Some pearl millet-based foods promote satiety or reduce glycaemic response in a crossover trial.

In a previous trial in Mali, we showed that traditional pearl millet couscous and thick porridge delayed gastric emptying (about 5 h half-emptying times) in a normal-weight population compared with non-traditional carbohydrate-based foods (pasta, potatoes, white rice; about 3 h half-emptying times), and in a gastric simulator we showed millet couscous had slower digestion than wheat couscous. In light of these findings, we tested the hypothesis in a normal-weight US population (n 14) that millet foods would reduce glycaemic response (continuous glucose monitor), improve appetitive sensations (visual analogue scale ratings), as well as reduce gastric emptying rate (13C-octanoic acid breath test). Five carbohydrate-based foods (millet couscous - commercial and self-made, millet thick porridge, wheat couscous, white rice) were fed in a crossover trial matched on available carbohydrate basis. Significantly lower overall glycaemic response was observed for all millet-based foods and wheat couscous compared with white rice (P ≤ 0·05). Millet couscous (self-made) had significantly higher glycaemic response than millet couscous (commercial) and wheat couscous (P < 0·0001), but as there were no differences in peak glucose values an extended glycaemic response was indicated for self-made couscous. Millet couscous (self-made) had significantly lower hunger ratings and higher fullness ratings (P < 0·05) than white rice, millet thick porridge and millet couscous (commercial). A normal gastric emptying rate (<3 h half-emptying times) was observed for all foods, with no significant differences among them. In conclusion, some traditionally prepared pearl millet foods show the potential to reduce glycaemic response and promote satiety.

Protein Digestion and Quality of Goat and Cow Milk Infant Formula and Human Milk Under Simulated Infant Conditions.

OBJECTIVE: The aim of this study was to determine the kinetics of true ileal protein digestion and digestible indispensable amino acid score (DIAAS) of a goat milk-based infant formula (GIF), a cow milk-based infant formula (CIF), and human milk (HM). METHODS: The GIF, CIF, and HM were investigated in an in vitro gastrointestinal model simulating infant conditions. Digested compounds were dialyzed from the intestinal compartment as bioaccessible fraction. Dialysate was collected in 15 to 60-minute periods for 4 hours. True ileal protein digestibility and DIAAS were determined as bioaccessible nitrogen (N) and amino acids. RESULTS: N bioaccessibility from the GIF showed similar kinetics to that of HM. The CIF showed a delay in N bioaccessibility versus the GIF and HM. In the 1st hour of digestion, N bioaccessibility was 19.9% ±â€Š3.5% and 23.3% ±â€Š1.3% for the GIF and HM, respectively, and 11.2% ±â€Š0.6% for CIF (P < 0.05 vs HM). In the 3rd hour of digestion, the N bioaccessibility was higher (P < 0.05) for the CIF (28.9% ±â€Š1.2%) than for the GIF (22.5% ±â€Š1.6%) and HM (20.6% ±â€Š1.0%). After 4 hours, the true ileal protein digestibility of the GIF, CIF, and HM was 78.3% ±â€Š3.7%, 73.4% ±â€Š2.7%, and 77.9% ±â€Š4.1%, respectively. The DIAAS for the GIF, CIF, and HM for 0- to 6-month-old infants was 83%, 75%, and 77% for aromatic AA. CONCLUSION: The protein quality is not different between the GIF, CIF, and HM, but the kinetics of protein digestion of the GIF is more comparable to that of HM than that of the CIF.

Progress and future of in vitro models to study translocation of nanoparticles.

The increasing use of nanoparticles in products likely results in increased exposure of both workers and consumers. Because of their small size, there are concerns that nanoparticles unintentionally cross the barriers of the human body. Several in vivo rodent studies show that, dependent on the exposure route, time, and concentration, and their characteristics, nanoparticles can cross the lung, gut, skin, and placental barrier. This review aims to evaluate the performance of in vitro models that mimic the barriers of the human body, with a focus on the lung, gut, skin, and placental barrier. For these barriers, in vitro models of varying complexity are available, ranging from single-cell-type monolayer to multi-cell (3D) models. Only a few studies are available that allow comparison of the in vitro translocation to in vivo data. This situation could change since the availability of analytical detection techniques is no longer a limiting factor for this comparison. We conclude that to further develop in vitro models to be used in risk assessment, the current strategy to improve the models to more closely mimic the human situation by using co-cultures of different cell types and microfluidic approaches to better control the tissue microenvironments are essential. At the current state of the art, the in vitro models do not yet allow prediction of absolute transfer rates but they do support the definition of relative transfer rates and can thus help to reduce animal testing by setting priorities for subsequent in vivo testing.

