Recent progress in hydrogel delivery systems for improving nutraceutical bioavailability

Abstract

Nutraceuticals are bioactive molecules found in foods that may improve human performance, wellbeing, or health. The potential health benefits of many nutraceuticals are not fully realized because they are chemically degraded during storage or within the gastrointestinal tract. Consequently, there is a need to develop food-grade delivery systems to encapsulate and protect nutraceuticals until they reach an appropriate location within the human body, e.g., mouth, stomach, small intestine, or colon. Hydrogel beads ("microgels") assembled from proteins and/or polysaccharides can improve nutraceutical performance by protecting them from chemical degradation. These beads can be fabricated using simple and inexpensive processing operations that typically involve two steps: (i) formation of biopolymer-enriched particles; (ii) cross-linking of the biopolymers. Hydrophilic nutraceuticals are usually mixed directly with the biopolymer solution prior to formation of the hydrogel beads, whereas hydrophobic nutraceuticals are typically incorporated into lipid droplets (emulsions or nanoemulsions) prior to mixing with the biopolymer solution. Common particle-formation methods include injection, shearing, templating, and phase separation, whereas common cross-linking methods include changes in solvent quality, counter-ion addition, heating, and cooling. This article provides an overview of recent progress in the design and fabrication of foodgrade hydrogel beads to encapsulate and protect nutraceuticals, including some examples of their potential applications.

Bioavailability of nutraceuticals: Role of the food matrix, processing conditions, the gastrointestinal tract, and nanodelivery systems

“…Most hydrophilic nutraceuticals are in a solid state. This category includes salts, acids, bases, water‐soluble polyphenols, and vitamins (McClements, 2015, 2017). In the GIT fluids, slightly acidic or alkaline hydrophilic molecules ionize differently depending on the pH values.…”

Delivery by Design (DbD): A Standardized Approach to the Development of Efficacious Nanoparticle‐ and Microparticle‐Based Delivery Systems

“…Hydrogel particles (sometimes called nanogels or microgels) may also be fabricated from synthetic or natural polymers, but they contain higher levels of water (typically >80% to 90%). A wide variety of different methods are available for producing hydrogel particles including injection, templating, emulsion, and phase separation methods (McClements ). The composition and porosity of hydrogel particles must be carefully controlled to ensure appropriate loading, retention, and release properties (Figure a and b).…”

“…Complex delivery systems are usually fabricated by applying structural design principles to modify the properties and functionality of simple delivery systems (Figure ) (McClements ). In this section, some of the major structural design principles that are typically used are highlighted.…”

“…The embedding approach can also be used to modify the properties of other types of colloidal dispersion so as to enhance their functional attributes. For example, nanoparticles can be embedded in microparticles to improve their stability or to control their release profile (McClements ). As an example, lipid droplets have been trapped inside calcium alginate microgels so as to protect them from degradation during storage, but then to release them in response to a specific environmental trigger (Zeeb and others , ).…”

“…The rate of chemical degradation of many bioactive agents depends on pH. In this example, the impact of pH on degradation of curcumin is shown after 1 mo storage at 37 °C (Kharat and McClements ).…”