Review of in vitro digestion models for rapid screening of emulsion-based systems

An examination of the impact of unmelted, melted, and deconstructed cheese on lipid metabolism: a 6-week randomised trial

Background: Evidence suggests cheese has a favourable or neutral effect on cardiometabolic health, compared to butter. To date, studies have only considered the cheese matrix in its unmelted form, while the effect of melted cheese remains unknown. Objective: To test the effect of 6-week daily consumption of ∼40 g dairy fat, eaten in either as unmelted cheese, melted cheese, or in a fully deconstructed form, on markers of metabolic health in overweight adults aged ≥50 years of age. Design: A 6-week randomised parallel intervention, where 162 participants (43.3% male) received ∼40 g of dairy fat per day, in 1 of 3 treatments: (A) 120 g full-fat Irish grass-fed cheddar cheese, eaten in unmelted form (n 58); (B) 120 g full-fat Irish grass-fed cheddar cheese eaten in melted form (n 53); or (C) the equivalent components; butter (49 g), calcium caseinate powder (30 g), and Ca supplement (CaCO3; 500 mg) (n 51). Results: There was no difference in weight, fasting glucose, or insulin between the groups post-intervention. Melted cheese, compared to unmelted cheese, increased total cholesterol (0.23 ± 0.79 mmol L-1vs. 0.02 ± 0.67 mmol L-1, P = 0.008) and triglyceride concentrations (0.17 ± 0.39 mmol L-1vs. 0.00 ± 0.42 mmol L-1, P = 0.016). Melted cheese increased total cholesterol concentrations by 0.20 ± 0.15 mmol L-1 and triglyceride concentrations by 0.17 ± 0.08 mmol L-1 compared to unmelted cheese. No significant differences were observed between the cheese forms for change in HDL, LDL or VLDL cholesterol. Conclusion: Compared to unmelted cheese, melted cheese was found to increase total cholesterol and triglyceride concentrations in middle-aged, overweight adults with no effect on weight or glycaemic control.

Lipolysis and Sterol Stability and Bioaccessibility of Wholemeal Rye Bread Enriched with Plant Sterols Subjected to Adult and Elderly Digestion Conditions

This study evaluated the impact of different digestion conditions (adult and senior) on lipolysis and bioaccessibility of plant sterols (PS) and phytosterol oxidation products (POPs) in PS-enriched wholemeal rye bread. Under adult digestion conditions, the addition of gastric lipase (GL) reduced lipolysis products (by 6.1% for free fatty acids and 11.7% for monoacylglycerols) and the bioaccessibility of PS by 6.7%, compared to the control. In digestion with both GL and cholesterol esterase (CE), these reductions were 12.9, 20.1, and 11.3%, respectively. Both modifications (GL and GL + CE) increased the bioaccessibility of POPs by 4.5-4.0%. When simulating the elderly digestion, the modified gastric and intestinal phases did not alter PS bioaccessibility but decreased POPs bioaccessibility by 21.8% compared to control, along with reduced lipolysis. Incorporating GL and CE thus approached physiological conditions and influenced lipid digestion. Elderly simulated digestion conditions resulted in a positive outcome by maintaining PS bioaccessibility while reducing potentially harmful POPs.

Biological activity, limitations and steady-state delivery of functional substances for precision nutrition

Food-related functional substances with biological activity serve as a crucial material foundation for achieving precision nutrition, which has gained increasing attraction in regulating physiological functions, preventing chronic diseases, and maintaining human health. Nutritional substances typically include bioactive proteins, peptides, polysaccharides, polyphenols, functional lipids, carotenoids, probiotics, vitamins, saponins, and terpenes. These functional substances play an essential role in precise nutrition. This chapter introduces and summarizes typical functional substances to demonstrate the challenges in precision nutrition for their stability, solubility, and bioavailability. The current status of delivery systems of functional substances is described to give an insight into the development of desirable characteristics, such as food grade status, high loading capacity, site targeting, and controlled release capacity. Finally, the applications of food-borne delivery systems of functional substances for precision nutrition are emphasized to meet the requirement for precision nutrition during nutritional intervention for chronic diseases.

The construction of Moringa oleifera seed protein emulsion: in vitro digestibility and delivery of β-carotene

BACKGROUND

β-Carotene (BC) is difficult to apply effectively in the food industry due to its low solubility and bioavailability. This work aimed to fabricate Moringa oleifera seed protein (MOSP) stabilized emulsions as delivery vehicles for BC and investigate the effect of aqueous phase conditions including pH and ionic strength on this system.

RESULTS

All MOSP samples were positively charged and the particle size of MOSP increased with the increase of pH. At pH 5.0 and 0.2 mol L-1 sodium chloride (NaCl), the MOSP emulsion demonstrated the highest stability coefficient and minimal creaming index, while exhibiting a lower release rate in vitro digestion. The rheological behavior of all MOSP emulsions within the frequency range of 0.1-10 Hz was dominated by viscoelasticity, forming an elastic network structure through dispersed droplets. Additionally, the MOSP emulsion loaded with BC prepared at pH 5.0 and 0.2 mol L-1 NaCl displayed enhanced ultraviolet light stability (52.31 ± 0.03% and 51.86 ± 0.05%) as well as thermal stability (72.39 ± 8.67% and 86.78 ± 10.69%). Furthermore, the BC in the emulsion at pH 7.0 exhibited favorable stability (65.14 ± 0.02%) and optimal bioaccessibility (40.30 ± 0.04%) in vitro digestion.

CONCLUSION

The results provided reference data for utilizing MOSP as a novel emulsifier and broadening the application of BC in the food industry. © 2024 Society of Chemical Industry.

