Gastric emptying rate and chyme characteristics for cooked brown and white rice meals in vivo

A review of the use of numerical analysis in stomach modeling

Food digestion is important for human health. Advances have been made using in vitro models to study food digestion, but there is considerable potential for numerical approaches in stomach modeling, as they can provide a comprehensive understanding of the complex flow and chemistry in the stomach. The focus of this study is to provide a concise review of the developed numerical stomach models over the past two decades. The gastric physiological parameters that are required for a computational model to represent the human gastric digestion process are discussed, including the stomach geometry, gastric motility, gastric emptying, and gastric secretions. Computational methods used to model gastric digestion are introduced and compared, including different computational fluid dynamics as well as solid mechanics methods. The challenges and limitations of current studies are discussed, as well as the areas for future research that need to be addressed. There has been progress in simulating gastric fluid flow with stomach wall motion, but much work remains to be done. The complex food breakdown mechanisms and a comprehensive chemical digestion process have not been implemented in any developed models. Numerical method that was once computationally expensive will be revolutionized as computing power continues to improve. Ultimately, the advancement of modeling of gastric food digestion will allow for additional hypothesis testing to streamline the development of food products that are beneficial to human health.

Particle size of insoluble fibres and gelation of soluble fibres influence digesta passage rate throughout the gastrointestinal tract of finishing pigs

Fibres, as abundant in agricultural by-products, exhibit a large range of physicochemical properties that can influence digestive processes such as digesta mean retention time (MRT), thereby affecting nutrient digestion kinetics. In this study, we investigated the effects of particle size of insoluble fibres, and gelation of soluble fibres on MRT of liquids, fine solids, and fibrous particles in the different segments of the gastrointestinal tract (GIT) of pigs. Twenty-four boars (51.6 ± 4.90 kg) were allocated to four diets; two diets contained 15% wheat straw, either coarsely chopped or finely ground (1-mm screen), two diets contained 27% wheat bran without or with the addition of 10% low-methylated pectin. After 14 days of adaptation to the diet, a total collection of faeces was performed to determine the total tract digestibility of nutrients. Thereafter, pigs were fed diets supplemented with tracers for at least 5 days and dissected following a frequent feeding procedure to approach steady-state passage of digesta. The MRT of liquids (Co-EDTA), fine solids (TiO2), and fibrous particles (Chromium-mordanted fibres) in the different segments of the GIT were quantified. In the stomach, particle size reduction of straw decreased the MRT of fine solids by 02:39 h, and fibrous particles by 07:21 h (P < 0.10). Pectin addition to the wheat bran diet reduced the MRT of fine solids by 03:09 h, and fibrous particles by 07:10 h (P < 0.10), but not of liquids, resulting in less separation between digesta phases in the stomach compared with the bran diet (P < 0.05). In the mid-small intestine (SI), pectin addition reduced the MRT of fibrous particles and the separation between fibrous particles and fine solids. No further effects of particle size reduction of straw nor pectin addition on MRT and digestibility of starch, nitrogen, or fat were observed in the SI. In the large intestine (LI), particle size reduction of straw reduced separation between fibrous particles and fine solids (P < 0.10), while pectin addition had no effects. Total tract, non-starch polysaccharide degradation of straw was poor (∼31%), and unaffected by particle size reduction (P > 0.10). The complete fermentation of pectin did not influence the degradation of wheat bran fibres (∼51%). In conclusion, the effects of particle size of insoluble fibres and gelling properties of soluble fibres on the passage of digesta phases were most pronounced in the stomach, but less prominent in distal segments of the GIT.

Dynamic Stomach Model-Capillary Electrophoresis-ICPMS for Evaluation of Release and Transformation Behaviors of Arsenic Species from Microplastics during Digestion

