Elaboration and characterization of whey protein beads by an emulsification/cold gelation process: application for the protection of retinol

A comparative study of the impacts of preparation techniques on the rheological and textural characteristics of emulsion gels (emulgels)

A subtype of soft solid-like substances are emulsion gels (emulgels; EGs). These composite material's structures either consist of a network of aggregated emulsion droplets or a polymeric gel matrix that contains emulsion droplets. The product's rheological signature can be used to determine how effective it is for a specific application. The interactions between these structured system's separate components and production process, however, have a substantial impact on their rheological imprint. Therefore, rational comprehension of interdependent elements, their structural configurations, and the resulting characteristics of a system are essential for accelerating our progress techniques as well as for fine-tuning the technological and functional characteristics of the finished product. This article presents a comprehensive overview of the mechanisms and procedures of producing EGs (i.e., cold-set and heat-set) in order to determine the ensuing rheological features for various commercial applications, such as food systems. It also describes the influence of these methods on the rheological and textural characteristics of the EGs. Diverse preparation methods are the cause of the rheological-property correlations between different EGs. In many ways, EGs can be produced using various matrix polymers, processing techniques, and purposes. This may lead to various EG matrix structures and interactions between them, which in turn may affect the composition of EGs and ultimately their textural and rheological characteristics.

Research Progress of Protein-Based Bioactive Substance Nanoparticles

Bioactive substances exhibit various physiological activities-such as antimicrobial, antioxidant, and anticancer activities-and have great potential for application in food, pharmaceuticals, and nutraceuticals. However, the low solubility, chemical instability, and low bioavailability of bioactive substances limit their application in the food industry. Using nanotechnology to prepare protein nanoparticles to encapsulate and deliver active substances is a promising approach due to the abundance, biocompatibility, and biodegradability of proteins. Common protein-based nanocarriers include nano-emulsions, nano-gels, nanoparticles, and nano complexes. In this review, we give an overview of protein-based nanoparticle fabrication methods, highlighting their pros and cons. Additionally, we discuss the applications and current issues regarding the utilization of protein-based nanoparticles in the food industry. Finally, we provide perspectives on future development directions, with a focus on classifying bioactive substances and their functional properties.

Fabrication of whey protein/pectin double layer microcapsules for improving survival of Lacticaseibacillus rhamnosus ZFM231

To improve the viability of Lacticaseibacillus rhamnosus ZFM231 strain in the gastrointestinal tract and exhibit better probiotic effect, an internal emulsification/gelation technique was employed to encapsulate this strain using whey protein and pectin as wall materials to fabricate the double layer microcapsules. Four key factors affecting the encapsulation process were optimized using single factor analysis and response surface methodology. Encapsulation efficiency of L. rhamnosus ZFM231 reached 89.46 ± 0.82 %, the microcapsules possessed a particle size of 172 ± 1.80 μm and ζ-potential of -18.36 mV. The characters of the microcapsules were assessed using optical microscope, SEM, FT-IR and XRD analysis. It was found that after exposure to simulated gastric fluid, the bacterial count (log (CFU g^-1)) of the microcapsules only lost 1.96 units, the bacteria were released readily in simulated intestinal fluid, reaching 86.56 % after 90 min. After stored at 4 °C for 28 days and 25 °C for 14 days, bacterial count of the dry microcapsules decreased from 10.59 to 9.02 and 10.49 to 8.70 log (CFU g^-1), respectively. The double layered microcapsules could significantly increase the storage and thermal abilities of bacteria. Such L. rhamnosus ZFM231 microcapsules could find applications as ingredient of the functional foods and the dairy products.

Engineering Emulsion Gels as Functional Colloids Emphasizing Food Applications: A Review

Gels are functional materials with well-defined structures (three-dimensional networks) assembled from the dispersed colloids, and capable of containing a large amount of water, oil, or air (by replacing the liquid within the gel pores), known as a hydrogel, oleogel, and aerogel, respectively. An emulsion gel is a gelled matrix filled with emulsion dispersion in which at least one phase, either continuous phase or dispersed phase forms spatial networks leading to the formation of a semisolid texture. Recently, the interest in the application of gels as functional colloids has attracted great attention in the food industry due to their tunable morphology and microstructure, promising physicochemical, mechanical, and functional properties, and superior stability, as well as controlled release, features for the encapsulated bioactive compounds. This article covers recent research progress on functional colloids (emulsion gels), including their fabrication, classification (protein-, polysaccharide-, and mixed emulsion gels), and properties specifically those related to the gel-body interactions (texture perception, digestion, and absorption), and industrial applications. The emerging applications, including encapsulation and controlled release, texture design and modification, fat replacement, and probiotics delivery are summarized. A summary of future perspectives to promote emulsion gels' use as functional colloids and delivery systems for scouting potential new applications in the food industry is also proposed. Emulsion gels are promising colloids being used to tailor breakdown behavior and sensory perception of food, as well as for the processing, transportation, and targeted release of food additives, functional ingredients, and bioactive substances with flexibility in designing structural and functional parameters.

