γ-Cyclodextrin Metal-Organic Frameworks: Do Solvents Make a Difference?

Conventionally, methanol is the solvent of choice in the synthesis of gamma-cyclodextrin metal-organic frameworks (γ-CD-MOFs), but using ethanol as a replacement could allow for a more food-grade synthesis condition. Therefore, the aim of the study was to compare the γ-CD-MOFs synthesised with both methanol and ethanol. The γ-CD-MOFs were characterised by scanning electron microscopy (SEM), surface area and pore measurement, Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD). The encapsulation efficiency (EE) and loading capacity (LC) of the γ-CD-MOFs were also determined for curcumin, using methanol, ethanol and a mixture of the two as encapsulation solvent. It was found that γ-CD-MOFs synthesised by methanol and ethanol do not differ greatly, the most significant difference being the larger crystal size of γ-CD-MOFs crystallised from ethanol. However, the change in solvent significantly influenced the EE and LC of the crystals. The higher solubility of curcumin in ethanol reduced interactions with the γ-CD-MOFs and resulted in lowered EE and LC. This suggests that different solvents should be used to deliberately manipulate the EE and LC of target compounds for better use of γ-CD-MOFs as their encapsulating and delivery agents.

Identifying key priorities for research to protect the consumer with food hypersensitivity: A UK Food Standards Agency Priority Setting Exercise.

INTRODUCTION: Food hypersensitivity (FHS), including food allergy, coeliac disease and food intolerance, is a major public health issue. The Food Standards Agency (FSA), an independent UK Government department working to protect public health and consumers' wider interests in food, sought to identify research priorities in the area of FHS. METHODS: A priority setting exercise was undertaken, using a methodology adapted from the James Lind Alliance-the first such exercise with respect to food hypersensitivity. A UK-wide public consultation was held to identify unanswered research questions. After excluding diagnostics, desensitization treatment and other questions which were out of scope for FSA or where FSA was already commissioning research, 15 indicative questions were identified and prioritized by a range of stakeholders, representing food businesses, patient groups, health care and academia, local authorities and the FSA. RESULTS: 295 responses were received during the public consultation, which were categorized into 70 sub-questions and used to define 15 key evidence uncertainties ('indicative questions') for prioritization. Using the JLA prioritization framework, this resulted in 10 priority uncertainties in evidence, from which 16 research questions were developed. These could be summarized under the following 5 themes: communication of allergens both within the food supply chain and then to the end consumer (ensuring trust in allergen communication); the impact of socio-economic factors on consumers with FHS; drivers of severe reactions; mechanism(s) underlying loss of tolerance in FHS; and the risks posed by novel allergens/processing. DISCUSSION: In this first research prioritization exercise for food allergy and FHS, key priorities identified to protect the food-allergic public were strategies to help allergic consumers to make confident food choices, prevention of FHS and increasing understanding of socio-economic impacts. Diagnosis and treatment of FHS was not considered in this prioritization.

Importance of Bile Composition for Diagnosis of Biliary Obstructions.

Determination of the cause of a biliary obstruction is often inconclusive from serum analysis alone without further clinical tests. To this end, serum markers as well as the composition of bile of 74 patients with biliary obstructions were determined to improve the diagnoses. The samples were collected from the patients during an endoscopic retrograde cholangiopancreatography (ERCP). The concentration of eight bile salts, specifically sodium cholate, sodium glycocholate, sodium taurocholate, sodium glycodeoxycholate, sodium chenodeoxycholate, sodium glycochenodeoxycholate, sodium taurodeoxycholate, and sodium taurochenodeoxycholate as well as bile cholesterol were determined by HPLC-MS. Serum alanine aminotransferase (ALT), aspartate transaminase (AST), and bilirubin were measured before the ERCP. The aim was to determine a diagnostic factor and gain insights into the influence of serum bilirubin as well as bile salts on diseases. Ratios of conjugated/unconjugated, primary/secondary, and taurine/glycine conjugated bile salts were determined to facilitate the comparison to literature data. Receiver operating characteristic (ROC) curves were determined, and the cut-off values were calculated by determining the point closest to (0,1). It was found that serum bilirubin was a good indicator of the type of biliary obstruction; it was able to differentiate between benign obstructions such as choledocholithiasis (at the concentration of >11 µmol/L) and malignant changes such as pancreatic neoplasms or cholangiocarcinoma (at the concentration of >59 µmol/L). In addition, it was shown that conjugated/unconjugated bile salts confirm the presence of an obstruction. With lower levels of conjugated/unconjugated bile salts the possibility for inflammation and, thus, neoplasms increase.