Microplastics (MPs) can act as carriers of environmental arsenic species into the stomach with food and release arsenic species during digestion, which threatens human health. Herein, an integrated dynamic stomach model (DSM)-capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICPMS) is developed for online monitoring of the release and transformation behaviors of arsenic species loaded on MPs (As-MPs) in the simulated human stomach. The 3D-printed DSM with a soft stomach chamber enables the behaviors of gastric peristalsis, gastric and salivary fluid addition, pH adjustment, and gastric emptying (GE) to be controlled by a self-written program after oral ingestion of food with As-MPs. The gastric extract during digestion is introduced into the spiral channel to remove the large particulate impurity and online filtered to obtain the clarified arsenic-containing solution for subsequent speciation analysis of arsenic by CE-ICPMS. The digestion conditions and pretreatment processes of DSM are tracked and validated, and the release rates of As-MPs digested by DSM are compared with those digested by the static stomach model and DSM without GE. The release rate of inorganic arsenic on MPs is higher than that of organic arsenic throughout the gastric digestion process, and 8% of As(V) is reduced to As(III). The detection limits for As(III), DMA, MMA, and As(V) are 0.5-0.9 μg L-1 using DSM-CE-ICPMS, along with precisions of ≤8%. This present method provides an integrated and convenient tool for evaluating the release and transformation of As-MPs during human gastric digestion and provides a reference for exploring the interactions between MPs and metals/metalloids in the human body.

Understanding the physical breakdown and catechin bioaccessibility of third generation extruded snacks enriched with catechin using the human gastric simulator

The nutritional quality of third-generation snacks prepared from rice flour by extrusion can be improved by the addition of polyphenols such as catechins, which are known to be more stable at high temperatures. However, the extrusion parameters can impact the breakdown and release of bioactive compounds and decrease the catechin bioaccessibility. Accordingly, this study investigated the impact of different extrusion parameters, including different extrusion temperatures (110, 135, and 150 °C) and moisture content prior to extrusion (27 and 31%), on the breakdown and bioaccessibility of catechin-enriched snacks during in vitro dynamic digestion using the Human Gastric Simulator (HGS). The extrusion parameters did not significantly impact most measured variables by themselves, indicating that within the tested ranges, any of the processing conditions could be used to produce a product with similar digestive behavior. However, the interaction of extrusion parameters (temperature and moisture content) played a significant role in the snack behavior during digestion. For example, the combination of 27% moisture content and 150 °C extrusion temperature had higher catechin bioaccessibility and higher starch hydrolysis than the other treatments. Overall, these findings suggest that the processing conditions of third generation snacks enriched with catechin can be optimized within certain ranges with limited modifications in the digestive properties.

Particle size and water content impact breakdown and starch digestibility of chickpea snacks during in vitro gastrointestinal digestion

Chickpeas are an agriculturally-important legume that are an excellent source of protein, fiber, and minerals. Developing chickpea-based snacks could provide consumers with snack products rich in protein and other nutrients. In this study, chickpea puree (high moisture content) and cracker (low moisture content) were each produced with large (7 mm sieve; coarse) or small (2 mm sieve; fine) particle size to investigate the impact of initial particle size and moisture content on particle breakdown, starch hydrolysis, and protein hydrolysis during in vitro digestion. All treatments underwent static in vitro oral digestion, dynamic gastric digestion in the Human Gastric Simulator (HGS), and static in vitro small intestinal digestion. The emptying rate from the HGS was significantly (p < 0.05) higher for fine puree compared to the other treatments, due to higher saturation ratio and smaller initial particle size. The reducing sugars and free amino groups released (representing starch and protein hydrolysis, respectively) from fine puree were higher than coarse puree, and fine cracker was higher than coarse cracker due to the influence of initial particle size. For example, after 360 min total in vitro digestion, the starch hydrolysis of the fine cracker (48.1 ± 3.2%) was significantly higher than (p < 0.05) the coarse cracker (36.3 ± 5.8%). Overall, crackers had higher protein and starch hydrolysis compared to puree in the liquid phase during digestion. The study showed that both the smaller initial particle size and drying significantly (p < 0.05) increased the particle size reduction during gastric digestion and starch and protein digestibility in chickpea-based snacks.