Effect of preheating-induced denaturation of proteins and oleosomes on the structure of protein and soymilk properties

In this paper, effects of preheating-induced denaturation of proteins and oleosomes on protein structure and soymilk quality were studied. The protein in soybeans baked at 55 °C (B-55) and 85 °C (B-85) showed an increase of β-sheet content by 3.2 % and a decrease of α-helix content by 3.3 %, indicating that proteins were gradually unfolded while oleosomes remained intact. The protein resisted thermal denaturation during secondary heating, and soymilks were stable as reflected by a small d3,2 (0.4 μm). However, raw soymilk from soybeans baked at 115 °C (B-115), steamed for 1 min (ST-1) and 5 min (ST-5) presented oleosomes destruction and lipids aggregates. The proteins were coated around the oil aggregates. The β-turn content from soybeans steamed for 10 min (ST-10) increased by 9.5 %, with a dense network where the OBs were tightly wrapped, indicating the serious protein denaturation. As a result, the soymilks B-115 or steamed ones were unstable as evidenced by the serious protein aggregation and larger d3,2 (5.65-12.48 μm). Furthermore, the soymilks were graininess and the protein digestion was delayed due to the formation of insoluble protein aggregates. The flavor and early-stage lipid digestion of soymilk from steamed soybeans was improved owing to lipid release.

Single-Cell Oral Delivery Platform for Enhanced Acid Resistance and Intestinal Adhesion

Oral delivery of cells, such as probiotics and vaccines, has proved to be inefficient since cells are generally damaged in an acidic stomach prior to arrival at the intestine to exert their health benefits. In addition, short retention in the intestine is another obstacle which affects inefficiency. To overcome these obstacles, a cell-in-shell structure was designed with pH-responsive and mucoadhesive properties. The pH-responsive shell consisting of three cationic layers of chitosan and three anionic layers of trans-cinnamic acid (t-CA) was made via layer-by-layer (LbL) assembly. t-CA layers are hydrophobic and impermeable to protons in acid, thus enhancing cell gastric resistance in the stomach, while chitosan layers endow strong interaction between the cell surface and the mucosal wall which facilitates cell mucoadhesion in the intestine. Two model cells, probiotic L. rhamnosus GG and dead Streptococcus iniae, which serve as inactivated whole-cell vaccine were chosen to test the design. Increased survival and retention during oral administration were observed for coated cells as compared with naked cells. Partial removal of the coating (20-60% removal) after acid treatment indicates that the coated vaccine can expose its surface immunogenic protein after passage through the stomach, thus facilitating vaccine immune stimulation in the intestine. As a smart oral delivery platform, this design can be extended to various macromolecules, thus providing a promising strategy to formulate oral macromolecules in the prevention and treatment of diseases at a cellular level.

Structural and interfacial properties of acetylated Millettia speciosa Champ polysaccharide and stability evaluation of the resultant O/W emulsion containing β-carotene

The aim of this study was to investigate the effects of acetylation modification on the structural, interfacial and emulsifying properties of Millettia speciosa Champ polysaccharide (MSCP). Besides, the influence of acetylation modification on the encapsulation properties of polysaccharide-based emulsion was also explored. Results indicated that modification resulted in a prominent reduction in molecular weight of MSCP and the interfacial layer thickness formed by acetylated MSCP (AC-MSCP) was also decreased, but the adsorption rate and ability of AC-MSCP to reduce interfacial tension were improved. AC-MSCP formulated emulsion possessed smaller droplet size (6.8 μm) and exhibited better physical stability under stressful conditions. The chemical stability of β-carotene was also profoundly enhanced by AC-MSCP fabricated emulsion. Moreover, AC-MSCP improved lipids digestion extent, thus facilitating the formation of micelle and increasing bioaccessibility of β-carotene. This study provided insights for rational modification of polysaccharide-based emulsifier and designing delivery system for chemically labile hydrophobic bioactive components.

Fatty Acid Release and Gastrointestinal Oxidation Status: Different Methods of Processing Flaxseed

Flaxseed has been recognized as a superfood worldwide due to its abundance of diverse functional phytochemicals and nutrients. Various studies have shown that flaxseed consumption is beneficial to human health, though methods of processing flaxseed may significantly affect the absorption and metabolism of its bioactive components. Hence, flaxseed was subjected to various processing methods including microwaving treatment, microwave-coupled dry milling, microwave-coupled wet milling, and high-pressure homogenization. In vitro digestion experiments were conducted to assess the impact of these processing techniques on the potential gastrointestinal fate of flaxseed oil. Even though more lipids were released by the flaxseed at the beginning of digestion after it was microwaved and dry-milled, the full digestion of flaxseed oil was still restricted in the intestine. In contrast, oil droplets were more evenly distributed in wet-milled flaxseed milk, and there was a greater release of fatty acids during simulated digestion (7.33 ± 0.21 μmol/mL). Interestingly, wet-milled flaxseed milk showed higher oxidative stability compared with flaxseed powder during digestion despite the larger specific surface area of its oil droplets. This study might provide insight into the choice of flaxseed processing technology for better nutrient delivery efficiency.

Physical properties and in-vitro gastrointestinal digestion of oil-in-water emulsions stabilized by single- and dual-modified cassava starches with cross-linking and octenylsuccinylation

The different modified cassava starches (MCS) obtained by either single or dual modifications with cross-linking (CL) and octenylsuccinylation (OS), including 2%CL, 3%OS, 2%CL-3%OS, and 3%OS-2%CL, were used to stabilize soybean oil-in-water emulsions (oil content 10% (w/w)) at a concentration of 4.5% (w/w) compared to native cassava starch (NCS) and their physical properties and in-vitro gastrointestinal digestion were investigated. The emulsions stabilized with NCS and 2%CL-MCS had larger oil droplet sizes, higher viscosity, and lower negative charge than the emulsions stabilized by single- or dual-MCS with 3%OS. All MCS-stabilized emulsions showed a higher emulsion stability against creaming than the NCS-stabilized emulsion. Under a simulated gastrointestinal tract, all 3%OS-MCS promoted droplet flocculation, while the less ionic NCS and the 2%CL-MCS showed a decrease in droplet size after passing through the mouth and stomach stages. The lipid digestion rate of emulsions stabilized with different MCS and NCS followed the following order: 3%OS >2%CL-3%OS > 3%OS-2%CL > 2%CL > NCS. The NCS- and 2%CL-stabilized emulsions had a lower lipid digestion rate, possibly due to the larger droplet sizes and higher viscosity of the initial emulsions, which delays access of lipase enzymes to lipid droplet surfaces, compared to all 3%OS-MCS-stabilized emulsions.

