Bioaccessibility of Nutrients and Micronutrients from Dispersed Food Systems: Impact of the Multiscale Bulk and Interfacial Structures

Unraveling the intricate connection between dietary factors and the success in long-term space missions

In recent decades of spaceflight, inadequate caloric intake has posed significant nutritional challenges, contributing to muscle degradation, weakened immune and cardiovascular systems during and after space missions. This challenge becomes more acute on longer exploration missions, where transporting all food for the entire mission becomes a logistical challenge. This places immense pressure on the food system, requiring energy-dense, varied, stable, and palatable food options. Prolonged storage can lead to nutrient degradation, reducing their bioavailability and bioaccessibility to astronauts. Research is essential not only to improve the quality and stability of space food but also to enhance nutrient bioavailability, thereby reducing weight and volume of food. Muscle and bone loss represent major risks during extended spaceflight, prompting extensive efforts to find exercise countermeasures. However, increased exercise requires additional energy intake, and finding the optimal balance between energy needs and the preservation of muscle and bone mass is challenging. Currently, there is no reliable way to measure total energy expenditure and activity-related energy expenditures in real-time. Systematic research is necessary to develop onboard technology for accurate energy expenditure and body composition monitoring. This research should aim to establish an optimal exercise regimen that balances energy requirements while maintaining astronaut strength and minimizing food transport. In summary, this overview outlines key actions needed for future exploration missions to maintain body mass and physical strength of space travellers. It addresses the requirements for food processing and preservation, considerations for space food formulation and production, and the essential measures to be implemented.

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.

Cholecalciferol- and α-tocopherol-loaded walnut oil emulsions stabilized by whey protein isolate and soy lecithin for food applications

BACKGROUND

To overcome the limitations in the use of protein as an emulsifier, soy lecithin, a natural surfactant, was used along with whey protein isolate (WPI) to produce o/w emulsions containing cholecalciferol and α-tocopherol. The physical stability of the emulsions prepared with WPI and varying concentrations of lecithin (0, 1, 2, and 3% w/w) was measured in different heat, pH, and ionic-strength food environmental conditions.

RESULTS

All emulsions were shown to be less than 250 nm in size and less than 0.3 in polydispersity index (PDI). The morphology of the emulsions was spherical, and the droplets of the emulsion containing lecithin were thicker and larger than those of the emulsion without lecithin (WPI_L0). After autoclaving, WPI_L0 increased in size from 197.8 ± 1.7 nm to 528.5 ± 28.4 nm, and the retention of cholecalciferol and α-tocopherol decreased to 40.83 ± 0.63% and 49.68 ± 1.84%, respectively. At pH 5.5, near the isoelectric point of WPI, WPI_L0 increased in size due to aggregation, but emulsions containing lecithin remained stable at a PDI under 0.3. Turbiscan stability index of the emulsion prepared with WPI and 3% lecithin was the lowest, indicating good storage stability. In addition, it was confirmed that the higher the lecithin content, the higher the viscosity, and the higher the amount of free fatty acids released in the in vitro digestion model.

CONCLUSION

This study can provide theoretical evidence for enhancing the physical stability of protein emulsions by co-stabilization with lecithin, promoting their application in various foods. © 2022 Society of Chemical Industry.

Compositional, Structural, and Kinetic Aspects of Lipid Digestion and Bioavailability: In Vitro, In Vivo, and Modeling Approaches

Lipid digestion and bioavailability are usually investigated separately, using different approaches (in vitro, modeling, in vivo). However, a few inclusive studies show that their kinetics are closely linked. Lipid bioavailability kinetics is likely involved in the development and evolution of several diseases, so lipid digestion kinetics could be involved as well and can be modulated by food design or combination. To illustrate this possibility, the compositional and structural aspects of lipid digestion kinetics, as investigated using in vitro and modeling approaches, are presented first. Then, in vivo and mixed approaches enabling the study of both kinetics are reviewed and discussed. Finally, disparate modeling approaches are introduced, and a unifying modeling scheme is proposed, opening new perspectives for understanding the role and interactions of various factors (chemical, physical, and biological) involved in lipid metabolism.

Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Improvement of nutrient bioavailability in millets: Emphasis on the application of enzymes

Millets are a traditional staple food of the dryland regions of the world and are rich in essential nutrients like protein, fatty acids, minerals, vitamins, and dietary fiber. Also, millets commonly synthesize a range of secondary metabolites to protect themselves against adverse conditions. These factors are collectively termed anti-nutritional factors and the existence of these factors in millets might reduce the accessibility of the nutrients in humans. Some of these factors include protease inhibitors, tannins, non-starch polysaccharides-glucans, phytates, and oxalates each of which might directly or indirectly affect the digestibility of nutrients. Methods like soaking, germination, autoclaving, debranning, and the addition of exogenous enzymes have been used to reduce the anti-nutritional factors and elevate the bioavailability of the nutrients. This review summarizes various methods that have been used to improve nutrient bioavailability, specifically emphasizing the use of enzymes to improve nutrient bioavailability from millets. © 2021 Society of Chemical Industry.

Influence of food matrix and food processing on the chemical interaction and bioaccessibility of dietary phytochemicals: A review

Consumption of phytochemicals-rich foods shows the health effect on some chronic diseases. However, the bioaccessibility of these phytochemicals is extremely low, and they are often consumed in the diet along with the food matrix. The food matrix can be described as a complex assembly of various physical and chemical interactions that take place between the compounds present in the food. Some studies indicated that the physiological response and the health benefits of phytochemicals are resultant in these interactions. Some food substrates inhibit the absorption of phytochemicals via this interaction. Moreover, processing technologies have been developed to facilitate the release and/or to increase the accessibility of phytochemicals in plants or breakdown of the food matrix. Food processing processes may disrupt the activity of phytochemicals or reduce bioaccessibility. Enhancement of functional and sensorial attributes of phytochemicals in the daily diet may be achieved by modifying the food matrix and food processing in appropriate ways. Therefore, this review concisely elaborated on the mechanism and the influence of food matrix in different parts of the digestive tract in the human body, the chemical interaction between phytochemicals and other compounds in a food matrix, and the various food processing technologies on the bioaccessibility and chemical interaction of dietary phytochemicals. Moreover, the enhancing of phytochemical bioaccessibility through food matrix design and the positive/negative of food processing for dietary phytochemicals was also discussed in this study.

Microtechnological Tools to Achieve Sustainable Food Processes, Products, and Ingredients

One of the major challenges we face as humankind is supplying a growing world population with sufficient and healthy foods. Although from a worldwide perspective sufficient food is produced, locally, the situation can be dire. Furthermore, the production needs to be increased in a sustainable manner for future generations, which also implies prevention of food waste, and making better use of the available resources. How to contribute to this as food technologists is an ultimate question, especially since the tools that can investigate processes at relevant time scales, and dimensions, are lacking. Here we propose the use of microtechnology and show examples of how this has led to new insights in the fields of ingredient isolation (filtration), and emulsion/foam formation, which will ultimately lead to better-defined products. Furthermore, microfluidic tools have been applied for testing ingredient functionality, and for this, various examples are discussed that will expectedly contribute to making better use of more sustainably sourced starting materials (e.g., novel protein sources). This review will wrap up with a section in which we discuss future developments. We expect that it will be possible to link food properties to the effects that foods create in vivo. We thus expand the scope of this review that is technical in nature, toward physiological functionality, and ultimately to rational food design that is targeted to improve human health.

Ethylcellulose Oleogels: Structure, Functionality, and Food Applications

The structuring edible oils by nontraditional means has become a popular strategy for improving the lipid profile of food products while retaining the functionality of a crystalline triglyceride network. Although numerous oleogelator systems have now been identified, the polymer gelator ethylcellulose (EC) may present the greatest potential for applications in a diverse range of food systems which require unique physical attributes and structuring properties in the fat phase. The first portion of this chapter will provide a brief overview of oleogelation strategies, outline the basic physical characteristics of the polymer EC, and describe the mechanism of gelation and some basic physical characteristics of EC oleogels. The subsequent sections will highlight different strategies which have been identified to manipulate the rheological and mechanical properties of these gels, including the addition of food-grade surfactants and other amphiphilic molecules, modulating bulk solvent polarity, and through the formation of EC/hybrid gelator systems. The final section will highlight various applications in food systems reported in the literature, outline recent work investigating the effect of structuring edible oils with EC on digestibility, and the potential applicability of these oleogels as a delivery vehicle for lipid-soluble molecules. The potential applications for EC oleogels in complex food systems are quite promising, and the strategies for manipulating their physical properties may also extend their applicability into the pharmaceutical, cosmetic, and manufacturing industries.

