Water solubility differentiates the impact of tea polyphenols and rutin on the postprandial glycemic response to cooked maize starch.

Postprandial hyperglycemia is an independent risk factor for cardiovascular diseases, and the impact of tea polyphenols (TP) and rutin, representative phenolic compounds with different water solubilities, on the postprandial glycemic response to cooked normal corn starch (CCS) was investigated. Comparatively, TP (DPPH50 = 0.12 mmol L-1) are more potent than rutin (DPPH50 = 0.50 mmol L-1) in scavenging the free radicals of DPPH, but both TP and rutin inhibited the activity of porcine pancreatic α-amylase (PPA), the major enzyme in starch digestion, with an IC50 of 4.09 mmol L-1 and 2.71 mmol L-1, respectively. However, an in vivo study showed that a significant reduction in postprandial blood glucose was only observed in the presence of rutin, and TP had no effect on the glycemic response to CCS. To find out the underlying mechanism, fluorescence spectroscopy and molecular docking were carried out and they showed that, compared to TP, rutin bound to the active site of PPA with higher affinity and a lower free energy (ΔG) driven by hydrogen bonds and π-stacking, and rutin also greatly increased the viscosity of starch. Collectively, water-soluble TP have a higher antioxidant property and a lower potency to inhibit PPA compared to water-insoluble rutin, and the weaker interaction between TP and PPA, and starch as well might synergistically contribute to TP's ineffectiveness in lowering the postprandial glycemic response, and water solubility linking the molecular structures and functions of phenolic compounds might be the fundamental basis for the observed difference in their biological functions, and water solubility can also be used to enrich specific phenolic compounds for desired functions.

The interaction between tea polyphenols and wheat gluten in dough formation and bread making.

The effect of tea polyphenols (TPL) on the gluten network structure in TPL-fortified bread and dough systems was investigated. In the bread system, the addition of tea polyphenols (TPL) dose-dependently (0, 0.5, 1.0, 1.5, and 2%) deteriorated the bread quality in terms of the loaf volume, hardness and sensory properties. In the gluten dough system (2% TPL), farinograph results showed that the stability and development time of the bread dough were decreased, resulting in a weak dough with a significantly increased elastic modulus (G'). The disulfide bonds, key to the dough network formation, were decreased by 9.9 µmol g-1 (24.2%), and their stability was also reduced due to the reduction (15.0%) of the relative content of the gauche-gauche-gauche structure. The addition of tea polyphenols also increased the internal hydrogen bonds and hydrophobic forces along with the increased random coil and decreased α-helix secondary structure of gluten. The water distribution experiment showed that the bound water peak in the nuclear magnetic resonance (NMR) spectrum disappeared, but the adsorbed water and free water were increased by 17.3% and 0.4%, respectively. Collectively, the interaction between wheat gluten and tea polyphenols affects the water-gluten relationship and the protein structure, which leads to a disrupted network structure of the wheat dough and deteriorated bread quality. Strategies to prevent gluten-phenolic interaction in functional bread preparation warrant further investigation.

Torularhodin Alleviates Hepatic Dyslipidemia and Inflammations in High-Fat Diet-Induced Obese Mice via PPARα Signaling Pathway.

Torularhodin is a ß-carotene-like compound from Sporidiobolus pararoseus, and its protective effect against high-fat diet (HFD)-induced hepatic dyslipidemia and inflammation was investigated. Compared to mice of C57BL/6J fed on HFD, the addition of Torularhodin into the HFD (HFD-T) significantly reduced body weight, serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and the inflammatory mediators of TNF-α, IL-6, IL-1ß, and lipopolysaccharide (LPS). A significant increase of high-density lipoprotein cholesterol (HDL-c), which is beneficial to cholesterol clearance, was also observed in HFD-T group. Proteomic analysis showed HDL-C-c is highly correlated with proteins (e.g., CPT1A and CYP7A1) involved in lipid ß-oxidation and bile acid synthesis, whereas the other phenotypic parameters (TC, TG, LDL, and inflammatory cytokines) are highly associated with proteins (e.g., SLC27A4) involved in lipid-uptake. The up-regulated anti-inflammation proteins FAS, BAX, ICAM1, OCLN, GSTP1, FAF1, LRP1, APEX1, ROCK1, MANF, STAT3, and INSR and down-regulated pro-inflammatory proteins OPTN, PTK2B, FADD, MIF, CASP3, YAP1, DNM1L, and NAMPT not only demonstrate the occurrence of HFD-induced hepatic inflammation, but also prove the anti-inflammatory property of Torularhodin. KEGG signaling pathway analysis revealed that the PPARα signaling pathway is likely fundamental to the health function of Torularhodin through up-regulating genes related to fatty acid ß-oxidation, cholesterol excretion, HDL-Cc formation, and anti-inflammation. Torularhodin, as a new food resource, may act as a therapeutic agent to prevent hepatic dyslipidemia and related inflammation for improved health.