Effect of marination in lemon juice on beef tenderization and in vitro gastric digestibility

BACKGROUND

There is limited knowledge regarding digestion and absorption of nutrients after cooked marinated meat is ingested. Most of the previous studies on food gastric digestion have focused on chemical digestion and did not reflect upon physical digestion driven by peristalsis. In the present study, we examined the effects of marinating beef in lemon juice on gastric digestibility using a human gastric digestion simulator (GDS) that mimics peristaltic motion called antral contraction waves.

RESULTS

Beef thigh slices were marinated in 100% lemon juice for 1 h and then grilled; an image of a stained tissue sample revealed that muscle tissue contraction (i.e. that usually occurs upon cooking) was suppressed. The measurement of physical properties using a rheometer and texture analyzer showed that the meat marinated in lemon juice had a soft texture. In vitro digestion experiments using the GDS revealed that the extent of both physical digestion driven by peristalsis and chemical digestion catalyzed by digestive enzymes was enhanced by the lemon juice marinade.

CONCLUSION

The results of the present study suggest that marinating beef in lemon juice affects nutrient digestibility. An integrated evaluation of tissue structure, physical properties and GDS digestion to analyze meat digestion would enhance our understanding of the effects of seasoning and cooking methods on meat. © 2023 Society of Chemical Industry.

Comparative study on the in vitro digestion of different lipids in starch-based Pickering emulsions

Starch-based Pickering stabilizer has attracted more attentions due to its health-friendly attribute. Lipid digestion in Pickering emulsion is the key to its delivery ability for active substances. Herein, in vitro oral-gastric-intestinal digestions of Pickering emulsions stabilized by starch particles with different oil phases (e.g., coconut, corn, olive, and sunflower oils) were investigated. The highest rate of lipid digestion was coconut oil (25.71 %), followed by olive (12.64 %), corn (11.16 %), and sunflower (8.99 %) oils. The lipid digestibility was influenced by saturation of fatty acids: coconut (91.41 %)>olive (16.58 %)>corn (14.63 %)>sunflower (10.85 %) oils. The increase of starch concentration (0.5 % - 4.0 %, w/w) had positive effects, while the increase of oil fraction (25 % - 70 %, v/v) had negative impacts on free fatty acid release due to the formation of different initial droplet sizes. The microstructures observed using confocal laser scanning microscope indicated that starch-based Pickering emulsion possessed super stability against oral and gastric digestions, which made it a superior delivery system for lipophilic active substances under severe gastric environment. These results may promote the design of functional food emulsions stabilized by starch particles which can regulate digestion of triglycerides.

Emulsifying performance of the hexadecyltrimethylammonium bromide (CTAB) complexed alginate microgels: Effects from their deformability on oil-water interface

Hexadecyltrimethylammonium bromide complexed alginate-Ca2+ microgels (C/AMGs) were developed as emulsifiers, which shown remarkably improved emulsifying performance than non-complexed alginate-Ca2+ microgels (AMGs) in previous study. This work focus on the impact of deformability on the emulsifying performance of C/AMGs. By regulating alginate concentration (1.0-4.0 wt%), microgels with different deformability were prepared. Deformability was proved to have great influence on the emulsifying performance of C/AMGs, which was evaluated by Langmuir trough measurements, emulsion appearance, centrifugation stability, digestive behavior, and oxidative stability. Particle size and SEM images indicated microgels prepared with lower alginate concentration are more deformable. C/AMGs (2.0 wt%) exhibits the best emulsifying performance, which could be ascribed to the appreciated deformability and mechanical strength. Digestive behavior and oxidative stability of alginate-Ca2+ microgel (2.0 wt%) stabilized emulsions were further investigated. Compared with alginate-Ca2+ microgel (2.0 wt%) stabilized emulsions, C/AMGs (2.0 wt%) stabilized emulsions shown delayed lipid digestion and lower POV. Results of this work supporting that Mickering mechanism have potential in fabricating functional emulsions based on natural polysaccharides.

Co-encapsulation of Paprika and Cinnamon Oleoresins by Spray Drying in a Mayonnaise Model: Bioaccessibility of Carotenoids Using in vitro Digestion

This study aimed to investigate the digestibility and bioaccessibility of spray-dried microparticles co-encapsulating paprika and cinnamon oleoresins using simulated gastrointestinal conditions. It focused on exploring the potential of these co-encapsulated active compounds, which possess diverse technological and functional properties, particularly within a food matrix, in order to enhance their bioavailability. Mayonnaise was selected as the food matrix for its ability to promote the diffusion of carotenoids, as most hydrophobic compounds are better absorbed in the intestine when accompanied by digestible lipids. Model spice mayonnaise, containing 0.5 wt% paprika and cinnamon microparticles content, was formulated in compliance with Brazilian regulations for spices, seasonings, and sauce formulations. Droplet size distribution, optical microscopy and fluorescence microscopy analyses were conducted on the microparticles, model spice mayonnaise, and standard mayonnaise both before and after in vitro gastric and intestinal digestion. Following digestion, all samples demonstrated droplet aggregation and coalescence. Remarkably, dispersed particles (37.40 ± 2.58%) and model spice mayonnaise (17.76 ± 0.07%) showed the highest release rate of free fatty acids (FFAs), indicating efficient lipid digestion. The study found that using mayonnaise as a delivery system significantly increased bioaccessibility (22.7%). This suggests that particles in an aqueous medium have low solubility, while the high lipid composition of mayonnaise facilitates the delivery of active compounds from carotenoids present in paprika and cinnamon oleoresin after digestion.

