Dynamic In Vitro Gastric Digestion Behaviour of Commercial Infant Formulae Made with Cow, Goat and Sheep Milk.

There are a wide range of commercial infant formulae available on the market. These are made using milk from different species, such as goat, sheep, and cow. The different protein compositions of these milks and the process used during infant-formulae manufacture, such as heat treatment, may impact the digestion of nutrients. This study compared the effect of protein composition and heat treatment on the in vitro gastric digestion behaviour of commercial infant formulae made with cow, goat, and sheep milk using a dynamic infant human gastric simulator (IHGS). During the simulated dynamic gastric digestion, the goat milk infant formula (GIF) showed earlier signs of aggregate formation compared to cow milk infant formula (CIF) and sheep milk infant formula (SIF). In addition, the microstructures of GIF chyme showed fragmented and porous structures. On the contrary, CIF formed dense protein networks that trapped oil droplets, whereas SIF exhibited a microstructure of smooth oil droplets surrounded by fewer protein networks. The different aggregation behaviours and aggregate structures of the three infant-formulae chyme were related to their different protein compositions, especially the different casein compositions. Furthermore, the open fragile structure of GIF aggregates provided easier access to pepsin, allowing it to hydrolyse protein. The results from the present study provided some information to assist in understanding the coagulation and digestion behaviours of commercial infant formulae made from different species of milk.

Delivery of encapsulated bioactive compounds within food matrices to the digestive tract: recent trends and future perspectives.

Encapsulation technologies have achieved encouraging results improving the stability, bioaccessibility and absorption of bioactive compounds post-consumption. There is a bulk of published research on the gastrointestinal behavior of encapsulated bioactive food materials alone using in vitro and in vivo digestion models, but an aspect often overlooked is the impact of the food structure, which is much more complex to unravel and still not well understood. This review focuses on discussing the recent findings in the application of encapsulated bioactive components in fabricated food matrices. Studies have suggested that the integration of encapsulated bioactive compounds has been proven to have an impact on the physicochemical characteristics of the finished product in addition to the protective effect of encapsulation on the fortified bioactive compound. These products containing bioactive compounds undergo further structural reorganization during digestion, impacting the release and emptying rates of fortified bioactive compounds. Thus, by manipulation of various food structures and matrices, the release and delivery of these bioactive compounds can be altered. This knowledge provides new opportunities for designing specialized foods for specific populations.

Food structure confers specific functionalities to supplemented encapsulated bioactive compounds during processing and digestion.Encapsulation of bioactive compounds prevents changes in physicochemical attributes of foods during processing.The unique disintegration patterns of foods in the gut impacts how bioactive substances are released and absorbed.

The impact of differently structured starch gels on the gastrointestinal fate of a curcumin-containing nanoemulsion.

In this study, we focused on the in vitro gastrointestinal digestion of curcumin-nanoemulsion-loaded corn starch gels formed using starches with different amylose contents, i.e. waxy (WCS), normal (NCS) and high amylose (HACS) corn starches and their impact on the release and bioaccessibility of curcumin. Curcumin nanoemulsion (CNE) loading significantly increased the storage modulus of the WCS and NCS gels by interspersing in the gelatinized continuous phase, whereas it decreased in the HACS gel due to the formation of a weak network structure as a result of the incomplete gelatinized amylose granules. During the gastric digestion, the disintegration and emptying of the WCS + CNE gel from the stomach was the slowest compared to the other two gels. The changes in the stomach, influenced the emptying of total solids (HACS + CNE > NCS + CNE > WCS + CNE) into the gastric digesta, which further affected the rate of starch and lipid digestion during the intestinal phase. The HACS + CNE and NCS + CNE gels showed a higher and faster release of curcumin compared to the WCS + CNE gel that showed a slower and sustained release during the intestinal digestion. This study demonstrated that the oral-gastric digestion of these starch gels was more dependent on the gel structures rather than on the molecular properties of the starches. The dynamic gastric environment resulted in the formation of distinct gel structures, which significantly influenced the composition and microstructure of the emptied digesta, further affecting starch hydrolysis and curcumin bioaccessibility in the small intestine.