Influence of Hofmeister anions on structural and thermal properties of a starch-protein-lipid nanoparticle.

A self-assembled soluble nanoparticle, composed of common food biopolymers (carbohydrate, protein) and lipid, was previously reported by our laboratory. Although carrying capacity of valuable small molecules was demonstrated, physical functional properties are also important. Given the stabilization or destabilization characteristics of Hofmeister anion on macromolecular structures, mainly on proteins, here, we investigated the effects of different sodium salts composed of different Hofmeister anions on the structural and thermal properties of these self-assembled nanoparticles for improved functionalities. The salts were added into the mixture that was prepared in a diluted system during nanoparticle formation. Increased concentration of kosmotropic anions, in contrast to the chaotropic anion tested, resulted in nanoparticles with higher molar mass, hydrodynamic radius, and molecular density with more compact arrangement. The nanoparticles produced in presence of kosmotropic anions dissociated at higher temperatures and required higher enthalpies compared to the control sample. Spherical nanoparticles were formed for the kosmotropes with shear thinning behavior, contrary to rod-like nanoparticles for the chaotrope with near-Newtonian behavior. These findings help to gain an understanding of the effect of altering environmental conditions on the nanoparticles with an aim of producing desired structures for applications.

The impact of the physical form of torularhodin on its metabolic fate in the gastrointestinal tract.

Torularhodin is a fungal carotenoid with multiple health benefits. However, the relationship between its physical form and metabolic fate in the gastrointestinal tract (GIT), which is essential to its bioavailability and health efficacy, has rarely been studied. Thus, physical forms of torularhodin including nanoemulsion powder (T-EP), capsules of the T-EP by alginate (T-EPA), and solution in MCT oil (T-oil) were used in the study. T-EP was produced through OSA-starch-mediated torularhodin emulsification and spray drying whereas the T-EPA was alginate-based capsules of the T-EP particles that were entrapped in the network structure of the alginate matrix as observed by scanning electron microscopy (SEM). The oil digestibility in the simulated small intestine was decreased from T-EP (100%), T-oil (60%) to T-EPA (40%), and the bioaccessibilities were 27%, 15% and 12%, respectively. The in vivo study using mice revealed that the content of torularhodin gradually decreased along with the digestion time in both the stomach and small intestine while a significantly higher colonic accumulation was observed in T-EPA compared to T-oil and T-EP. In vitro fecal fermentation showed that propionate (32 mM) was the predominant metabolite produced by torularhodin in the physical form of T-EPA. Thus, the physical form of torularhodin is a significant contributing factor to its GIT metabolic fate, and a health outcome-oriented design of the physical form of torularhodin or other nutraceuticals is beneficial for the development of functional foods with enhanced health benefits.

Slow digestion-oriented dietary strategy to sustain the secretion of GLP-1 for improved glucose homeostasis.

Dysregulated glucose metabolism is associated with many chronic diseases such as obesity and type 2 diabetes mellitus (T2DM), and strategies to restore and maintain glucose homeostasis are essential to health. The incretin hormone of glucagon-like peptide-1 (GLP-1) is known to play a critical role in regulating glucose homeostasis and dietary nutrients are the primary stimuli to the release of intestinal GLP-1. However, the GLP-1 producing enteroendocrine L-cells are mainly distributed in the distal region of the gastrointestinal tract where there are almost no nutrients to stimulate the secretion of GLP-1 under normal situations. Thus, a dietary strategy to sustain the release of GLP-1 was proposed, and the slow digestion property and dipeptidyl peptidase IV (DPP-IV) inhibitory activity of food components, approaches to reduce the rate of food digestion, and mechanisms to sustain the release of GLP-1 were reviewed. A slow digestion-oriented dietary approach through encapsulation of nutrients, incorporation of viscous dietary fibers, and enzyme inhibitors of phytochemicals in a designed whole food matrix will be implemented to efficiently reduce the digestion rate of food nutrients, potentiate their distal deposition and a sustained secretion of GLP-1, which will be beneficial to improved glucose homeostasis and health.