Comparison of four digestion protocols on the physical characteristics of gastric digesta from cooked couscous using the Human Gastric Simulator

In vitro digestion is widely employed in food, nutraceutical and pharmaceutical research, and numerous in vitro gastric digestion protocols have been proposed, with a wide range of experimental conditions. Differences in the simulated gastric fluids (pH, mineral content, enzyme type and enzyme activity) of different digestion protocols may alter the results for the digestion of the same meal. This study aimed to investigate how variations in the gastric secretion rate and composition in four in vitro digestion protocols (Infogest Riddet, Infogest Semi-dynamic, UC Davis and United States Pharmacopeia) impacted the physical properties of the emptied gastric digesta. Cooked couscous was used as a model meal and subjected to simulated gastric digestion using a dynamic gastric model, the Human Gastric Simulator (HGS). The digesta were collected from the outlet of the HGS after 15, 30, 60, 90, 120, 150, or 180 min. The gastric emptying of dry matter, pH, rheological properties, and particle size were evaluated. The digestion protocol significantly influenced the solid content and moisture content of the digesta (p < 0.001), particles per gram of dry matter (p < 0.0001), gastric emptying of dry matter (p < 0.003), shear stress at 0.45 s-1 and consistency coefficient (p < 0.0001). The presence of NaHCO3 in the Infogest Riddet and Infogest Semi-dynamic gastric secretions provided an additional buffering effect and increased the digesta pH during gastric digestion. Similarly, the inclusion of mucin in the UC Davis protocol resulted in a higher flow and viscoelastic properties of the emptied digesta. The highest dilution of gastric content in the United States Pharmacopeia (USP) protocol resulted in larger particles emptied from the HGS and the longest gastric emptying half-time of all digestion protocols. These findings provide new insights into the impact of digestion protocols on the digesta properties, which can be beneficial for the design and standardization of in vitro digestion models.

Insoluble fibers affect digesta transit behavior in the upper gastrointestinal tract of growing pigs, regardless of particle size

Physicochemical characteristics of dietary fibers may modulate digesta transit behavior. The present study was conducted to clarify the effect of level and particle size (PS) of insoluble fibers on digesta mean retention time (MRT) in the proximal gastrointestinal tract (mouth-ileocecal junction). Six ileal-cannulated pigs (26.8 ± 2.08 kg) were assigned to 3 dietary treatments in a 3 × 3 replicated Latin-square design. Finely ground (1 mm screen) or coarse (intact) oat husks (OH) and soybean hulls (SBH) were added (50:50, w/w) to a maize-whey protein-wheat-based diet at 50 (low) or 250 g/kg (high) inclusion levels to obtain a low-fine fiber (LF), high-fine fiber (HF), and high-coarse fiber (HC) diet. Markers to follow liquids (Co-EDTA), fine solids (Y3O2), or fibrous particles (Yb-mordanted OH and Cr-mordanted SBH) were given as a single pulse dose and marker concentrations were subsequently measured hourly in digesta for 13 h after administration. Mean retention time values were obtained from the concentration of markers in digesta observed over time by fitting a generalized Michaelis-Menten equation and calculating the time of peak. Fiber addition and fiber particle size neither affected the MRT of liquid nor solid digesta phases (P = 0.903). Segregation between solid and liquid digesta phases was observed for all diets (P < 0.0001), although the extent of segregation was greater for LF compared with HF and HC (P = 0.0220). The MRT of SBH particles, but not of OH-particles was longer for coarse vs fine PS (96 min, P < 0.05). In conclusion, digesta MRT was influenced by the dietary concentration but not by PS of insoluble fibers. The addition of insoluble fibers reduces digesta phase segregation from mouth to distal ileum in growing pigs.

Sodium caseinate enhances the effect of konjac flour on delaying gastric emptying based on a dynamic in vitro human stomach-IV (DIVHS-IV) system

BACKGROUND

In the context of the increasing prevalence of overweight and obesity worldwide, satiety-enhancing foods may help people control their energy intake and weight. In this study, an advanced near-real human gastric simulator equipped with a dynamic in vitro human stomach-IV (DIVHS-IV) system was used to determine the gastric digestion and gastric retention ratio of konjac flour (KF)/sodium caseinate (SC) mixtures with different ratios.

RESULTS

The apparent viscosity, viscoelastic properties, confocal laser scanning microscopy (CLSM) of the digested products were collected and analyzed to further study the effect of SC on the physical properties of KF during digestion. The results showed that the addition of SC could enhance the effect of KF on delaying gastric emptying in vitro. Besides, the addition of SC was shown to weaken the effect of gastric juice on the dilution of gastric contents by forming SC gel blocks in the acid environment. In particular, the synergistic gastric emptying delaying effect was the strongest in the KF/SC mixture containing 1% KF and 8% SC, and obvious massive aggregates were observed.