Dairy structures and physiological responses: a matter of gastric digestion.

Digestion and health properties of food do not solely rely on the sum of nutrients but are also influenced by food structure. Dairy products present an array of structures due to differences in the origin of milk components and the changes induced by processing. Some dairy structures have been observed to induce specific effects on digestion rates and physiological responses. However, the underlying mechanisms are not fully understood. Gastric digestion plays a key role in controlling digestion kinetics. The main objective of this review is to expose the relevance of gastric phase as the link between dairy structures and physiological responses. The focus is on human and animal studies, and physiological relevant in vitro digestion models. Data collected showed that the structure of dairy products have a profound impact on rate of nutrient bioavailability, absorption and physiological responses, suggesting gastric digestion as the main driver. Control of gastric digestion can be a tool for delivering specific rates of nutrient digestion. Therefore, the design of food structure targeting specific gastric behavior could be of great interest for particular population needs e.g. rapid nutrient digestion will benefit elderly, and slow nutrient digestion could help to enhance satiety.

Calcium Alters the Interfacial Organization of Hydrolyzed Lipids during Intestinal Digestion.

Calcium plays an important dual role in lipid digestion: promoting removal of long-chain fatty acids from the oil-water interface by forming insoluble calcium soaps while also limiting their bioaccessibility. This becomes more significant in food containing high calcium concentration, such as dairy products. Nevertheless, scarce attention has been paid to the effect of calcium on the interfacial properties during lipid digestion, despite this being largely an interfacial reaction. This study focused on the dynamics of the formation of calcium soaps at the oil-water interface during lipolysis by pancreatic lipase in the absence and presence of the two primary human bile salts (sodium glycocholate or sodium glycochenodeoxycholate). The competitive adsorption of lipase, bile salts, and lipolysis products, as well as the formation of calcium soaps in the presence of increasing concentrations of calcium were mainly characterized by recording the interfacial tension and dilatational modulus in situ. In the absence of bile salts, calcium complexes with fatty acids at the oil-water interface forming a relatively strong viscoelastic network of calcium soaps over time. The dilatational modulus of the calcium soap network is directly related to the interfacial concentration of lipolysis products and the calcium bulk concentration. Calcium soaps are also visualized forming a continuous rough layer on the surface of oil droplets immersed in simulated intestinal aqueous phase. Despite bile salts having different surface activity, they play a similar role on the interfacial competition with lipase and lipolysis products although altering their kinetics. The presence of bile salts disrupts the network of calcium soaps, as suggested by the decrease in the dilatational modulus and the formation of calcium soap islands on the surface of the oil droplets. The accelerant effect of calcium on lipolysis is probably because of fatty acid complexation and subsequent removal from the interface rather than reduced electrostatic repulsion between lipase and bile salt molecules and promoted lipase adsorption. The work shown here has implications for the delivery of oil-soluble bioactives in the presence of calcium.

Oatmeal particle size alters glycemic index but not as a function of gastric emptying rate.