The preparation of modified nano-starch and its application in food industry.

Starch, which is a carbohydrate polymer with a semicrystalline granular structure, has been the subject of academic research for decades due to its renewable and biodegradable property as well as various applications in food, pharmaceutical and other industries. Nano-starch (NS) is a novel type of starch material with unique physiochemical properties due to its small size. However, the nano-size nature of NS determines its tendency to agglomeration as a natural process to approach a thermodynamically steady state, and the single hydroxyl functional group is also not favorable to its applications in hydrophobic environments. Thus, modified-NS with improved dispersion property, hydrophobicity, and stability is emerging as a new research direction. However, information about modified-NS is sporadic in literature, and a systematic review from its preparation, application, the problem and challenge as well as related health concerns is carried out to further the understanding of modified-NS. It is expected that the theoretical basis and new insight into the development of modified-NS will be improved.

Cross-linked arabinoxylan in a Ca2+-alginate matrix reversed the body weight gain of HFD-fed C57BL/6J mice through modulation of the gut microbiome.

Here, we compared the effects of different physical forms of arabinoxylan (AX) - a microsphere of cross-linked arabinoxylan (CAX) in a Ca2+-alginate matrix (MC) and physical mixture of AX and alginate (PM) on gut microbiota and development of obesity in C57BL/6J mice. Supplementation of MC in high fat (HF) diet to mice for 10 weeks significantly reversed the body weight gain induced by the HF diet, along with less fat accumulation in both livers and the epididymal adipose than the PM group. Microbiome analysis showed that MC significantly altered the gut microbiota composition with a noticeable increase of butyrogenic bacteria of Lachnospiraceae. The butyrate produced by MC fermentation and the increased abundance of Lachnospiraceae might be the underlying mechanism of the anti-obesity effect of MC. The results indicated that the physical forms of dietary fiber are closely associated with its health benefits, and MC might be served as a new functional food ingredient to prevent obesity.

A proteomic study on the protective effect of kaempferol pretreatment against deoxynivalenol-induced intestinal barrier dysfunction in a Caco-2 cell model.

Deoxynivalenol (DON) is one of the most widely distributed mycotoxins in the food chain, and the protective effect of kaempferol (KAM) pretreatment against the barrier dysfunction induced by DON in a Caco-2 cell model was investigated using a proteomic approach. The results showed that after KAM pretreatment, both the numbers of down- and up-regulated differentially expressed proteins were significantly lower than those in the DON group. Gene ontology analysis revealed that differentially expressed proteins were enriched in cell adhesion molecule binding, cell junction, and cell junction assembly. Further study demonstrated that KAM pretreatment affected the expression and assembly of tight junction and adherens junction proteins through the PKA pathway and MAPK/ERK pathway to improve the barrier integrity of the Caco-2 cell monolayer, and nutraceutical approach based on bioactive phytochemicals to improve the body's immunity might be an effective strategy to combat the adverse effects of mycotoxins on intestinal barrier function.

Carbohydrates designed with different digestion rates modulate gastric emptying response in rats.

We sought to determine whether design of carbohydrate-based microspheres to have different digestion rates, while retaining the same material properties, could modulate gastric emptying through the ileal brake. Microspheres made to have three slow digestion rates and a rapidly digested starch analogue (maltodextrin) were administrated to rats by gavage and starch contents in the stomach, proximal and distal small intestine, and caecum were measured 2 h post-gavage. A stepwise increase in the amount of starch retained in the stomach was found for microspheres with incrementally slower rates of digestion. Postprandial glycaemic and insulinaemic responses were incrementally lower for the different microspheres than for the rapidly digestible control. A second-meal effect was observed for slowly digestible starch (SDS) microspheres compared to glucose. Thus, dietary slowly digestible carbohydrates were designed to elicit incremental significant changes in gastric emptying, glycaemic and insulinaemic responses, and they may be a means to trigger the ileal brake.

Starch and ß-glucan in a whole-grain-like structural form improve hepatic insulin sensitivity in diet-induced obese mice.

