Food-grade filled hydrogels for oral delivery of lipophilic active ingredients: Temperature-triggered release microgels

A comprehensive review of food gels: formation mechanisms, functions, applications, and challenges

Gels refer to the soft and flexible macromolecular polymeric materials retaining a large amount of water or biofluids in their three-dimensional network structure. Gels have attracted increasing interest in the food discipline, especially proteins and polysaccharides, due to their good biocompatibility, biodegradability, nutritional properties, and edibility. With the advancement of living standards, people's demand for nutritious, safe, reliable, and functionally diverse food and even personalized food has increased. As a result, gels exhibiting unique advantages in food application will be of great significance. However, a comprehensive review of functional hydrogels as food gels is still lacking. Here, we comprehensively review the gel-forming mechanisms of food gels and systematically classify them. Moreover, the potential of hydrogels as functional foods in different types of food areas is summarized, with a special focus on their applications in food packaging, satiating gels, nutrient delivery systems, food coloring adsorption, and food safety monitoring. Additionally, the key scientific issues for future food gel research, with specific reference to future novel food designs, mechanisms between food components and matrices, food gel-human interactions, and food gel safety, are discussed. Finally, the future directions of hydrogels for food science and technology are summarized.

Release of bioactive compounds from delivery systems by stimuli-responsive approaches; triggering factors, mechanisms, and applications

Recent advances in emerging nanocarriers and stimuli-responsive (SR) delivery systems have brought about a revolution in the food and pharmaceutical industries. SR carriers are able to release the encapsulated bioactive compounds (bioactives) upon an external trigger. The potential of releasing the loaded bioactives in site-specific is of great importance for the pharmaceutical industry and medicine that can deliver the cargo in an appropriate condition. For the food industry, release of encapsulated bioactives is considerably important in processing or storage of food products and can be used in their formulation or packaging. There are various stimuli to control the favorite release of bioactives. In this review, we will shed light on the effect of different stimuli such as temperature, humidity, pH, light, enzymatic hydrolysis, redox, and also multiple stimuli on the release of encapsulated cargo and their potential applications in the food and pharmaceutical industries. An overview of cargo release mechanisms is also discussed. Furthermore, various alternatives to manipulate the controlled release of bioactives from carriers and the perspective of more progress in these SR carriers are highlighted.

Advanced approaches for improving bioavailability and controlled release of anthocyanins

Anthocyanins are a group of phytochemicals responsible for the purple or red color of plants. Additionally, they are recognized to have health promoting functions including anti-cardiovascular, anti-thrombotic, anti-diabetic, antimicrobial, neuroprotective, and visual protective effect as well as anti-cancer activities. Thus, consumption of anthocyanin supplement or anthocyanin-rich foods has been recommended to prevent the risk of development of chronic diseases. However, the low stability and bioavailability of anthocyanins limit the efficacy and distribution of anthocyanins in human body. Thus, strategies to achieve target site-local delivery with good bioavailability and controlled release rate are necessary. This review introduced and discussed the latest advanced techniques of designing lipid-based, polysaccharide-based and protein-based complexes, nano-encapsulation and exosome to overcome the limitation of anthocyanins. The improved bioavailability and controlled release of anthocyanins have great significance for gastrointestinal tract absorption, transepithelial transportation and cellular uptake. The techniques of applying different biocompatible materials and modifying the solubility of anthocyanins complex could achieve target site-local delivery with negligible degradation and good bioavailability in human body.

Food-grade systems for delivery of DHA and EPA: Opportunities, fabrication, characterization and future perspectives

Docosahexaenoic acid (C22: 6n-3, DHA) and eicosapentaenoic acid (C20: 5n-3, EPA) have been shown to provide the opportunity to inhibit onset and escalation of chronic diseases. Nevertheless, their undesirable characteristics including poor water solubility, oxidation sensitivity, high melting point and unpleasant sensory attributes hinder their application in the food industry. In recent years, utilizing food-grade delivery systems to deliver DHA/EPA and improve their biological efficacy has emerged as an attractive approach with fascinating prospects. This review focuses on introducing potential delivery systems for DHA/EPA, including microemulsions, nanoemulsions, Pickering emulsions, hydrogels, lipid particles, oleogels, liposomes, microcapsules and micelles. The opportunities, fabrication and characterization of these delivery systems loaded with DHA/EPA are highlighted. Besides, food sources of DHA/EPA, their benefits to the human body and a series of challenges for effective utilization of DHA/EPA are discussed. Promising future research trends of food-grade systems for delivery of DHA/EPA are also presented. Conducting in vivo experiments, applying DHA/EPA-loaded delivery systems into real food, improving the applicability of such delivery systems in industrial production, co-encapsulating DHA/EPA with other substances, seeking measures to improve the performance of existing delivery systems and developing novel food-grade delivery systems inspired by other fields are various future considerations.

