Duodenal Conditions Research Articles

A Rare Case of Signet Ring Cell Carcinoma Arising on Duodenal Brunner’s Gland Hyperplasia Successfully Treated Via Endoscopic Resection

Signet-ring cell carcinoma (SRCC) is a rare tumor that most commonly occurs in the stomach. Duodenal SRCCs are extremely uncommon and account for approximately 1% of duodenal adenocarcinomas. Although Brunner’s gland hyperplasia (BGH) is a benign duodenal condition, studies have reported several cases of adenocarcinoma originating in an area of BGH. We report a rare case of early-stage SRCC originating in an area of BGH that was successfully treated using endoscopic mucosal resection. Based on the mucin phenotype observed in this case, it is reasonable to conclude that SRCC originated from gastric metaplasia in the area of BGH. Although BGH is a benign condition, careful evaluation is warranted for early detection of combined neoplasms.

Comparative Investigation of pH-Dependent Availability of Pancreatic Enzyme Preparations In Vitro.

This study aimed to compare different pancreatic enzyme preparations (PEPs) available in Germany regarding particle geometry and size, and to evaluate enzyme activity under physiologically relevant conditions in vitro. Pancreatic endocrine insufficiency is characterized by deficiency of pancreatic enzymes resulting in maldigestion. It is orally treated by pancreatic enzyme replacement therapy. The formulations differ in their physical properties and enzyme release behavior, potentially resulting in inconsistent dosages and poor interchangeability of products. A total of 25 products were analyzed for particle size and number of particles per capsule. Enzyme activities of lipase, amylase, and protease were measured by digestion of olive oil emulsion, starch, and casein, respectively. To analyze enzyme release, gastric environments were simulated by incubating PEPs at pH 1, 4, or 5. Duodenal conditions were simulated by subsequent incubation at pH 6. Regarding physical properties and enzyme release kinetics, considerable differences between different PEPs were found. Furthermore, compared to the label claim, excess lipase activity was observed for most products, reaching up to 148%. These in vitro results suggest poor interchangeability of PEPs, potentially explained by physical and release characteristics. Physicians and patients should be aware of the potential gap between label claims and the real-life performance of different PEPs.

Graphene oxide as inhibitor on the hydrolysis of fats under simulated in vitro duodenal conditions

Obesity is a global pandemic, thus novel developments that reduce the absorption of fats is of interest. We have evaluated the effect of graphene oxide (GO) on the lipase catalyzed hydrolysis of fats (tributyrin, sunflower and olive oil) under simulated duodenal conditions. Results indicate that the presence of GO in the digestion mixture can inhibit lipase activity up to a 90% of the initial reaction rate, and this inhibition lasts even during 2 h of digestion. The inhibition mechanism seems non competitive and could be opposite to the effect of bile salts, although the direct interaction between GO and the enzyme cannot be discarded. The inhibition is found also in alimentary fats suggesting that GO could be a strong inhibitor for fat hydrolysis.

Nanoliposomes for Controlled Release of Cannabinodiol at Relevant Gastrointestinal Conditions.