Whole-grain food (WGF) is well known for its anti-diabetic effect, and alleviation of obesity-induced insulin resistance (IR) might be one of the underlying mechanisms. In the current study, the effects of starch, as the main component in WGF, and ß-glucan in a whole-grain-like structural form (WGLSF) on hepatic IR and glucose homeostasis were investigated using high-fat (HF)-induced obese C57BL/6J mice. After treatment for 8 weeks, the body weight gain and IR of the mice were significantly reduced. The hepatic Akt, the key component in insulin signaling, was activated, and the hepatic expression and protein levels of glucose-6-phosphatase (G-6-P) and phosphoenolpyruvate carboxykinase (PEPCK) were reduced. Moreover, WGLSF effectively reduced the hepatic levels of free fatty acids and the pro-inflammatory cytokines TNF-α, IL-6, and NF-κB. Additionally, the reduced level of the phosphorylated c-Jun-N-terminal kinases (JNK) indicated that WGLSF treatment might inactivate the JNK signaling, leading to improved hepatic IR. These results demonstrated that starch and ß-glucan in a whole grain-like structural form have the potential as a dietary strategy to combat obesity-induced hepatic IR for improved health.

Impact of deoxynivalenol and kaempferol on expression of tight junction proteins at different stages of Caco-2 cell proliferation and differentiation.

The barrier function of intestinal tract is essential to gut health, and the expression of tight junction (TJ) proteins in human epithelial colorectal adenocarcinoma (Caco-2) cells, mimicking the intestinal stem cell proliferation and differentiation, was investigated after treatment by the mycotoxin of deoxynivalenol (DON) and phenolic compound of kaempferol (KAM). The results showed that DON (5 µM) significantly reduced the expression of claudin-4 while kaempferol (100 µM) increased the expression of claudin-3 during Caco-2 cell proliferation. After being cultured for 11 days, the DON treatment, unexpectedly, augmented the expression of claudin-4 with an increased TEER. For differentiated Caco-2 cells after a 21 day culture, both the TEER and claudin-4 levels were significantly reduced by DON while KAM pretreatment alleviated the damage caused by DON accompanying an increase of TEER, claudin-3, and ZO-1. Thus, kaempferol and DON differentially affected the expression of tight junction proteins at different stages of Caco-2 cell proliferation and differentiation, and an increase of the integrity of TJ after KAM pretreatment indicates KAM has the potential to protect the integrity of the barrier function of the intestinal epithelium for improved health.

The anti-obesity effect of starch in a whole grain-like structural form.

Obesity is a risk factor for many chronic diseases, and the anti-obesity effect of starch in a whole grain-like structural form (WGLSF) prepared through co-gelation with oat ß-glucan and alginate was studied using high-fat (HF) induced obese male C57BL/6J mice. In vitro human fecal fermentation of WGLSF-starch showed a slower rate of fermentation and a higher production of butyric acid (132.0 µmol per 50 mg sample) when compared to the physical mixture counterpart of starch, ß-glucan, and alginate (PM) (110.5 µmol per 50 mg) or ß-glucan itself (96.2 µmol per 50 mg). The body weight gain of obese mice fed with a HF-WGLSF diet was significantly reduced (42.0% lower than the HF group, 30.2% lower than the physical mixture) with decreased cell size in white adipose tissue and similar levels of serum lipid profiles to the control of the low-fat (LF) group. Western blotting experiments showed the down-regulated lipogenic transcription factor of SREBP-1c and fatty acid synthase (FAS), but the lipid-oxidation related transcription factors of peroxisome proliferator-activated receptor-α (PPAR-α) and phosphorylated AMP-activated protein kinase (p-AMPK) were up-regulated. Energy metabolism analysis revealed increased lipid-sourced energy expenditure with higher heat production and respiratory exchange ratios. Consistently, the expression of hypothalamic pro-opiomelanocortin (POMC), favoring energy expenditure, was increased significantly while the neuropeptide Y (NPY) was reduced. Thus, the increased energy expenditure stimulated by starch in a whole-grain-like structural form is responsible for the reduced body weight gain of obese mice fed with a high fat-based diet.

Dietary Slowly Digestible Starch Triggers the Gut-Brain Axis in Obese Rats with Accompanied Reduced Food Intake.

