Fiber complex-stabilized high-internal-phase emulsion for allicin encapsulation: microstructure, stability, and thermal-responsive properties.

BACKGROUND: Stimuli-responsive emulsions have garnered significant attention for their ability to enhance sensory qualities and control the release of encapsulated nutrient in emulsion-based products. However, the characteristics of synthetic materials of fabricating stimuli-responsive emulsions have been a crucial limitation in the food industry. Regulating the behavior of molecules at the interface could potentially achieve the desired stimuli-responsive behavior, but currently there is limited information available. RESULTS: High-internal-phase emulsions (HIPEs) were fabricated for the encapsulation of allicin, stabilized by a complex of 20 g kg-1 whey protein amyloid fibrils (WPF) and 20 g kg-1 glycyrrhizin fibers (GA). The intermolecular interactions between WPF and GA in the fiber complexes were predominantly governed by hydrophobic and electrostatic forces. These complexes adsorbed and stacked around the oil droplets, forming a protective interfacial film that enhanced droplet stability. An increased proportion of WPF (WPF = 3:1 or 4:1) surrounding the oil droplets enhanced the accelerated storage stability of HIPEs, with instability indexes approaching 0.2. Additionally, HIPEs displayed a temperature-dependent modulus, with the emulsion stabilized by a WPF ratio of 3:1 showing the highest modulus at 85 °C. The encapsulation efficiency of allicin in HIPEs ranged from 88.69 ± 6.62% to 101 ± 1.37% at 25 °C, and from 31.95 ± 1.92% to 78.69 ± 4.63% after incubation at 85 °C for 8 h. The release profile of allicin from the HIPEs exhibited thermal responsiveness, depending on the interfacial content of GA. CONCLUSION: These findings indicated that the thermal-responsive properties of HIPEs can be strategically engineered by manipulating their interfacial characteristics. © 2024 Society of Chemical Industry.

Improving norbixin dispersibility and stability by liposomal encapsulation using the pH-driven method.

BACKGROUND: Norbixin, a carotenoid extracted from annatto seeds, is widely utilized as a natural pigment in foods, cosmetics and medicines. Its water solubility is relatively high under neutral or alkaline conditions but low under acidic conditions, which limits its application in some food products. RESULTS: This problem was overcome by utilizing liposomes to encapsulate the carotenoids so that they could be easily dispersed within acidic solutions. The norbixin was loaded into the liposomes using the pH-driven method. Liposomes were produced by passing aqueous phospholipid dispersions through a microfluidizer under high pressure. Norbixin was then added to the liposome dispersions at pH 7.0 and then driven into the hydrophobic domains of the phospholipid bilayers by acidifying the system. Measurements of the encapsulation efficiency showed that the norbixin was successfully loaded into the liposomes using the pH-driven method. X-ray diffraction analysis showed that the norbixin was in an amorphous state after incorporation into the liposomes. Encapsulation of norbixin within the liposomes was also shown to increase its water dispersibility and chemical stability under acidic pH conditions. CONCLUSION: The pH-driven method therefore provides a useful means of increasing the application of this bioactive carotenoid within functional foods and other products. © 2021 Society of Chemical Industry.

Comparing the effect of benzoic acid and cinnamic acid hydroxyl derivatives on polyphenol oxidase: activity, action mechanism, and molecular docking.

BACKGROUND: Polyphenol oxidase (PPO) is considered to have a key role in the food industry because it initiates enzymatic browning in the processing and storage of fruit and vegetables. Increasing numbers of benzoic and cinnamic acid derivatives have been found to be efficient inhibitors of polyphenol oxidase, but a comparison study on activity and action mechanism is lacking. In this study, 18 benzoic acid and cinnamic acid hydroxy derivatives were selected and investigated. RESULTS: Three substrates, four activators and 11 inhibitors were identified from benzoic and cinnamic acid derivatives. 2,4-Dihydroxycinnamic acid and benzoic acid showed the strongest inhibitory effect on PPO, with IC50 of 0.092 and1.425 mmol L-1 , respectively. Benzoic acid reversibly inhibited PPO in a competitive manner, while 2,4-dihydroxycinnamic acid showed a mixed-type inhibition. Both of them showed that static-type fluorescence quenching and electrostatic interaction were the main driving force in the bonding process. Compared with benzoic acid, 2,4-dihydroxycinnamic acid more easily formed hydrogen bonds in the active site of PPO, making the interaction more stable. CONCLUSION: Comparative analysis showed that the inhibition effect of cinnamic acid hydroxyl derivatives on PPO was stronger than that of benzoic acid derivatives. Benzoic acid and 2,4-dihydroxycinnamic acid were the strongest inhibitors. PPO inhibitors identified from benzoic and cinnamic acid derivatives are expected to be promising inhibitors for controlling fruit and vegetable browning. © 2021 Society of Chemical Industry.