The aim of this study was to determine the extent to which oat particle size in a porridge could alter glucose absorption, gastric emptying, gastrointestinal hormone response, and subjective feelings of appetite and satiety. Porridge was prepared from either oat flakes or oat flour with the same protein, fat, carbohydrate, and mass. These were fed to eight volunteers on separate days in a crossover study, and subjective appetite ratings, gastric contents, and plasma glucose, insulin, and gastrointestinal hormones were determined over a period of 3 h. The flake porridge gave a lower glucose response than the flour porridge, and there were apparent differences in gastric emptying in both the early and late postprandial phases. The appetite ratings showed similar differences between early- and late-phase behavior. The structure of the oat flakes remained sufficiently intact to delay their gastric emptying, leading to a lower glycemic response, even though initial gastric emptying rates were similar for the flake and flour porridge. This highlights the need to take food structure into account when considering relatively simple physiological measures and offering nutritional guidance.NEW & NOTEWORTHY The impact of food structure on glycemic response even in simple foods such as porridge is dependent on both timing of gastric emptying and the composition of what is emptied as well as duodenal starch digestion. Thus structure should be accounted for when considering relatively simple physiological measures and offering nutritional guidance.

Application of recent advances in hydrodynamic methods for characterising mucins in solution.

Mucins are the primary macromolecular component of mucus--nature's natural lubricant--although they are poorly characterised heterogeneous substances. Recent advances in hydrodynamic methodology now offer the opportunity for gaining a better understanding of their solution properties. In this study a combination of such methods was used to provide increased understanding of a preparation of porcine intestinal mucin (PIM), MUC2 mucin, in terms of both heterogeneity and quantification of conformational flexibility. The new sedimentation equilibrium algorithm SEDFIT-MSTAR is applied to yield a weight average (over the whole distribution) molar mass of 7.1 × 10(6) g mol(-1), in complete agreement with size exclusion chromatography coupled with multi-angle light scattering (SEC-MALS), which yielded a value of 7.2 × 10(6) g mol(-1). Sedimentation velocity profiles show mucin to be very polydisperse, with a broad molar mass distribution obtained using the Extended Fujita algorithm, consistent with the elution profiles from SEC-MALS. On-line differential pressure viscometry coupled to the SEC-MALS was used to obtain the intrinsic viscosity [η] as a function of molar mass. These data combined with sedimentation coefficient data into the global conformation algorithm HYDFIT show that PIM has a flexible linear structure, with persistence length L p ~10 nm and mass per unit length, M L ~2380 g mol(-1) nm(-1), consistent with a Wales-van Holde ratio of ~1.2 obtained from the concentration dependence of the sedimentation coefficient.

Re-evaluation of the mechanisms of dietary fibre and implications for macronutrient bioaccessibility, digestion and postprandial metabolism.

The positive effects of dietary fibre on health are now widely recognised; however, our understanding of the mechanisms involved in producing such benefits remains unclear. There are even uncertainties about how dietary fibre in plant foods should be defined and analysed. This review attempts to clarify the confusion regarding the mechanisms of action of dietary fibre and deals with current knowledge on the wide variety of dietary fibre materials, comprising mainly of NSP that are not digested by enzymes of the gastrointestinal (GI) tract. These non-digestible materials range from intact cell walls of plant tissues to individual polysaccharide solutions often used in mechanistic studies. We discuss how the structure and properties of fibre are affected during food processing and how this can impact on nutrient digestibility. Dietary fibre can have multiple effects on GI function, including GI transit time and increased digesta viscosity, thereby affecting flow and mixing behaviour. Moreover, cell wall encapsulation influences macronutrient digestibility through limited access to digestive enzymes and/or substrate and product release. Moreover, encapsulation of starch can limit the extent of gelatinisation during hydrothermal processing of plant foods. Emphasis is placed on the effects of diverse forms of fibre on rates and extents of starch and lipid digestion, and how it is important that a better understanding of such interactions with respect to the physiology and biochemistry of digestion is needed. In conclusion, we point to areas of further investigation that are expected to contribute to realisation of the full potential of dietary fibre on health and well-being of humans.

Sodium alginate decreases the permeability of intestinal mucus.