SCOPE: Slowly digestible starch (SDS), as a functional carbohydrate providing a slow and sustained glucose release, may be able to modulate food intake through activation of the gut-brain axis. METHODS AND RESULTS: Diet-induced obese rats were used to test the effect on feeding behavior of high-fat (HF) diets containing an SDS, fabricated to digest into the ileum, as compared to rapidly digestible starch (RDS). Ingestion of the HF-SDS diet over an 11-week period reduced daily food intake, through smaller meal size, to the same level as a lean body control group, while the group consuming the HF-RDS diet remained at a high food intake. Expression levels (mRNA) of the hypothalamic orexigenic neuropeptide Y (NPY) and Agouti-related peptide (AgRP) were significantly reduced, and the anorexigenic corticotropin-releasing hormone (CRH) was increased, in the HF-SDS fed group compared to the HF-RDS group, and to the level of the lean control group. CONCLUSION: SDS with digestion into the ileum reduced daily food intake and paralleled suppressed expression of appetite-stimulating neuropeptide genes associated with the gut-brain axis. This novel finding suggests further exploration involving a clinical study and potential development of SDS-based functional foods as an approach to obesity control.

The nutritional property of endosperm starch and its contribution to the health benefits of whole grain foods.

Purported health benefits of whole grain foods in lowering risk of obesity, type 2 diabetes, cardiovascular disease, and cancer are supported by epidemiological studies and scientific researches. Bioactive components including dietary fibers, phytochemicals, and various micronutrients present in the bran and germ are commonly considered as the basis for such benefits. Endosperm starch, as the major constituent of whole grains providing glucose to the body, has been less investigated regarding its nutritional property and contribution to the value of whole grain foods. Nutritional quality of starch is associated with its rate of digestion and glucose absorption. In whole grain foods, starch digestion and glucose delivery may vary depending on the form in which the food is delivered, some with starch being rapidly and others slowly digested. Furthermore, there are other inherent factors in whole grain products, such as phenolic compounds and dietary fibers, that may moderate glycemic profiles. A good understanding of the nutritional properties of whole grain starch is important to the development of food processing technologies to maximize their health benefits.

The protective effect of resveratrol against cytotoxicity induced by mycotoxin, zearalenone.

Zearalenone (ZEA), a non-steroidal estrogenic mycotoxin, is widely present in cereals and agricultural products. The literature reports suggest that oxidative damage seems to be a key determinant of ZEA-induced toxicity, and the protective effect of resveratrol (RSV), an antioxidant phenolic compound, on ZEA-induced cytotoxicity to HEK293 cells was investigated. The experimental results showed that ZEA decreased cell viability in a dose dependent manner with an IC50 value of 80 µM, and induced an increase in intracellular reactive oxygen species (ROS) in HEK293 cells. A remarkable elevation of MDA and decreased activity of manganese superoxide dismutase (MnSOD) were also observed. A decrease in mitochondrial membrane potential (MMP), cell cycle arrest at the G0/G1 phase, and increased cell apoptosis indicate a mitochondria-mediated apoptosis. RSV (2 µM) pretreatment not only recovered the activity of MnSOD, but also improved ZEA-induced cytotoxicity evidenced by increased MMP and cell viability, and decreased ROS. Furthermore, RSV pretreatment substantially upregulated the expression of the SIRT1 gene by 6.8 fold, reduced the acetylation level of the forkhead transcription factor FOXO3a, and decreased the expression ratio of Bax/Bcl-2. All these results demonstrated that RSV exhibited significant protective effects on ZEA-induced cell damage, and this effect may be attributed to the upregulation of SIRT1 and activation of FOXO3a-mediated pathways to enhance the resistance of cells to oxidative stress induced by ZEA exposure.

Fluorescent magnetic bead-based mast cell biosensor for electrochemical detection of allergens in foodstuffs.

