Heat-moisture and acid treatments can increase levels of resistant starch in arrowroot starch without adversely affecting its prebiotic activity in human colon microbiota.

Carbohydrates are an important macronutrient whose processing and digestive fate can have numerous beneficial or adverse effects on consumer health. This study investigated the impact of heat-moisture treatments (HMT) and citric acid treatments (CAT) on arrowroot starch (ARS) with a focus on its physicochemical properties, digestibility, and influence on gut microbiota. The results revealed that HMT and CAT did not alter the colloidal characteristics of ARS but significantly affected the balance between amorphous and crystalline regions. Changes in thermal properties, morphology, and particle size were also observed. These can influence ARS shelf life and functional properties in various food applications. Furthermore, certain treatments in both processing methods increased the resistant starch (RS) content of ARS, with HMT for 16 hours at 80 °C and CAT with 0.6 M citric acid, resulting in the most pronounced effects. These changes coincided with reductions in rapidly digestible starch (RDS) levels and improvements in the ratio of slowly digestible starch (SDS) to RDS, which could potentially improve glycemic control. This study also examined the impact of processed ARS on colonic microbiota composition. It found that ARS-derived RS formed under HMT and CAT did not negatively affect the prebiotic potential of the RS fraction. Both treatments were associated with lowering the Firmicutes to Bacteroidetes ratio (F/B), a marker of gut health, and decreasing the relative abundance of Proteobacteria, microbes associated with adverse health effects. Additionally, CAT-derived RS showed a significant increase in the relative abundance of Roseburia, a beneficial gut bacterium. In conclusion, processing ARS through HMT and CAT techniques has the potential for enhancing its RS content, improving its glycemic impact, and positively influencing the gut microbiota composition, potentially contributing to gut health and metabolic well-being.

Carrageenan impact on digestive proteolysis of meat proteins in meatballs or soluble hydrolyzed collagen.

In a health-conscious age, vivid discussion has been made on the healthfulness of processed foods and food additives. This study focuses on carrageenan (CGN), an approved but debated family of sulphated galactans from algae used as gelling, thickening and stabilizing agents but with indications of possible adverse effects, including as an inhibitor of digestive proteolysis. To challenge this inhibitory hypothesis, food-grade kappa-, iota and lambda-CGN preparations were used to produce beef meatballs whose proteolysis was studied using an in vitro digestion model coupled to various proteomic analyses. Results show that CGN anti-nutritional effects are abolished in beef meatballs. Specifically, proteomic analysis of gastric digesta of myosin light chain 1 (MYL1), alpha skeletal muscle (ACTA1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and fructose-bisphosphate aldolase (ALDOA) reveal no appreciable differences in the profiles of bioaccessible peptides. Separate digestions of a soluble collagen hydrolysate show CGN does inhibit proteolysis of soluble collagen, therefore supporting the notion that the meat matrix confers a shielding effect that eliminates CGN ability to interfere with digestive proteolysis. Thus, this work shows that CGN ability to hinder digestive proteolysis may not apply to all foods and contributes evidence important to the discussions on CGN uses, indications and regulatory status.

In vitro digestion models for the design of safe and nutritious foods.

Responsible development of future foods requires in depth understanding of food digestion in the human body based on robust research models, ranging from in vitro models to randomized controlled human trials. This chapter overviews fundamental aspects of food digestion, namely bioaccessibility and bioavailability, and models mirroring gastric, intestinal, and colonic conditions. Second, the chapter demonstrates the potential of in vitro digestion models to help screen adverse effects of food additives, such as Titanium dioxide or carrageenan, or underpin the determinants of macro- and micronutrient digestion in different strata of the population, for example digestion of emulsions. Such efforts support rationalized design of functional foods, such as infant formulae, cheese, cereals and biscuits which are validated in vivo or in randomized controlled trials.

Inclusion of phenolic bioactives in high amylose corn starch for gastro-intestinal delivery.