Cannabidiol (CBD) has significant therapeutic potential; nevertheless, its advance as an effective drug by the pharmaceutical business is hindered by its inherent characteristics, such as low bioavailability, low water solubility, and variable pharmacokinetic profiles. This research aimed to develop nanoliposomes using an easy and low-cost method to improve the hydrosolubility of CBD and achieve a controlled delivery of the active principle under relevant physiological conditions from the mouth to the intestine; the cytotoxic and antitumor activities were also evaluated. To achieve the objective, core-shell nanoliposomes based on CBD were synthesized in three easy steps and characterized in terms of shape, size, surface chemistry, thermal capacity, and surface charge density through transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and potential charge (PZ), respectively. CBD-controlled delivery trials were carried out under simulated mouth-duodenal conditions and fitted to Korsmeyer-Peppas and Noyes-Whitney models to conclude about the pharmacokinetics of CBD from nano-CBD. Cytotoxicity studies on nonmalignant human keratinocytes (HaCaT) were carried out to evaluate its safety and the recommended consumption dose, and finally, the antiproliferative capacity of nano-CBD on human colon carcinoma cells (SW480) was determined as beginning proposal for cancer treatment. The characterization results verified the water solubility for the CBD nanoencapsulated, the core-shell structure, the size in the nanometric regime, and the presence of the synthesis components. The dissolution rate at duodenal conditions was higher than that in buccal and stomach environments, respectively, and this behavior was associated with the shell (lecithin) chemical structure, which destabilizes at pH above 7.2, allowing the release by non-Fickian diffusion of CBD as corroborated by the Korsmeyer-Peppas model. In vitro biological tests revealed the innocuousness and cyto-security of nano-CBD up to 1000 mg·L-1 when evaluated on HaCaT cells and concentrations higher than 1000 mg·L-1 showed antitumor activity against human colon carcinoma cells (SW480) taking the first step as a chemotherapeutic proposal. These results are unprecedented and propose a selective delivery system based on nano-CBD at low cost and that provides a new form of administration and chemo treatment.

Cross-sectional Imaging of the Duodenum: Spectrum of Disease.

Cross-sectional Imaging of the Duodenum: Spectrum of Disease.

The Combination of In Vitro Assessment of Stress Tolerance Ability, Autoaggregation, and Vitamin B-Producing Ability for New Probiotic Strain Introduction.

The health benefits of probiotics are beyond doubt. The positive effects of lactobacilli and bifidobacteria on the function of many body systems have been repeatedly proven by various studies. To completely realize the potential of probiotic microorganisms, the strains should be tested by the greatest combination of characteristics that contribute to the wellness of the host. In this work, for the first time, a combined assessment of the probiotic properties and vitamin B-producing potential of various species and strains of bifidobacteria and lactobacilli was carried out. The presence of an additional advantage, such as vitamin-producing ability, can prevent vitamin deficiency both at the level of the consumption of fermented foods, when the enrichment will occur naturally on the spot, and during colonization by these intestinal strains, when synthesis will occur in vivo. To select potential probiotics, the stress tolerance ability of 16 lactic acid bacteria and bifidobacteria strains to low pH values, bile, and proteolytic enzymes, as well as their ability to autoaggregate, were studied under conditions of modeling the gastrointestinal tract in vitro. The ability of the strains to extracellularly accumulate water-soluble B vitamins was evaluated by capillary electrophoresis. Among the tested strains of bifidobacteria, B. adolescentis VKPM AC-1662 is of interest; it was characterized by the greatest stress tolerance ability and the ability to autoaggregate, in addition to the extracellular synthesis of riboflavin and pyridoxine. Among lactic acid bacteria, L. sakei VKPM B-8936 demonstrated the greatest tolerance to low pH, L. plantarum VKPM B–11007 to duodenal conditions, L. acidophilus VKPM B-2213 to pepsin, and L. salivarius VKPM B–2214 to pancreatin. The highest percentage of autoaggregation was observed in L. salivarius VKPM B-2214, which also accumulated the largest amount of pantothenic acid, but it was sensitive to stress conditions. The obtained results could be used to create new products enriched with probiotics and B vitamins.

Application of the INFOGEST Standardized Method to Assess the Digestive Stability and Bioaccessibility of Phenolic Compounds from Galician Extra-Virgin Olive Oil

The INFOGEST standardized method was applied to assess the potential bioaccessibility and bioaccessibility of the phenolic compounds from a Galician extra-virgin olive oil (EVOO). The in vitro digestion model involves three steps and generates two fractions after each one: an aqueous fraction (namely, water phase (Wp)) and an oily fraction (namely, oily phase (Op)). The results showed that secoiridoids were the most abundant family in the Galician EVOO polar fraction, representing 98% of the total phenolic compounds. After oral digestion, phenolic acids and simple phenols were mainly detected in Wp, while lignans and flavonoids were mostly found in Op. After gastric digestion, extensive hydrolysis of secoiridoids was observed to generate free tyrosol, hydroxytyrosol, and hydroxytyrosol acetate. The instability of secoiridoids after intestinal digestion was again responsible for the release of simple phenols, which were mainly recovered in Wp together with flavonoids. In contrast, lignans were stable to duodenal conditions and remained in Op.