The digestion and absorption characteristics of human milk phospholipid analogs: a combination study between in vitro and in vivo

Phospholipids play a crucial role in the growth and neurodevelopment of infants. Currently, soybean phospholipids (SPLs) are the common phospholipid component in most infant formulas (IFs), which, however, shows an obvious difference with the phospholipid (PL) composition of human milk fat. Therefore, in the present study, human milk phospholipid analogs (HMPAs) were prepared by mimicking the composition of PE, PC, PI, PS, and SM in breast milk phospholipids and the composition of the major fatty acids (C16:0, C18:0, C18:1, and C18:2), and their digestion and absorption characteristics were explored using in vitro and mice models. The prepared HMPA contained 26.48% PE, 24.64% PC, 36.19% SM, 6.35% PI, and 6.32% PS, with 40.51% C16:0, 17.02% C18:0, 29.19% C18:1, and 13.26% C18:2, showing different digestive properties relative to SPL. There was little effect on the physical and chemical properties of HMPA under in vitro gastric conditions. The hydrolysis degree, fatty acids release rate, and average particle size decreasing rate of HMPA was significantly higher than that of SPL during digestion in vitro intestine (P < 0.05), showing better digestive process relative to SPL. In terms of the mice model, HMPA had a higher hydrolysis degree in the intestinal tract. Based on the area under curve (AUC) analysis of serum fatty acids, it was found that despite HMPA being absorbed at a slower rate than SPL, it was absorbed more than SPL. In summary, the digestion and absorption of HMPA were preferred to SPL, and these obtained results might provide a theoretical basis for the development and utilization of HMPA in IF.

Pancreatic lipase digestion: The forgotten barrier in oral administration of lipid-based delivery systems?

This review highlights the importance of controlling the digestion process of orally administered lipid-based delivery systems (LBDS) and their performance. Oral LBDS are prone to digestion via pancreatic lipase in the small intestine. Rapid or uncontrolled digestion may cause the loss of delivery system integrity, its structural changes, reduced solubilization capacity and physical stability issues. All these events can lead to uncontrolled drug release from the digested LBDS into the gastrointestinal environment, exposing the incorporated drug to precipitation or degradation by luminal proteases. To prevent this, the digestion rate of orally administered LBDS can be estimated by appropriate choice of the formulation type, excipient combinations and their ratios. In addition, in vitro digestion models like pH-stat are useful tools to evaluate the formulation digestion rate. Controlling digestion can be achieved by conventional lipase inhibitors like orlistat, sterically hindering of lipase adsorption on the delivery system surface with polyethylene glycol (PEG) chains, lipase desorption or saturation of the interface with surfactants as well as formulating LBDS with ester-free excipients. Recent in vivo studies demonstrated that digestion inhibition lead to altered pharmacokinetic profiles, where Cmax and Tmax were reduced in spite of same AUC compared to control or even improved oral bioavailability.

Bioactive profiles of edible vegetable oils determined using 10D hyphenated comprehensive high-performance thin-layer chromatography (HPTLC×HPTLC) with on-surface metabolism (nanoGIT) and planar bioassays

Introduction

Vegetable oils rich in unsaturated fatty acids are assumed to be safe and even healthy for consumers though lipid compositions of foods vary naturally and are complex considering the wealth of minor compounds down to the trace level.

Methods

The developed comprehensive high-performance thin-layer chromatography (HPTLC×HPTLC) method including the on-surface metabolization (nanoGIT) and bioassay detection combined all steps on the same planar surface. The pancreatic lipolysis (intestinal phase) experiment and the subsequent analysis of the fatty acid composition including its effect-directed detection using a planar bioassay was performed without elaborate sample preparation or fractionation to ensure sample integrity. Thus, no sample part was lost, and the whole sample was studied on a single surface regarding all aspects. This made the methodology as well as technology miniaturized, lean, all-in-one, and very sustainable.

Results and discussion

To prioritize important active compounds including their metabolism products in the complex oil samples, the nanoGIT method was used to examine the pancreatic lipolysis of nine different vegetable oils commonly used in the kitchen and food industry, e.g., canola oil, flaxseed oil, hemp oil, walnut oil, soybean oil, sunflower oil, olive oil, coconut oil, and palm oil. The digested oils revealed antibacterial and genotoxic effects, which were assigned to fatty acids and oxidized species via high-resolution tandem mass spectrometry (HRMS/MS). This finding reinforces the importance of adding powerful techniques to current analytical tools. The 10D hyphenated nanoGIT-HPTLC×HPTLC-Vis/FLD-bioassay-heart cut-RP-HPLC-DAD-HESI-HRMS/MS has the potential to detect any potential hazard due to digestion/metabolism, improving food safety and understanding on the impact of complex samples.

Effect of Heat Treatment on the Digestive Characteristics of Different Soybean Oil Body Emulsions