Evaluation of the physicochemical stability and digestibility of microencapsulated esterified astaxanthins using in vitro and in vivo models

Esterified astaxanthins are used as functional nutraceuticals in many food products. Unfortunately, their utilization is currently limited owing to their poor water solubility, chemical instability, and low bioavailability. In this study, esterified astaxanthin microcapsules were fabricated through electrostatic complexation of whey protein and gum arabic by adjusting the pH to 4.0. After their encapsulation, the stability of the esterified astaxanthins was effectively better than that of the oleoresin. In vitro tests revealed a 26% rate of astaxanthin release from the microcapsules, which was significantly higher than the 14.6% rate from the oleoresin (P < 0.05). In vivo experiments showed that the AUC_0-t value after oral gavage of the microcapsules (8.23 ± 1.33 h·μg·mL^-1) was approximately 2-fold higher than that after gavage of the oleoresin (3.72 ± 0.98 h·μg·mL^-1). In conclusion, the bioavailability of esterified astaxanthins can be significantly improved by microencapsulation.

Polysaccharides in Human Health Care

Polysaccharides are abundant natural polymers found in plants, animals and microorganisms with exceptional properties and essential roles to sustain life. They are well known for their high nutritive value and the positive effects on our immune and digestive functions and detoxification system. The knowledge and recognition of the important role they play for promoting and maintaining human health and wellbeing is continuously increasing. This review describes some important polysaccharides (e.g. mucilages and gums, glycosamine glycans and chitin/chitosan) and their medical, cosmetic and pharmaceutical applications, with emphasis on the relationship between structure and function. Next, the use of polysaccharides as nutraceuticals and vaccines is discussed in more detail. An analysis of the trends and challenges in polysaccharide research concludes the paper.

Bioaccessibility of hydroxytyrosol and n-3 fatty acids as affected by the delivery system: simple, double and gelled double emulsions

This study examines the influence of different food-grade n-3 PUFA-enriched simple emulsion (SE), double emulsion (DE) and gelled double emulsion (GDE) delivery systems on the extent of lipolysis, antioxidant capacity and the bioaccessibility of hydroxytyrosol (HTy). GDE emulsion offered better protection for HTy (89%) than the other systems (79% in SE and DE). The reducing capacity of the emulsions containing HTy were not altered during oral digestion. However, "in vitro" gastric and intestinal phases significantly reduced the antioxidant activity of all systems. The structural and physical state of GDE entailed a slowing-down of triacylglyceride hydrolysis (36.4%) in comparison with that of SE and DE (22.7 and 24.8% for SE and DE, respectively).

Bioavailability of Nutrients and Micronutrients: Advances in Modeling and In Vitro Approaches

The bioavailability of food nutrients and microconstituents is recognized as a determinant factor for optimal health status. However, human and animal studies are expensive and limited by the large amount of potential food bioactive compounds. The search for alternatives is very active and raises many questions. On one hand, in vitro digestion systems are good candidates, but to date only bioaccessibility has been correctly assessed. To go further, to what degree should natural processes be reproduced? What techniques can be used to measure the changes in food properties and structures in situ in a noninvasive way? On the other hand, modeling approaches have good potential, but their development is time-consuming. What compromises should be done between food and physiology realism and computational ease? This review addresses these questions by identifying highly resolved analytical methods, detailed computer models and simulations, and the most promising dynamic in vitro systems.

Plant Food Residues as a Source of Nutraceuticals and Functional Foods

This chapter describes the use of different plant and vegetable food residues as nutraceuticals and functional foods. Different nutraceuticals are mentioned and explained. Their uses are well addressed along with their disease management and their action as nutraceutical delivery vehicles.

