical concerns, the FAO strongly encourages as well the development of validated in vitro methods, which complement the in vivo experiments. Method: Recently, an in vitro workflow, based on the validated static INFOGEST protocol, was developed and compared towards in vivo data. In parallel to the validation with in vivo data, the repeatability and reproducibility of the in vitro protocol were tested in an international ring trial (RT) with the aim to establish an international ISO standard method within the International Dairy Federation (IDF). Five different dairy products (skim milk powder, whole milk powder, whey protein isolate, yoghurt, and cheese) were analyzed in 32 different laboratories from 18 different countries, across 4 continents. Results: in vitro protein digestibilities based on Nitrogen, free R-NH2, and total amino acids as well as DIAAS values were calculated and compared to in vivo data, where available. Conclusion: The in vitro method is suited for quantification of digestibility and will be further implemented to other food matricesinfo:eu-repo/semantics/publishedVersio

Structure Formation in Tailor-Made Buriti Oil Emulsion During Simulated Digestion

Functional food emulsions enriched in health-promoting nutrients can help to maintain and improve health and lifestyle. The oil extracted from the Amazonian buriti fruit is renowned for its high levels of carotenoid, vitamin E, and unsaturated fatty acids, which have been linked to improvements in cardiometabolic health. Here, buriti oil in water emulsions are developed and their colloidal transformations are investigated in an advanced digestion model with oral, gastric, and intestinal parts with in situ synchrotron small-angle X-ray scattering, cryogenic electron microscopy, and dynamic light scattering under simulated “healthy” and “compromised” digestive conditions. The interior oil phase of whey-stabilized buriti oil-in-water emulsion transforms into highly ordered lyotropic liquid crystalline structures during simulated intestinal digestion at compromised bile conditions. Simulated gastric digestion influences intestinal digestion by slowing it down, resulting in less ordered structures. The digestion-triggered structure formation is pH- and bile salt-dependent and can be modulated by adding vitamin E to the oil. This tailoring of structures during digestion offers a new pathway to steer digestion kinetics and nutrient bioavailability.ISSN:1616-3028ISSN:1616-301

Structure-Function Characterization and Optimization of a Plant-Derived Antibacterial Peptide

Crushed seeds of the Moringa oleifera tree have been used traditionally as natural flocculants to clarify drinking water. We previously showed that one of the seed peptides mediates both the sedimentation of suspended particles such as bacterial cells and a direct bactericidal activity, raising the possibility that the two activities might be related. In this study, the conformational modeling of the peptide was coupled to a functional analysis of synthetic derivatives. This indicated that partly overlapping structural determinants mediate the sedimentation and antibacterial activities. Sedimentation requires a positively charged, glutamine-rich portion of the peptide that aggregates bacterial cells. The bactericidal activity was localized to a sequence prone to form a helix-loop-helix structural motif. Amino acid substitution showed that the bactericidal activity requires hydrophobic proline residues within the protruding loop. Vital dye staining indicated that treatment with peptides containing this motif results in bacterial membrane damage. Assembly of multiple copies of this structural motif into a branched peptide enhanced antibacterial activity, since low concentrations effectively kill bacteria such as Pseudomonas aeruginosa and Streptococcus pyogenes without displaying a toxic effect on human red blood cells. This study thus identifies a synthetic peptide with potent antibacterial activity against specific human pathogens. It also suggests partly distinct molecular mechanisms for each activity. Sedimentation may result from coupled flocculation and coagulation effects, while the bactericidal activity would require bacterial membrane destabilization by a hydrophobic loop

Standardization of in vitro digestibility and DIAAS method based on the static INFOGEST protocol

International audienceThe FAO recommends the digestible indispensable amino acid score (DIAAS) as the measure for protein quality, for which the true ileal digestibility needs to be assessed in humans or pigs. However, due to high costs and ethical concerns, the FAO strongly encourages as well the development of validated in vitro methods, which complement the in vivo experiments. Method: Recently, an in vitro workflow, based on the validated static INFOGEST protocol, was developed and compared towards in vivo data. In parallel to the validation with in vivo data, the repeatability and reproducibility of the in vitro protocol were tested in an international ring trial (RT) with the aim to establish an international ISO standard method within the International Dairy Federation (IDF). Five different dairy products (skim milk powder, whole milk powder, whey protein isolate, yoghurt, and cheese) were analyzed in 32 different laboratories from 18 different countries, across 4 continents. Results: in vitro protein digestibilities based on Nitrogen, free R-NH2, and total amino acids as well as DIAAS values were calculated and compared to in vivo data, where available. Conclusion: The in vitro method is suited for quantification of digestibility and will be further implemented to other food matrices