In the small intestine the nature of the environment leads to a highly heterogeneous mucus layer primarily composed of the MUC2 mucin. We set out to investigate whether the soluble dietary fibre sodium alginate could alter the permeability of the mucus layer. The alginate was shown to freely diffuse into the mucus and to have minimal effect on the bulk rheology when added at concentrations below 0.1%. Despite this lack of interaction between the mucin and alginate, the addition of alginate had a marked effect on the diffusion of 500 nm probe particles, which decreased as a function of increasing alginate concentration. Finally, we passed a protein stabilised emulsion through a simulation of oral, gastric and small intestinal digestion. We subsequently showed that the addition of 0.1% alginate to porcine intestinal mucus decreased the diffusion of fluorescently labelled lipid present in the emulsion digesta. This reduction may be sufficient to reduce problems associated with high rates of lipid absorption such as hyperlipidaemia.

How much is too much? Threshold dose distributions for 5 food allergens.

BACKGROUND: Precautionary labeling is used to warn consumers of the presence of unintended allergens, but the lack of agreed allergen thresholds can result in confusion and risk taking by patients with food allergy. The lack of data on threshold doses below which subjects are unlikely to react is preventing the development of evidence-based allergen management strategies that are understood by clinician and patient alike. OBJECTIVE: We sought to define threshold dose distributions for 5 major allergenic foods in the European population. METHODS: Patients with food allergy were drawn from the EuroPrevall birth cohort, community surveys, and outpatient clinic studies and invited to undergo a food challenge. Low-dose, double-blind, placebo-controlled food challenges were undertaken with commercially available food ingredients (peanut, hazelnut, celery, fish, and shrimp) blinded into common matrices. Dose distributions were modeled by using interval-censoring survival analysis with 3 parametric approaches. RESULTS: Of the 5 foods used for challenge, 4 produced similar dose distributions, with estimated doses eliciting reactions in 10% of the allergic population (ED10), ranging from 1.6 to 10.1 mg of protein for hazelnut, peanut, and celery with overlapping 95% CIs. ED10 values for fish were somewhat higher (27.3 mg of protein), although the CIs were wide and overlapping between fish and plant foods. Shrimp provided radically different dose distributions, with an ED10 value of 2.5 g of protein. CONCLUSION: This evidence base will contribute to the development of reference doses and action levels for allergens in foods below which only the most sensitive subjects might react.

Characterisation, in vitro digestibility and expected glycemic index of commercial starches as uncooked ingredients.

In this study native starches as ingredients (corn, rice, wheat, tapioca and potato) were characterized for microstructure, physicochemical, functional and thermal properties, in vitro digestibility and glycemic index. There was a significant variation in the granule shape and size distribution of the starches. Particle size monomodal (corn, tapioca, potato) and bimodal (rice, wheat) distribution was observed amongst the starches. The potato starch showed the biggest size granules while the rice showed the smallest. The examined properties and nutritional characteristics of starches were significantly different. Thermal properties were studied using Differential Scanning Calorimeter (DSC). DSC results showed that the transition temperatures (58.8-78.7 °C) and enthalpies of gelatinization (2.3-8.2 J/g) of the starches appeared to be greatly influenced by microstructure and chemical composition (e.g. resistant starch). Nutritional properties such as slowly digestible starch and expected glycemic index values followed the order: rice > wheat > tapioca > corn > potato. In particular, the highest resistant starch was recorded for potato starch.

Cross-linking of sodium caseinate-structured emulsion with transglutaminase alters postprandial metabolic and appetite responses in healthy young individuals.