Soybean oil body (SOB) emulsions were prepared using OBs extracted at pH 11.0 and pH 7.0. The pH 11.0-SOB comprised oleosins, whereas pH 7.0-SOB comprised extrinsic proteins and oleosins. All SOB emulsions were heated at 60-100 °C for 15 min. Heating may lead to the release of extrinsic proteins from the surface of pH 7.0-SOB due to heat-induced denaturation. The total proportion of α-helix and β-sheets gradually decreased from 77 (unheated) to 36.2% (100 °C). During stomach digestion, the extrinsic protein hydrolysis of heated pH 7.0-SOB emulsions was fast between 60 and 80 °C, and it then slowed between 90 and 100 °C; heating inhibited the oleosin hydrolysis of pH 7.0- and 11.0-SOBs. Heat treatment promoted aggregation and coalescence, and it resulted in increased particle sizes for all emulsions. Larger aggregates were found in heated pH 7.0-SOB emulsions, and larger oil droplets were found in heated pH 11.0-SOB emulsions. After intestinal digestion, the droplets of all SOB emulsions gradually dispersed, and particle sizes decreased. Different heating temperatures had lesser effects on particle sizes and microstructures. Lipolysis was affected by the extraction pH and heating. For pH 11.0-SOB emulsions, the FFA release tendency was greatly affected by the heating temperature, and heating to 80 °C resulted in the highest FFA release (74%). However, all pH 7.0-SOB emulsions had similar total FFA releases. In addition, the droplet charges of heated pH 7.0-SOB emulsions were lower than those of unheated pH 7.0-SOB emulsions in both the intestine and stomach phases; however, the charge changes in different pH 11.0-SOB emulsions showed the opposite tendency. This study will offer guidance regarding the application of SOB emulsions in food.

Influence of Proteins on Bioaccessibility of α-Tocopherol Encapsulation within High Diacylglycerol-Based Emulsions

α-Tocopherol has been widely used in medicine, cosmetics, and food industry as a nutritional supplement and antioxidant. However, α-tocopherol showed low bioaccessibility, and there is a widespread α-tocopherol deficiency in society today. The preparation of oil-in-water emulsions with high safety and low-calorie property is necessary. The aim of this research was to investigate the effects of different protein emulsifiers (whey protein isolate (WPI), soy protein isolate (SPI), and sodium casein (SC)) on the properties of emulsions delivery system, and diacylglycerol (DAG) was picked as a low-accumulated lipid. The interfacial changes, microstructural alterations, and possible interactions of the protein-stabilized DAG emulsions were investigated during the in vitro digestion. The results show that different proteins affect the degree of digestibility and α-tocopherol bioaccessibility of the emulsions. Both WPI- and SPI-coated emulsions showed good digestibility and α-tocopherol bioaccessibility (77.64 ± 2.93%). This might be due to the strong hydrolysis resistance of WPI (β-lactoglobulin) and the good emulsification ability of SPI. The SC-coated emulsion showed the lowest digestibility and α-tocopherol bioaccessibility, this might be due to the emulsification property of hydrolysis products of SC and the potential interaction with calcium ions. This study provides new possibilities for the application of DAG emulsions in delivery systems.

Human milk phospholipid analog improved the digestion and absorption of 1,3-dioleoyl-2-palmitoyl-glycerol

The present study investigated the effects of a human milk phospholipid analog (HPLA) on the digestion and absorption of 1,3-dioleoyl-2-palmitoyl-glycerol (OPO). The HPLA contained 26.48% phosphatidylethanolamine (PE), 24.64% phosphatidylcholine (PC), 36.19% sphingomyelin (SM), 6.35% phosphatidylinositol (PI), and 6.32% phosphatidylserine (PS), with 40.51% C16:0, 17.02% C18:0, 29.19% C18:1, and 13.26% C18:2. The HPLA prevented OPO from hydrolysis during the in vitro gastric phase, while it facilitated the digestion of OPO during the in vitro intestinal stage, resulting in the production of large amounts of diglycerides (DAGs) and monoglycerides (MAGs). In vivo experimental results showed that the HPLA might increase the gastric emptying rate of OPO and increase the hydrolysis and absorption of OPO at an early stage of intestinal digestion. Notably, fatty acids in the serum of the OPO group decreased to their initial value at 5 h, while the serum of the OPO + HPLA (OPOH) group still contained a high level of fatty acids indicating that the HPLA was helpful in maintaining serum lipid at a high level, which might be beneficial for sustainably providing energy for babies. The present study provides data support for the potential application of Chinese human milk phospholipid analogs in infant formulas.

Formation, digestion properties, and physicochemical stability of the rice bran oil body carrier system

Rice bran is a major by-product of rice processing with abundant nutrient content. Oil bodies (OBs), which are fat particles with unique physicochemical stability, are specialized organelles for the storage of oils and fats in plant tissues. In this study, we extracted OBs from rice bran, to evaluate the function of hydrophobic nutrients efficiently delivered by OBs. The carrier system was prepared by sonicating curcumin with medium chain triglycerides (MCT) into rice bran oil bodies (RBOBs). Emulsions comprising different RBOB mass fractions were characterized. The results showed that the highest encapsulation efficiency (EE, 87.67%), optimal particle size (190 nm), and best storage stability were achieved with the 1.5 wt% RBOBs. Based on activity evaluation data, the carrier system can achieve sustained oil release in the intestine and shows high bioaccessibility (61.04%; IC50 in Caco-2 cells was 77.21 μg/mL), which is important for promoting grain by-product utilization.

Food nanoemulsions: how simulated gastrointestinal digestion models, nanoemulsion, and food matrix properties affect bioaccessibility of encapsulated bioactive compounds

Food nanoemulsions are known as very effective and excellent carriers for both lipophilic and hydrophilic bioactive compounds (BCs) and have been successfully used for controlled delivery and protection of BCs during gastrointestinal digestion (GID). However, due to sensitive and fragile morphology, BCs-loaded nanoemulsions have different digestion pathways depending on their properties, food matrix properties, and applied models for testing their digestibility and BCs bioaccessibility. Thus, this review gives a critical review of the behavior of encapsulated BCs into food nanoemulsions during each phase of GID in different static and dynamic in vitro digestion models, as well as of the influence of nanoemulsion and food matrix properties on BCs bioaccessibility. In the last section, the toxicity and safety of BCs-loaded nanoemulsions evaluated on in vitro and in vivo GID models have also been discussed. Better knowledge of food nanoemulsions' behavior in different models of simulated GI conditions and within different nanoemulsion and food matrix types can help to standardize the protocol for their testing aiming for researchers to compare results and design BCs-loaded nanoemulsions with better performance and higher targeted BCs bioaccessibility.

