ABSTRACT
Probiotics are live microorganisms that confer health benefits to host organisms when consumed in adequate amounts and are often incorporated into foods for human consumption. However, this has negative implications on their viability as large numbers of these beneficial bacteria are deactivated when subjected to harsh conditions during processing, storage, and passage through the gastrointestinal tract. To address these issues, numerous studies on encapsulation techniques to protect probiotics have been conducted. This review focuses on emulsion technology for probiotic encapsulation, with a special focus on Pickering emulsions. Pickering emulsions are stabilized by solid particles, which adsorb strongly onto the liquid-liquid interfaces to prevent aggregation. Pickering emulsions have demonstrated enhanced stability, high encapsulation efficiency, and cost-effectiveness compared to other encapsulation techniques. Additionally, Pickering emulsions are regarded as safe and biocompatible and utilize natural materials, such as cellulose and chitosan derived from plants, shellfish, and fungi, which may also be viewed as more acceptable in food systems than common synthetic and natural molecular surfactants. This article reviews the current status of Pickering emulsion use for probiotic delivery and explores the potential of this technique for application in other fields, such as livestock farming, pet food, and aquaculture.
ABSTRACT
Vitamin C (VC), widely used in food, pharmaceutical and cosmetic products, is susceptible to degradation, and new formulations are necessary to maintain its stability. To address this challenge, VC encapsulation was achieved via electrostatic interaction with glycidyltrimethylammonium chloride (GTMAC)-chitosan (GCh) followed by cross-linking with phosphorylated-cellulose nanocrystals (PCNC) to form VC-GCh-PCNC nanocapsules. The particle size, surface charge, degradation, encapsulation efficiency, cumulative release, free-radical scavenging assay, and antibacterial test were quantified. Additionally, a simulated human gastrointestinal environment was used to assess the efficacy of the encapsulated VC under physiological conditions. Both VC loaded, GCh-PCNC, and GCh-Sodium tripolyphosphate (TPP) nanocapsules were spherical with a diameter of 450 â± â8 and 428 â± â6 ânm respectively. VC-GCh-PCNC displayed a higher encapsulation efficiency of 90.3 â± â0.42% and a sustained release over 14 days. The release profiles were fitted to the first-order and Higuchi kinetic models with R2 values greater than 0.95. VC-GCh-PCNC possessed broad-spectrum antibacterial activity with a minimum inhibition concentration (MIC) of 8-16 âµg/mL. These results highlight that modified CNC-based nano-formulations can preserve, protect and control the release of active compounds with improved antioxidant and antibacterial properties for food and nutraceutical applications.
ABSTRACT
Cellulose nanocrystals (CNC) are sustainable nanomaterials that possess high tensile strength, stiffness and surface functional groups suitable for various types of modifications. In this study, phosphorylated cellulose nanocrystals (P-CNC) were prepared via acid hydrolysis with phosphoric acid to decorate phosphate groups on the surface of CNC. Also, chitosan was modified with glycidyltrimethylammonium chloride (GTMAC) to improve its solubility. GTMAC-Chitosan (GCh) and phosphorylated cellulose nanocrystals (P-CNC) were complexed via ionic gelation to produce GCh-P-CNC nanoparticles under mild sonication. Although sodium tripolyphosphate (TPP) is a common cross-linking agent used with chitosan, its application is compromised by its metastable structure that resulted in the rapid release of its encapsulated compound. Therefore, phosphorylated cellulose nanocrystal was developed as a "nanoparticle" cross-linker and a Pickering emulsifier. The nanocomplexes transformed from a rod-like to hard sphere and random coil morphology with increasing ratio of GCh/P-CNC. In comparison with TPP-Chitosan emulsion, Pickering emulsion prepared using GCh-P-CNC complex was more stable over 3 months without coalescence and phase separation.