CONCLUSION

The combination of 1% KF and 8% SC was shown to synergistically delay gastric emptying and potentially enhance the sense of fullness. © 2022 Society of Chemical Industry.

Simulating human gastrointestinal motility in dynamic in vitro models

The application of dynamic in vitro gastrointestinal (GI) models has grown in popularity to understand the impact of food structure and composition on human health. Given that GI motility is integral to digestion and absorption, a predictive in vitro model should faithfully replicate the motility patterns and motor functions in vivo. In this review, typical characteristics of gastric and small intestinal motility in humans as well as the biomechanical and hydrodynamic events pertinent to gut motility are summarized. The simulation of GI motility in the presently existing dynamic in vitro models is discussed from an engineering perspective and categorized into hydraulic, piston/probe-driven, roller-driven, pneumatic, and other systems. Each system and its representative models are evaluated in terms of their motility patterns, the key hydrodynamic characteristics concerning gut motility, their performance in simulating the key physiological events, and their ability to establish in vitro-in vivo correlations. Practical Application: The review paper provided useful information in the design of dynamic GI models and the simulation of human gastric and small intestinal motility which are important for understanding food and health.

Effect of Apple Consumption on Postprandial Blood Glucose Levels in Normal Glucose Tolerance People versus Those with Impaired Glucose Tolerance

The present study investigated the effect of apple consumption on postprandial blood glucose and insulin levels in subjects with normal versus impaired glucose tolerance. The study participants were ten healthy subjects with no glucose intolerance (normal subjects) (mean, 24.4 ± 4.8 years) and nine subjects with impaired glucose tolerance (mean, 45.2 ± 11.1 years, including 2 on insulin therapy). The test meal included white rice (148 g) and a Fuji apple (150 g). The normal subjects were randomly divided into two groups: the apple-first group, wherein the subjects consumed white rice 5 min after consuming the apple, and the rice-first group, wherein the subjects consumed an apple 5 min after consuming the white rice. Blood samples were then taken from both groups for 3 h. In addition, the subjects with impaired glucose tolerance received the same treatment as the normal subjects, with the difference being glucose level monitoring according to the order in which the apples were consumed. In the normal subjects, the Cmax of Δblood glucose and Δinsulin levels were 54.0 ± 5.0 mg/dL and 61.9 ± 7.2 µU/dL versus 46.2 ± 5.9 mg/dL and 49.8 ± 8.5 µU/dL in the rice-first and apple-first groups, respectively. The incremental area under the curve (iAUC) of insulin tended to decrease in the apple-first group. In the impaired glucose tolerance subjects, the Cmax of Δblood glucose was 75.2 ± 7.2 mg/dL in the apple-first group compared to 90.0 ± 10.0 mg/dL in the rice-first group, which was a significant difference (p < 0.05). The iAUC of blood glucose was lower in the apple-first group. Eating an apple before a meal may be a simple and effective strategy for managing the glycaemic response in individuals with impaired glucose tolerance.

Starch and protein hydrolysis in cooked quinoa (Chenopodium quinoa Willd.) during static and dynamic in vitro oral and gastric digestion

Quinoa is a pseudocereal that has a favorable nutrient profile and may be a beneficial addition to the diet. To evaluate potential health-promoting properties of foods, it is important to understand the rate of macronutrient hydrolysis, which is commonly quantified through in vitro digestion studies. Additionally, limited information is available comparing starch and protein hydrolysis of solid foods using static and dynamic digestion models. The objective of this study was to examine starch and protein hydrolysis in cooked quinoa using a combination of a static (saliva only) or dynamic (saliva + mincing) oral digestion model with a static (gastric fluids only) or dynamic (Human Gastric Simulator) gastric digestion model. Disruption of the pericarp of the cooked quinoa seeds during dynamic oral digestion released additional surface area, which led to faster gastric emptying during dynamic gastric digestion. Starch and protein hydrolysis were impacted by type of gastric model due to differences in pH and variations in structural breakdown. Starch hydrolysis was 29.04 ± 1.83% after 180 min dynamic gastric digestion compared to 2.85 ± 1.88% during static gastric digestion (averaged across both oral digestion models). The degree of protein hydrolysis was 4.85 ± 0.01% after 180 min in the static gastric model compared to 3.94 ± 0.18% in the dynamic gastric model (averaged across both oral digestion models). This information provides evidence on the role of food structure and breakdown (through use of static vs. dynamic oral and gastric digestion models) on quinoa starch and protein hydrolysis.

