Digestion In Gastrointestinal Tract Research Articles

Alteration in rheological and digestive properties of O/W emulsions using controlled aggregation of konjac glucomannan and xanthan gum in aqueous phases

The modulation of lipid digestion and emulsion stability remains a pivotal area of research, crucial for developing healthier food products with enhanced sensory and nutritional attributes. This study investigates the influence of konjac glucomannan (KGM) and xanthan gum (XG) on oil-in-water (O/W) emulsions throughout simulated gastrointestinal tract (GIT) digestion, focusing on rheological properties, microstructure evolution, and lipid release kinetics. Three distinct O/W emulsions were formulated with 20 wt% oil content, incorporating either 0.8 wt% XG, a 1:1 mixture of KGM and XG (KGM/XG), or a blend of KGM-XG. Rheological assessments revealed all emulsions exhibited shear-thinning behavior across applied shear rates (0.1–100 1/s). During gastric and small intestinal digestion phases, the KGM-XG emulsion exhibited significantly higher viscosity at higher shear rates (2.512–100 1/s), indicating robust molecular interactions between KGM and XG under digestive conditions. The analysis of microstructure, particle size, and flow behavior showed that the KGM-XG emulsion exhibited significantly (p < 0.05) higher viscosity and smaller particle sizes compared to other systems throughout the digestion process. This finding indicates that KGM-XG emulsion demonstrates a strong resistance to enzymes and digestive fluid during the transition from oral to small intestinal phases. Importantly, the extent of free fatty acid (FFA) release at the end of the small intestinal phase was highest for XG (34.4%), followed by KGM/XG (15.65%) and KGM-XG (13.23%). These findings highlight the potential of KGM-XG emulsions to modulate lipid digestion kinetics, offering applications in designing emulsion-based foods, such as sauces, beverages, and reduced-fat foods.

Characteristics and Bioactivities of Protein Hydrolysate from Cricket (Acheta domesticus) Powder Defatted Using Ethanol with Aid of Vacuum Impregnation.

Cricket is a potential proteinaceous source used for protein hydrolysate (PH) preparation, having several biological activities. Nevertheless, cricket has high lipid contents, which are susceptible to oxidation during PH preparation. Thus, ethanol was used together with vacuum impregnation (VI) to enhance defatting efficacy before PH preparation. Also, bioavailability of the digest of PH after gastrointestinal tract (GIT) digestion via the Caco-2 monolayer was assessed. Cricket powder was defatted using ethanol for 1-4 h. Lipid contents were decreased with enhancing time until 2 h. Additionally, the defatting efficacy was augmented when ethanol combined with VI at 4 cycles for 2 h (VI-E-2) was implemented. Lowered mono- and polyunsaturated fatty acid contents were also observed in the VI-E-2 sample. The VI-E-2 sample was used to prepare PH using Alcalase and Flavourzyme (0.2-0.4 units/g dry sample). PH prepared by Alcalase hydrolysis at 0.2 units/g dry sample (A-0.2) showed the higher ABTS radical-scavenging activity and FRAP, compared to that prepared by Flavourzyme hydrolysis (p < 0.05). Thus, the A-0.2 sample was selected for digestion via the GIT system. The obtained digest (500-1000 μg/mL) had bioavailability of peptides, depending on the levels used. Therefore, PH from defatted cricket powder could be a promising ingredient for food applications.

Synaptic cell adhesion molecule Cdh6 identifies a class of sensory neurons with novel functions in colonic motility.

Intrinsic sensory neurons are an essential part of the enteric nervous system (ENS) and play a crucial role in gastrointestinal tract motility and digestion. Neuronal subtypes in the ENS have been distinguished by their electrophysiological properties, morphology, and expression of characteristic markers, notably neurotransmitters and neuropeptides. Here we investigated synaptic cell adhesion molecules as novel cell type markers in the ENS. Our work identifies two Type II classic cadherins, Cdh6 and Cdh8, specific to sensory neurons in the mouse colon. We show that Cdh6+ neurons demonstrate all other distinguishing classifications of enteric sensory neurons including marker expression of Calcb and Nmu, Dogiel type II morphology and AH-type electrophysiology and I H current. Optogenetic activation of Cdh6+ sensory neurons in distal colon evokes retrograde colonic motor complexes (CMCs), while pharmacologic blockade of rhythmicity-associated current I H disrupts the spontaneous generation of CMCs. These findings provide the first demonstration of selective activation of a single neurochemical and functional class of enteric neurons, and demonstrate a functional and critical role for sensory neurons in the generation of CMCs.