Starch is a staple food component with intricate architectures, some of which can be utilized as polysaccharidic delivery vehicles for bioactive compounds. This work describes the use of high amylose corn starch (HACS) to fabricate V-amylose inclusion complexes entrapping capsaicin or curcumin. In line with past studies, X-ray diffraction, differential scanning calorimetry, static laser scattering and scanning electron microscopy help affirm the formation of V6III-type complexes. Such HACS complexes entrap capsaicin and curcumin in structures with higher levels of crystallinity compared to HACS alone (14.61 ± 0.08%, 14.65 ± 0.08% vs. 10.24 ± 0.24%, respectively), high levels of encapsulation efficiency (88.77 ± 5.7% and 66.3 ± 0.99%, respectively) but without significant differences in colloid sizes between the various inclusion complexes (58.25 ± 1.34 µm or 58.98 ± 2.32 µm, respectively). In turn, in vitro gastro-intestinal digestion of HACS complexes with capsaicin or curcumin revealed both, phenolic bioactives significantly (p < 0.05) attenuated the intestinal breakdown of HACS. Interestingly, this attenuated HACS digestibility was accompanied by high gastric retention of the payloads and their sustained release during 2 h of exposure to intestinal conditions. Altogether, this work presents starch-based delivery systems that can entrap phenolic bioactives, release the payload in the intestine and possibly attenuate starch breakdown (because of its increased crystallinity). Thus, this work offers a platform for infusing foods with bioactive phenolics and stall the breakdown of starch.

Mechanisms of absorption of vitamin D3 delivered in protein nanoparticles in the absence and presence of fat.

Novel protein-based nanovehicles offer alternatives to fat for delivery of lipophilic bioactives (nutraceuticals and drugs), yet they raise important questions regarding the bioavailability and absorption mechanism of the bioactive without fat. To provide answers, we chose vitamin D3 (VD3) as a model lipophilic-nutraceutical, re-assembled casein-micelles (rCM) as model protein-based nanovehicles, and non-fat yoghurt as a model food. We prepared three yoghurt formulations: 3% fat with VD3 dissolved in milk-fat, non-fat and 3% fat, both latter enriched with VD3 within rCM. Following in vitro digestion, VD3 retention and bioaccessibility were high (∼90% and ∼70%, respectively) in all formulations. VD3 uptake by Caco-2 cells was three-fold higher (p < 0.005) in the non-fat yoghurt enriched with VD3 in rCM compared with enriched fat-containing yoghurts. SR-BI, CD36 and NPC1L1 transporters were involved in VD3 absorption irrespective of the composition. Thus, our findings demonstrate that protein nanovehicles may improve VD3 bioavailability, without altering its absorption mechanism compared to that from fat.

Capsaicin stability and bio-accessibility affected by complexation with high-amylose corn starch (HACS).

Delivery of pungent bioactives such as capsaicin from hot peppers is a scientific, technological and sensorial challenge. While capsaicin intake is positively related to various bowel diseases, its high pungency and instability upon digestion generate a problem in its delivery to the target organ. Helical V-amylose architectures have been shown to be a possible nano-sized delivery vehicle for such hydrophobic bioactives. This study sought to entrap capsaicin (CAP) within high amylose corn starch (HACS), quantitate and optimize the encapsulation efficiency and other techno-functional properties as well as evaluate the release of capsaicin in the duodenum. By adapting an acidification protocol, HACS was processed to form nanocapsules loaded with capsaicin. The capsaicin content and loading ratio were optimized to 44.0% (±0.4) and 1 : 1 (CAP : HACS, w/w), respectively. AFM and XRD measurements of the complexes confirmed the formed nanocapsules to be V-type crystals with a 1 : 10 (CAP : HACS, w/w) loading ratio showing the highest level of crystallinity. Laser scattering measurements demonstrated an increase in poly-dispersity as the loading ratio increased as well as a higher surface-area diameter. Scanning electron microscopy (SEM) revealed the formation of irregular circular starch inclusion complexes upon acidification treatment. Finally, an in vitro digestion model was utilized to ascertain capsaicin release under gastro-intestinal conditions that coincides with complex degradation under digestive conditions. Both adult and elderly in vitro digestion models were applied, showing the effect of age on the nanocapsule degradation and capsaicin bioaccessibility. Overall, this work provides practical information about the use of HACS for nano-encapsulation of capsaicin and its controlled release under digestive conditions, and provides insight regarding the correlation between nanocomplex characteristics and the consumer physiology. Such a nano-encapsulation platform could prove to be useful in the fortification and supplementation of starchy foods with challenging bioactives, such as the pungent capsaicin.

Bovine alpha-lactalbumin assemblies with capsaicin: Formation, interactions, loading and physiochemical characterization.