Fat crystal-stabilized water-in-oil emulsion breakdown and marker release during in vitro digestion

We demonstrate that continuous phase fat structuring affects the release of a model marker from the dispersed aqueous phase of water-in-oil (W/O) emulsions subjected to simulated gastrointestinal conditions. Model W/O emulsions consisting of a 20 wt% dispersed aqueous phase containing 1 mM methylene blue added as a marker were stabilized via either continuous phase core-shell stabilization, network stabilization or a combination thereof. The network-stabilized emulsion showed the lowest extent of marker release under gastric (<3% after 1 h) and duodenal conditions (~5% after 2 h). The independent contributions of dilution, osmotic gradient, pH and bile salts all affected emulsion stability and marker release, with bile salts showing the greatest contribution. The key finding of this study was that the presence of a fat crystal network provided greater resistance against marker release than core-shell emulsion stabilization during in vitro digestion. Overall, this study has shown that fat phase structuring is a key parameter to control W/O emulsion breakdown and marker release.

Clay Minerals Affect the Solubility of Zn and Other Bivalent Cations in the Digestive Tract of Ruminants In Vitro.

Simple SummaryAdverse weather conditions and harvesting technique have broad effects on forage quality including contamination with soil particles, e.g., clay minerals. Clay minerals are organised in a layered structure which enables adsorption of bivalent cations. Accordingly, ingested clay minerals may interact with dietary bivalent trace elements, such as Cu, Fe, Mn, and Zn. This study aimed to assess the relationship between clay mineral ingestion and the solubility of dietary trace elements along the digestive tract in vitro. In the presence of clay minerals, we found a reduction of solubilised Zn, Cu, and Mn under ruminal, abomasal, and duodenal conditions. However, clay minerals led to an increase in dissolved Fe under abomasal and duodenal conditions. Therefore, ingested clay minerals may be assumed to alter the solubility of essential dietary trace elements in the digestive tract of ruminants.Ruminants ingest large quantities of clay minerals along with inorganic soil constituents in roughages. The layered structure of clay minerals, however, may adsorb cations and may, thus, interfere with the ruminants’ supply of essential trace metals, such as Zn, Mn, Cu, and Fe. As quantitative knowledge about interactions between clay ingestion and essential trace metal metabolism are largely lacking, this in vitro study focussed on the effect of clay on the solubility of dietary Zn and other bivalent trace metals in the digestive tract of ruminants. Therefore, buffered rumen fluid was used for the simulation of ruminal conditions (RC), acidified rumen fluid (pH 2) was used for abomasal conditions (AC), and duodenal chyme was used for duodenal conditions (DC). These media were added with gradient levels of zinc and incubated at 39 °C for 24 h in the absence or presence of clay minerals. Soluble Zn, Cu, Mn, and Fe were derived by centrifugation (10,000× g) of incubated media, and the supernatants were analysed. Clay depressed the solubility of added Zn in ruminal (65.3% vs. 16.5%), abomasal (97.7% vs. 33.7%), and duodenal conditions (41.3% vs. 21.1%), the results of which were statistically significant (p < 0.001). Moreover, clay reduced dissolved Cu (µg/mL) (RC: 0.13 vs. 0.10; AC: 0.16 vs. 0.13; DC: 0.10 vs. 0.08) and Mn (µg/mL) (RC: 3.00 vs. 1.80; AC: 5.53 vs. 4.80; DC: 3.18 vs. 1.77) (p < 0.05 in all cases). The presence of clay minerals increased the concentrations of solubilised Fe (µg/mL) in abomasal (1.80 vs. 2.86, p < 0.05) and duodenal conditions (1.76 vs. 2.67; p < 0.05). In total, the present in vitro study demonstrates the potential of clay minerals ingested with ruminant feeds for depressing the solubility of dietary Zn, as well as the depression of dietary Cu and Mn along the passage of the digesta from the rumen until the duodenum. Additionally, clay minerals may release Fe into the digesta.