Advancements in Nano-Mandoor Bhasma: Unravelling the Particle Size-Ascorbic Acid Synergy for Enhanced Iron Bioavailability for Anemia Treatment.

Mandoor Bhasma (MB) medicine, based on classical Indian Ayurveda, was size- and surface-modified to improve its therapeutic efficiency for treating iron-deficient anemia. Physical grinding reduced the size of MB to the nanoparticle (nano-MB) range without changing its chemical composition, as measured by particle size distribution. The surface of nano-MB was modified with ascorbic acid (nano-AA-MB) and confirmed using scanning electron microscopy and Fourier transformed infrared spectroscopy. Enhanced iron dissolution from the surface-modified nano-AA-MB under neutral-to-alkaline pH conditions, and in the intestinal region of the simulated gastrointestinal tract (GIT) digestion model was determined using inductively coupled plasma mass spectroscopy. GIT digestae of MB microparticles and nano-AA-MB were found to be biocompatible in human colon epithelial (Caco-2) cells, with the latter showing threefold higher iron uptake. Subsequently, a dose-dependent increase in cellular ferritin protein was observed in the nano-AA-MB digestae-treated Caco-2 cells, indicating the enhanced bioavailability and storage of dissolved iron. Overall, the study showed that reducing the size of centuries-old traditional Mandoor Bhasma medicine to nanoscale, and its surface-modification with ascorbic acid would help in enhancing its therapeutic abilities for treating iron-deficient anemia.

Assessment of Ingested Micro- and Nanoplastic (MNP)-Mediated Genotoxicity in an In Vitro Model of the Small Intestinal Epithelium (SIE).

Micro- and nanoplastics (MNPs) have become ubiquitous contaminants of water and foods, resulting in high levels of human ingestion exposure. MNPs have been found in human blood and multiple tissues, suggesting that they are readily absorbed by the gastrointestinal tract (GIT) and widely distributed. Growing toxicological evidence suggests that ingested MNPs may pose a serious health threat. The potential genotoxicity of MNPs, however, remains largely unknown. In this study, genotoxicity of primary and environmentally relevant secondary MNPs was assessed in a triculture small intestinal epithelium (SIE) model using the CometChip assay. Aqueous suspensions of 25 and 1000 nm carboxylated polystyrene spheres (PS25C and PS1KC), and incinerated polyethylene (PEI PM0.1) were subjected to simulated GIT digestion to create physiologically relevant exposures (digestas), which were applied to the SIE model at final MNP concentrations of 1, 5, and 20 μg/mL for 24 or 48 h. PS25C and PS1KC induced DNA damage in a time- and concentration-dependent manner. To our knowledge, this is one of the first assessment of MNP genotoxicity in an integrated in vitro ingestion platform including simulated GIT digestion and a triculture SIE model. These findings suggest that ingestion of high concentrations of carboxylated PS MNPs could have serious genotoxic consequences in the SIE.

Enhancing probiotic viability: Impact of soy hull polysaccharide concentration on stabilized high-internal-phase emulsions encapsulated with Lactobacillus plantarum and their release during gastrointestinal digestive