New Perspectives on the Delivery of Nutrients and Bioactive Compounds through Gastric Restructuring of Foods.

All foods come from living organisms in which macromolecules such as proteins and polysaccharides are assembled into complex hierarchical structures. Many of the nutrients and bioactive compounds are contained within these structures, from which they must be liberated and converted into an absorbable form during digestion. It has been realized that the modification of these structures during digestion plays a key role in determining the bioaccessibility and rates of absorption of bioactive compounds. The concept of "food structure design" has been applied to developing food structures to control the perception of fat, salt, and sugar in food products, but the role of food structure as a variable in nutrient and bioactive delivery is relatively unknown. Understanding the architecture and structures of foods and how they interact within the physiological environment of the GIT could lead to new foods that provide optimal bio-accessibility and absorption of bioactive compounds. Recent work at our institute has demonstrated the importance of understanding the state and structures of food materials in the environment of the GIT, particularly in the stomach, and the critical role of 'modified' structures on the kinetics of the release of nutrients and bioactive compounds from the food matrix (e.g., the rate, extent and type of released nutrients), gastric emptying and subsequent digestion of foods in the small intestine. The use of dynamic in vitro digestion in combination with in-vivo studies has provided new insights into the structural dynamics of complex food systems and subsequent interactions of food components during the gastrointestinal transit.

Plant oil bodies and their membrane components: new natural materials for food applications.

Plants store triacylglycerols in the form of oil bodies (OBs) as an energy source for germination and subsequent seedling growth. The interfacial biomaterials from these OBs are called OB membrane materials (OBMMs) and have several applications in foods, e.g., as emulsifiers. OBMMs are preferred, compared with their synthetic counterparts, in food applications as emulsifiers because they are natural, i.e., suitable for clean label, and may stabilize bioactive components during storage. This review focuses mainly on the extraction technologies for plant OBMMs, the functionality of these materials, and the interaction of OB membranes with other food components. Different sources of OBs are evaluated and the challenges during the extraction and use of these OBMMs for food applications are addressed.

Impact of Recombined Milk Systems on Gastrointestinal Fate of Curcumin Nanoemulsion.

Milk powder is an important ingredient in various foods and pediatric formulations. The textural and digestion properties of the formulations depend on the preheat treatment of the milk powder during manufacture. Thus, it is interesting to know how these modifications can influence on the release of fortified bioactive compounds during digestion with a milk matrix. In this study, a curcumin nanoemulsion was incorporated into milks reconstituted from low-heat, medium-heat and high-heat skim milk powders (SMPs) and the milks were subjected to semi dynamic in vitro digestion. All the recombined milk systems formed a curd under gastric conditions, which reduced the gastric emptying of protein and curcumin-loaded oil droplets. Because of the formation of heat-induced casein/whey protein complexes, the open fragmented curd formed by the high-heat-treated reconstituted powder resulted in higher protein and oil droplets emptying to the intestine and higher curcumin bioaccessibility. This study provides useful information for how protein ingredients can govern the fate of added health-promoting compounds during digestion.

Food Structure and Nutrition Interface: New Perspectives in Designing Healthy and Sustainable Foods.

The increasing world population, impact of food production on climate change, and ongoing issues with diet-related diseases (e.g., malnutrition and obesity) are global major challenges. Recent advances in how food structure impacts the extent and kinetics of uptake of nutrients and its consequent effects on the physiological outcomes are beginning to shift our understanding of nutrition. This understanding is important to designing future foods that provide optimum nutrient bioavailability and deliver healthy outcomes. We discuss perspectives and scientific challenges in understanding the complex relationship between food structure/matrix modification during the digestion process and the absorption of nutrients as well as designing food structures with more sustainable materials.

How plants solubilise seed fats: revisiting oleosin structure and function to inform commercial applications.