In-vitro digestion models: a critical review for human and fish and a protocol for in-vitro digestion in fish

Digestive systems in human, animals, and fish are biological reactors and membranes to digest food and extract nutrients. Therefore, static and dynamic models of in-vitro digestion systems are developed to study e.g. novel food and feed before in-vivo studies. Such models are well developed for human, but not to the same extent for animals and fish. On the other hand, recent advances in aquaculture nutrition have created several potential fish meal replacements, and the assessment of their nutrient digestibility is critical in the application as a fish meal replacement. Using an in-vitro method, the assessment of an ingredient digestibility could be faster and less expensive compared to using an in-vivo experiment. An in-vitro method has been widely used to assess food nutrient digestibility for humans; however, its application for fish is still in the early stages. Both the human and fish as monogastric vertebrates share similar gastrointestinal systems; thus, the concept from the application for humans could be applied for fish. This review aims to improve the in-vitro digestion protocol for fish by adapting the concept from then study for humans, summarizing the current available in-vitro digestion model developed for human and fish in-vitro digestion study, identifying challenges specifically for fish required to be tackled and suggesting an engineering approach to adapt the human in-vitro gastrointestinal model to fish. Protocols to conduct in-vitro digestion study for fish are then proposed.

Integrated Analysis of Metabolome and Volatile Profiles of Germinated Brown Rice from the Japonica and Indica Subspecies

In the present study, germinated brown rice (GBR) from three Japonica and three Indica rice cultivars were subjected to metabolomics analysis and volatile profiling. The statistical assessment and pathway analysis of the metabolomics data demonstrated that in spite of significant metabolic changes in response to the germination treatment, the Japonica rice cultivars consistently expressed higher levels of several health-promoting compounds, such as essential amino acids and γ-aminobutyric acid (GABA), than the Indica cultivars. No clear discriminations of the volatile profiles were observed in light of the subspecies, and the concentrations of the volatile organic compounds (VOCs), including alkenes, aldehydes, furans, ketones, and alcohols, all exhibited significant reductions ranging from 26.8% to 64.1% after the germination. The results suggest that the Japonica cultivars might be desirable as the raw materials for generating and selecting GBR food products for health-conscious consumers.

Rice as an alternative feed ingredient in swine diets

It has become important to explore alternative feed ingredients to reduce feed costs, which are burdensome for livestock production. In addition, it is desirable to find efficient and functional alternative ingredients for traditional feed ingredients in pig diets, considering the stress and sensitivity of disease of pig. Rice is produced around the world like corn that is the typical energy source in pig diets. Although the nutritional quality varies depending on the degree of milling, rice, except whole grains (paddy rice), contains more starch than corn and its structure and granule size are easier to digest than corn. In addition, the fact that rice has fewer non-starch polysaccharides (NSP) and anti-nutritional factors (ANFs) is also effective in improving digestibility and various polyphenols in rice can help modulation of immune responses, which can be beneficial to the gastrointestinal environment and health of pig. Many studies have been conducted on rice focusing on things such as degree of milling, substitution rates of corn, granule size, and processing methods. Most results have shown that rice can be partially or completely used to replace corn in pig diets without negatively affecting pig growth and production. While further research should focus on the precise biological mechanisms at play, it was confirmed that the use of rice could reduce the use of antibiotics and pig removal and protect pigs from gastrointestinal diseases including diarrhea. From this point of view, rice can be evaluated as a valuable feed ingredient for swine diets.

Tracking physical breakdown of rice- and wheat-based foods with varying structures during gastric digestion and its influence on gastric emptying in a growing pig model

There is currently a limited understanding of the effect of food structure on physical breakdown and gastric emptying of solid starch-based foods during gastric digestion. Moisture uptake, pH, particle size, rheological, and textural properties of six solid starch-based diets from different sources (Durum wheat and high amylose white rice) and of different macrostructures (porridge, native grain, agglomerate/couscous, and noodle) were monitored during 240 min of gastric digestion in a growing pig model. Changes in the physical properties of the gastric digesta were attributed to the influence of gastric secretions and gastric emptying, which were both dependent on the buffering capacity and initial macrostructure of the diets. Differences between the proximal and distal stomach regions were found in the intragastric pH and texture of the gastric digesta. For example, rice couscous, which had the smallest particle size and highest buffering capacity among the rice-based diets, had the shortest gastric emptying half-time and no significant differences between proximal and distal stomach digesta physical properties. Additionally, a relationship between gastric breakdown rate, expressed as gastric softening half-time from texture analysis, and gastric emptying half-time of dry matter was also observed. These findings provide new insights into the breakdown processes of starch-based solid foods in the stomach, which can be beneficial for the development of food structures with controlled rates of breakdown and gastric emptying during digestion.

