Lutein-enriched emulsion-based delivery systems: Influence of emulsifiers and antioxidants on physical and chemical stability

Unraveling the binding mechanism between soybean protein isolate and selected bioactive compounds

The present study was aimed to investigate the interactions between soybean protein isolate (SPI) with resveratrol (RESV) and lutein (LUT). The binding forces, molecular interactions and functional properties were explored by multi-spectroscopic analysis, molecular docking and functional property indexes between SPI and RESV/LUT. The RESV/LUT quenched SPI chromophore residues with static mechanism and the endothermic reaction. The SPI- RESV/LUT complexes were formed through hydrogen bond, electrostatic and hydrophobic interactions. Molecular docking confirmed van-der-Waals force as one of the important forces. The interaction of RESV/LUT led to SPI's secondary structure alterations with a decrease in α-helix and random coil and an increase in β-sheet and β-turns. RESV/LUT developed foaming and emulsifying properties of SPI and showed a significant decrease of the surface hydrophobicity with RESV/LUT concentrations increase attributed to SPI's partial unfolding. Our study exposed molecular mechanisms and confirmations to understand the interactions in protein- RESV/LUT complexes for protein industrial base promotion.

Arabinoxylan hydrolysates improved physical and oxidative stability of oil-in-water emulsions

This study was to improve the physical and oxidative stability of sodium caseinate (NaCas)-stabilized oil-in-water (O/W) emulsions with arabinoxylan hydrolysates (AXHs). AXHs with different molecular sizes were prepared using xylanase treatment for 0 (AXH0), 30 (AXH30), 60 (AXH60), and 120 (AXH120) min, respectively. Compared with the emulsion without AXHs, all AXHs emulsions showed increased coalescence stability, evidenced by no change occurred in the droplet size with the pH variation from 7.0 to 5.0. Moreover, at pH 7.0 and 5.0, AXH60 and AXH120 emulsions showed no flocculation, coalescence, or creaming before and after 21 d storage. All the AXH samples showed excellent antioxidant capacities, demonstrated by the slow accumulation of lipid hydroperoxides and thiobarbituric acid reactive substances during storage. In sum, rice bran arabinoxylans hydrolyzed ≥60 min possess a potential as effective antioxidants to form physically and oxidatively stable O/W emulsions at pH above the emulsifier pI, and substances with high antioxidant activity below the emulsifier pI still need to be explored.

Developing biopolymer-stabilized emulsions for improved stability and bioaccessibility of lutein

Lutein is essential for infant visual and cognitive development but has low stability and solubility. This study aimed to enhance the stability and bioaccessibility of lutein using oil-in-water emulsions stabilized with biopolymers. Commercially available octenylsuccinylated (OS) starches, including capsule TA® (CTA), HI-CAP®100 (HC), and Purity Gum® 2000 (PG), along with gum Arabic (GA) variants Ticaloid acacia Max® (TAM), TICAmulsion® 3020 (TM), and pre-hydrate gum Arabic (PHGA), were chosen as emulsifiers. By screening the effect of biopolymer concentration and oil volume fraction (Φ), emulsions stabilized with CTA, HC, or TM at 20% and 30% (w/v) concentration and 70% Φ exhibited a gel-like structure and were selected for further assessments. After a week at 25 °C, emulsions stabilized by CTA and HC showed no significant change in droplet size, while TM emulsion exhibited a 1.58-fold increase. At 45 °C, all emulsions exhibited increase in droplet size. Lutein retention is higher in CTA emulsions at both storage temperatures than free lutein. In vitro bioaccessibility of all lutein emulsions was higher than that of free lutein. These findings highlight the superior stability and bioaccessibility of the lutein emulsion stabilized by OS starch, positioning it as a promising carrier to broaden lutein applications in infant foods.

Utilization of Biopolymer-Based Lutein Emulsion as an Effective Delivery System to Improve Lutein Bioavailability in Neonatal Rats

Newborns' eyes and brains are prone to oxidative stress. Lutein has antioxidant properties and is the main component of macular pigment essential for protecting the retina, but has low bioavailability, thereby limiting its potential as a nutritional supplement. Oil-in-water emulsions have been used as lutein delivery systems. In particular, octenylsuccinated (OS) starch is a biopolymer-derived emulsifier safe to use in infant foods, while exhibiting superior emulsifying capacity. This study determined the effects of an OS starch-stabilized lutein emulsion on lutein bioavailability in Sprague-Dawley neonatal rats. In an acute study, 10-day-old pups received a single oral dose of free lutein or lutein emulsion, with subsequent blood sampling over 24 h to analyze pharmacokinetics. The lutein emulsion group had a 2.12- and 1.91-fold higher maximum serum lutein concentration and area under the curve, respectively, compared to the free lutein group. In two daily dosing studies, oral lutein was given from postnatal day 5 to 18. Blood and tissue lutein concentrations were measured. The results indicated that the daily intake of lutein emulsion led to a higher lutein concentration in circulation and key tissues compared to free lutein. The OS starch-stabilized emulsion could be an effective and safe lutein delivery system for newborns.