The physico-chemical and interfacial properties of fat emulsions influence lipid digestion and may affect postprandial responses. The aim of the present study was to determine the effects of the modification of the interfacial layer of a fat emulsion by cross-linking on postprandial metabolic and appetite responses. A total of fifteen healthy individuals (26.5 (sem 6.9) years and BMI 21.9 (sem 2.0) kg/m2) participated in a cross-over design experiment in which they consumed two isoenergetic (1924 kJ (460 kcal)) and isovolumic (250 g) emulsions stabilised with either sodium caseinate (Cas) or transglutaminase-cross-linked sodium caseinate (Cas-TG) in a randomised order. Blood samples were collected from the individuals at baseline and for 6 h postprandially for the determination of serum TAG and plasma NEFA, cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1), glucose and insulin responses. Appetite was assessed using visual analogue scales. Postprandial TAG and NEFA responses and gastric emptying (GE) rates were comparable between the emulsions. CCK increased more after the ingestion of Cas-TG than after the ingestion of Cas (P< 0.05), while GLP-1 responses did not differ between the two test emulsions. Glucose and insulin profiles were lower after consuming Cas-TG than after consuming Cas (P< 0.05). The overall insulin, glucose and CCK responses, expressed as areas above/under the curve, did not differ significantly between the Cas and Cas-TG meal conditions. Satiety ratings were reduced and hunger, desire to eat and thirst ratings increased more after the ingestion of Cas-TG than after the ingestion of Cas (P< 0.05). The present results suggest that even a subtle structural modification of the interfacial layer of a fat emulsion can alter the early postprandial profiles of glucose, insulin, CCK, appetite and satiety through decreased protein digestion without affecting significantly on GE or overall lipid digestion.

Trehalose-containing hydrocolloid edible films prepared in the presence of transglutaminase.

In this article, edible hydrocolloid films were prepared by using Citrus pectins and the protein phaseolin in the presence of microbial transglutaminase, an enzyme able to catalyze isopeptide bonds between endo-protein-reactive glutamine and lysine residues. For the first time, trehalose, a nonreducing homodisaccharide into which two glucose units are linked together by a α-1,1-glycosidic linkage, was used as a component of hydrocolloid films constituted of both proteins and carbohydrates. Our data have demonstrated that these films act as very effective barriers to gases, especially to CO2 . They also present a high antioxidant capability as measured by the 2,2-diphenyl-1-picrylhydrazyl scavenging assay. In addition, the films were characterized using Atomic Force Microscopy, a powerful tool used to evaluate film surface topography and roughness. The results of our experiments clearly indicate that the trehalose-containing films prepared both in the presence and absence of transglutaminase are composed of nanoparticles with a smooth surface, having similar roughness values (Rα). In conclusion, according to barrier and antioxidant properties and to their structure, it is possible to consider the trehalose-containing films as innovative bioplastics potentially able to protect different kinds of foods.

Specificity of infant digestive conditions: some clues for developing relevant in vitro models.

Digestion of nutrients is an essential function of the newborn infant gut to allow growth and development and understanding infant digestive function is essential to optimize nutrition and oral drug delivery. Ethical considerations prohibit invasive in vivo trials and as a consequence in vitro assays are often conducted. However, the choice of in vitro model parameters are not supported by an exhaustive analysis of the literature and do not mimic precisely the digestive conditions of the infant. This review contains a compilation of the studies which characterized the gastroduodenal conditions in full-term or preterm infants of variable postnatal age from birth up to six months. Important data about healthy full-term infants are reported. The enzymatic (type of enzymes and level of activity) and nonenzymatic (milk-based diet, frequency of feeding, bile salt concentrations) conditions of digestion in infants are shown to differ significantly from those in adults. In addition, the interindividual and developmental variability of the digestive conditions in infants is also highlighted.

The role of food structure in gastric-emptying rate, absorption and metabolism.

The high levels of non-communicable diseases such as CVD and type 2 diabetes mellitus are linked to obesity and poor diet. This continuing emphasis on health in relation to food is proving a powerful driver for the development of cheap but palatable and more functional foods. However, the efficacy of such foods is often hard to prove in human subjects. Thus, a suite of tools has been developed including in silico and in vitro simulations and animal models. Although animal models offer physiologically relevant platforms for research, their use for experimentation is problematic for consumers. Thus, in vitro methods such as Infogest protocols have been developed to provide digestion endpoints or even an indication of the kinetics of digestion. These protocols have been validated for a range of food systems but they still miss the final absorption step. This review discusses the use of such in vitro models and what further steps need to be included to make the bioaccessibility determination more relevant to bioavailability and human health.