Structural breakdown of starch-based foods during gastric digestion and its link to glycemic response: In vivo and in vitro considerations

The digestion of starch-based foods in the small intestine as well as factors affecting their digestibility have been previously investigated and reviewed in detail. Starch digestibility has been studied both in vivo and in vitro, with increasing interest in the use of in vitro models. Although previous in vivo studies have indicated the effect of mastication and gastric digestion on the digestibility of solid starch-based foods, the physical breakdown of starch-based foods prior to small intestinal digestion is often less considered. Moreover, gastric digestion has received little attention in the attempt to understand the digestion of solid starch-based foods in the digestive tract. In this review, the physical breakdown of starch-based foods in the mouth and stomach, the quantification of these breakdown processes, and their links to physiological outcomes, such as gastric emptying and glycemic response, are discussed. In addition, the physical breakdown aspects related to gastric digestion that need to be considered when developing in vitro-in vivo correlation in starch digestion studies are discussed. The discussion demonstrates that physical breakdown prior to small intestinal digestion, especially during gastric digestion, should not be neglected in understanding the digestion of solid starch-based foods.

In vitro gastrointestinal digestion and fermentation models and their applications in food carbohydrates

Food nutrients plays a crucial role in human health, especially in gastrointestinal (GI) health. The effect of food nutrients on human health mainly depends on the digestion and fermentation process in the GI tract. In vitro GI digestion and fermentation models had the advantages of reproducibility, simplicity, universality, and could integrally simulate the in vivo conditions to mimic oral, gastric, small intestinal and large intestinal digestive processes. They could not only predict the relationship among material composition, structure and digestive characteristics, but also evaluate the bioavailability of material components and the impact of digestive metabolites on GI health. This review systematicly summarized the current state of the in vitro simulation models, and made detailed descriptions for their applications, advantages and disadvantages, and specially their applications in food carbohydrates. In addition, it also provided the suggestions for the improvement of in vitro models and firstly proposed to establish a set of standardized methods of in vitro dynamic digestion and fermentation conditions for food carbohydrates, which were in order to further evaluate more effects of the nutrients on human health in future.

Using Nutritional Strategies to Shape the Gastro-Intestinal Tracts of Suckling and Weaned Piglets

This is a comprehensive review on the use of nutritional strategies to shape the functioning of the gastro-intestinal tract in suckling and weaned piglets. The progressive development of a piglet's gut and the associated microbiota and immune system offers a unique window of opportunity for supporting gut health through dietary modulation. This is particularly relevant for large litters, for which sow colostrum and milk are insufficient. The authors have therefore proposed the use of supplemental milk and creep feed with a dual purpose. In addition to providing nutrients to piglets, supplemental milk can also serve as a gut modulator in early life by incorporating functional ingredients with potential long-term benefits. To prepare piglets for weaning, it is important to stimulate the intake of solid feed before weaning, in addition to stimulating the number of piglets eating. The use of functional ingredients in creep feed and a transition diet around the time of weaning helps to habituate piglets to solid feed in general, while also preparing the gut for the digestion and fermentation of specific ingredients. In the first days after weaning (i.e., the acute phase), it is important to maintain high levels of feed intake and focus on nutritional strategies that support good gastric (barrier) function and that avoid overloading the impaired digestion and fermentation capacity of the piglets. In the subsequent maturation phase, the ratio of lysine to energy can be increased gradually in order to stimulate piglet growth. This is because the digestive and fermentation capacity of the piglets is more mature at this stage, thus allowing the inclusion of more fermentable fibres. Taken together, the nutritional strategies addressed in this review provide a structured approach to preparing piglets for success during weaning and the period that follows. The implementation of this approach and the insights to be developed through future research can help to achieve some of the most important goals in pig production: reducing piglet mortality, morbidity and antimicrobial use.