Plants store triacylglycerides in organelles called oil bodies, which are important fuel sources for germination. Oil bodies consist of a lipid core surrounded by an interfacial single layer membrane of phospholipids and proteins. Oleosins are highly conserved plant proteins that are important for oil body formation, solubilising the triacylglycerides, stabilising oil bodies, and playing a role in mobilising the fuel during the germination process. The domain structure of oleosins is well established, with N- and C-terminal domains that are hydrophilic flanking a long hydrophobic domain that is proposed to protrude into the triacylglyceride core of the oil body. However, beyond this general understanding, little molecular level detail on the structure is available and what is known is disputed. This lack of knowledge limits our understanding of oleosin function and concomitantly our ability to engineer them. Here, we review the state of play in the literature regarding oleosin structure and function, and provide some examples of how oleosins can be used in commercial settings.

Biophysical insights into modulating lipid digestion in food emulsions.

During the last decade, major scientific advances on understanding the mechanisms of lipid digestion and metabolism have been made, with a view to addressing health issues (such as obesity) associated with overconsumption of lipid-rich and sucrose-rich foods. As lipids in common foods exist in the form of emulsions, the structuring of emulsions has been one the main strategies for controlling the rate of lipid digestion and absorption, at least from a colloid science viewpoint. Modulating the kinetics of lipid digestion and absorption offers interesting possibilities for developing foods that can provide control of postprandial lipaemia and control the release of lipophilic compounds. Food emulsions can be designed to achieve considerable differences in the kinetics of lipid digestion but most research has been applied to relatively simple model systems and in in vitro digestion models. Further research to translate this knowledge into more complex food systems and to validate the results in human studies is required. One promising approach to delay/control lipid digestion is to alter the stomach emptying rate of lipids, which is largely affected by interactions of emulsion droplets with the food matrices. Food matrices with different responses to the gastric environment and with different interactions between oil droplets and the food matrix can be designed to influence lipid digestion. This review focuses on key scientific advances made during the last decade on understanding the physicochemical and structural modifications of emulsified lipids, mainly from a biophysical science perspective. The review specifically explores different approaches by which the structure and stability of emulsions may be altered to achieve specific lipid digestion kinetics.

Structural and Physicochemical Characteristics of Oil Bodies from Hemp Seeds (Cannabis sativa L.).

The structural and physicochemical characteristics of oil bodies from hemp seeds were explored in this study. Oil bodies from several plant-based sources have been previously studied; however, this is the first time a characterisation of oil bodies from the seeds of industrial hemp is provided. The morphology of oil bodies in hemp seeds and after extraction was investigated using cryo-scanning electron microscopy (cryo-SEM), and the interfacial characteristics of isolated oil bodies were studied by confocal laser scanning microscopy (CLSM). Proteins associated with oil bodies were characterised using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The effect of pH and ionic strength on colloidal properties of the oil bodies was investigated. Oil bodies in hemp seeds appeared spherical and sporadically distributed in the cell, with diameters of 3 to 5 µm. CLSM images of isolated oil bodies revealed the uniform distribution of phospholipids and proteins at their interface. Polyunsaturated fatty acids were predominant in the lipid fraction and linoleic acid accounted for ≈61% of the total fatty acids. The SDS-PAGE analysis of washed and purified oil bodies revealed major bands at 15 kDa and 50-25 kDa, which could be linked to membrane-specific proteins of oil bodies or extraneous proteins. The colloidal stability of oil bodies in different pH environments indicated that the isoelectric point was between pH 4 and 4.5, where oil bodies experienced maximum aggregation. Changes in the ionic strength decreased the interfacial charge density of oil bodies (ζ-potential), but it did not affect their mean particle size. This suggested that the steric hindrance provided by membrane-specific proteins at the interface of the oil bodies could have prevented them from flocculation at low interfacial charge density. The results of this study provide new tertiary knowledge on the structure, composition, and colloidal properties of oil bodies extracted from hemp seeds, which could be used as natural emulsions or lipid-based delivery systems for food products.