Effect of beta glucan coating on controlled release, bioaccessibility, and absorption of ß-carotene from loaded liposomes.

Recently, the use of biopolymers as coating material to stabilise phospholipid-based nanocarriers has increased. One such class of biopolymers is the dietary fibre beta-glucan (ßG). In this study, we developed and characterized beta-carotene (ßC) loaded ßG coated nanoliposomes (GNLs) to investigate the effect of ßG coating on the stability, controlled release, bioaccessibility, diffusion and subsequent absorption of the lipophilic active agent. The size, charge (Z-potential), and FTIR spectra were measured to determine the physicochemical stability of GNLs. ßG coating reduced the bioaccessibility, provided prolonged release and improved the antioxidant activity of the nanoliposomes. Multiple particle tracking (MPT) data suggested that ßC-GNLs were less diffusive in porcine intestinal mucus (PIM). Additionally, the microviscosity of the PIM treated with GNLs was observed to be higher (0.04744 ± 0.00865 Pa s) than the PIM incubated with uncoated NLs (0.015 ± 0.0004 Pa s). An Ex vivo experiment was performed on mouse jejunum to measure the absorption of beta-carotene from coated (ßC-GNLs) and uncoated nanoliposomes (ßC-NLs). Data showed that after 2 hours, 27.7 ± 1.3 ng mL-1 of ßC encapsulated in GNLs and 61.54 ± 3 ng mL-1 of the ßC encapsulated in uncoated NLs was absorbed by mouse intestinal mucosa. These results highlight that coating with ßG stabilise NLs during gastrointestinal digestion and provides more sustained release of ßC from nanoliposomes.

Effects of Ferulic Acid on Cognitive Function: A Systematic Review.

SCOPE: Plant (poly) phenolic compounds have been reported to decrease the risk of developing dementia and have been associated with maintenance of cognitive performance in normal ageing. Ferulic acid (FA) is a phenolic acid, present in a wide variety of foods including cereals, fruits, vegetables, and coffee. The aim of this systematic review is to examine the effect of FA on cognitive function in humans and animals. METHODS AND RESULTS: The search terms "Ferulic acid AND cognit*" and "Ferulic acid OR feruloyl OR ferula AND (memory OR attention OR learning OR recognition)" are used in Web of Science, Scopus, PubMED, OVID (Medline/PsycInfo), and CINAHL through October 2023. No human studies are identified that matched the inclusion criteria. Twenty-six animal studies are identified. A small number (n = 5) of these studies examined FA in healthy animals whilst the remainder examined animal models of dementia. Alzheimer's disease (n = 11) is the most prevalent model. CONCLUSION: Overall, results from studies employing disease models suggest that FA ameliorates induced cognitive decline in a time and dose-dependent manner. Similarly, studies in healthy animals show a beneficial effect of FA. However, further studies are required to determine the effects of FA on human cognitive function.

Specific food structures supress appetite through reduced gastric emptying rate.

The aim of this study was to determine the extent to which gastric layering and retention of a meal could be used to reduce appetite using the same caloric load. Liquid (control) and semi-solid (active) meals were produced with the same protein, fat, carbohydrate, and mass. These were fed to 10 volunteers on separate days in a crossover study, and subjective appetite ratings, gastric contents, and plasma cholecystokinin (CCK) were assessed over a period of 3 h. The active meal showed food boluses in the stomach persisting for ~45 min, slower emptying rates, and lower plasma CCK levels over the first hour. After the first hour, both gastric emptying rates and plasma CCK levels were similar for both systems and slightly increased compared with the unfed situation. Despite the lower plasma CCK levels for the active meal over the first hour, this meal reduced appetite more than the control meal over the 3 h of the study. For a moderately increased plasma CCK level in the fed state, appetite was correlated with the volume of gastric contents rather than gastric emptying rates or plasma CCK. This suggests that enhanced gastric retention was the key factor in decreasing appetite and was probably mediated by a combination of intestinal nutrient sensing and increased viscosity in the stomach.