This study investigated the impact of soy hull polysaccharide (SHP) concentration on the formation of high-internal-phase emulsions (HIPEs) stabilized with soy protein isolate (SPI), encapsulated with Lactobacillus plantarum, and explored its gastrointestinal digestive mechanism. The results of Zeta potential, particle size and rheological properties revealed the excellent viscoelastic and thermal stability of the HIPEs. Compared to free probiotics, the in vitro digestion of probiotics encapsulated with 1.8% SHP HIPEs demonstrated a significant improvement in activity, with an encapsulation efficiency of 71.1%. Throughout the three stages of Gastrointestinal Tract (GIT) digestion, HIPEs maintained robust stability during the gastric digestion phase. Subsequent to trypsin enzymolysis, interactions between –NH3+ and –COOH led to binding and aggregation, initiating the collapse of HIPEs' structure. Concurrently, the hydrolyzed SHP and SPI formed small molecules of that further combine and flocculate. This critical juncture resulted in the release of L. plantarum into the simulated colonic environment. These findings proposed a promising strategy for employing HIPEs-encapsulated probiotics as targeted delivery systems in food applications.

Enhancing physicochemical, rheological properties, and in vitro rumen fermentation of starch with Melastoma candidum D. Don fruit extract.

The utilization of polyphenol-modified starch in ruminants has not undergone extensive exploration. This study aimed to investigate the impact of the complex formed between starch and Melastoma candidum D. Don fruit extract on physicochemical properties, phenol release kinetics in various buffers simulating the gastrointestinal tract, methane production, and post-rumen digestibility. The interaction between starch and M. candidum D. Don fruit extract significantly (p < 0.001) increased resistant starch and particle size diameter. The maximum phenolic release from complex between starch and M. candidum D. Don fruit extract, due to gastrointestinal tract-simulated buffers, ranged from 22.96 to 34.60 mg/100 mg tannic acid equivalent. However, rumen and abomasum-simulated buffers released more phenolic content, whereas the intestine-simulated buffer showed higher antioxidant activity (ferric ion-reducing antioxidant power). Furthermore, complex between starch and M. candidum D. Don fruit extract significantly decreased dry matter rumen digestibility (p < 0.001) and maximum methane gas production (p < 0.001).

Up-scalable approaches for yeast mannan oligosaccharides (MOS) production: characterization and immunomodulatory properties

Mannan oligosaccharides (MOS) are widely used as feed additives due to their effects on gut microbiome modulation. Its application in the nutraceutical and functional food industries is also increasing. Numerous studies portraying MOS production from β-mannans can be found, but its production from yeast mannans is barely explored. Herein, two up-scalable approaches to produce yeast-derived MOS are presented: hydrothermal and acidic processing. Process efficiency was evaluated, and the resulting extracts were characterized (ATR-FT-IR, PXRD, SEM, MWD, DSC, sugar, and protein content). Extracts were also evaluated for their cytotoxicity and immunomodulatory effect; furthermore, a simulated gastrointestinal tract digestion was performed to confirm their biological potential. The hydrothermal process resulted in the highest yield, whereas the acidic process resulted in lower molecular weight populations. Immunomodulatory results indicate that MOS digested extracts do not hold anti-inflammatory activity but grant an immunostimulant effect, whereas the non-digested MOS acidic extract showed an anti-inflammatory potential. This work provides valuable contributions towards the industrial production of yeast-derived MOS extracts, highlighting their potential for applications in various fields while contributing to a circular economy approach.

Serotonin production of the developing gastrointestinal tract of human embryos in 6th gestation week

Background: Local regulation of gastrointestinal tract digestion is performed by a large number of hormones produced by the mucosal enteroendocrine cells. Some of the earliest differentiating cells in the gastrointestinal tract are enteroendocrine cells. Serotonin-producing cells - EC cells are found mostly in the stomach and duodenum. Aim: The aim of our study is to establish the presence and to make morphological and morphofunctional characteristic of ЕС cells in the developing gastrointestinal tract of a human. Materials and methods: Our study was performed with biopsy specimen from human stomach and duodenum and fragments of gastrointestinal tract of human embryos 6th gestation week, studied by immunohistochemical, electron microscopy and morphometric methods. Results: EC cells have already been differentiated in the 6th gestation week. Embryonic EC cells had identical characteristics with those of adults. They were in two morphofunctional conditions: stage of increased synthesis and stage of relative secretory rest. Conclusion: In the early embryonic period - 6th gestation week EC cells have already been differentiated. The occurrence of EC cells with hormonal production prior to the definitive differentiation of tissues presupposes participation of serotonin in the digestive tube histogenetic processes.