Dried Fruits: Bioactives, Effects on Gut Microbiota, and Possible Health Benefits—An Update

Dried fruits contain many bioactive compounds broadly classified as phytochemicals including phenolics, flavonoids, carotenoids, proanthocyanidins, stilbenes, chalcones/dihydrochalcones, and phytoestrogens. These compounds have antioxidant effects that may benefit health. Dried fruits are also a diverse group of foods with varying fibre contents. The evaluation of the biological activity of these bioactive compounds, including their bioaccessibility and bioavailability, may contribute to the understanding of the health effects of dried fruits. Limited evidence suggests that dried fruits (raisins, cranberries, dates, and prunes) affect human gut microbiota composition in a potentially beneficial manner (in terms of effects on Bifidobacteria, Faecalibacterium prausnitzii, Lactobacillus, Ruminococcaceae, Klebsiella spp., and Prevotella spp.). There is little epidemiological evidence about the association of dried fruit consumption with cardiovascular disease incidence and mortality, as well as the risk of type 2 diabetes or obesity. Clinical trial evidence for the effects of dried fruit consumption on cardiovascular risk factors, including glycaemic control, is mixed. Clinical trial evidence suggests prunes might preserve bone mineral density in postmenopausal women. Consumption of dried fruits is associated with higher-quality diets. Studies are needed to increase our understanding of the health effects of dried fruits and the underlying biological mechanisms.

The modulatory effect of encapsulated bioactives and probiotics on gut microbiota: improving health status through functional food

The gut microbiota can be a determining factor of the health status of the host by its association with some diseases. It is known that dietary intake can modulate this microbiota through the consumption of compounds like essential oils, unsaturated fatty acids, non-digestible fiber, and probiotics, among others. However, these kinds of compounds can be damaged in the gastrointestinal tract as they pass through it to reach the intestine. This is due to the aggressive and changing conditions of this tract. For this reason, to guarantee that compounds arrive in the intestine at an adequate concentration to exert a modulatory effect on the gut microbiota, encapsulation should be sought. In this paper, we review the current research on compounds that modulate the gut microbiota, the encapsulation techniques used to protect the compounds through the gastrointestinal tract, in vitro models of this tract, and how these encapsulates interact with the gut microbiota. Finally, an overview of the regulatory status of these encapsulates is presented. The key findings are that prebiotics are the best modulators of gut microbiota fermentation metabolites. Also, probiotics promote an increase of beneficial gut microorganisms, which in some cases promotes their fermentation metabolites as well. Spray drying, freeze drying, and electrodynamics are notable encapsulation techniques that permit high encapsulation efficiency, high viability, and, together with wall materials, a high degree of protection against gastrointestinal conditions, allowing controlled release in the intestine and exerting a modulatory effect on gut microbiota.

The Effects of Pectin Structure on Emulsifying, Rheological, and In Vitro Digestion Properties of Emulsion

Pectin, a complex hydrocolloid, attracts extensive attention and application stemming from its good emulsification. However, the source of emulsification remains a conundrum. In this experiment, the structures of six kinds of commercial pectin, including LM 101 AS (101), LM 104 AS (104), 121 SLOW SET (121), YM 150 H (150), LM 13 CG (13CG), and β-PECTIN (β-P) were determined, and the effects of pectin structure on emulsion emulsification, rheology and in vitro digestibility were studied. The results showed that the β-P pectin contained a higher content of protein, ferulic acid, and acetyl and had a lower interfacial tension; this pectin-stabilized emulsion exhibited a smaller droplet size and superior centrifugal and storage stability. The results showed that β-P pectin had higher contents of protein, ferulic acid, and acetyl and lower interfacial tension than other pectins, and its stabilized emulsion exhibited smaller droplet size and superior centrifugation and storage stability. Furthermore, the emulsion formed by the pectin with high molecular weight and degree of methoxylation (DM) had a higher viscosity, which can inhibit the aggregation of emulsion droplets to some extent. However, the DM of pectin affected the charge and digestion behavior of pectin emulsion to a great extent. The smaller the DM, the more negative charge the emulsion carried, and the higher the release rate of free fatty acids. The results provided a basis for the rational selection and structural design of the pectin emulsifier.

Bioaccessibility of Plant Sterols in Wholemeal Rye Bread Using the INFOGEST Protocol: Influence of Oral Phase and Enzymes of Lipid Metabolism

Bioaccessibility of plant sterols (PS) in an enriched wholemeal rye bread was evaluated, for the first time, using the INFOGEST protocol without gastric lipase (GL) and cholesterol esterase (CE), with GL or GL + CE. Moreover, human chewing and an in vitro oral phase (simulated salivary fluid and α-amylase) were evaluated for this purpose. The addition of GL decreased the bioaccessibility of total PS (from 23.8 to 18.5%), whereas the use of GL + CE does not significantly affect PS bioaccessibility. The in vitro oral phase resulted in an ineffective homogenization of the fresh vs partially dried and milled bread, reducing the bioaccessibility of total (from 20.2 to 12.8%) and individual PS. The INFOGEST digestion including the use of GL and CE, as well as an oral phase with human chewing, is proposed for the assessment of PS bioaccessibility in a solid matrix such as wholemeal rye bread since it more closely approximates the in vivo situation.