A review of recent progress in improving the bioavailability of nutraceutical-loaded emulsions after oral intake.

Increasing awareness of the health benefits of specific constituents in fruits, vegetables, cereals, and other whole foods has sparked a broader interest in the potential health benefits of nutraceuticals. Many nutraceuticals are hydrophobic substances, which means they must be encapsulated in colloidal delivery systems. Oil-in-water emulsions are one of the most widely used delivery systems for improving the bioavailability and bioactivity of these nutraceuticals. The composition and structure of emulsions can be designed to improve the water dispersibility, physicochemical stability, and bioavailability of the encapsulated nutraceuticals. The nature of the emulsion used influences the interfacial area and properties of the nutraceutical-loaded oil droplets in the gastrointestinal tract, which influences their digestion, as well as the bioaccessibility, metabolism, and absorption of the nutraceuticals. In this article, we review recent in vitro and in vivo studies on the utilization of emulsions to improve the bioavailability of nutraceuticals. The findings from this review should facilitate the design of more efficacious nutraceutical-loaded emulsions with increased bioactivity.

The Formation of Chitosan-Coated Rhamnolipid Liposomes Containing Curcumin: Stability and In Vitro Digestion.

There is growing interest in developing biomaterial-coated liposome delivery systems to improve the stability and bioavailability of curcumin, which is a hydrophobic nutraceutical claimed to have several health benefits. The curcumin-loaded rhamnolipid liposomes (Cur-RL-Lips) were fabricated from rhamnolipid and phospholipids, and then chitosan (CS) covered the surface of Cur-RL-Lips by electrostatic interaction to form CS-coated Cur-RL-Lips. The influence of CS concentration on the physical stability and digestion of the liposomes was investigated. The CS-coated Cur-RL-Lips with RL:CS = 1:1 have a relatively small size (412.9 nm) and positive charge (19.7 mV). The CS-coated Cur-RL-Lips remained stable from pH 2 to 5 at room temperature and can effectively slow the degradation of curcumin at 80 °C; however, they were highly unstable to salt addition. In addition, compared with Cur-RL-Lips, the bioavailability of curcumin in CS-coated Cur-RL-Lips was relatively high due to its high transformation in gastrointestinal tract. These results may facilitate the design of a more efficacious liposomal delivery system that enhances the stability and bioavailability of curcumin in nutraceutical-loaded functional foods and beverages.

Inhibitory effects of organic acids on polyphenol oxidase: From model systems to food systems.

Organic acids are widely utilized in the food industry for inhibiting the activity of polyphenol oxidase (PPO) and enzymatic browning. This review discusses the mechanisms of inhibition of PPO and enzymatic browning by various organic acids based on studies in model systems, critically evaluates the relevance of such studies to real food systems and assesses the implication of the synergistic inhibitory effects of organic acids with other physicochemical processing techniques on product quality and safety. Organic acids inhibit the activity of PPO and enzymatic browning via different mechanisms and therefore the suitability of a particular organic acid depends on the structure and the catalytic properties of PPO and the physicochemical properties of the food matrix. Studies in model systems provide an invaluable insight into the inhibitory mechanisms of various organics acids. However, the difference in the effectiveness of PPO inhibitors between model systems and food systems and the lack of correlation between the degree of PPO inhibition based on in vitro assays and enzymatic browning imply that the effectiveness of organic acids can be accurately evaluated only via direct assessment of browning inhibition in a particular food system. Combination of organic acids with physical processing techniques is one of the most viable approaches for PPO inhibition since the observed synergistic effect helps to reduce the undesirable organoleptic quality changes from the use of excessive concentration of organic acids or intense physical processing.

Gliadin Nanoparticles Pickering Emulgels for ß-Carotene Delivery: Effect of Particle Concentration on the Stability and Bioaccessibility.

