Encapsulation of β-Carotene in Oil-in-Water Emulsions Containing Nanocellulose: Impact on Emulsion Properties, In Vitro Digestion, and Bioaccessibility

Palm-based nanofibrillated cellulose (NFC) in carotenoid encapsulation and its incorporation into margarine-like reduced fat spread as fat replacer

Nanofibrillated cellulose (NFC) from plant biomass is becoming popular, attributed to the protective encapsulation of bioactive compounds in Pickering emulsion, preventing degradation and stabilizing the emulsion. NFC, as a natural dietary fiber, is a prominent fat replacer, providing a quality enhancement to reduced-fat products. In this study, NFC Pickering emulsions were prepared at NFC concentrations of 0.2%, 0.4%, 0.6%, 0.8%, and 1% to encapsulate carotenoids. The NFC Pickering emulsions at NFC concentrations of 0.4%, 0.6%, 0.8%, and 1% were incorporated into margarine-like reduced fat (3%) spreads as the aqueous phase. Characterization of both NFC Pickering emulsion and the incorporated NFC Pickering emulsion, margarine-like reduced fat spreads, was conducted with mastersizer, rheometer, spectrophotometer, and texture analyzer. The particle size (73.67 ± 0.35 to 94.73 ± 2.21 nm), viscosity (138.36 ± 3.35 to 10545.00 ± 567.10 mPa s), and creaming stability (25% to 100% stable) of the NFC Pickering emulsions were increased significantly when increasing the NFC concentration, whereas the encapsulation efficiency was highest at NFC 0.4% and 0.6%. Although imitating the viscoelastic solid-like behavior of margarine was difficult, the NFC Pickering emulsion properties were still able to enhance hardness, slip melting point, and color of the reduced fat spreads compared to the full-fat margarine, especially at 0.6% of NFC. Overall, extensive performances of NFC can be seen in encapsulating carotenoids, especially at NFC concentrations of 0.4% and 0.6%, with the enhancement of Pickering emulsion stability while portraying futuristic possibilities as a fat replacer in margarine optimally at 0.6% of NFC concentration. PRACTICAL APPLICATION: Nanocellulose extracted from palm dried long fiber was utilized to encapsulate carotenoids and replace fats in margarine-like reduced fat (3%) spreads. Our study portrayed high encapsulation efficiency and successful fat replacement with promising stability performances. Hence, nanocellulose displayed extensive potential as encapsulating agents and fat replacers while providing quality and sustainability enhancements in reduced-fat food.

Lipase-Responsive Lignin Composite Nanoparticles for the Delivery of Insoluble Bioactives

Low solubility and chemical instability are the main problems with insoluble bioactives. Lignin, with its exceptional biological properties and amphiphilicity, holds promise as a delivery system material. In this study, glycerol esters were incorporated into alkali lignin (AL) through ether and ester bonds, resulting in the successful synthesis of three hydrophobically modified alkali lignins (AL-OA, AL-OGL, and AL-SAN-OGL). Subsequently, lignin composite nanoparticles (LNPs@BC) encapsulating β-carotene were prepared using antisolvent and sonication techniques. The encapsulation rates were determined to be 37.69 ± 2.21%, 84.01 ± 5.55%, 83.82 ± 5.23%, and 83.11 ± 5.85% for LNP@BC-1, LNP@BC-2, LNP@BC-3, and LNP@BC-4, respectively, with AL, AL-OA, AL-OGL, and AL-SAN-OGL serving as the wall materials under optimized preparation conditions. The antioxidant properties and UV-absorbing capacity of the four lignins were characterized, demonstrating their efficacy in enhancing the oxygen and photostability of β-carotene. Following 6 h of UV irradiation, LNP@BC-4 exhibited a retention rate of 83.03 ± 2.85% for β-carotene, while storage under light-protected conditions at 25 °C for 7 days retained 73.33 ± 7.62% of β-carotene. Furthermore, the encapsulated β-carotene demonstrated enhanced thermal and storage stability. In vitro release experiments revealed superior stability of LNPs@BC in simulated gastric fluid (SGF), with β-carotene retention exceeding 77% in both LNP@BC-3 and LNP@BC-4. LNP@BC-4 exhibited the highest bioaccessibility in simulated intestinal fluid (SIF) at 46.96 ± 0.80%, that LNP@BC-1 only achieved 10.87 ± 0.90%. The enzymatic responsiveness of AL-OGL and AL-SAN-OGL was confirmed. Moreover, LNPs@BC exhibited no cytotoxicity toward L929 cells and demonstrated excellent hemocompatibility. In summary, this study introduces a novel enzyme-responsive modified lignin that has promising applications in the fields of food, biomedicine, and animal feed.

High internal phase emulsions stabilized by whey protein covalently modified with carboxymethyl cellulose: Enhanced environmental stability, storage stability and bioaccessibility

In this work, the effects of whey protein-carboxymethyl cellulose (WP-CMC) conjugates on the environmental stability, in vitro digestion stability, storage stability and bioaccessibility of high internal phase emulsions (HIPEs) were investigated. Compared to the HIPEs stabilized by the mixture of WP and CMC, the HIPEs stabilized by WP-CMC were less sensitive to environmental changes by particle size and zeta-potential, and showed better stability and bioavailability of pine nut oil as well as β-carotene during simulated gastrointestinal digestion. In addition, the inclusion function and pine nut oil oxidative stability of the HIPEs stabilized by WP-CMC were better during 16 days of storage than those of the pine nut oil and HIPEs stabilized by the mixture of WP and CMC, and also expressed higher storage stability of β-carotene. These results suggested that the conjugate-stabilized emulsions developed in this study have potential applications as protectors and carriers of liposoluble active ingredients.