Limosilactobacillus reuteri DS0384 promotes intestinal epithelial maturation via the postbiotic effect in human intestinal organoids and infant mice

Little is known about the modulatory capacity of the microbiota in early intestinal development. We examined various intestinal models that respond to gut microbial metabolites based on human pluripotent stem cell-derived human intestinal organoids (hIOs): physiologically relevant in vitro fetal-like intestine, intestinal stem cell, and intestinal disease models. We found that a newly isolated Limosilactobacillus reuteri strain DS0384 accelerated maturation of the fetal intestine using 3D hIO with immature fetal characteristics. Comparative metabolomic profiling analysis revealed that the secreted metabolite N-carbamyl glutamic acid (NCG) is involved in the beneficial effect of DS0384 cell-free supernatants on the intestinal maturation of hIOs. Experiments in an intestinal stem cell spheroid model and hIO-based intestinal inflamed model revealed that the cell-free supernatant from DS0384 comprising NCG promoted intestinal stem cell proliferation and was important for intestinal protection against cytokine-induced intestinal epithelial injury. The probiotic properties of DS0384 were also evaluated, including acid and bile tolerance and ability to adhere to human intestinal cells. Seven-day oral administration of DS0384 and cell-free supernatant promoted the intestinal development of newborn mice. Moreover, NCG exerted a protective effect on experimental colitis in mice. These results suggest that DS0384 is a useful agent for probiotic applications and therapeutic treatment for disorders of early gut development and for preventing intestinal barrier dysfunction.

Structuring and De-Structuring of Nanovectors from Algal Lipids: Simulated Digestion, Preliminary Antioxidant Capacity and In Vitro Tests

Biocompatible nanocarriers can be obtained by lipid extraction from natural sources such as algal biomasses, which accumulate different lipid classes depending on the employed culture media. Lipid aggregates can be distinguished according to supramolecular architecture into lamellar and nonlamellar structures. This distinction is mainly influenced by the lipid class and molecular packing parameter, which determine the possible values of interfacial curvature and thus the supramolecular symmetries that can be obtained. The nanosystems prepared from bio-sources are able to self-assemble into different compartmentalized structures due to their complex composition. They also present the advantage of increased carrier-target biocompatibility and are suitable to encapsulate and vehiculate poorly water-soluble compounds, e.g., natural antioxidants. Their functional properties stem from the interplay of several parameters. Following previous work, here the functionality of two series of structurally distinct lipid nanocarriers, namely liposomes and cubosomes deriving from algal biomasses with different lipid composition, is characterized. In the view of their possible use as pharmaceutical or nutraceutical formulations, both types of nanovectors were loaded with three well-known antioxidants, i.e., curcumin, α-tocopherol and piperine, and their carrier efficacy was compared considering their different structures. Firstly, carrier stability in biorelevant conditions was assessed by simulating a gastrointestinal tract model. Then, by using an integrated chemical and pharmacological approach, the functionality in terms of encapsulation efficiency, cargo bioaccessibility and kinetics of antioxidant capacity by UV-Visible spectroscopy was evaluated. Subsequently, in vitro cytotoxicity and viability tests after administration to model cell lines were performed. As a consequence of this investigation, it is possible to conclude that nanovectors from algal lipids, i.e., cubosomes and liposomes, can be efficient delivery agents for lipophilic antioxidants, being able to preserve and enhance their activity toward different targets while promoting sustained release.

Zein/pullulan complex colloidal particle-stabilized Pickering emulsions for oral delivery of polymethoxylated flavones: protection effect and in vitro digestion

BACKGROUND

Polymethoxylated flavones (PMFs) show multiple biological functions, while their high hydrophobicity leads to a low bioaccessibility and limits their wide applications. The design of a reasonable food-grade drug delivery system is an effective strategy to improve the low bioaccessibility of PMFs. In this study, sinensetin, tangeretin and nobiletin were encapsulated in Pickering emulsions stabilized by zein/pullulan complex colloidal particles (ZPPs), and the protection effect and in vitro digestion were characterized.

RESULTS

Rheological analysis revealed that ZPP-Pickering emulsion loading with PMFs maintained a strong gel-like network structure. Moreover, the ability to scavenge free radicals of PMFs was improved by the emulsion delivery system. The antioxidant activity of PMFs encapsulated in Pickering emulsion was positively correlated with the oil volume fraction (φ). ZPP-Pickering emulsion loading with PMFs can effectively delay lipid oxidation, and the φ (70%) of Pickering emulsion showed the most pronounced effects, in which the lipid hydroperoxide content and malondialdehyde content decreased by 64.3% and 38.3% after 15 days of storage, compared with the bulk oil group, respectively. The bioaccessibility of the three PMFs has been increased by ZPP-Pickering emulsion simultaneously and it presented the highest values as its φ was 50%, in which the bioaccessibility of sinensetin, tangeretin and nobiletin increased by 2.5, 3.2 and 3.9 times, compared with the bulk oil group, respectively.

CONCLUSION

Pickering emulsion stabilized by ZPPs is an excellent nutrient delivery system for delivering three PMFs simultaneously and imparting functional properties to bioactive delivery systems. © 2022 Society of Chemical Industry.

Fabrication of nanoemulsion delivery system with high bioaccessibility of carotenoids from Lycium barbarum by spontaneous emulsification

The interest in incorporating carotenoids into foods and beverages is growing due to their potential health benefits. However, the poor water solubility and low bioavailability of carotenoids are still challenges in food application. This work aimed to study the influence of system composition and preparation conditions on the physical properties of carotenoids-loaded nanoemulsions prepared by spontaneous emulsification. Furthermore, the bioaccessibility of carotenoids in the nanoemulsions was evaluated. The nanoemulsions with the smallest droplet size were produced when the ratio of Span 80:Tween 80 was 1.5:8.5. The droplet size increased slightly with the increase of organic phase content (24%-40%). The droplet size decreased gradually with the increase of stirring speed (200-1000 rpm (revolutions per minute)). The ratio of mixed surfactants and surfactant-to-oil ratio (SOR) had an appreciable impact on the droplet size. Carotenoids-loaded nanoemulsions with small mean droplet size (d < 50 nm) could be prepared with the optimized conditions. The initial digestion rate decreased as the SOR increased. The bioaccessibility could reach up to about 80% at SOR=2-5 in vitro digestion. These results have important implications for the design of effective delivery systems to encapsulate carotenoids and other lipophilic bioactive components in food applications.

