Interfacial and emulsifying properties of the electrostatic complex of β-lactoglobulin fibril and gum Arabic (Acacia Seyal)

Encapsulation of lycopene in Pickering emulsion stabilized by complexes of whey protein isolate fibrils and sodium alginate: Physicochemical property, structural characterization and in vitro digestion property

In present study, whey protein isolate fibrils and sodium alginate complexes (WPIFs-SA) were prepared and further used to stabilize Pickering emulsions for lycopene delivery. The optimal interaction between WPIFs and SA occurred at pH 3.0, with a mass ratio of 2:1. Increasing the oil fractions and the content of WPIFs-SA complexes significantly improved Pickering emulsions' stability, concurrently reducing droplet size and increasing viscoelasticity. Meanwhile, it facilitated the formation of a thicker protective layer and a compact network structure around the oil droplets, offering better protection for lycopene against thermal and photo degradation. In vitro digestion studies revealed that as the oil fractions and complex contents increased, the lipolysis degree decreased. The engineered WPIFs-SA Pickering emulsion could be used as an innovative delivery system for the protection and delivery of lycopene.

Design of Novel Knot-like Structures Based on Ovotransferrin Fibril-Gum Arabic Complexes: Effective Strategies to Stabilize Pickering Emulsions

This work aimed to clarify the effects of gum arabic (GA) on the morphology and properties of ovotransferrin fibrils (OVTFs). By constructing OVTF-GA complexes and exploring the dispersion stability, turbidity and the ζ-potential of the complexes, the optimum mass ratio of OVTFs to GA and pH for complex formation were confirmed as being 1:1 and pH 4.6, respectively. The interaction between OVTFs and GA was determined to be predominantly driven by electrostatic attraction. The OVTF-GA complexes exhibited a knot-like structure when observed using atomic force microscopy. Then, OVTFs and OVTF-GA complexes were compared in terms of contact angle, surface hydrophobicity and dynamic interfacial tension. The combination of OVTFs and GA decreased the contact angle of OVTFs from 80.85° to 70.36°. In comparison with OVTFs, OVTF-GA complexes reduced the oil-water interfacial tension to a lower level (8.14 mN/m). Furthermore, the capacities of OVTF-GA complexes in stabilizing emulsions were explored. OVTF-GA complex-stabilized oleogel-based Pickering emulsion (OGPE) was constructed, and OVTF-stabilized oleogel-based Pickering emulsion (OPE) was used as the control. OGPE had a higher emulsified phase volume fraction (EPVF) and stability index (SI). The EPVF of OGPE was 100.0% and 99.4% before and after one-month storage, respectively, compared with 98.3% and 95.7% of OPE. This work can provide some useful references for the design of biopolymers with novel structures composed of protein fibrils and polysaccharides, which may also help to construct and apply protein fibril-polysaccharide complexes under specific needs.

Effects of pile fermentation on the physicochemical, functional, and biological properties of tea polysaccharides

This study investigated the influence of pile fermentation on the physicochemical, functional, and biological properties of tea polysaccharides (TPS). Results indicated that the extraction yield, uronic acid content, and polyphenol content of TPS greatly increased from 1.8, 13.1 and 6.3 % to 4.1, 27.9, and 7.8 %, respectively, but the molecular weight markedly decreased from 153.7 to 76.0 kDa after pile fermentation. Additionally, the interfacial, emulsion formation, and emulsion stabilization properties of TPS were significantly improved after pile fermentation. For instance, 1.0 wt% TPS isolated from dark tea (D-TPS) can fabricate 8.0 wt% MCT oil-in-water nanoemulsion (d₃₂ ≈ 159 nm) with potent storage stability. Moreover, the antioxidant and α-glucosidase inhibitory activities of D-TPS was higher than that of TPS isolated from sun-dried raw tea (R-TPS). Overall, this study indicated that pile fermentation markedly affected the physicochemical and structural characteristics of TPS, thereby improving their functional and biological properties.

Adsorption and Assembly of Octenyl Succinic Anhydride Starch/Chitosan Electrostatic Complexes at Oil-Water Interface

Biopolymer electrostatic complexes are popular Pickering stabilizers whose structures greatly affect their interfacial properties. This study comprehensively demonstrated the interfacial adsorption and assembly of dissolved octenyl succinic anhydride (OSA) starch (OSA-D)/chitosan (CS) electrostatic complexes with different structures through complementary characterization methods. We found that compared with single-component systems, OSA-D/CS complexes exhibited significantly increased wetting stability and adsorption rate to the interface, which was reinforced by molecular dynamics simulations. Their soft structures and the entanglement of molecular chains led to the formation of thick and highly viscoelastic multilayer adsorbed films, which greatly resisted deformation against shearing forces. The adsorption and assembly of the complexes were strongly influenced by OSA-D/CS ratios and pH, which could be related to the different interfacial interaction strengths. Overall, the electrostatic complexation, structural characteristics, and interfacial properties of OSA-D/CS complexes were well related, thereby providing valuable information for the regulation of controlled interfaces and bulk system properties.