In vivo bioavailability and in vitro toxicological evaluation of the new butyric acid releaser N-(1-carbamoyl-2-phenyl-ethyl) butyramide

A large body of evidence suggests that supplementation of butyric acid exerts beneficial intestinal and extra-intestinal effects. Unfortunately, unpleasant sensorial properties and unfavourable physico-chemical properties strongly limit its use in food supplements and foods for medicinal purposes. N-(1-carbamoyl-2-phenyl-ethyl) butyramide (FBA) is a new butyric acid releaser in solid form with neutral sensorial properties. The aim of this investigation is to provide preliminary information on its pharmacokinetic and toxicological properties through the study of a) in vivo bioavailability of FBA administered by oral gavage to male and female Swiss CD1 mice in comparison with sodium butyrate, b) the influence of digestion on FBA stability through an in vitro simulated oro-gastro-duodenal digestion process, and c) in vitro toxicological profile by means of the Ames Test and Micronucleus Test. The results reveal that FBA is a good butyric acid releaser, being able to increase butyrate serum concentration in a dose and time dependent manner in both male and female mice with a pharmacokinetic profile similar to that obtained from sodium butyrate as such. These data are confirmed by investigating the influence of digestion on FBA, which undergoes extensive hydrolysis following oro-gastro-duodenal digestion, especially in duodenal conditions, with a residual concentration of less than 10% of the initial FBA concentration. Finally, in the Ames and Micronucleus Tests, FBA does not show any in vitro genotoxicity as it is non mutagenic in the Ames Test and results to be unable to induce chromosome breaks in the Micronucleus Test. In conclusion, FBA is a new butyric acid releaser that can overcome the disadvantages of butyric acid while maintaining the same pharmacokinetic properties and safety profile, as shown by the results of the preliminary in vitro toxicological studies performed in this investigation.

Use of Silica Based Materials as Modulators of the Lipase Catalyzed Hydrolysis of Fats under Simulated Duodenal Conditions.

The effect of silica materials and their functionalization in the lipase catalyzed fat hydrolysis has been scarcely studied. Fifteen silica materials were prepared and their effect on the fat hydrolysis was measured, under simulated duodenal conditions, using the pH-stat method. The materials are composed of the combination of three supports (Stöber massive silica nanoparticles, Stöber mesoporous nanoparticles and UVM-7) and four surface functionalizations (methyl, trimethyl, propyl and octyl). In addition, the non-functionalized materials were tested. The functional groups were selected to offer a hydrophobic character to the material improving the interaction with the fat globules and the lipase. The materials are able to modulate the lipase activity and their effect depending on the support topology and the organic covering, being able to increase or reduce the fat hydrolysis. Depending of the material, relative fat hydrolysis rates of 75 to 140% in comparison with absence of the material were obtained. The results were analyzed by Partial Least Square Regression and suggest that the alkyl modified mesopores are able to improve the fat hydrolysis, by contrast the non-porous nanoparticles and the textural pores tend to induce inhibition. The effects are more pronounced for materials containing long alkyl chains and/or in absence of taurodeoxycholate.

Imaging Spectrum of Duodenal Emergencies.