Changes of physicochemical properties and bioactivities of resveratrol-loaded core-shell biopolymer nanoparticles during in vitro gastrointestinal digestion.

Resveratrol loaded nanoparticles (nano-resveratrol) containing a zein core surrounded by surfactant (Tween-NPs) or carboxymethyl chitosan (CMCS-NPs) shell were fabricated with different particle sizes, surface charges and colloidal stabilities. Changes of physicochemical properties for the two nano-resveratrols, as well as their antioxidant potentials and cytotoxicity were investigated during a static in vitro gastrointestinal tract (GIT) digestion. Results showed that the Tween-NPs had a much higher bioaccessibility (84.1±19.2%) than that of CMCS-NPs (36.6±4.2%) after the GIT digestion, which was expected due to the steric barrier of the CMCS coating. Both nano-resveratrols could sustained their antioxidant activities after digestion. However, the Tween-NPs had a significantly higher cytotoxicity against MCF-7 cells than CMCS-NPs and free resveratrol, while a reduction in cytotoxicity of Tween-NPs was observed after the digestion. The bioactivities results were well correlated with the physicochemical properties and dissolution of resveratrol under environmental stress.

Assessment of the bioaccessibility and bioavailability prediction of omega 3 and conjugated fatty acids by in vitro standardized digestion model (INFOGEST) and cell model

Omega 3 EPA and DHA are polyunsaturated fatty acids with relevant health benefits. Conjugated linoleic and linolenic acids are known for their anti-carcinogenic effect, anti-inflammatory properties and body weight reduction. To achieve therapeutical doses, high amounts of these fatty acids’ food sources must be consumed. Thus, the intake of enriched oils with a high concentration of these fatty acids is often used. But several factors influence their bioavailability. Here, by using the INFOGEST static in vitro protocol of gastrointestinal tract digestion it was studied the bioaccessibility of these fatty acids in different matrixes: Pomegranate and Fish oil and omega 3, CLA and CLNA soft-gel enriched capsules. After digestion, the Recovery Index for the major bioactive PUFAs are very low: Pomegranate oil is 2%, Fish oil 11–13%, CLNA 17%, CLA 6% and Omega 3 capsules 3%. Higher initial concentrations of these PUFAs seem to be related to higher degrees of oxidation. In Pomegranate oil, CLNA and Omega 3 capsules, the digestion process negatively influenced the antioxidant potential. The opposite was verified for the Fish oil and CLA capsules. Importantly, bioaccessibility studies of similar matrixes are very scarce and intestinal permeability is absent in most of the studies. Intestinal permeability studies were performed using a Caco-2/HT29-MTX co-culture: there is significative incorporation of the bioactive fatty acids into the intestinal cells, which may affect their permeability performance. Interestingly, most fatty acids remain in the non-bioaccessible fraction which may be relevant when designing oral routes of administration and in gut microbiota modulation.

Impact of gastrointestinal digestion simulation on brewer’s spent grain green extracts and their prebiotic activity