Numerous human conditions can benefit from diets rich in proteins and bioactives, such as capsaicin (CAP), yet their effective delivery is a sensorial, scientific and technological challenge. This study hypothesized that CAP can form various complexes with native bovine alpha-lactalbumin (holo-ALA) and decalcified-ALA (apo-ALA). Calorimetric and spectroscopic techniques reveals ALA-CAP molecular complexation is spontaneous, exothermic and accompanied by various conformational changes. ITC shows the interaction stoichiometry (n) and binding constant (Kb) for holo-ALA to be 0.87 ± 0.03, 1.54 ± 0.23 × 105 M-1 and for apo-ALA to be 0.64 ± 0.09, 9.41 ± 2.16 × 104 M-1. Molecular docking further elucidates that hydrogen bonds govern CAP binding to holo-ALA while hydrophobic interactions dominate binding to apo-ALA in a structural cleft. Finally, this work shows these interactions along with controlled aggregation can be utilized to form CAP-loaded colloids with encapsulation efficiency of 47.1 ± 1.0%. Thus, this study shows great promise in the prospective use of ALA as an edible delivery vehicle for CAP.

Addition of Anionic Polysaccharide Stabilizers Modulates In Vitro Digestive Proteolysis of a Chocolate Milk Drink in Adults and Children.

There is a need to better understand the possible anti-nutritional effect of food stabilizers on the digestibility of important macronutrients, like proteins. This study hypothesized that the anionic nature of κ-, ι-, λ-, Carrageenan (CGN) and xanthan gum directs their interactions with food proteins leading to their subsequent attenuated digestive proteolysis. Model chocolate milk drinks were tested for their colloidal properties, viscosity and proteolytic breakdown in adults and children using in vitro digestion models coupled with proteomic analyses. SDS-PAGE analyses of gastro-intestinal effluents highlight stabilizers hinder protein breakdown in adults and children. Zeta potential and colloidal particle size were the strongest determinants of stabilizers' ability to hinder proteolysis. LC-MS proteomic analyses revealed stabilizer addition significantly reduced bioaccessibility of milk-derived bioactive peptides with differences in liberated peptide sequences arising mainly from their location on the outer rim of the protein structures. Further, liberation of bioactive peptides emptying from a child stomach into the intestine were most affected by the presence of ι-CGN. Overall, this study raises the notion that stabilizer charge and other properties of edible proteins are detrimental to the ability of humans to utilize the nutritional potential of such formulations. This could help food professionals and regulatory agencies carefully consider the use of anionic stabilizers in products aiming to serve as protein sources for children and other liable populations.

Controlling lipid intestinal digestibility using various oil structuring mechanisms.

This research demonstrates the ability to direct the rate and extent of lipid hydrolysis of oleogels using a combination of different structuring agents. Combinations of ethyl cellulose (EC) (20 cP and 45 cP) and commercial mixture of mono and di-glycerides (E471), at different ratios, were examined. The results suggest that the combination of E471 and EC significantly affects both gel physical properties and intestinal lipolysis. The gelation profile of the combined system demonstrated the EC sol-gel transition, which is characterized by G' = G'' at high temperatures (∼100 °C) followed by a soft-to-hard gel transition at low temperatures ∼30 °C, which corresponds to E471 crystallization. Such a profile suggests the formation of two gel networks, with the polymer network acting as a platform for E471 crystallization. Mechanical analysis reveals harder gels in the E471 : EC 20 cP mixture compared with the simple addition of each component contribution, suggesting a synergistic effect with a typical maximum at 7 : 3 E471 : EC 20 cP ratio. No significant additive effect was observed for E471 : EC 45 cP mixtures. Maximum lipolysis in the order of EC < E471 : EC < E471 was obtained, implying an effect of the structuring agent used on the lipolysis profile. A first-order kinetics analysis fitted to the lipolysis profiles demonstrated rate constant values in the order of E471 < E471 : EC < EC. Such behavior was attributed to the oil state, liquid vs. solid, and the network strength, both of which limit the lipase activity by hindering liquid TAG accessibility. Overall, the results demonstrate the ability to control gel properties and hydrolysis by manipulating gel composition. Such rational design can be exploited when developing new fat mimetic systems aimed at controlling the lipid digestion profile or the release of hydrophobic components present in the oil phase.

The impact of food-grade carrageenans and consumer age on the in vitro proteolysis of whey proteins.