Sterol bioaccessibility in a plant sterol-enriched beverage using the INFOGEST digestion method: Influence of gastric lipase, bile salts and cholesterol esterase

This study evaluates the influence of increasing bile salts and the addition of key enzymes of the lipidic metabolism in the INFOGEST digestion method on sterol bioaccessibility from a plant sterol (PS)-enriched beverage. The assayed modifications were increasing concentration of bovine bile salts (10 vs. 17.5 mM), and addition of gastric lipase (GL) (60U/mL), cholesterol esterase (CE) (0.075 or 2U/mL) or both. Compared to the original method (10 mM bile salts without enzymes), the assayed conditions significantly reduced bioaccessibility of individual (from 11.3 to 19.7 to 5.1-16.6%) and total PS (13.7 to 6.9-8.0%), and cholesterol (52.8 to 20.9-26.1%), except only when CE is added not allowing cholesterol quantification. The bioaccessibility achieved when lipolytic enzymes were tested was similar for all sterols. For a more physiological approach to in vivo conditions, incorporation of bile salts (10 mM), GL (60U/mL) and CE (0.075U/mL) to the INFOGEST method is proposed, although it increases the cost compared to the established method.

Fabrication, characterization and in vitro digestion of camellia oil body emulsion gels cross-linked by polyphenols

This study was designed to investigate the formation of camellia oil body (OB) emulsion gels covalently cross-linked by oxidized polyphenols: catechin (OCT), caffeic acid (OCF), chlorogenic acid (OCA), and tannic acid (OTA). The structural characteristics, thermal stabilities, antioxidant activities, rheological properties, and lipid digestion kinetics of the cross-linked OB-polyphenol emulsion gels were studied. The results of free sulfhydryl and amino group contents, FT-IR, fluorescence spectroscopy, surface hydrophobicity and thermal stability analyses confirmed the formation of covalent interactions between polyphenols and OB emulsions. Based on the second-order structural kinetic model, OB emulsion gel cross-linked by OTA had stronger intermolecular interactions and more developed 3-D network structures than those of OCA, OCF and OCT. Furthermore, lipid digestion kinetics showed that the cross-linking of polyphenols with the OBs slowed down the disintegration of protein matrix under gastric conditions, resulting in delay the release of free fatty acid, which was confirmed by CLSM observations.

In vitro digestion of designed emulsions based on milk protein and guar gum systems

There is a growing interest in designing novel food microstructures that can control nutrient digestion and provide satiety for tackling obesity. In this study, phase separated microstructures of skimmed milk powder (SMP) and guar gum (GG) were the main focus, and these can be considered as water-in-water (W/W) emulsions. Through the incorporation of oil into these systems, it was possible to form model systems of SMP-GG-OIL, showing the lipid phase within the protein phase within the polysaccharide phase. The in vitro digestibility of such phase separated model systems of SMP-GG-OIL with different microstructures was investigated using a pH stat method. Confocal laser scanning microscopy also revealed structural changes that occurred to the emulsified lipid droplets as they passed through a gastrointestinal (GI) model. The microstructures were created based on the tie-lines on a previously established phase diagram of SMP-GG, and shown to be able to control lipid digestion. For a selected tie-line, the lipolysis follows the order: protein continuous > bi-continuous > polysaccharide continuous system, at a certain level of oil addition. The mechanism involved in the lipolysis of the designed formulations/microstructures was dependent upon the protein, rather than GG, and was driven by the protein concentration. These findings provide insights for potential applications in functional food designing in the food industry.

The role of nanostructured lipid carriers and type of biopolymers on the lipid digestion and release rate of curcumin from curcumin-loaded oleogels

Curcumin-nanostructured lipid carrier-loaded oleogels (Cur-NLC-OGs) have been developed with biopolymer cryogels as an efficient delivery system to overcome the extremely low water solubility and instability of curcumin. The effect of NLC and biopolymer types on the encapsulation and release of curcumin from Cur-OGs was investigated. Alginate, carboxymethyl cellulose (CMC), and pectin solutions were firstly freeze dried to make biopolymer cryogels and they were mixed with Cur and Cur-NLC to obtain stable and self-standing Cur-OGs and Cur-NLC-OGs, respectively. As compared to Cur-OGs, Cur-NLC-OGs had higher encapsulation efficiency and showed slower release of curcumin under acidic condition. Although Cur-NLC affected the rapid release of free fatty acids, the Cur-NLC-OGs prepared with CMC cryogel was most efficient in delaying lipid digestion. Overall, NLC and CMC-based OGs could be effectively used to improve encapsulation efficiency and control lipolysis of lipid droplets. These results will be advantageous for the development of oleogels with desirable functionality.

Proanthocyanidins as the main pancreatic lipase inhibitors in chokeberry fruits

Pancreatic lipase inhibitors are recognized as important in strategies for the management of overweight and obesity. The phytocompounds in chokeberry fruit show multidirectional pro-health effects, including anti-obesity activity. The aims of this study were to fractionate and identify the phenolic compounds of chokeberry fruit phenolic-rich extract that are active as pancreatic lipase inhibitors. Phenolic compounds were fractionated using Sephadex LH-20 resin, followed by polyphenol profile analysis using chromatographic and spectrophotometric methods, while pancreatic inhibitory activity was determined using 4-methylumbelliferyl oleate and emulsified triolein as enzyme substrates. Among the six fractions isolated from extract, two fractions rich in highly polymerized proanthocyanidins showed the greatest ability to inhibit pancreatic lipase activity. In comparison, fractions containing mainly low-molecular-weight phenolic compounds, such as phenolic acids, flavonols and anthocyanins, were 11-64 times less active. The most active fraction showed a mixed mode of pancreatic lipase inhibition, as determined by Lineweaver-Burk plot analysis, and exhibited a cumulative effect with orlistat. This study shows that black chokeberry polyphenols, particularly highly polymerized procyanidins, can effectively inhibit pancreatic lipase activity determined by in vitro methods.