Sulforaphane formation and bioaccessibility are more affected by steaming time than meal composition during in vitro digestion of broccoli

Broccoli is a rich source of the glucosinolate glucoraphanin (GR). After hydrolysis of GR by the endogenous enzyme myrosinase, sulforaphane (SF) or sulforaphane nitrile (SFN) are produced, depending on environmental conditions. How the conversion of GR and bioaccessibility of released breakdown products are affected by steaming (raw, 1min, 2min and 3min steamed) and meal composition (protein or lipid addition) was studied with an in vitro digestion model (mouth, stomach, intestine, but not colonic digestion). The main formation of SF and SFN occurred during in vitro chewing. The contents of GR, SF and SFN did not change after further digestion, as the irreversible inactivated myrosinase under gastric conditions caused no further GR hydrolysis. SF concentrations were up to 10 times higher in raw and 1min steamed broccoli samples after digestion compared to longer-steamed broccoli. Protein or lipid addition had no influence on the formation and bioaccessibility of SF or SFN.

Intactness of cell wall structure controls the in vitro digestion of starch in legumes

Increasing the level of starch that is not digested by the end of the small intestine and therefore enters the colon (‘resistant starch’) is a major opportunity for improving the nutritional profile of foods.

Subphase exchange experiments with the pendant drop technique

INTRODUCTION

The development of the coaxial double capillary 15 years ago opened up the possibility to undertake accurate desorption and penetration studies of interfacial layers in the pendant drop technique. Drop and bubble methods offer several advantages with respect to other interfacial techniques. They allow a more stringent control of the environmental conditions, use smaller amounts of material and provide a much higher interface/volume ratio than in conventional Langmuir Troughs.

EXPERIMENTAL

The coaxial capillary was developed 15 years ago at the University of Granada as an accessory for the pendant drop surface film balance. It allows exchanging the subphase of the drop without disturbing the surface film and preserving the drop volume throughout the subphase exchange. Hence, this methodology enables one to carry out a great variety of interfacial studies well beyond the usual adsorption profiles. Penetration studies, sequential adsorption measurements, desorption kinetics, reversibility of adsorption and testing of enzymatic treatments on interfacial layers are amongst the principal applications. The coaxial capillary has been recently upgraded to a multi-exchange device which has boosted its applicability. It can be now used to address multilayer formation, create soft interfacial nano-composites such as membranes, polyelectrolyte assemblies and simulate in vitro digestion in a single droplet.

APPLICATIONS

This review aims to compile the experimental work done, using the pendant drop subphase exchange in the last decade, and how its use has provided new insights into the surface/interfacial properties of many different materials. Special emphasis is placed on recent work regarding simulation of in vitro digestion in order to address issues relating to metabolism degradation profiles. The use of this methodology when dealing with interfacial studies allows setting the foundations of interfacial engineering technology. Based on subphase exchange experiments, we aim to develop models for competitive adsorption of different compounds at the interface and build up layer-by-layer interfacial structures. Future challenges comprise the design of finely adjusted nanoengineering systems, based on multilayer assemblies with tailored functionalities, to match the application demand.

In vitro digestion of emulsions: high spatiotemporal resolution using synchrotron SAXS

Although the biochemical processes of lipid digestion are well-known, the biophysical ones, responsible for the assembly of molecules into functional structures, lack studies resolving both time and space scales. About 35 years ago, the seminal microscopy study of Patton and Carey constituted a major advance to reach this goal. Nowadays, new perspectives arise from the availability of large facilities scattering techniques, able to monitor the dynamics of multi-scale assemblies with unprecedented resolutions. The present small angle X-ray scattering (SAXS) study focused on the roles of the emulsifier and triglyceride in the formation of lipid assemblies during emulsion digestion in vitro. By developing several interpretations of the data in the whole space range (qualitative, shape-dependent and shape-independent models), the characteristic size of the assemblies and their transition times were obtained, which depended on the triglyceride, but not on the emulsifier. The major assembly formed was found to be a spherical mixed micelle, but vesicle was also found to coexist throughout the digestion, although in a lower proportion. The quantitative determination of the sizes and proportions of these assemblies, as well as the evolution of these characteristics during digestion are precious information for nutritional sciences, as these assemblies are the vehicles of lipophilic nutrients and micronutrients towards their absorption site.