The food additive carrageenan (E407) (CGN) is a family of sulphated galactans widely used in numerous processed foods, including dairy. There are various indications that CGN may hinder digestive proteolysis. This study sought to link CGN macromolecular characteristics to its implications on digestive proteolysis of whey protein isolate (WPI) in toddlers, adults and seniors. Size exclusion chromatography and dynamic laser scattering reveal commercial CGN samples differ in molecular weight distributions, zeta-potentials and flow behavior of WPI-CGN mixtures. Moreover, κ-CGN, ι-CGN and λ-CGN were found to contain low MW (<200 kDa) fractions at levels of 6.36 ± 2.11% (w/w), 3.64 ± 1.06% (w/w) and 2.08 ± 1.41% (w/w), respectively. In vitro human digestion of WPI-CGN mixtures and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of digesta indicate that CGN alters the breakdown of alpha-lactalbumin, beta-lactoglobulin and lactoferrin differentially in toddlers, adults and seniors digestion conditions. Interestingly, proteomic analyses indicate there is a possible correlation between CGN degree of sulphation and the release of bioactive peptide homologues in the gut lumen. Moreover, these analyses indicate CGN compromises the bioaccessibility of essential amino acids. Altogether, this study shows CGN may attenuate whey digestive proteolysis. This effect should be taken in account by food manufacturers and regulatory agencies in view of the rising levels of exposure to CGN in the human diet.

Impact of thermal processing on physicochemical properties of silk moth pupae (Bombyx mori) flour and in-vitro gastrointestinal proteolysis in adults and seniors.

Elimination of insects' appearance by processing may increase their consumer acceptance in the western world. This study elucidates the outcomes of cooking and baking in presence and absence of fructose on silk worm pupae (Bombyx mori) flour (SWF). Elemental analyses of SWF reveal it is rich in lipids, protein and minerals like calcium. ζ-potential analyses revealed charge reversal at pH values below pH = 4. Particle size analyses showed heat-induced Maillard glycation significantly (p < .05) accentuated reduction in mean volume weighed (d4,3) diameters. In vitro gastrointestinal digestion of SWF and processed SWF showed different breakdown patterns evident in SDS-PAGE and LC-MS/MS analyses. Interestingly, baking with fructose significantly (α < 0.01) diminished the number of peptides liberated by pepsinolysis. Moreover, cooking or baking in the presence of fructose induced a reduction of bioaccessible peptides that are homologous to arthropoda phylum bioactive peptides (>70% homology), such as antimicrobial and Acyl-Co-A binding peptides. Predictive software (PeptideRanker) analysis showed a decrease in the total number of potentially novel bioactive peptides (bioactivity probability >80%) in baked SWF with fructose. Comparison of SWF and processed SWF proteolytic breakdown in adults and seniors highlighted seniors may be less apt to digest SWF products, yet, 14 potentially novel bioactive peptides were uniquely liberated in the elderly gut. Overall, this study shows process-related Maillard glycation may interfere with SWF potential to generate bioactive peptides during digestion in adults and seniors.

INFOGEST static in vitro simulation of gastrointestinal food digestion.

Developing a mechanistic understanding of the impact of food structure and composition on human health has increasingly involved simulating digestion in the upper gastrointestinal tract. These simulations have used a wide range of different conditions that often have very little physiological relevance, and this impedes the meaningful comparison of results. The standardized protocol presented here is based on an international consensus developed by the COST INFOGEST network. The method is designed to be used with standard laboratory equipment and requires limited experience to encourage a wide range of researchers to adopt it. It is a static digestion method that uses constant ratios of meal to digestive fluids and a constant pH for each step of digestion. This makes the method simple to use but not suitable for simulating digestion kinetics. Using this method, food samples are subjected to sequential oral, gastric and intestinal digestion while parameters such as electrolytes, enzymes, bile, dilution, pH and time of digestion are based on available physiological data. This amended and improved digestion method (INFOGEST 2.0) avoids challenges associated with the original method, such as the inclusion of the oral phase and the use of gastric lipase. The method can be used to assess the endpoints resulting from digestion of foods by analyzing the digestion products (e.g., peptides/amino acids, fatty acids, simple sugars) and evaluating the release of micronutrients from the food matrix. The whole protocol can be completed in ~7 d, including ~5 d required for the determination of enzyme activities.

Reply to the Comment on "Revisiting the carrageenan controversy: do we really understand the digestive fate and safety of carrageenan in our foods?" by M. Weiner and J. McKim, Food Funct., 2019, 10: DOI: 10.1039/C8FO01282B.