In Vitro Simulation of the Environment in the Upper Gastrointestinal Lumen After Drug Administration in the Fed State Using the TIM-1 System and Comparison With Luminal Data in Adults.

We evaluated the environment in TIM-1 luminal compartments using paracetamol and danazol solutions and suspensions and the fed state configuration. Data were compared with recently published data in healthy adults. TIM-1 experiments were performed with a 3-fold downscale. Volumes of secretions in gastric and duodenal compartments adequately reflected the luminal data in adults up to 3 h post drug dosing. pH values in duodenal and jejunal compartments adequately reflected average pH values in adults. In gastric compartment pH values where initially higher than average values in adults and reached baseline levels earlier than in adults. The environment in the TIM-1 gastric compartment and jejunal compartment adequately reflected the average total paracetamol and danazol amounts per volume of contents in the adult stomach and upper small intestine, respectively. Total bile acids concentrations in the micellar phase of contents in duodenal and jejunal compartments overestimated micellar concentrations in the upper small intestine of adults. Adjustments in gastric emptying/acid secretion rates and bile acids identities in the duodenal and jejunal compartments, and application of dynamic bile acids secretion rates are expected to further improve the relevance of luminal conditions in TIM-1 compartments with those in adults.

Evaluation of the bioaccessibility of a carotenoid beadlet blend using an in vitro system mimicking the upper gastrointestinal tract.

The release characteristics of a unique blend of carotenoid beadlets designed to increase bioavailability were tested using the dynamic gastrointestinal model TIM-1. Individual carotenoid bioaccessibility peaks were observed over approximately 3-4 hr in the order of lutein and zeaxanthin first, followed by lycopene, and then finally α- and ß-carotene; when tested as a beadlet blend or when the beadlets were compressed into tablets. Bioaccessibility measurements of 7%-20% were similar to those previously reported in literature and comparable between the two formulations, beadlet blend and tablet formulations. Total recovery of carotenoids from all compartments ranged from 70% to 90% for all carotenoids, except lycopene where almost 50% was unrecoverable after digestion in the TIM system.

Appetite ratings of foods are predictable with an in vitro advanced gastrointestinal model in combination with an in silico artificial neural network.

The expected increase of global obesity prevalence makes it necessary to have information about the effects of meal intakes on the feeling of appetite. Because human clinical studies are time and cost intensive, there is a need for a reliable alternative. The aim of this study was to develop and evaluate an in vitro-in silico technology to predict the feelings of fullness and hunger after consumption of different types of meals. In this technology the results from an in vitro gastrointestinal model (tiny-TIMagc) on gastric viscosity and intestinal digestion of different meals were used as input data for an in silico artificial neural network (ANN). The predictions of the feeling of fullness and hunger were compared with actual human scores for these parameters after intake of the same type of meals. From these first series of experiments, with a relatively small number of in vitro digestive parameters as input for in silico modeling, a reasonable prediction of appetite rating for foods can be realized at a time- and cost-effective way.

Subjective feelings of appetite of wholegrain breakfasts evaluated under controlled, laboratory and 'at home' conditions.

BACKGROUND: Appetite regulating properties of foods are usually investigated under laboratory conditions, whereas in real life, foods are consumed under at home conditions. The objective of this study was to compare the acute effects of breakfasts when tested in a laboratory condition and in an at home condition. Appetite regulating properties of two bread breakfasts and two cereal breakfasts were also compared. SUBJECTS AND METHODS: In this randomized cross-over trial balanced for laboratory and at home test conditions, thirty-two women consumed five breakfasts, i.e. two bread breakfasts, two cereal breakfasts and one fried-egg breakfast. Visual analogue scales for measuring appetite were captured via an on-line scoring system and were analyzed as incremental area under the curve, as satiation phase and as satiety phase. RESULTS: Location effects were limited to two small effects only. An overall location effect in hunger feelings was observed (p = 0.040), which occurred specifically during the short satiation period (p = 0.0002) where hunger feelings scored higher under laboratory conditions. Similarly, a location effect was observed for desire to eat (p = 0.001); this was again higher under laboratory conditions. No other location effects were observed. Bread breakfasts did not differ in their appetite regulating properties. The Steel Cut oatmeal breakfast was reported to be more satiating (p = 0.001) as compared to the ready-to-eat cereal. CONCLUSIONS: Whereas the five breakfasts varied somewhat in their appetite regulating properties, evaluation under laboratory conditions overall did not result in different appetite scores compared to the at home conditions. This suggests that at home testing may be a useful alternative to laboratory test conditions for nutrition research.