Vitamin A fortification: Recent advances in encapsulation technologies

Vitamin A is an essential micronutrient whose deficiency is still a major health concern in many regions of the world. It plays an essential role in human growth and development, immunity, and vision, but may also help prevent several other chronic diseases. The total amount of vitamin A in the human diet often falls below the recommended dietary allowance of approximately 900-1000 μ $ \umu $ g/day for a healthy adult. Moreover, a significant proportion of vitamin A may be degraded during food processing, storage, and distribution, thereby reducing its bioactivity. Finally, the vitamin A in some foods has a relatively low bioavailability, which further reduces its efficacy. The World Health Organization has recommended fortification of foods and beverages as a safe and cost-effective means of addressing vitamin A deficiency. However, there are several factors that must be overcome before effective fortified foods can be developed, including the low solubility, chemical stability, and bioavailability of this oil-soluble vitamin. Consequently, strategies are required to evenly disperse the vitamin throughout food matrices, to inhibit its chemical degradation, to avoid any adverse interactions with any other food components, to ensure the food is palatable, and to increase its bioavailability. In this review article, we discuss the chemical, physical, and nutritional attributes of vitamin A, its main dietary sources, the factors contributing to its current deficiency, and various strategies to address these deficiencies, including diet diversification, biofortification, and food fortification.

Microgels at fluid-fluid interfaces for food and drinks

Various aspects of microgel adsorption at fluid-fluid interfaces of relevance to emulsion and foam stabilization have been reviewed. The emphasis is on the wider non-food literature, with a view to highlighting how this understanding can be applied to food-based systems. The various different types of microgel, their methods of formation and their fundamental behavioral traits at interfaces are covered. The latter includes aspects of microgel deformation and packing at interfaces, their deformability, size, swelling and de-swelling and how this affects their surface activity and stabilizing properties. Experimental and theoretical methods for measuring and modelling their behaviour are surveyed, including interactions between microgels themselves at interfaces but also other surface active species. It is concluded that challenges still remain in translating all the possibilities synthetic microgels offer to microgels based on food-grade materials only, but Nature's rich tool box of biopolymers and biosurfactants suggests that this field will still open up important new avenues of food microstructure development and control.

Bioaccessibility of β-Lactoglobulin Nanoemulsions Containing Coenzyme Q10: Impact of Droplet Size on the Bioaccessibility of Coenzyme Q10

The aims of this research were to examine the effect of heating temperature (65, 75, and 85℃) and CaCl2 concentration level (3, 4, and 5 mM) on the physicochemical properties of β-lactoglobulin (β-lg) nanoemulsions (NEs) and to study how the droplet size of NEs affects the bioaccessibility (BA) of coenzyme Q10 (CoQ10). The droplet size of NEs and BA of CoQ10 was assessed by particle size analyzer and UV-Vis spectrophotometer, respectively. An increase in heating temperature and CaCl2 concentration level resulted in a significant (p<0.05) increase in the droplet size of NEs while there were no significant differences in polydispersity index and zeta-potential of NEs. When NEs containing CoQ10 were incubated in simulated small intestinal phases, an increase in the droplet size and polydispersity index of NEs was observed. This indicated that NEs were not stable in small intestine and digestion of NEs occurred. As heating temperature and CaCl2 concentration level were decreased, a significant (p<0.05) increase in BA of CoQ10 was observed. There was a significant (p<0.05) increase in BA of CoQ10 with a decrease in the droplet size of NEs. In conclusion, heating temperature and CaCl2 concentration level were key-parameters affecting the initial droplet size of NEs and BA of CoQ10 was negatively correlated with initial droplet size of NEs.

Properties of microparticles from a whey protein isolate/alginate emulsion gel

Designing soft, palatable and nutritious texture-modified foods for the elderly is a challenge for food technologists. The aim of this work was to produce and characterize emulsion-gelled microparticles (EGM) made from whey protein isolate (WPI) and sodium alginate (NaAlg) that may be used to modify the rheology of liquid foods and as carriers of lipids and lipophilic nutrients and bioactives. Olive oil microdroplets became embedded in the WPI/NaAlg gel matrix in the form of an emulsion produced by ultrasound (US) or high-speed blending (HSB). Oil microdroplets were obtained by US and HSB, with an average equivalent diameter varying between 2.0-3.2 µm and 4.5-6.7 µm, respectively. Oil incorporation increased compression stress of bulk emulsion gels at small deformations compared to the no-oil microgel, but this effect was reversed at high strains. EGM were prepared by shear-induced size reduction. Rheological tests at 20 ℃ and 40 ℃ showed that US-EGM and HSB-EGM exhibited a predominant elastic behavior, with G' >  G″ throughout the frequency range. However, when HSB-EGM were heated at 60 ℃ their rheological behavior changed to a more fluid-like condition, but not that of US-EGM. Consequently, EGM have the properties needed to improve food texture for people with masticatory/swallowing dysfunctions or needing special nutrition.