Ruminant Milk-Derived Extracellular Vesicles: A Nutritional and Therapeutic Opportunity?

Milk has been shown to contain a specific fraction of extracellular particles that are reported to resist digestion and are purposefully packaged with lipids, proteins, and nucleic acids to exert specific biological effects. These findings suggest that these particles may have a role in the quality of infant nutrition, particularly in the early phase of life when many of the foundations of an infant's potential for health and overall wellness are established. However, much of the current research focuses on human or cow milk only, and there is a knowledge gap in how milk from other species, which may be more commonly consumed in different regions, could also have these reported biological effects. Our review provides a summary of the studies into the extracellular particle fraction of milk from a wider range of ruminants and pseudo-ruminants, focusing on how this fraction is isolated and characterised, the stability and uptake of the fraction, and the reported biological effects of these fractions in a range of model systems. As the individual composition of milk from different species is known to differ, we propose that the extracellular particle fraction of milk from non-traditional and minority species may also have important and distinct biological properties that warrant further study.

A higher-protein nut-based snack product suppresses glycaemia and decreases glycaemic response to co-ingested carbohydrate in an overweight prediabetic Asian Chinese cohort: the Tu Ora postprandial RCT.

Nut-based products may aid low-glycaemic dietary strategies that are important for diabetes prevention in populations at increased risk of dysglycaemia, such as Asian Chinese. This randomised cross-over trial assessed the postprandial glycaemic response (0-120 min) of a higher-protein nut-based (HP-NB) snack formulation, in bar format (1009 kJ, Nutrient Profiling Score, NPS, -2), when compared with an iso-energetic higher-carbohydrate (CHO) cereal-based bar (HC-CB, 985 kJ, NPS +3). It also assessed the ability to suppress glucose response to a typical CHO-rich food (white bread, WB), when co-ingested. Ten overweight prediabetic Chinese adults (mean, sd: age 47⋅9, 15⋅7 years; BMI 25⋅5, 1⋅6 kg/m2), with total body fat plus ectopic pancreas and liver fat quantified using dual-energy X-ray absorptiometry and magnetic resonance imaging and spectroscopy, received the five meal treatments in random order: HP-NB, HC-CB, HP-NB + WB (50 g available CHO), HC-CB + WB and WB only. Compared with HC-CB, HP-NB induced a significantly lower 30-120 min glucose response (P < 0⋅05), with an approximately 10-fold lower incremental area under the glucose curve (iAUC0-120; P < 0⋅001). HP-NB also attenuated glucose response by approximately 25 % when co-ingested with WB (P < 0⋅05). Half of the cohort had elevated pancreas and/or liver fat, with 13-21 % greater suppression of iAUC0-120 glucose in the low v. high organ fat subgroups across all five treatments. A nut-based snack product may be a healthier alternative to an energy equivalent cereal-based product with evidence of both a lower postprandial glycaemic response and modulation of CHO-induced hyperglycaemia even in high-risk, overweight, pre-diabetic adults.

In vitro dynamic gastric digestion of soya protein/milk protein blended beverages: influence of protein composition and co-processing.

The gastric digestion behaviours of blended protein beverages containing different ratios of casein, whey protein and soya protein that were heat-treated at 60 °C or 80 °C were investigated using an in vitro dynamic human gastric simulator. All beverages showed protein aggregation and curd formation under gastric conditions; the extent of protein aggregation/curd formation was dependent on the protein composition of the beverage. The beverages with high proportions of milk proteins showed a greater degree of curd formation during gastric digestion, due to the coagulation of casein micelles. These beverages also showed a lower rate of protein emptying from the stomach. Increasing the relative proportion of soya protein in the beverage increased the rate of protein emptying, because of changes in the curd structure caused by the interactions of soya protein with casein micelles. There was a relatively small effect of heating to 80 °C on the protein emptying rate and the protein content of the clot. The results suggest that protein beverages with different protein compositions could be developed to provide controlled delivery of proteins and amino acids.