This commentary re-emphasizes the aim of our recent review (David et al., 2018) and addresses some of the points raised in the adjacent commentary by M. Weiner and J. McKim, Food Funct., 2019, 10, DOI: 10.1039/C8FO01282B. In agreement with the commentary, the discussed review highlights the need to adequately understand the complex physicochemistry of the food additive carrageenan (CGN) and its fate in the alimentary canal. In fact, there is a realm of scientific findings that justify the continuation of an open discussion of CGN safety. This response emphasizes that there is sparse information on [i] the physicochemical properties of commercial CGN, [ii] human levels of exposure to CGN from foods, [iii] the role of CGN in gut microbiome dysbiosis and inflammation, and [iv] the effects of CGN on susceptible populations. As long as the determinants of the increased prevalence of chronic and autoimmune diseases are not identified, we must continue to explore the possible beneficial or deleterious effects that may arise from extrinsic factors, including food additives, and do so in meticulous independent studies.

Revisiting the carrageenan controversy: do we really understand the digestive fate and safety of carrageenan in our foods?

Carrageenan (CGN), a family of marine polysaccharides isolated from seaweeds, has been at the heart of considerable debate in recent years. To date, CGN is generally recognized as safe based on a history of safe use, various acute toxicology studies and some recent chronic toxicology tests. This review offers readers an overview of evidence on CGN characteristics and digestive fate that highlight various gaps in our understanding. Specifically, three unresolved gaps are identified. Firstly, little information can be found on the current levels of public exposure to CGN. Secondly, the link between CGN physicochemical properties, its impact on digestive proteolysis, the colon microbiome and inflammation are yet to be fully resolved. Thirdly, scant scientific evidence exists on the differential digestive fate of CGN in the gut of liable and predisposed populations, such as elderly people or IBD patients. Altogether, revisiting the scientific evidence indicates that more research is needed to elucidate the possibility that continued exposure to increasing levels of CGN in the human diet may compromise human health and well-being.

Implications of the Maillard reaction on bovine alpha-lactalbumin and its proteolysis during in vitro infant digestion.

This study investigated the functionality and digestibility of Maillard reaction products (MRPs) of alpha-lactalbumin (α-la), a major whey protein and component of infant formulas. The impact of different carbohydrates (glucose, galactose or galacto-oligosaccharides (GOS)) and heating duration was studied. SDS-PAGE, UV and color measurements monitored reaction extent, which varied between carbohydrates whereby galactose reacted more readily than glucose. Surface hydrophobicity and antioxidant capacity were found to be significantly (p < 0.05) higher following Maillard conjugation, with GOS-based MRPs elevating antioxidant capacity ∼50-fold compared to α-la. In addition, the digestive proteolysis of MRPs was evaluated using an infant in vitro gastro-duodenal model. SDS-PAGE analyses of digesta revealed Maillard conjugation generally increased α-la's susceptibility to proteolysis. Interestingly, GOS-based MRPs presented an optimization challenge, since heating for 12 h delayed proteolysis, while extended heating resulted in the highest susceptibility to proteolysis. Proteomic analyses further demonstrated the differences in enzymatic cleavage patterns and helped identify bioactive peptides rendered bioaccessible during the digestion of α-la or its MRPs. Bioinformatic mining of the proteomic data using PeptideRanker also gave rise to two potentially novel bioactive peptides, FQINNKIW and GINYWLAHKALCS. Finally, antioxidant capacity of luminal contents, measured by DPPH, revealed Maillard conjugation increased the antioxidant capacity of both gastric and duodenal digesta. Overall, this work draws a link between the Maillard reaction, digestive proteolysis and the bioaccessibility of bioactive peptides and antioxidant species in the infant alimentary canal. This could help rationally process infant formulas towards improved nutritional and extra-nutritional benefits.

Re-assembled casein micelles improve in vitro bioavailability of vitamin D in a Caco-2 cell model.

The pandemic of vitamin D (VD) deficiency, and the global rise in obesity stimulate a need for staple low-fat foods and beverages enriched with VD. In light of consumer demand for a clean label, the use of natural endogenous food ingredients as delivery vehicles is of great interest. To this end, re-assembled casein micelles (rCM) have been shown to help retain VD during processing and shelf life and provide high bioavailability in low-fat milk and non-fat yoghurt. This follow-up study focused on the performance of VD-loaded rCM after drying and reconstitution, considering VD retention during simulated digestion, and the subsequent in vitro bioavailability of the vitamin. rCM conferred great protection to VD3 during simulated digestion with a significant increase in vitamin retention for 1 h under gastric conditions. This observation is believed to arise from the vitamin-casein binding and the system's natural gelation (curd formation) near the casein isoelectric point that seclude the vitamin from environmental stressors and couple its release with digestive proteolysis of the rCM matrix. Vitamin absorption by Caco-2 cells from digested rCM was not significantly different from the absorption of the digested free VD. However, thanks to the highly protective effect of the rCM, against VD gastric degradation, the overall effect of the rCM was a 4-fold higher bioavailability, compared to the free VD.