The duodenum, the first portion of the small bowel, is divided into four segments and extends to both retro- and intraperitoneal spaces. Some conditions arise primarily from the duodenum, but it can be secondarily affected by processes that involve neighboring structures. When duodenal emergencies are not identified and treated promptly, they may result in high morbidity and mortality. Imaging plays an important role in the diagnosis of duodenal conditions in the acute setting. However, the radiologic findings can be subtle, and awareness of relevant patient history and clinical presentation is important as it may increase the index of suspicion and one's ability to diagnose these conditions. Duodenal peptic disease is common and can be complicated by bleeding and perforation. The duodenum can be secondarily involved by pancreatitis and gallbladder pathologic conditions and may be affected by iatrogenic complications following endoscopic procedures. Traumatic injuries to the duodenum are generally uncommon, with penetrating traumatic injury being the most frequent mechanism of injury. Duodenal vascular pathologic conditions such as aortoduodenal fistula are uncommon but can be life threatening. The knowledge of which pathologic condition can involve which duodenal segment can help the radiologist establish a differential diagnosis and achieve a more targeted imaging approach. The online slide presentation from the RSNA Annual Meeting is available for this article. ©RSNA, 2020.

Bulk and interfacial interactions between hydroxypropyl-cellulose and bile salts: Impact on the digestion of emulsified lipids

Hydroxypropyl-cellulose (HPC) is a surface-active, non-digestible polysaccharide, commonly used in food emulsions as thickener and/or emulsifier. Due to these dual characteristics, HPC is a potential ingredient to modulate lipid digestion. Since bile salts (BS) are key players during lipid digestion, the aim of this work was to investigate the impact that interactions of HPC with BS has on the digestion of emulsified lipids. We studied the effect of two BS species differing in bile-acid moiety, sodium-taurocholate (NaTC) and sodium-taurodeoxycholate (NaTDC). A Quartz-Crystal-Microbalance (QCM-D) was used to evaluate HPC-BS interfacial interactions during the sequential and simultaneous adsorption of both components at a hydrophobic surface, while micro-Differential-Scanning-Calorimetry was used to examine bulk interactions. In vitro lipid digestion was studied by using a pH-stat method. Results showed that, under fed-state conditions, NaTDC micelles were more effective at displacing a pre-adsorbed HPC layer from the surface than NaTC monomers. Nevertheless, HPC was resistant to complete displacement by both BS. Additionally, HPC was more susceptible to interact with NaTDC in the bulk, compared to NaTC, which made the adsorption more competitive for NaTDC. The reduced amount of free NaTDC in solution could explain the delayed lipolysis shown by HPC-stabilized emulsions when NaTDC was used to simulate duodenal conditions. These findings show that the delay of lipid digestion by HPC is due to the combined effect of HPC-BS interfacial and bulk interactions, with BS-binding in solution mostly contributing to this effect, and the BS molecular and micellar structure playing essential roles on both situations.

Structurally Different Dry Bean Matrices Modulate in Vitro Lipid Digestion (FS14-08-19)

ObjectivesEpidemiological evidence suggests that common beans are hypolipidemic agents and therefore able to alleviate obesity and cardiovascular disease. The observed positive effect of bean consumption on blood lipid levels is mainly attributed to their high content of dietary fiber (DF) and it is linked to the ability of DF to interfere with lipid digestion in different ways. Some proposed mechanisms are related to the physicochemical properties of DF and involve binding of bile acids (BA) which could decrease the rate of lipid digestion and absorption in the duodenum. This study aimed to investigate the effect of bean matrices varying in structure, content and distribution of DF fractions on lipid digestion kinetics in vitro. MethodsStructurally different bean matrices obtained by several processing techniques (i.e., hydrothermal, high pressure and mechanical treatments) as well isolated DF fractions were investigated. b-glucan was used as comparison. The viscosity, particle size and water and oil-binding ability of bean matrices were determined. We used dialysis, under duodenal conditions and HPLC analysis to determine BA-binding capacity. A standardized multistage static in vitro digestion protocol was used to assess the effect of bean matrices on the lipolysis rate of extrinsic lipids. ResultsBeans matrices reduced the extent and rate of digestion of corn oil compared to blank, with the water-soluble DF showing the largest reduction. Hydrothermal-treated beans and bean matrices with larger particle size showed the lowest capacity to retain BA and consequently were less effective at reducing the extent of lipolysis. The lower lipolysis rate observed in specific samples was related to their higher BA-binding. ConclusionsDifferent processing variables generated bean microstructures with different potential to modulate lipid digestion. Overall, processing decreased the ability of bean matrices to delay lipolysis. Isolated bean DF has the potential to control lipolysis depending on DF distribution and BA-binding ability. However, none of the bean matrices reached the levels observed with b-glucan. Funding SourcesUS Dry Bean Council and Hatch Program (NIFA), USDA.

