Microencapsulation of active ingredients in functional foods: From research stage to commercial food products

Background: Twelves categories of active ingredients have been recognised to enhance human health. They are to some extent susceptible to certain conditions such as heat, light and low pH. To reduce their susceptibility and achieve controlled release at the target site, various microencapsulation strategies have been introduced. Scope and approach: In this review, the chemical structures, physicochemical properties and beneficial effects of the active components are summarised. Different encapsulation techniques and tailored shell materials have been investigated to optimise the functional properties of microcapsules. Several encapsulated constituents (e.g., amino acids) have been successfully incorporated into food products while others such as lactic acid bacteria are mostly used in the free format. Encapsulating some of these active ingredients will extend their ability to withstand process conditions such as heat and shear, and prolong their shelf stability. Key findings and conclusions: The functional properties of a microcapsule are encapsulation efficiency, size, morphology, stability, and release characteristics. Several microencapsulation strategies include the use of double emulsions, hybrid wall materials and crosslinkers, increasing intermolecular attraction between shell and core, physical shielding of shell materials, and the addition of certain ions. Other approaches such as the use of hardening agents, nanoencapsulation, or secondary core materials, and the choice of shell materials possessing specific interactions with the core may be used to achieve targeted release of active ingredients. The physicochemical properties of shell materials influence where the active ingredients will be released in vivo. A suitable microencapsulation strategy of active ingredients will therefore expand their applications in the functional foods industry

Modification of molecular conformation of spray-dried whey protein microparticles improving digestibility and release characteristics

This study reports on the preparation of riboflavin-loaded whey protein isolate (WPI) microparticles, using desolvation and then spray drying. Ethanol desolvation led to the exposure of embedded hydrophobic amino acids of WPI to riboflavin, facilitating the formation of riboflavin-WPI complexes. The extent of desolvation and cross-linking influenced the morphology of the spray-dried microparticles, while the moisture content of microparticles decreased with desolvation and increased with crosslinking. The modification of WPI conformation upon desolvation could be retained in the dry state via spray drying. The gastric resistance, release site and release characteristics of microparticles were readily adjusted by varying the ethanol and calcium ion contents from 0 to 50% v/v and from 0 to 2 mM, respectively. The sample prepared from 30% v/v ethanol without calcium crosslinking displayed rapid peptic digestion in less than 30 min. The samples from 30% v/v ethanol at 1 and 2 mM Ca 2+ exhibited excellent gastric resistance and intestinal release

Stable nanoemulsions for poorly soluble curcumin: From production to digestion response in vitro

Curcumin, a polyphenol, can induce anticancer activity depending on dose. However, oral curcumin administration is limited by its low bioavailability due to aqueous insolubility and instability against physiological conditions. This study aims at formulating nanoemulsions by phase inversion temperature to enhance curcumin loading, stability, antioxidant performance, bioaccessibility, and in vitro absorption. The selection mechanisms for oil phase (coconut oil), surfactant (polyoxyl 40 hydrogenated castor oil), co-surfactant (soy phospholipid), and aqueous phase (2 % wt citrate buffer at pH 4.5) are established. The nanoemulsions show tunable mean droplet size (26–129 nm), high curcumin loading (9.53 ± 0.49 mg/mL), polydispersity 0.05). The curcumin nanoemulsions show ∼ 11 %, 24 %, and 57 % higher retention and ∼ 10 %, 12 %, and 17 % higher antioxidant activity than raw curcumin after 3-hour simulated gastric, intestinal, and physiological incubations, respectively. During in vitro digestion and absorption, the encapsulated curcumin shows higher bioaccessibility and absorption than free curcumin (P < 0.05). The samples are stable during 4-week storage at 4˚C and room temperature without preservatives. These findings suggest the potential to develop a nanoencapsulation strategy, particularly for an oral delivery system of oil-soluble drugs

Assessing the effect of Maillard reaction products on the functionality and antioxidant properties of Amaranth-red seaweed blends

Plant-based proteins, represented by amaranth in our study, embrace a potential as an ingredient for the functional-food formulation. However, their efficacy is hindered by inherent limitations in solubility, emulsification, and antioxidant traits. The Maillard reaction, a complex chemical-process resulting in a diverse array of products, including Maillard conjugates and Maillard reaction products (MRPs), can employ variable effects on these specific attributes. To elucidate the influence of this reaction and the MRPs on the aforementioned properties, we used a complex blend of dehydrated seaweed Gracilaria and amaranth protein to create a conjugate-MRP blend. Our investigations revealed that the resultant incorporation enhanced solubility, emulsification, and antioxidant properties, while the intermediates formed did not progress to advanced glycation stages. This change is likely attributed to the dual effect of conjugates that altered the secondary protein structure, while the generation and/or preservation of MRPs post ultrasonication and spray drying enhanced its antioxidant potential