Gastric emptying pattern and disintegration kinetics of cooked rice in a 3D printed in vitro dynamic digestion model ARK®

Understanding the gastric digestion process is essential for evaluating the bioaccessibility of nutrients from food matrices. The objective of this study was to investigate the kinetics of disintegration and gastric emptying patterns in a 3D printed stomach (ARK®) with white rice as the study sample. Modified power exponential model was used to fit the gastric retention data and the average t 1/2 and t lag values of the solid fractions were found to be 109.22 ± 4.20 and 84.16 ± 5.72 min, respectively. During the disintegration process, the weight percentage of medium size particles (∼0.35 mm) was found to be higher at 30 and 60 min. Moreover, there was a sharp decrease in the percentage of fine particles (<0.125 mm) at 90 and 120 min. The ARK® could effectively mimic the physiochemical process of the human stomach, providing promising insights for future studies on the development of novel and functional food products.

Breakdown mechanisms of whey protein gels during dynamic in vitro gastric digestion

Particle geometry influenced the breakdown mechanisms impacting the pH, pepsin activity, and protein hydrolysis of whey protein gels during dynamic in vitro gastric digestion.

Effects of endogenous proteins on rice digestion during small intestine (in vitro) digestion

Rices with higher protein contents are nutritionally desirable. This study investigates the effects of endosperm proteins on starch in vitro digestibility in cooked and uncooked rice, and the mechanisms underlying any changes. The composition of rice endosperm proteins and the morphologies of proteins and starch granules were determined by SDS-PAGE and confocal microscopy. Starch molecular fine structure was examined using size-exclusion chromatography. In vitro digestion showed that the digestion rate coefficients (k) of cooked rice flour were significantly lower than those of isolated starch or of a starch-protein mixture. (e.g for samples from SWR4, k is 9.6, 12.9 and 11.6 × 10^-2 min^-1 for cooked rice flour, isolated starch and starch-protein mixture, respectively). For uncooked samples, digestion rate coefficients were 1.4, 1.5 and 1.8 × 10^-2 min^-1 for flour, starch-protein mixture and starch, respectively. The digestion rates in cooked samples were higher than those in uncooked samples. This suggests that, in cooked samples, starch digestion rates are more affected by the protein physical barrier than by some chemical effect (e.g. hydrogen bonding between protein and starch), while in uncooked samples, a chemical effect from protein is more pronounced than a physical barrier from protein.

In vitro gastric emptying characteristics of konjac glucomannan with different viscosity and its effects on appetite regulation

Konjac glucomannan (KGM) is associated with the satiety-enhancing property by imparting the food matrix with high viscosity. In the present study, rheology tests on KGM sol with different viscosities were conducted to understand its flow behavior as they presented in the mouth and stomach, and the in vitro gastric emptying characteristics of KGM were examined with a human gastric simulator. Then, their effects on subjective appetite, glycemia, and appetite-related hormones (insulin, GLP-1, PYY3-36, CCK-8, ghrelin) response were investigated by conducting a randomized, single-blind, crossover trial in 22 healthy adults (11 female and 11 male, mean age (years): 23.2 ± 2.0, BMI (kg m-2): 20.6 ± 2.1). The blood samples and ratings for subjective appetite were collected at regular time intervals after the subjects were fed with four test breakfasts (one control treatment and three experimental treatments) on four different days. An ad libitum lunch was provided to the subjects once they consumed the breakfasts and their food intake was recorded. As the viscosity increased, the gastric emptying rate was delayed despite a large part of the chyme viscosity lost during digestion. The satiating capacity of the test breakfast was significantly enhanced as its viscosity increased, the and subjects' sensation for hunger, fullness, desire-to-eat, and prospective food consumption differed significantly (p = 0.006, 0.000, 0.002, and 0.001, respectively) between the treatments. The secretion of glycemia and satiety-related hormones were beneficially modulated by the increased viscosity of the test meal but a small decrease in the ad libitum food intake was observed after the intervention of the viscous test breakfasts. Overall, elevating the meal viscosity moderately by using KGM could contribute to combating the challenge of hunger for people in the bodyweight management.