Dose-Dependent Prebiotic Effect of Lactulose in a Computer-Controlled In Vitro Model of the Human Large Intestine.

Lactulose, a disaccharide of galactose and fructose, used as a laxative or ammonia-lowering drug and as a functional food ingredient, enhances growth of Bifidobacterium and Lactobacillus at clinically relevant dosages. The prebiotic effect of subclinical dosages of Lactulose, however, remains to be elucidated. This study analyses changes in the microbiota and their metabolites after a 5 days Lactulose treatment using the TIM-2 system, a computer-controlled model of the proximal large intestine representing a complex, high density, metabolically active, anaerobic microbiota of human origin. Subclinical dosages of 2-5 g Lactulose were used. While 2 g Lactulose already increased the short-chain fatty acid levels of the intestinal content, 5 g Lactulose were required daily for 5 days in this study to exert the full beneficial prebiotic effect consisting of higher bacterial counts of Bifidobacterium, Lactobacillus, and Anaerostipes, a rise in acetate, butyrate and lactate, as well as a decrease in branched-chain fatty acids, pH (suggested by an increase in NaOH usage), and ammonia.

Herring roe protein has a high digestible indispensable amino acid score (DIAAS) using a dynamic in vitro gastrointestinal model.

It is hypothesized that the digestible indispensable amino acid score (DIAAS) can be determined based on dynamic in vitro gastrointestinal digestion experiments as replacement for invasive animal studies. We determined the in vitro DIAAS for immature herring eggs (roe) proteins in comparison with reference proteins. The true ileal digestibility of protein and indispensable amino acids (IAA) was measured under human conditions simulated in a gastrointestinal model (tiny-TIM). The in vitro true ileal digestibility of ovalbumin, cooked and raw chicken egg white, and casein was similar to that found in humans (r(2) = 0.96), providing a casual observation to support the validity of tiny-TIM. The digestibility of the immature herring egg proteins was 71% to 92%. The highest IAA digestibility was found for immature whole herring egg protein (55%-80%) in comparison to immature herring egg membrane and immature de-membraned herring protein (50%-70%). The DIAAS as recommended by FAO for children and adults, but measured in vitro, were 91% for immature whole herring egg protein (lysine first limiting), 71% for immature herring egg membrane protein (histidine first limiting), and 88% for immature herring egg de-membraned protein (sulfur AA first limiting). True ileal protein and amino acid digestibility can be determined in a dynamic gastrointestinal model, such as tiny-TIM, which can be used for estimating the DIAAS. Immature herring egg proteins, a previously underutilized resource, were determined to be an important and valuable source of IAA for human consumption.

Mammalian gastrointestinal tract parameters modulating the integrity, surface properties, and absorption of food-relevant nanomaterials.

Many natural chemicals in food are in the nanometer size range, and the selective uptake of nutrients with nanoscale dimensions by the gastrointestinal (GI) tract is a normal physiological process. Novel engineered nanomaterials (NMs) can bring various benefits to food, e.g., enhancing nutrition. Assessing potential risks requires an understanding of the stability of these entities in the GI lumen, and an understanding of whether or not they can be absorbed and thus become systemically available. Data are emerging on the mammalian in vivo absorption of engineered NMs composed of chemicals with a range of properties, including metal, mineral, biochemical macromolecules, and lipid-based entities. In vitro and in silico fluid incubation data has also provided some evidence of changes in particle stability, aggregation, and surface properties following interaction with luminal factors present in the GI tract. The variables include physical forces, osmotic concentration, pH, digestive enzymes, other food, and endogenous biochemicals, and commensal microbes. Further research is required to fill remaining data gaps on the effects of these parameters on NM integrity, physicochemical properties, and GI absorption. Knowledge of the most influential luminal parameters will be essential when developing models of the GI tract to quantify the percent absorption of food-relevant engineered NMs for risk assessment.