Cross-linking of interfacial casein layer with genipin prevented pH-induced structural instability and lipase digestibility of the fat droplets

The present study provided a new approach to enhance the stability of protein-emulsified nanoemulsions and to control the lipase digestibility of lipid droplets through spontaneous cross-linking of the interfacial layer with genipin, a functional ingredient isolated from the fruit of Gardenia jasminoides E. Cross-linking casein-emulsified nanoemulsions under different genipin/casein mass ratios (1:20, 1:10, 1:5) significantly (p < 0.05) or very significantly (p < 0.01) enhanced their stability under harsh gastric pH environments and prevented nanoemulsion flocculation. As observed by transmission electron microscope (TEM), under the pH 1.2 condition, the genipin cross-linked nanoemulsion showed more compact microstructure with clear and defined contour as well as "core-shell" structure caused by the swelling of the surface protein film. Interestingly, the intestinal digestibility of lipid droplets was delayed very significantly (p < 0.01) after cross-linking the interfacial casein layer with genipin, which was enhanced by the increase in genipin/casein mass ratio and cross-linking time.

Refining in silico simulation to study digestion parameters affecting the bioaccessibility of lipophilic nutrients and micronutrients

A numerical study of more parameters influencing the gastro-intestinal digestion and bioaccessibility of lipophilic nutrients and micronutrients (the graphical abstract presents the gastric digestion).

Bioaccessibility of lipophilic micro-constituents from a lipid emulsion

The physicochemical parameters controlling the transfer of lipophilic micro-constituents from emulsion droplets to mixed micelles (bioaccessibility) are reviewed.

Enhancing vitamin E bioaccessibility: factors impacting solubilization and hydrolysis of α-tocopherol acetate encapsulated in emulsion-based delivery systems

Impact of free fatty acid chain length on vitamin E bioaccessibility: long chain FFAs form mixed micelles that easily accommodate vitamin E, whereas medium chain FFAs do not.

Multiscale analysis of structure development in expanded starch snacks

In this paper we perform a multiscale analysis of the food structuring process of the expansion of starchy snack foods like keropok, which obtains a solid foam structure. In particular, we want to investigate the validity of the hypothesis of Kokini and coworkers, that expansion is optimal at the moisture content, where the glass transition and the boiling line intersect. In our analysis we make use of several tools, (1) time scale analysis from the field of physical transport phenomena, (2) the scale separation map (SSM) developed within a multiscale simulation framework of complex automata, (3) the supplemented state diagram (SSD), depicting phase transition and glass transition lines, and (4) a multiscale simulation model for the bubble expansion. Results of the time scale analysis are plotted in the SSD, and give insight into the dominant physical processes involved in expansion. Furthermore, the results of the time scale analysis are used to construct the SSM, which has aided us in the construction of the multiscale simulation model. Simulation results are plotted in the SSD. This clearly shows that the hypothesis of Kokini is qualitatively true, but has to be refined. Our results show that bubble expansion is optimal for moisture content, where the boiling line for gas pressure of 4 bars intersects the isoviscosity line of the critical viscosity 10(6) Pa.s, which runs parallel to the glass transition line.

Influence of heat and shear induced protein aggregation on the in vitro digestion rate of whey proteins

Protein intake is essential for growth and repair of body cells, the normal functioning of muscles, and health related immune functions.

A microfluidic device to study the digestion of trapped lipid droplets

Digestion of 140 μm lipid droplets generated and trapped in a microfluidic device, with continuous digestive juice renewal.

The search for a new paradigm to study micronutrient and phytochemical bioavailability: from reductionism to holism

The study of micronutrient and phytochemical (MaP, i.e., non-energy nutrients) bioavailability has been mainly studied through a reductionist and pharmacological approach. This has led to associate one health effect to one MaP. However, human interventional studies have given conflicting and disappointing results about MaP supplementation. This is because the health effect is the result of the synergetic action of numerous MaPs supplied by foods and/or diets at nutritional doses. A food is not a drug. Therefore, there is a need for more holistic approach to study MaP bioavailability, then their health effect to achieve general recommendations. This paper aims to hypothesize for such a paradigm shift in this topic and to lay new foundations for research in MaP bioavailability.