Brewer’s spent grain (BSG) is a by-product of the beer industry and a potential source of bioactive compounds. In this study, two methods of extracting bioactive compounds from brewer’s spent grain were used – solid-to-liquid conventional extraction (SLE) and solid-to-liquid ohmic heating extraction (OHE) coupled with two ratio combinations of solvents: 60 % and 80 % ethanol:water (v/v). The bioactive potential of the BSG extracts was assessed during the gastrointestinal tract digestion (GID) and the differences in their antioxidant activity, total phenolic content and characterization of the polyphenol profile was measured. The SLE extraction using 60 % ethanol:water (v/v) was the extraction method with higher antioxidant activity (33.88 mg ascorbic acid/g BSG – initial; 16.61 mg ascorbic acid/g BSG - mouth; 15.58 mg ascorbic acid/g BSG – stomach; 17.26 mg ascorbic acid/g BSG – duodenum) and higher content in total phenolics (13.26 mg gallic acid/g BSG – initial; 4.80 mg gallic acid/g BSG – mouth; 4.88 mg gallic acid/g BSG – stomach; 5.00 mg gallic acid/g BSG – duodenum). However, the OHE extraction using 80 % ethanol:water (v/v), had a higher bioaccessibility index (99.77 % for ferulic acid, 72.68 % for 4-hydroxybenzoic acid, 65.37 % for vanillin, 28.99 % for p-coumaric, 22.54 % for catechin) values of polyphenols. All the extracts enhanced (except for SLE for 60 % ethanol:water (v/v) at 2 and 1.5 %, and for 80 % ethanol:water (v/v) at 2 % with Bifidobacterium animalis spp. lactis BB12, where no growth was observed) the growth of the probiotic microorganisms tested (Bifidobacterium animalis B0 – O.D.’s between 0.8240 and 1.7727; Bifidobacterium animalis spp. lactis BB12 – O.D.’s between 0.7219 and 0.8798; Lacticaseibacillus casei 01 – O.D.’s between 0.9121 and 1.0249; and Lactobacillus acidophilus LA-5 – O.D.’s between 0.8595 and 0.9677), demonstrating a potential prebiotic activity of BSG extracts.

Digestion, absorption, and transport properties of soy-fermented douchi hypoglycemic peptides VY and SFLLR under simulated gastrointestinal digestion and Caco-2 cell monolayers

Two novel hypoglycemic peptides VY and SFLLR were identified from douchi as the major peptides responsible for the glucose uptake activity. The present work aimed to elucidate their digestion, absorption and transport properties using simulated digestion and Caco-2 cell monolayers transport models. Besides, the effects of digestion and absorption on the structure and activity were also studied. The results showed that VY was resistant to gastrointestinal tract digestion and could cross Caco-2 cell monolayers intactly via both TJs-mediated passive paracellular pathway and PepT1-mediated active route. In comparison, SFLLR was partially degraded into small fragments of SFLL, SFL, and SF by the digestive system, leading to increased glucose uptake activity. Notably, SFLLR, SFLL, and SFL were partly hydrolyzed by aminopeptidase N or dipeptidyl peptidase IV during transport, but they were transported intact. SFL was transported via both paracellular diffusion and PepT1-mediated routes, while SFLLR and SFLL were via paracellular route only.

Enhancing the Dispersion Stability and Sustained Release of S/O/W Emulsions by Encapsulation of CaCO3 Droplets in Sodium Caseinate/Xanthan Gum Microparticles.

In this study, solid/oil/water (S/O/W) emulsions were prepared by sodium caseinate (NaCas) and Xanthan gum (XG) binary composite to improve the dispersion stability of calcium carbonate (CaCO3) and achieve a targeted slow-release effect. CaCO3 S/O/W emulsions were determined by particle size, Zeta potential, physical stability, and microstructure. X-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR) were used to characterize the molecular interactions among components. Molecular docking technology was used to predict the possible binding mode between NaCas-XG. The percentage of free Ca2+ released in the gastrointestinal tract (GIT) model was also studied. It was found that when the concentration of XG was 0.5 wt% and pH was 7, the particle size was smaller, the distribution was uniform, and the physical stability was improved. The microstructure results showed that the embedding effect of S/O/W emulsions was better, the particle size distribution was more uniform when XG concentration increased and formed a filament-like connector with a relatively more stereoscopic structure. XRD results confirmed that the CaCO3 was partially covered due to physical embedding. Infrared and Raman analysis and molecular docking results showed electrostatic and hydrophobic interaction between NaCas and XG. In the GIT digestion model, S/O/W emulsion released Ca2+ slowly in the gastric digestion stage, which proved the targeted slow-release effect of the S/O/W emulsions delivery vector. The results showed that the S/O/W emulsions delivery system is an effective way to promote the application of CaCO3.