Complexing hemp seed protein with pectin for improved emulsion stability

Hemp seed protein has the potential to be used in food systems as an emulsifying agent; however, there are still some shortcomings associated with hemp seed protein, such as poor solubility and tendency to aggregate. This study aims to improve the dispersibility of hemp seed protein as an emulsifier by complexing with pectin, driven by electrostatic force. Three protein to pectin ratios were used for complexation, from 1:1, 2:1 to 4:1. The complexation improved the polydispersity of hemp seed protein when dispersed in the aqueous phase. The hemp seed protein displayed multimodal size distribution in water at pH = 3.0 due to aggregation, while the incorporation of pectin helped to diminish those aggregated proteins. When the hemp seed protein was used to stabilize the oil-in-water emulsion, its stabilized emulsion showed promising homogenous droplet size distribution after emulsification. However, during the accelerated storage conditions (55°C), the emulsion stabilized solely by hemp seed protein was subjected to extensive coalescence. From day 0 to 9, the droplet size (d_4,3 ) increased by 50 folds from 3.215 to 161.6 µm. In contrast, the hemp seed protein-pectin complex exhibited extraordinary stability during the storage test, where size evolution in all three samples was negligible compared to the emulsion stabilized by hemp seed protein. Rheological characterization suggests that pectin provided physical strength, which may help the emulsion droplets to maintain structural integrity under environmental stress. The underlying mechanism could be associated with the formation of a three-dimensional structure by pectin through bridging adjacent emulsion droplets. PRACTICAL APPLICATION: Hemp seed protein is gaining more and more attention as an emerging plant protein. Recently, hemp seed protein has been explored as an emulsifier, but its stabilized emulsion encounters instability issues during storage. Our study suggests pectin could be used as a co-stabilizer for hemp seed protein emulsions.

Emulsion, hydrogel and emulgel systems and novel applications in cannabinoid delivery: a review

Emulsions, hydrogels and emulgels have attracted a high interest as tools for the delivery of poorly soluble hydrophobic nutraceuticals by enhancing their stability and bioavailability. This review provides an overview of these delivery systems, their unique qualities and their interactions with the human gastrointestinal system. The modulation of the various delivery systems to enhance the bioavailability and modify the release profile of bioactive encapsulates is highlighted. The application of the delivery systems in the delivery of cannabinoids is also discussed. With the recent increase of cannabis legalization across North America, there is much interest in developing cannabis edibles which can provide a consistent dose of cannabinoids per portion with a rapid time of onset. Indeed, the long time of onset of psychoactive effects and varied metabolic responses to these products result in a high risk of severe intoxication due to overconsumption. Sophisticated emulsion or hydrogel-based delivery systems are one potential tool to achieve this goal. To date, there is a lack of evidence linking specific classes of delivery systems with their pharmacokinetic profiles in humans. More research is needed to directly compare different classes of delivery systems for the gastrointestinal delivery of cannabinoids.

Texture-Modified Food for Dysphagic Patients: A Comprehensive Review

Food texture is a major food quality parameter. The physicochemical properties of food changes when processed in households or industries, resulting in modified textures. A better understanding of these properties is important for the sensory and textural characteristics of foods that target consumers of all ages, from children to the elderly, especially when food product development is considered for dysphagia. Texture modifications in foods suitable for dysphagic patients will grow as the numbers of elderly citizens increase. Dysphagia management should ensure that texture-modified (TM) food is nutritious and easy to swallow. This review addresses how texture and rheology can be assessed in the food industry by placing particular emphasis on dysphagia. It also discusses how the structure of TM food depends not only on food ingredients, such as hydrocolloids, emulsifiers, and thickening and gelling agents, but also on the applied processing methods, including microencapsulation, microgels as delivery systems, and 3D printing. In addition, we address how to modify texture for individuals with dysphagia in all age groups, and highlight different strategies to develop appropriate food products for dysphagic patients.