Nature-Assembled Structures for Delivery of Bioactive Compounds and Their Potential in Functional Foods.

Consumers are demanding more natural, healthy, and high-quality products. The addition of health-promoting substances, such as bioactive compounds, to foods can boost their therapeutic effect. However, the incorporation of bioactive substances into food products involves several technological challenges. They may have low solubility in water or poor stability in the food environment and/or during digestion, resulting in a loss of their therapeutic properties. Over recent years, the encapsulation of bioactive compounds into laboratory-engineered colloidal structures has been successful in overcoming some of these hurdles. However, several nature-assembled colloidal structures could be employed for this purpose and may offer many advantages over laboratory-engineered colloidal structures. For example, the casein micelles and milk fat globules from milk and the oil bodies from seeds were designed by nature to deliver biological material or for storage purposes. These biological functional properties make them good candidates for the encapsulation of bioactive compounds to aid in their addition into foods. This review discusses the structure and biological function of different nature-assembled carriers, preparation/isolation methods, some of the advantages and challenges in their use as bioactive compound delivery systems, and their behavior during digestion.

Nanoemulsion structure and food matrix determine the gastrointestinal fate and in vivo bioavailability of coenzyme Q10.

In this work, we sought to incorporate coenzyme Q10-loaded nanoemulsions into a food system and to understand the impact of food digestion on the in vivo bioavailability of this bioactive compound. We selected octenyl succinic anhydride modified starch as emulsifier to prepare the nanoemulsions (with approximately 200 nm droplet diameter) after comparing with two other food-grade surfactants (whey protein isolate and lecithin) in terms of their colloidal stability during simulated gastrointestinal digestion. The change in ζ-potential revealed that the initial emulsifier might be partially replaced by bile salts under intestinal conditions, and the mixed micelles formed after digestion showed an apparent permeability coefficient of 4.79 × 10-6 cm/s in a rat intestinal epithelial cell line, without compromising the trans-epithelial electrical resistance. In a second step, a high protein beverage that incorporated the coenzyme Q10-loaded nanoemulsion was developed in a food pilot plant. The beverage had a particle size of D4,3 = 18 µm and D3,2 = 2.5 µm, corresponding to its different components. The changes in particle morphology and size distribution were analysed to understand the behaviour of this beverage during simulated gastrointestinal digestion. When coenzyme Q10 was encapsulated into the nanoemulsions and the beverage, its bioavailability in vivo increased 1.8- and 2.8-fold respectively, compared with coenzyme Q10 dissolved in oil. The higher coenzyme Q10 bioavailability in the beverage was probably because of a significantly higher level of lipolytic activity found for beverage than for nanoemulsions during gastrointestinal digestion. These results show the potential of using natural food materials to generate formulations to improve the bioavailability of bioactive compounds. More importantly, we highlight the influence of food digestion (i.e. lipolysis) on the absorption of hydrophobic bioactive components and suggest that food systems can be utilised as a dosage form to further enhance oral bioavailability.

Modulating Biopolymer Electrical Charge to Optimize the Assembly of Edible Multilayer Nanofilms by the Layer-by-Layer Technique.

The aim of this work was to study the influence of biopolymer (alginate, ALG; chitosan, CHI) charge on the formation of multilayer nanofilms by the layer-by-layer (LbL) technique. The electrical charge of ALG and CHI (high, medium, or low) was modulated by adjusting the pH of biopolymer solutions. The amount of biopolymer deposited in multilayers depended on the charge of ALG and CHI solutions. The lower the charge the higher the deposition rate due to the higher number of biopolymer molecules needed to neutralize the previous layer. Medium and low charge biopolymers led to a drastic change in the wettability of multilayers, with ALG layers being strongly hydrophilic and CHI layers strongly hydrophobic. The surface ζ-potential alternatively changed from negative to positive using ALG or CHI. This effect was more pronounced using highly charged biopolymers. Results obtained in this study evidenced that the multilayers properties can be tuned by controlling the biopolymer electrical charge.