Structural characterisation of two polysaccharides from white common bean (Phaseolus vulgaris L.) and the application in microencapsulation of probiotics

SummaryIncreasing attention has been focused on the application of plant polysaccharides in the area of microencapsulation of probiotic bacteria. It remained to be clarified how the chemical structure of plant polysaccharides affects their feasibility as wall materials. In this study, two structurally different polysaccharides, namely NSP‐1 (2.91 × 106 Da) and NSP‐2 (4.57 × 105 Da), were isolated from white common bean seeds. NSP‐1 was predominantly composed of Glc and Gal, and mainly linked as →4)‐Glcp‐(1→, →3,6)‐Glcp‐(1→ and →4)‐Galp‐(1→. NSP‐2 was predominantly composed of Gal and Ara, with main glycosidic bonds of →4)‐Galp‐(1→, Galp‐(1→ and →5)‐Araf‐(1→. NSP‐1 and NSP‐2 were co‐used with calcium alginate as wall materials for microencapsulation of Lactobacillus plantarum. NSP‐1 increased the encapsulation efficiency more than NSP‐2 (P &lt; 0.05), while NSP‐2 mainly improved the survival of the probiotic during simulated gastrointestinal tract digestion and storage at 4 °C (P &lt; 0.05). These findings will give a valuable perspective on plant polysaccharides applied in microencapsulation technology.

Actinidin reduces gluten-derived immunogenic peptides reaching the small intestine in an in vitro semi-dynamic gastrointestinal tract digestion model

Actinidin, a cysteine protease in green kiwifruit (Actinidia deliciosa), has been identified as a potential enzyme to hydrolyse gluten within the lumen of the gastrointestinal tract (GIT). The present study aimed to further evaluate the effect of purified actinidin sourced from green kiwifruit on the digestion of gluten and the release of immunogenic peptides during GIT digestion using an in vitro semi-dynamic GIT digestion model. Purified gluten was digested for 180 min with or without actinidin and subsequently analysed for free amino groups (o-phthaldialdehyde) to determine the degree of hydrolysis (DH), gluten R5 epitopes (ELISA), and peptide profiles (mass spectrometry). Strong interactions were observed between treatment (GIT digestion with or without actinidin) and digestion time for the DH of gluten (P < 0.01), amount of free amino groups released into the small intestine (P < 0.01), and amount of gluten epitopes present in the small intestine (P < 0.001). The rate of increase of DH of gluten and the amount of R5 epitopes present in the small intestine during the first 30 min of GIT digestion with actinidin was 0.3%/min and 4.8 ng/g of gluten respectively, whereas it was 0.01%/min and 60.9 ng/g of gluten respectively without actinidin. These results were corroborated by untargeted peptidomics, with a 1.5-fold lower number of known immunogenic epitopes reaching the small intestine at 30 min of GIT digestion when actinidin was present compared to the control. Present results demonstrate that actinidin enhanced the rate of proteolysis of gluten and reduced the number of immunogenic gluten epitopes reaching the small intestine during simulated semi-dynamic GIT digestion.

Particle Size Effect of Integral Carob Flour on Bioaccessibility of Bioactive Compounds during Simulated Gastrointestinal Digestion.

Carob fruit is native to the Mediterranean region and produced mainly in Portugal, Italy, Morocco and Turkey. The production of the carob fruit in Portugal is highly extensive and sustainable. Currently, carob flour (CF) production is mainly achieved after pulp separation, despite it having been demonstrated that the seeds improve the extraction efficiency of bioactive compounds such as polyphenols, promoting human health. This study aimed to produce an integral CF through an innovative process and assess its physicochemical and bioactive properties at different particle sizes throughout simulated gastrointestinal tract (GIT) digestion. The sugar content profile obtained throughout GIT digestion indicated that sucrose, the sugar present at the highest concentration in undigested CF, was digested and broken down into simple sugars, namely glucose and fructose. The total phenolic content (TPC) and antioxidant activity obtained for the ≤100 µm fraction were in accordance and gastric digestion promoted an increase in the TPC value compared to the undigested sample. The >100 µm fractions displayed a distinct profile from the ≤100 µm fraction. This study showed that the particle size affects the sugar, antioxidant and total phenolic content of CFs and also their gastrointestinal tract digestion. The ≤100 µm fraction demonstrated the most suitable profile as a functional food ingredient.