In this study, a novel electrochemical rat basophilic leukemia cell (RBL-2H3) cell sensor, based on fluorescent magnetic beads, has been developed for the detection and evaluation of different allergens in foodstuffs. Fluorescein isothiocyanate (FITC) was successfully fused inside the SiO2 layer of SiO2 shell-coated Fe3O4 nanoparticles, which was superior to the traditional Fe3O4@SiO2@FITC modification process. The as-synthesized fluorescent magnetic beads were then encapsulated with lipidosome to form cationic magnetic fluorescent nanoparticles (CMFNPs) for mast cell magnetofection. The CMFNPs were then characterized by SEM, TEM, VSM, FTIR, and XRD analyses, and transfected into RBL-2H3 cells through a highly efficient, lipid-mediated magnetofection procedure. Magnetic glassy carbon electrode (MGCE), which possesses excellent reproducibility and regeneration qualities, was then employed to adsorb the CMFNP-transfected RBL-2H3 cells activated by an allergen antigen for electrochemical assay. Results show that the exposure of model antigen-dinitrophenol-bovine serum albumin (DNP-BSA) to anti-DNP IgE-sensitized mast cells induced a robust and long-lasting electrochemical impedance signal in a dose-dependent manner. The detection limit was identified at 3.3×10(-4) ng/mL. To demonstrate the utility of this mast cell-based biosensor for detection of real allergens in foodstuffs, Anti-Pen a1 IgE and Anti-PV IgE-activated cells were employed to quantify both shrimp allergen tropomyosin (Pen a 1) and fish allergen parvalbumin (PV). Results show high detection accuracy for these targets, with a limit of 0.03 µg/mL (shrimp Pen a 1) and 0.16 ng/mL (fish PV), respectively. To this effect, we conclude the proposed method is a facile, highly sensitive, innovative electrochemical method for the evaluation of food allergens.

Self-assembled nanoparticle of common food constituents that carries a sparingly soluble small molecule.

A previously reported nanoparticle formed through the self-assembly of common food constituents (amylose, protein, and fatty acids) was shown to have the capacity to carry a sparingly soluble small molecule (1-naphthol) in a dispersed system. Potentiometric titration showed that 1-naphthol locates in the lumen of the amylose helix of the nanoparticle. This finding was further supported by calorimetric measurements, showing higher enthalpies of dissociation and reassociation in the presence of 1-naphthol. Visually, the 1-naphthol-loaded nanoparticle appeared to be well-dispersed in aqueous solution. Molecular dynamics simulation showed that the self-assembly was favorable, and at 500 ns, the 1-naphthol molecule resided in the helix of the amylose lumen in proximity to the hydrophobic tail of the fatty acid. Thus, sparingly soluble small molecules, such as some nutraceuticals or drugs, could be incorporated and delivered by this soft nanoparticle carrier.

Slow digestion property of octenyl succinic anhydride modified waxy maize starch in the presence of tea polyphenols.

The in vivo slow digestion property of octenyl succinic anhydride modified waxy corn starch (OSA-starch) in the presence of tea polyphenols (TPLs) was studied. Using a mouse model, the experimental results showed an extended and moderate postprandial glycemic response with a delayed and significantly decreased blood glucose peak of OSA-starch after cocooking with TPLs (5% starch weight base). Further studies revealed an increased hydrodynamic radius of OSA-starch molecules indicating an interaction between OSA-starch and TPLs. Additionally, decreased gelatinization temperature and enthalpy and reduced viscosity and emulsifiability of OSA-starch support their possible complexation to form a spherical OSA-starch-TPLs (OSAT) complex. The moderate and extended postprandial glycemic response is likely caused by decreased activity of mucosal α-glucosidase, which is noncompetitively inhibited by tea catechins released from the complex during digestion. Meanwhile, a significant decrease of malondialdehyde (MDA) and increased DPPH free radical scavenging activity in small intestine tissue demonstrated the antioxidative functional property of the OSAT complex. Thus, the complex of OSAT, acting as a functional carbohydrate material, not only leads to a flattened and prolonged glycemic response but also reduces the oxidative stress, which might be beneficial to health.

Gut feedback mechanisms and food intake: a physiological approach to slow carbohydrate bioavailability.

Glycemic carbohydrates in foods are an important macronutrient providing the biological fuel of glucose for a variety of physiological processes. A classification of glycemic carbohydrates into rapidly digestible carbohydrate (RDC) and slowly digestible carbohydrate (SDC) has been used to specify their nutritional quality related to glucose homeostasis that is essential to normal functioning of the brain and critical to life. Although there have been many studies and reviews on slowly digestible starch (SDS) and SDC, the mechanisms of their slow digestion and absorption were mostly investigated from the material side without considering the physiological processes of their in vivo digestion, absorption, and most importantly interactions with other food components and the gastrointestinal tract. In this article, the physiological processes modulating the bioavailability of carbohydrates, specifically the rate and extent of their digestion and absorption as well as the related locations, in a whole food context, will be discussed by focusing on the activities of the gastrointestinal tract including glycolytic enzymes and glucose release, sugar sensing, gut hormones, and neurohormonal negative feedback mechanisms. It is hoped that a deep understanding of these physiological processes will facilitate the development of innovative dietary approaches to achieve desired carbohydrate or glucose bioavailability for improved health.