Modulating in vitro gastrointestinal digestion of nanocellulose-stabilized pickering emulsions by altering particle surface charge

An in vitro model of human gastrointestinal digestion was introduced to investigate the effects of surface charge of cellulose nanoparticles on emulsion structure during gastric phase, lipase activity, bile salt diffusion, and free fatty acid (FFA) release. Four carboxymethylated cellulose nanofibrils (CNF; C0, C0.36, C0.72, and C1.24) were used, showing different surface charge (p < 0.05). First, four carboxymethylated CNFs had no inhibition effects on lipase activity and bile salt diffusion. Moreover, we found that the lipid emulsion containing CNF formed gel structure to induce oil droplets aggregation during simulated gastric phase. Additionally, the particle surface charge greatly influenced the gel structure of emulsion where a denser gel structure was observed in the C0 (lowest surface charged CNF) stabilized emulsion. Finally, the released FFA results showed that the formed gel structure lowered the lipid emulsion digestion attributed to the restricted adherent area of oil droplets for lipase and bile salt.

Anthocyanin-Rich Butterfly Pea Petal Extract Loaded Double Pickering Emulsion Containing Nanocrystalline Cellulose: Physicochemical Properties, Stability, and Rheology

Butterfly pea petal extract (BPE)-loaded water-in-oil-in-water (W/O/W) emulsions were fabricated using nanocrystalline cellulose (NCC) as a hydrophilic stabilizer and polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier. The impact of different concentrations of NCC and PGPR in different phase proportions on the emulsion formation, rheology, and stability of an anthocyanin-loaded (pH ≈ 7.0) emulsion was investigated. The mean droplet size of the emulsions increased as the NCC concentration increased, while color intensity (greenness) decreased as the PGPR and NCC concentrations increased. A microscopic examination confirmed that the NCC nanoparticles stabilized the inner W1/O phase, whereas the excess concentration of non-adsorbing NCC nanoparticles was suspended in the continuous aqueous phase. The rheological results showed that robust emulsion networks were formed when the NCC concentration increased. A network structure between the droplets and the development of the NCC network during the continuous phase were attributed to a gel-like behavior. Over the course of seven days, the emulsions with a higher proportion of NCC remained stable, as in samples 3%P-%N, 5%P-2%N, and 5%P@1%N, the total anthocyanin content decreased from 89.83% to 76.49%, 89.40% to 79.65, and 86.63% to 71.40%, respectively. These findings have significant implications for the accurate formulation of particle-stabilized double emulsions for anthocyanin delivery with higher stability.

Important Role and Properties of Granular Nanocellulose Particles in an In Vitro Simulated Gastrointestinal System and in Lipid Digestibility and Permeability

This research evaluated the role and feasibility of the granular nanocellulose particles (GNC) from sugarcane bagasse obtained from enzymatic hydrolysis in reducing lipid digestibility and permeability in an in vitro simulated gastrointestinal (GI) system. GNC concentration (0.02%, w/v) had significantly affected the released free fatty acids (FFA), with a reduction of approximately 20%. Pickering emulsion of a GNC and olive oil simulation mixture revealed higher oil droplet size distribution and stability in the initial stage than the vortexed mixture formation. The difference in particle size distribution and zeta potential of the ingested GNC suspension and GNC-olive oil emulsion were displayed during the in vitro gastrointestinal simulation. GNC particles interacted and distributed surrounding the oil droplet, leading to interfacial emulsion. The GNC concentration (0.01-0.10%, w/v) showed low toxicity on HIEC-6 cells, ranging from 80.0 to 99% of cell viability. The release of FFA containing the ingested GNC suspension and GNC-olive oil emulsion had about a 30% reduction compared to that without the GNC digestion solution. The FFA and triglyceride permeability through the HIEC-6 intestinal epithelium monolayer were deceased in the digesta containing the ingested GNC and emulsion. This work indicated that GNC represented a significantly critical role and properties in the GI tract and reduced lipid digestion and absorption. This GNC could be utilized as an alternative food additive or supplement in fatty food for weight control due to their inhibition of lipid digestibility and assimilation.

Astaxanthin-Loaded Pickering Emulsions Stabilized by Nanofibrillated Cellulose: Impact on Emulsion Characteristics, Digestion Behavior, and Bioaccessibility

Astaxanthin (AX) is one of the major bioactives that has been found to have strong antioxidant properties. However, AX tends to degrade due to its highly unsaturated structure. To overcome this problem, a Pickering O/W emulsion using nanofibrillated cellulose (NFC) as an emulsifier was investigated. NFC was used because it is renewable, biodegradable, and nontoxic. The 10 wt% O/W emulsions with 0.05 wt% AX were prepared with different concentrations of NFC (0.3-0.7 wt%). After 30 days of storage, droplet size, ζ-potential values, viscosity, encapsulation efficiency (EE), and color were determined. The results show that more stable emulsions are formed with increasing NFC concentrations, which can be attributed to the formulation of the NFC network in the aqueous phase. Notably, the stability of the 0.7 wt% NFC-stabilized emulsion was high, indicating that NFC can improve the emulsion's stability. Moreover, it was found that fat digestibility and AX bioaccessibility decreased with increasing NFC concentrations, which was due to the limitation of lipase accessibility. In contrast, the stability of AX increased with increasing NFC concentrations, which was due to the formation of an NFC layer that acted as a barrier and prevented the degradation of AX during in vitro digestion. Therefore, high concentrations of NFC are useful for functional foods delivering satiety instead of oil-soluble bioactives.