ß-carotene is a promising natural active ingredient for optimum human health. However, the insolubility in water, low oral bioavailability, and instability in oxygen, heat, and light are key factors to limit its application as incorporation into functional foods. Therefore, gliadin nanoparticles (GNPs) Pickering emulgels were chosen as food-grade ß-carotene delivery systems. The objectives of the present study were to investigate the influence of GNPs concentration on the rheological properties, stability, and simulated gastrointestinal fate of ß-carotene of Pickering emulgels. The formulations of Pickering emulgels at low GNPs concentration had better fluidity, whereas at high GNPs concentration, they had stronger gel structures. Furthermore, the thermal stability of ß-carotene loaded in Pickering emulgels after two pasteurization treatments was significantly improved with the increase of GNPs concentration. The Pickering emulgels stabilized with higher GNPs concentration could improve the protection and bioaccessibility of ß-carotene after different storage conditions. This study demonstrated the tremendous potential of GNPs Pickering emulgels to carry ß-carotene.

The Stability, Sustained Release and Cellular Antioxidant Activity of Curcumin Nanoliposomes.

Curcumin is a multifunctional and natural agent considered to be pharmacologically safe. However, its application in the food and medical industry is greatly limited by its poor water solubility, physicochemical instability and inadequate bioavailability. Nanoliposome encapsulation could significantly enhance the solubility and stability of curcumin. Curcumin nanoliposomes exhibited good physicochemical properties (entrapment efficiency = 57.1, particle size = 68.1 nm, polydispersity index = 0.246, and zeta potential = -3.16 mV). Compared with free curcumin, curcumin nanoliposomes exhibited good stability against alkaline pH and metal ions as well as good storage stability at 4 °C. Curcumin nanoliposomes also showed good sustained release properties. Compared with free curcumin, curcumin nanoliposomes presented an equal cellular antioxidant activity, which is mainly attributed to its lower cellular uptake as detected by fluorescence microscopy and flow cytometry. This study provide theoretical and practical guides for the further application of curcumin nanoliposomes.

Shell-Core Microbeads Loaded with Probiotics: Influence of Lipid Melting Point on Probiotic Activity.

Probiotics have many beneficial physiological activities, but the poor stability during storage and gastrointestinal digestion limits their application. Therefore, in this study, a novel type of shell-core microbead for loading probiotics was prepared through high-precision concentric drop formation technology using gelatin as the shell material and lipids as the core material. The microbeads have a regular spherical structure, uniform size, low moisture content (<4%) and high probiotic activity (>9.0 log CFU/g). Textural testing showed that the hardness of the medium-chain triglyceride microbeads (MCTBs), cocoa butter replacer microbeads (CBRBs) and hydrogenated palm oil microbeads (HPOBs) increased gradually (319.65, 623.54, 711.41 g), but their springiness decreased (67.7, 43.3, 34.0%). Importantly, lipids with higher melting points contributed to the enhanced stability of probiotics during simulated digestion and storage. The viable probiotic counts of the HCTBs, CBRBs and HPOBs after being stored at 25 °C for 12 months were 8.01, 8.44, and 8.51 log CFU/g, respectively. In the simulated in vitro digestion process, the HPOBs resisted the destructive effects of digestive enzymes and gastric acid on probiotics, with a reduction in the probiotic viability of less than 1.5 log CFU/g. This study can provide new ideas for the preparation of intestinal delivery probiotic foods.

The improvement of water barrier property in gelatin/carboxymethyl cellulose composite film by electrostatic interaction regulation and its application in strawberry preservation.

Gelatin (GL) and carboxymethyl cellulose (CMC) are common natural components for edible films, but their water barrier performance are finite as hydrophilic polymers. In this study, a GL/CMC water barrier film was prepared, characterized and applied. The microstructure results showed that complex coacervation at pH 2.0 and cross-linking effect of sodium benzoate resulted in strong interaction forces and dense structure of this film. Compared with pure GL or CMC film, this novel composite film decreased water vapor permeability by approximately 90%, and possessed applicable water solubility (51.5%) and stronger barrier to oxygen and UV light. Acidic environment and sodium benzoate endowed antibacterial activity. Furthermore, the water barrier coating film decreased water loss by 47.8% and improved overall quality of fresh strawberries stored at 25 °C for 6 d. Therefore, the novel water barrier film based on complex coacervation and cross-linking is promising to control the postharvest quality of perishable berries.