Digestive fate of dietary carrageenan: Evidence of interference with digestive proteolysis and disruption of gut epithelial function.

SCOPE: The objective of this study was to interrogate two mechanisms by which commercial Carrageenans (E407) (CGN) may adversely affect human health: (i) Through modification of gastric proteolysis and (ii) Through affecting gut epithelial structure and function. METHODS AND RESULTS: Three commercial CGN samples with distinct zeta-potentials (stable at the pH range of 3-7 and varied with physiological levels of CaCl2 ) were mixed with milk, soy or egg protein isolates, then subjected to a semi-dynamic in vitro digestion model and analyzed by SDS-PAGE. This revealed varying levels of interference with gastric digestive proteolysis and a significant decrease in pepsin activity. Further, a Caco-2 cell model was used to explore various effects of physiologically digested CGN (pdCGN) on various epithelial cell functions and characteristics. Samples of pdCGN (0.005-0.5 mg/mL) affected the epithelial barrier function, including redistribution of the tight-junction protein Zonula Occludens (Zo)-1, changes in cellular F-actin architecture and increased monolayer permeability to the transfer of macromolecules. Moreover, pdCGN induced elevation in the levels of the pro-inflammatory IL-8 receptor CXCR1. CONCLUSION: This work raises the possibility that CGN may reduce protein and peptide bioaccessibility, disrupt normal epithelial function, promote intestinal inflammation, and consequently compromise consumer health.

Antioxidant activity of bovine alpha lactalbumin Maillard products and evaluation of their in vitro gastro-duodenal digestive proteolysis.

Food processing offers various pathways to tailor food functionality and digestibility. This work sought to study the impact of thermally-induced Maillard reaction between bovine alpha-lactalbumin (α-la) and fructose or fructo-oligosacchrides on physicochemical properties, antioxidant capacity and in vitro digestive fate under simulated adult and infant conditions. Colloidal stability (measured by DLS) was decreased as a result of the Maillard glycation, while antioxidant capacity (determined by FRAP) and surface hydrophobicity (H0 measurements) were elevated. Semi-dynamic in vitro digestion of Maillard conjugates revealed a mixed trend as a result of postulated competing effects of glycation on α-la's susceptibility to proteolysis; steric hindrance accompanied by protein unfolding could hinder or promote the availability of enzymatic cleavage sites. Results also showed thermal processing altered the digestive breakdown profile of α-la under infant conditions contrary to negligible effects observed under adult conditions. Evaluation of the antioxidant capacity during digestion (via DPPH assay) revealed that adult digesta possessed increased antioxidant activity throughout the gastric phase compared to infant digesta, whereas infant digesta of conjugates exhibited an increase in antioxidant capacity in the duodenum compared to adult. Moreover, during infant digestion of conjugates, an increase in antioxidant capacity was observed in the later stages of the digestion. Overall, this work demonstrates that controlled thermal processing of bovine α-la could potentially modulate its functionality and digestibility, particularly as it pertains to its ability to interfere with oxidative reactions in the lumen, possibly through the generation of bioactive peptides.

Bi-compartmental elderly or adult dynamic digestion models applied to interrogate protein digestibility.

The world's population is inevitably ageing thanks to modern progress; however, the development of food and oral formulations tailored to the needs of the elderly is still in its infancy. In vitro digestion models offer high throughput, robust and practically ethics free evaluation of the digestive fate of ingested products. To date, no data have been made publicly available to facilitate the development or application of an in vitro model mirroring the physicochemical conditions of the elderly gastrointestinal system. This study reports the development of a novel and highly bio-relevant in vitro model based on two serially connected bioreactors recreating the dynamic conditions of the adult or elderly alimentary canal. This report and its supplementary material describe in detail the set-up of the system, the applied physicochemical parameters and the development of the controlling software. These are intended to openly depict a versatile platform, which could assist future efforts to develop age-tailored oral formulations. SDS-PAGE analyses of samples collected from the in vitro digestion of ß-lactoglobulin, α-lactalbumin and lactoferrin suggest the bioaccessibility of "slow digesting" and "fast digesting" proteins identified in adult models do not necessarily maintain this trait under elderly gastro-intestinal conditions. Overall, this study brings forward a new generic yet advanced model that could facilitate age-tailoring the digestive fate of liquid formulations.