Modulation of Lipid Digestion Profiles Using Filled Egg White Protein Microgels

Colloidal delivery systems are required to encapsulate, protect, and release active food ingredients, such as vitamins, nutraceuticals, and minerals. In this study, lipid droplets were encapsulated within biopolymer microgels fabricated from egg white proteins using an injection-gelation process. Confocal fluorescence microscopy indicated that lipid droplets were dispersed within a network of cross-linked proteins within the microgels. The properties of the lipid-loaded microgels were compared to those of simple oil-in-water emulsions stabilized by egg white proteins. Light scattering and microscopy measurements indicated that both delivery systems exhibited good stability under acid conditions (pH 3-5) but aggregated at higher pH values as a result of a reduction in electrostatic repulsion. Simulated gastrointestinal tract studies indicated that lipid droplets encapsulated within protein microgels were digested more slowly than free lipid droplets. Our results therefore suggest that egg white protein microgels may be useful for encapsulation and controlled release of hydrophobic bioactive agents.

Atomization of denatured whey proteins as a novel and simple way to improve oral drug delivery system properties

In the sphere of drug delivery, denatured whey protein (DWP) has in recent times gained press. However, to date, no scalable and affordable dosage form has been developed. The objective of our study was to evaluate the potential use of spray-dried DWP as a ready to use excipient for oral drug delivery. Therefore, solid state, FTIR spectra and wettability were studied. Dissolution, mucoadhesion and the effect on paracellular permeability were also evaluated. The spray-dried DWP particles were spherical with 4μm mean diameter. Further, relative to native WP, the spray-dried DWP particles bore reduced wettability, and their structure was characterized by the exposure of a high amount of free thiol and by the formation of intermolecular β-sheets. The DWP powders were mucoadhesive, enzymatic inhibitors, biocompatible and they induced the opening of tight junctions. Our study shows great potential for the use of spray-drying as a technique to modify the dissolution rate of drugs and enhance the oral bioavailability of molecules. That is, the use of spray drying as a single step ready to use DWP excipient.

Nanotechnology Applications in Functional Foods; Opportunities and Challenges

Increasing knowledge on the link between diet and human health has generated a lot of interest in the development of functional foods. However, several challenges, including discovering of beneficial compounds, establishing optimal intake levels, and developing adequate food delivering matrix and product formulations, need to be addressed. A number of new processes and materials derived from nanotechnology have the potential to provide new solutions in many of these fronts. Nanotechnology is concerned with the manipulation of materials at the atomic and molecular scales to create structures that are less than 100 nm in size in one dimension. By carefully choosing the molecular components, it seems possible to design particles with different surface properties. Several food-based nanodelivery vehicles, such as protein-polysaccharide coacervates, multiple emulsions, liposomes and cochleates have been developed on a laboratory scale, but there have been very limited applications in real food systems. There are also public concerns about potential negative effects of nanotechnology-based delivery systems on human health. This paper provides an overview of the new opportunities and challenges for nanotechnology-based systems in future functional food development.

Recombinant protein materials for bioengineering and nanomedicine

Proteins are essential macromolecules supporting life. Being efficient catalyzers and offering specific cross-molecular contacts, proteins are largely exploited in biotechnology and biomedicine as therapeutics, in industrial catalysis or as molecular reagents. Recombinant enzymes, hormones, immunogens and antibodies are produced aiming to different applications, on the basis of their ability to interact with or modify substrates or biological targets. In nature, proteins also perform task-specific architectonic roles, and they can organize in supramolecular complexes with intriguing physical properties such as elasticity and adhesiveness, and with regulatable stiffness, flexibility and mechanical strength. Proteins have recently gained interest as materials for bioengineering and nanomedicine as they can combine these features with functionality, biocompatibility and degradability in unusually versatile composites. We revise here the fundamental properties of the diverse categories of emerging protein materials resulting from biological synthesis and how they can be genetically re-designed to engineer the interplay between mechanical and biological properties in a medically oriented exploitable way.

Cold-set whey protein microgels as pH modulated immobilisation matrices for charged bioactives

The ability of cold-set whey protein microgels to function as pH-sensitive immobilisation matrices for bioactives was investigated. A pH dependent interaction was confirmed between the microgels and charged bioactives and this binding was impeded by the presence of competing ions in the solution, suggesting an electrostatic interaction. The use of a computer generated prediction model for the pH-dependent association of the microgels and further bioactives (including cationic and anionic peptides) was validated. The prediction model was efficient at determining the pH at which the maximum microgel-bioactive interaction occurred. This study highlights the capabilities of these food-grade whey based microgels as matrices that enable the immobilisation of a variety of bioactives by a charge interaction, and shows the potential for these matrices to function as smart delivery systems, in which uptake and release of bioactives is facilitated by environmental pH change.