The impact of processing on the release and antioxidant capacity of ferulic acid from wheat: A systematic review.

The antioxidant capacity and bioaccessibility of ferulic acid (FA)1 in wheat are highly limited by the lack of free ferulic acid (FFA).2 However, many studies claim that wheat processing can efficiently increase FFA content and ultimately influence the overall antioxidant capacity. Hence, this systematic review investigated changes in FFA content, antioxidant capacity and bioaccessibility of wheat after different processing treatments. A literature search of two databases (PubMed and Web of Science) was undertaken covering the last 20 years, yielding 1148 articles. Studies which employed bioprocessing, thermal processing and milling of wheat were considered. After exclusion criteria were applied, 36 articles were included. These covered single processing methods (n = 25, bioprocessing: n = 9, thermal processing: n = 9, milling n = 7) and combined processing methods (n = 11, bioprocessing & thermal processing = 7, bioprocessing, thermal processing & milling = 2, thermal processing & milling = 2). The total ferulic acid (TFA)3 content, degree of covalent bond hydrolysis and the percentage of FFA degraded or transformed to other compounds dominated the final changes in FFA content, antioxidant capacity and bioaccessibility. This systematic review is the first to comprehensively summarize the best efficient processing method for releasing FA and increasing antioxidant capacity and or bioaccessibility in wheat. The combination of particle size reduction, pre-hydrolysis thermal processing (except at high temperature and extended duration) and enzymatic hydrolysis (ferulic acid esterase (FAE)4 or fermentation) has the highest potential of releasing FA. However, the literature on the bioaccessibility of FA in wheat is limited and more work is required to demonstrate the link between the release of FA by processing and the consequent health benefits.

An ex vivo intestinal absorption model is more effective than an in vitro cell model to characterise absorption of dietary carotenoids following simulated gastrointestinal digestion.

To get the most accurate food digestion-related data, and how this affects nutrient absorption, it is critical to carefully simulate human digestion systems using model settings. In this study, the uptake and transepithelial transportation of dietary carotenoids was compared using two different models that have previously been used to assess nutrient availability. The permeability of differentiated Caco-2 cells and murine intestinal tissue were tested using all-trans-ß-carotene and lutein prepared in artificial mixed micelles and micellar fraction from orange-fleshed sweet potato (OFSP) gastrointestinal digestion. Transepithelial transport and absorption efficiency were then determined using liquid chromatography tandem-mass spectrometry (LCMS-MS). Results showed that the mean uptake for all-trans-ß-carotene in the mouse mucosal tissue was 60.2 ± 3.2% compared to 36.7 ± 2.6% in the Caco-2 cells with the mixed micelles as the test sample. Similarly, the mean uptake was higher in OFSP with 49.4 ± 4.1% following mouse tissue uptake compared to 28.9 ± 4.3% using Caco-2 cells for the same concentration. In relation to the uptake efficiency, the mean percentage uptake for all-trans-ß-carotene from artificial mixed micelles was 1.8-fold greater in mouse tissue compared to Caco-2 cells (35.4 ± 1.8% against 19.9 ± 2.6%). Carotenoid uptake reached saturation at 5 µM when assessed with the mouse intestinal cells. These results demonstrate the practicality of employing physiologically relevant models simulating human intestinal absorption processes that compares well with published human in vivo data. When used in combination with the Infogest digestion model, the Ussing chamber model, using murine intestinal tissue, may thus be an efficient predictor of carotenoid bioavailability in simulating human postprandial absorption ex vivo.