Robotic Surgery for Benign and Low-Grade Malignant Diseases of the Duodenum

Robotic duodenal surgery (RDS) is a treatment option for many benign and low-grade malignant duodenal conditions that are not amenable to endoscopic intervention and can avoid morbidity related to open surgery. A retrospective review of all patients undergoing RDS (non-Whipple) at a tertiary care center from 2010-2017 was carried out. Indications, procedural details, and outcomes were reviewed. Twenty-four patients underwent RDS during the study period: transduodenal resection in 6 patients (25%), wedge resection in 6 patients (25%), transduodenal ampullectomy in 5 patients (21%), sleeve (segmental) resection in 5 patients (21%), duodenojejunostomy bypass in 1 patient (4%), and duodenal diverticulectomy in 1 patient (4%). Median age was 68 years, 54 per cent were male, and median BMI was 27. Adenoma was the most common diagnosis (68%) followed by neuroendocrine tumor (25%), duodenal diverticulum (4%), and refractory superior mesenteric artery syndrome (4%). Seventy-one per cent were symptomatic with gastroinstestinal bleed being the most common presentation. Median tumor size was 27 mm, and the most common location was D2 (58%) followed by D3/D4 (25%) and D1 (17%). Median operating time was 205 minutes and estimated blood loss was 50cc with no patient requiring intraoperative transfusion. Median length of stay was five days (3-21 days). Overall complication rate was 41 per cent (10/24): minor biliopancreatic leak in three patients; ileus in three patients; bleeding, arrhythmia, hypoxia, and headache in one patient each. Three (12%) patients had significant complications (Clavien-Dindo grade ≥ 3) requiring laparoscopic or robotic reoperation, but all three were discharged on or before POD 6 with resolution of complication. Ninety-day readmission rate was 8 per cent and 90-day mortality was 0. Recurrent disease or strictures were not seen in any patient after a median follow-up of 16 months. It has been concluded that RDS is a safe alternative to open or laparoscopic duodenal resection for benign and low-grade malignant conditions not amenable to endoscopic intervention.

Antioxidant and functional properties of protein hydrolysates obtained from starry triggerfish muscle using trypsin from albacore tuna liver

Abstract Protein hydrolysates from starry triggerfish (Abalistes stellaris) muscle with a degree of hydrolysis (DH) of 60% were prepared using trypsin from albacore tuna (Thunnus alalunga) liver. The hydrolysates were investigated for antioxidant activity and functional properties. Antioxidant activities including DPPH (2,2-diphynyl-1-picrylhydrazyl) radical scavenging activity, ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity, ferric reducing antioxidant power (FRAP) and metal chelating activity of hydrolysate samples were dose dependent. After being subjected to gastrointestinal model systems, the DPPH radical scavenging activity and metal chelating activity of the hydrolysates increased, especially in the duodenal condition, suggesting the enhancement of those activities of hydrolysates after ingestion. For functional properties, hydrolysis by the trypsin increased the solubility of hydrolysates to above 72.8% over a wide pH range. The hydrolysates possessed interfacial properties, which were governed by their concentrations. An increase in concentration of up to 2.0% (w/v) favoured the emulsifying activity index (EAI) and emulsion stability index (ESI), while a further increase to 3.0% (w/v) diminished emulsifying properties. Foam expansion and foam stability increased as the protein concentration increased. Therefore, the results of the present study suggest that starry triggerfish muscle can effectively be converted to protein hydrolysates, and the hydrolysates could be a potential ingredient in functional food as well as natural antioxidants in lipid food systems.

Chemo-profiling of anthocyanins and fatty acids present in pomegranate aril and seed grown in Indian condition and its bioaccessibility study.