Chitosan binding to a novel alfalfa phytoferritin nanocage loaded with baicalein: Simulated digestion and absorption evaluation

Phytoferritin was explored as an attractive nanocarrier to encapsulate bioactive compounds due to its excellent stability and biocompatibility. In the present study, a novel phytoferritin derived from alfalfa (Medicago sativa) was successfully expressed, purified and characterized. Results confirmed that alfalfa ferritin, self-assembled by 24 subunits, formed a spherical hollow structure. Baicalein exhibits superior antioxidant properties and nutritious values, but low bioavailability and solubility limit its application. Herein, we fabricated water-soluble chitosan-ferritin-baicalein nanoparticles to overcome its drawbacks. It was calculated that one apoferritin cage could encapsulate 52 molecules of baicalein. Moreover, chitosan-ferritin-baicalein nanoparticles prolonged the release of baicalein in simulated gastrointestinal tract digestion. Caco-2 cell monolayer absorption analysis demonstrated that baicalein encapsulated within ferritin-chitosan double layers was more efficient in cellular transportation. These results indicated that alfalfa ferritin, as a novel cage-like protein, has potential application in improving the bioavailability of insoluble bioactive molecules.

Impact of amylose from maize starch on the microstructure, rheology and lipolysis of W/O emulsions during simulated semi‐dynamic gastrointestinal digestion

SummaryThis study aims to examine the microstructure, rheology and lipolysis of water‐in‐oil (W/O) emulsions (40 wt.%) prepared with or without (Control) the addition of normal (NAM) and high amylose (HAM) maize starch during simulated digestion in a semi‐dynamic gastrointestinal tract (GIT) model. Microstructural examinations showed modification in initial W/O emulsion droplets to multiple W1/O/W2 droplets during in vitro digestion. This is in line with the rheological results, where the shear viscosity and moduli in the oral phase were remarkably reduced after entering the intestinal phase. In comparison to control and NAM emulsions, HAM emulsions showed a more compact and continuous network structure and greater viscosity and elastic modulus throughout GIT digestion. These results support lipolysis, where fewer free fatty acids were released in the HAM emulsion (70%) than in the control (86%) and NAM (78%) emulsions. This work has provided an in‐depth understanding of the digestion of W/O emulsions as influenced by amylose content, which is meaningful for the development of low‐fat products with reduced lipid digestibility.

Natural oil bodies from typical oilseeds: Structural characterization and their potentials as natural delivery system for curcumin

Natural oil body (OB), due to the fascinating surface membrane structure, has a great potential to be a typical natural delivery system. In this work, three kinds of OBs with different components and surface membrane structure were extracted from rapeseed, camellia and flaxseed, respectively. Their compositions and structural characteristics had been fully characterized by SDS-PAGE, low field nuclear magnetic resonance (NMR), the cryo-Scanning Electron Microscope etc. Furthermore, curcumin as bioactive compound was loaded into these OBs via pH-shift method. The impact of structural and membrane constructional differences between three kinds of OBs on both encapsulation and gastrointestinal digestion fate of curcumin were also investigated. The rapeseed OB had the highest surface membrane protein content and lowest particle size (0.77 μm), leading to a relative higher encapsulation efficiency (91.87%) and bioaccessibility (91.3%) of curcumin and the highest release of FFAs (18.19 μmol ml −1), while camellia OB the lowest. The stubborn flaxseed gum on flaxseed OB protected the surface membrane proteins from hydrolysis, which contribute to the highest bioaccessibility of curcumin (94.32%). The different surface membrane structure of the three kinds of OBs, especially the protein content, affected the loading process of curcumin and their digestion in gastrointestinal tract. The results of rheology also showed that OBs with high protein content might be more effective in encapsulation of bioactive molecules, coupled with a negative influence on the stability of interfacial layers. These results may contribute to the application of natural OBs from oilseeds in multiple food processing including plant-based milk, fortified food and so on.