Pearl millet (Pennisetum glaucum) couscous breaks down faster than wheat couscous in the Human Gastric Simulator, though has slower starch hydrolysis

Pearl millet couscous broke down into smaller, more numerous particles that had slower starch hydrolysis compared to wheat couscous.

Effects of convective drying and freeze-drying on the release of bioactive compounds from beetroot during in vitro gastric digestion

Drying may alter the microstructure of vegetables and influence the release of bioactive compounds during digestion.

An advanced near real dynamicin vitrohuman stomach system to study gastric digestion and emptying of beef stew and cooked rice

A near real dynamicin vitrohuman stomach (new DIVHS) system has recently been advanced in this study, based on the previous rope-drivenin vitrohuman stomach model (RD-IV-HSM).

Buffering capacity of protein-based model food systems in the context of gastric digestion

A standardized method to measure and quantify buffering capacity in the context of gastric digestion is proposed and the impact of protein content and surface area on buffering capacity was observed.

Traditional Malian Solid Foods Made from Sorghum and Millet Have Markedly Slower Gastric Emptying than Rice, Potato, or Pasta

From anecdotal evidence that traditional African sorghum and millet foods are filling and provide sustained energy, we hypothesized that gastric emptying rates of sorghum and millet foods are slow, particularly compared to non-traditional starchy foods (white rice, potato, wheat pasta). A human trial to study gastric emptying of staple foods eaten in Bamako, Mali was conducted using a carbon-13 (¹³C)-labelled octanoic acid breath test for gastric emptying, and subjective pre-test and satiety response questionnaires. Fourteen healthy volunteers in Bamako participated in a crossover design to test eight starchy staples. A second validation study was done one year later in Bamako with six volunteers to correct for endogenous ¹³C differences in the starches from different sources. In both trials, traditional sorghum and millet foods (thick porridges and millet couscous) had gastric half-emptying times about twice as long as rice, potato, or pasta (p < 0.0001). There were only minor changes due to the ¹³C correction. Pre-test assessment of millet couscous and rice ranked them as more filling and aligned well with postprandial hunger rankings, suggesting that a preconceived idea of rice being highly satiating may have influenced subjective satiety scoring. Traditional African sorghum and millet foods, whether viscous in the form of a thick porridge or as non-viscous couscous, had distinctly slow gastric emptying, in contrast to the faster emptying of non-traditional starchy foods, which are popular among West African urban consumers.

In vitro gastric digestion of cooked white and brown rice using a dynamic rat stomach model

The changes in physical, rheological and enzyme-digestive behaviours of cooked white and brown rice, with similar amylose content, were investigated using a dynamic in vitro rat stomach (DIVRS) model and a static soaking method. The brown rice had a higher resistance on disintegration and lower gastric emptying rate with 53% of the brown rice particles retained in the stomach at the end compared to 32% for the white rice. Furthermore, the release rate of maltose from the starch hydrolysis was higher in the white rice throughout the digestion suggesting the lower glycemic potency of the brown rice. These differences could be contributed from the rigid bran layer in the brown rice which would inhibit the moisture absorption into rice kernels, limit textural degradation, and generate higher gastric digesta viscosity leading to lower mixing and mass transfer efficiency. This study suggests that the structural difference could affect physiochemical properties during gastric digestion.

Effects of freezing, freeze drying and convective drying on in vitro gastric digestion of apples

The influence of processing (freezing at -196°C in liquid N2, FN sample; freeze-drying at -50°C and 30Pa, FD sample; and convective drying at 60°C and 2m/s, CD sample) on apple (var. Granny Smith) behavior during in vitro gastric digestion was investigated. Dried apples (FD and CD samples) were rehydrated prior to digestion. Changes in carbohydrate composition, moisture, soluble solids, acidity, total polyphenol content (TPC), and antioxidant activity (AA) of apple samples were measured at different times during digestion. Processing resulted in disruption of the cellular structure during digestion, as observed by scanning electron microscopy, light microscopy, and changes in carbohydrate composition. Moisture content increased (6-11% dmo), while soluble solids (55-78% dmo), acidity (44-72% dmo), total polyphenol content (30-61% dmo), and antioxidant activity (41-87%) decreased in all samples after digestion. Mathematical models (Weibull and exponential models) were used to better evaluate the influence of processing on apple behavior during gastric digestion.