The goal of the present study was to investigate the bioactive molecules (anthocyanins and fatty acids) present in the aril of pomegranate. Major anthocyanins present in the aril of pomegranate were identified by HRMS as delphinidin 3,5-diglucoside, cyanidin 3,5-diglucoside, pelargonidin 3,5-diglucoside, cyanidin 3-glucoside and delphinidin 3-glucoside. In-vitro study revealed that bioaccessibility of anthocyanin in duodenal condition was varied between 7.3 and 9.7%. Encapsulation enhances the bioaccessibility of both the phenolics to some extent in gastric as well as duodenal condition. Seed oil contains significant amount of unsaturated fatty acids especially ω-5 fatty acids. Geometrical isomers of ω-5 fatty acids were also identified by GC-MS. The spray dried anthocyanin formulation has potential for food application.

Editorial: isolated duodenal eosinophilia—clinical condition or just seeing spots?

Linked ContentThis article is linked to Genta paper. To view this article visit https://doi.org/10.1111/apt.14558.

Composite whey protein–cellulose nanocrystals at oil-water interface: Towards delaying lipid digestion

Lipid digestion is an interfacial process that is largely controlled by the adsorption of lipase + colipase + bile salts onto the surface of the emulsified lipid droplets. Therefore, engineering oil-in-water (O/W) interfaces that prevent competitive displacement by bile salts and/or delay the transportation of lipase to the hydrophobic lipid core can be effective strategies to delay lipolysis. In this study, we present such an interface using composite protein-particle system, consisting of whey protein isolate (WPI) (1 wt%) + cellulose nanocrystals (CNCs) (1–3 wt%). Droplet size, microscopy at various length scales (confocal, electron microscopy), ζ-potential and kinetics of fatty acid release were used to assess how the presence of CNCs impacted the microstructural stability of the emulsions in in vitro duodenal conditions (pH 6.8, 37 ○C). Adding CNCs at sufficiently high concentrations (3 wt%) significantly decreased the rate and degree of lipolysis as compared to that of protein-coated emulsion droplets. The principal cause of this altered lipolysis profile was the binding of bile salts by CNCs, which restricted both the interfacial displacement and solubilisation of lipid-digestion products by bile salts. The CNCs can be envisaged to be strongly bound to the protein-coated droplets by virtue of hydrogen bonding with the underlying protein. Furthermore, the ability of the CNCs in the continuous phase to bridge several protein-coated droplets reduced the overall surface area available for the lipolysis. Composite WPI + CNC interface holds promise in designing physiologically relevant emulsions to target satiety or delivery systems for sustained release of lipophilic components.

Interfacial behaviour of biopolymer multilayers: Influence of in vitro digestive conditions

Although multilayered emulsions have been related to reduced lipolysis, the involved interfacial phenomena have never been studied directly. In this work, we systematically built multilayers of whey protein and pectin, which we further subjected to digestive conditions, using two different techniques: droplet volume tensiometry to investigate interfacial rheology, and reflectometry to determine the amount of adsorbed material. Interfacial tension and dilatational rheology were linked to adsorption/desorption kinetics measured under static in vitro conditions.The interfacial tension and rheology of the multilayers was rather similar to those found for single whey protein layers, as well as their resistance to duodenal conditions and lipolytic components, which is explained by the rapid destabilisation of multilayers at neutral pH. Sequential adsorption of bile extract or lipase to pre-adsorbed films rapidly lowered the interfacial tension via co-adsorption and displacement, forming a viscoelastic film with low mechanical strength, and highly dynamic adsorption/desorption. When both were present, bile salts dominated the initial adsorption, followed by lipase co-adsorption and formation of lipolysis products that further lowered the interfacial tension, forming a complex interface (including biopolymers, bile salts, lipase, and lipolysis products), independent of pre-adsorbed biopolymer layers.Our study shows that the combination of drop volume tensiometry and reflectometry can be used to study complex interfacial behaviours under digestive conditions, which can lead to smart design of interfacial structures for controlled lipolysis in food emulsions.