Structural characterization of nanoemulsions stabilized with sodium caseinate and of the hydrogels prepared from them by acid-induced gelation

Hydrogels obtained by acidification with glucono-δ-lactone (GDL), starting from nanoemulsions formulated with different concentrations of sodium caseinate (1-4 wt%) or 4 wt% sodium caseinate and sucrose (2-8 wt%), were prepared with the aim of quantifying structural parameters of both, initial nanoemulsions and hydrogels after 2.5 h of GDL addition, using the Guinier-Porod (GP) or the generalized GP models. Gelation process was followed by performing in situ temperature-controlled X-ray small angle scattering experiments (SAXS) using synchrotron radiation. In nanoemulsions, the calculated radius of gyration for oil nanodroplets (Rg _oil ) decreased with increasing protein concentration and for the 4 wt% protein nanoemulsion, with increasing sucrose content. Calculated values of Rg _oil were validated correlating them with experimental Z-average values as measured by dynamic light scattering (DLS). For hydrogels, radii of gyration for the sphere equivalent to the hydrogel scattering object (R _gsph ) were close to 3 nm while correlation distances among building blocks (R _g2 ) were dependent on formulation. They increased with increasing contents of sodium caseinate and sucrose. R _g2 parameter linearly correlated with hydrogel strength (G' _∞ ): a more connected nanostructure led to a stronger hydrogel.

Natural biopolymer-based hydrogels for use in food and agriculture

Hydrogels are important materials that are of high scientific interest and with numerous applications. Natural polymer-based hydrogels are preferred to synthetic ones due to their safety, biocompatibility, and ecofriendly properties. They have been studied extensively and implemented in various fields, such as medicine, cosmetics, personal-care products, water purification, and more. This review focuses on the applications of nature-sourced polymer-based hydrogels in food and agriculture. Different types of biopolymers and crosslinking agents, and various methods for hydrogel formation are described. The physicomechanical properties and applied activities of the resulting materials are also comprehensively discussed. Biodegradable synthetic polymers are outside the scope of this review. © 2020 Society of Chemical Industry.

Casein-based hydrogels: A mini-review

Casein-based hydrogels are biocompatible, biodegradable, renewable, easy to obtain, inexpensive, and non-toxic. They exist in different physicochemical states, e.g. particle hydrogels, which can be dived in suspensions or emulsions and macro hydrogels that are gel colloid type. These biomaterials have drawn increasing attention in recent years due to their abilities to form networks of different tensile strengths and to encapsulate, protect and release biomolecules. This mini-review outlines the recent advances in casein-based hydrogel research and the uses of casein-based hydrogels as drug delivery system for both hydrophobic and hydrophilic molecules. The food and biomedical potential along with possible future uses of the casein-based hydrogels are discussed throughout the document.

Preparation and characterisation of a novel hydrogel based on Auricularia polytricha β-glucan and its bio-release property for vitamin B12 delivery

BACKGROUND

This study investigates a novel hydrogel synthesis method and its bio-release property. This hydrogel, with a three-dimensional network structure based on Auricularia polytricha β-glucan, was characterised by means of Fourier transform infrared spectroscopy, ¹ H NMR and scanning electron microscopy. Vitamin B₁₂ (VB₁₂ , cobalamin) as a hydrophilic functional food component was entrapped into these hydrogels. The in vitro release profile of VB₁₂ was established in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).

RESULTS

The results showed that the hydrogel had medium pore size from 30 to 300 µm, and the swelling ratio increased with the degree of substitution. The hydrogel demonstrated good stability in SGF and bio-release capability in SIF for VB₁₂ . The accumulated release rate is about 80% in SIF and below 20% in SGF, which indicated the significant different release property in stomach and intestine.

CONCLUSION

The Auricularia polytricha β-glucan-based hydrogel has a good swelling ratio, pepsin stability and pancrelipase-catalysed biodegradation property. The bio-release rate is significantly different in SIF and SGF, which indicated that this hydrogel could be a good intestinal target carrier of VB₁₂ . © 2017 Society of Chemical Industry.

Microfluidic fabrication of hollow protein microcapsules for rate-controlled release

Using an internal phase separation method to direct protein self-assembly and control the formation of microcapsules.

Designing food delivery systems: challenges related to the in vitro methods employed to determine the fate of bioactives in the gut

This review discussesin vitroavailable approaches to study delivery and uptake of bioactive compounds and the associated challenges.