Co-delivery of curcumin and epigallocatechin gallate in W/O/W emulsions stabilized by protein fibril-cellulose complexes

Hydrophobic curcumin and hydrophilic epigallocatechin gallate (EGCG) are reported to exhibit a variety of biological activities and may exhibit synergistic effects when used in combination. A co-encapsulation system was developed to improve their applicability and bioavailability. This delivery system consisted of a water-in-oil-in-water (W₁/O/W₂) double emulsion stabilized by whey protein isolate fibrils (WPIFs) and cellulose nanocrystals (CNCs). Double emulsions were fabricated using a two-step emulsification method using either WPIF-CNC complexes or WPIF alone. The physicochemical stability, encapsulation performance, and digestive properties of the delivery systems were then investigated. The double emulsions stabilized by the WPIF-CNC complexes were more resistant to heat and salt stress, exhibited greater encapsulation stability, and had a higher bioaccessibility for curcumin (67.8%) and EGCG (68.9%) than those stabilized by WPIFs. This research shows that the stability and bioaccessibility of curcumin and EGCG can be enhanced by co-encapsulating them in emulsion-based delivery systems using nanostructured protein-polysaccharide complexes.

Resveratrol-loaded α-lactalbumin-chitosan nanoparticle-encapsulated high internal phase Pickering emulsion for curcumin protection and its in vitro digestion profile

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RES-ALA-CHI colloidal particles were fabricated as CUR-loaded HIPPEs stabilizers.

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RES-ALA-CHI nanoparticle pronouncedly enhanced the chemical stability of CUR.

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Lipolysis of HIPPEs can be controlled with RES-ALA-CHI colloidal particles.

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CUR bioaccessibility can be controlled with RES-ALA-CHI colloidal particles.

The use of antioxidant-loaded protein-polysaccharide nanoparticle in stabilizing and delivering curcumin with high internal phase Pickering emulsions is comparatively scarce. Resveratrol (RES)-loaded α-lactalbumin (ALA)-chitosan (CHI) particles were fabricated and used for curcumin-loaded high internal phase Pickering emulsions (HIPPEs) stabilization and delivery. CLSM illustrated that RES-ALA-CHI nanoparticles were effectively adsorbed on oil/water (O/W) interface and a gel-like structure was formed surrounding oil droplets. All HIPPEs exhibited excellent physical stability. CUR retention was 75.4 % for HIPPEs with RES-ALA-CHI colloidal particles, which was appreciably higher than that with ALA-CHI colloidal particles (63.9 %) after 30 days storage. Compared to bulk medium-chain triglyceride (MCT), both lipolysis extent and curcumin (CUR) bioaccessibility were pronouncedly enhanced with HIPPEs-based delivery systems. But both HIPPEs (51.4 % and 43.7 %) exhibited lower extent of lipolysis than conventional emulsions (90.4 %). The occurrence of RES significantly restrained the lipolysis. These results demonstrated that HIPPEs could be excellent delivery systems for delivering lipophilic curcumin.

Polysaccharide conjugates from Chin brick tea (Camellia sinensis) improve the physicochemical stability and bioaccessibility of β-carotene in oil-in-water nanoemulsions

A natural antioxidant emulsifier, tea polysaccharide conjugate (TPC), was isolated from Chin brick tea. The impact of TPC on β-carotene stability and bioaccessibility in oil-in-water nanoemulsions was assessed. TPC exhibited strong antioxidant activity and could be used to fabricate stable nanoemulsions (d < 140 nm). The extent of lipid digestion was considerably lower for lipid droplets coated by TPC (68%) than Tween 80 (94%) or whey protein isolate (WPI) (89%), probably because TPC formed interfacial layers that hindered the access of lipases to lipids. The chemical stability of β-carotene in TPC-nanoemulsions was markedly higher than in those formulated with Tween 80 or WPI due to the high antioxidant activity of TPC. The bioaccessibility of β-carotene (20-30%) was independent of emulsifier type. TPC from Chin brick tea can therefore be used as a dual-purpose functional ingredient in emulsified foods.

Hydrogels assembled from ovotransferrin fibrils and xanthan gum as dihydromyricetin delivery vehicles

Novel ovotransferrin fibril–xanthan gum hydrogels were assembled to deliver dihydromyricetin effectively.