Impact of hypromellose acetate succinate and Soluplus® on the performance of β-carotene solid dispersions with the aid of sorbitan monolaurate: In vitro-in vivo comparative assessment

Solid dispersions (SDs) possess the potential to enhance the bioavailability of insoluble active pharmaceutical ingredients (APIs) by effectively converting them into amorphous state. However, SDs have a tendency to recrystallize unless appropriate excipients are employed. The objective of this study was to evaluate the ability of hypromellose acetate succinate HF (HPMCAS-HF) and Soluplus® to inhibit the recrystallization of β-carotene and improve its in vivo bioavailability through the fabrication of ternary β-carotene solid dispersions (SDs) with the aid of specific surfactant. Due to rapid micellization, the dissolution profiles of β-carotene SDs based on HPMCAS-HF/Span 20 (5:5, w/w) or Soluplus®/Span 20 (6:4, w/w) combinations exhibited significant improvement, which were almost 7-10 times higher than β-carotene bulk powder. DSC and PXRD analysis indicated a notable reduction in the crystallinity degree of β-carotene within the SDs. The stability study demonstrated a half-life of β-carotene in the SDs exceeding 30 days. Additionally, the in vivo pharmacokinetics analysis confirmed that the cellulose derivatives/surfactant combinations significantly enhanced the bioavailability of β-carotene by 1.37-fold and 2.3-fold, respectively. Notably, the HPMCAS-HF/Span 20 combination exhibited superior performance. Consequently, the HPMCAS-HF/Span 20 combination held potential for the advancement of an effective drug delivery system for β-carotene.

Improving the Physicochemical Stability of Soy Phospholipid-Stabilized Emulsions Loaded with Lutein by the Addition of Sphingomyelin and Cholesterol: Inspired by a Milk Fat Globule Membrane

The emulsifying performance of glycerophospholipids alone is inferior to proteins, etc., while the sphingomyelin (SM) and cholesterol (Chol) naturally existing in biological membranes could interact with glycerophospholipids to influence the polar lipid arrangement. Inspired by the natural membranes, the effect of SM and Chol on the physicochemical stability of soy phospholipid (SPL)-stabilized emulsions during storage or under environmental stresses was determined. The results indicated that the addition of SM and/or Chol could improve the storage stability of the emulsions and protective effect on lutein significantly (p < 0.05). Except for UV irradiation, the addition of Chol significantly improved the stability of the emulsions against acid, salt, and heat. The strong intermolecular hydrogen bonds and condensed assembly formed by SM and Chol contributed to the best stability of SPL + SM + Chol-stabilized emulsions. The results gave insight into improving the emulsifying properties of glycerophospholipids with SM and Chol.

Enzymatic acylation improves the stability and bioactivity of lutein: Protective effects of acylated lutein derivatives on L-O2 cells upon H2O2-induced oxidative stress

The instability of lutein has limited its wide application especially in the food industry. In this study, enzymatic acylation of lutein with divinyl adipate was investigated. Three new acylated lutein derivatives, lutein-3-O-adipate (compound 1), lutein-3'-O-adipate (compound 2) and lutein-di-adipate (compound 3), were identified and their stabilities and bioactivates were evaluated. Notably, compounds 1-3 showed better thermal, light stability and stronger scavenging capacity to ABTS radical cation (ABTS⁺) and hydroxyl radical (OH). Most importantly, these acylated lutein derivatives exhibited excellent protective effects on L-O2 cells upon hydrogen peroxide (H₂O₂)-induced oxidative stress. In particular, the acylated lutein derivative termed compound 3 prevented cellular oxidative stress via restraining the overproduction of reactive oxygen species (ROS), thereby increasing related antioxidant enzymes activity and inhibiting apoptosis by mitochondria pathway. Our research provides important insights into the application of acylated lutein derivatives in food, cosmetic, and pharmaceutical products.

Enhancing the stability of lutein emulsions with a water-soluble antioxidant and a oil-soluble antioxidant

Lutein is critical for protecting the eye against light damage. The low solubility and high sensitivity of lutein to environmental stresses prevent its further application. The hypothesis is that the combination of one water-soluble antioxidant and one oil-soluble antioxidant will be beneficial to improve the stability of lutein emulsions. A low-energy method was performed to prepare lutein emulsions. The combination of a lipid-soluble antioxidant (propyl gallate or ethylenediaminetetraacetic acid) and a water-soluble antioxidant (tea polyphenol or ascobic acid) were investigated for improving the lutein retention rates. It was shown that the highest lutein retention rate was achieved by using propyl gallate and tea polyphenol, 92.57%, at Day 7. It was proven that the lutein retention rates of emulsions with propyl gallate and tea polyphenol were 89.8%, 73.5% and 55.2% at 4 °C, 25 °C and 37 °C, respectively, at Day 28. The current study is helpful to prepare for the further application of lutein emulsions for ocular delivery.

Biopolymer- and Lipid-Based Carriers for the Delivery of Plant-Based Ingredients

Natural ingredients are gaining increasing attention from manufacturers following consumers’ concerns about the excessive use of synthetic ingredients. However, the use of natural extracts or molecules to achieve desirable qualities throughout the shelf life of foodstuff and, upon consumption, in the relevant biological environment is severely limited by their poor performance, especially with respect to solubility, stability against environmental conditions during product manufacturing, storage, and bioavailability upon consumption. Nanoencapsulation can be seen as an attractive approach with which to overcome these challenges. Among the different nanoencapsulation systems, lipids and biopolymer-based nanocarriers have emerged as the most effective ones because of their intrinsic low toxicity following their formulation with biocompatible and biodegradable materials. The present review aims to provide a survey of the recent advances in nanoscale carriers, formulated with biopolymers or lipids, for the encapsulation of natural compounds and plant extracts.

Red Raspberry Seed Oil Low Energy Nanoemulsions: Influence of Surfactants, Antioxidants, and Temperature on Oxidative Stability

The aim of this study was to assess and improve the oxidative stability of red raspberry seed oil−RO, a potential topical ingredient derived from food industry by-products, on its own and when incorporated in low energy nanoemulsion (NE). The RO’s oxidative stability was assessed at 5, 25, and 40 °C during one month of storage and expressed in: peroxide value, p-anisidine, and thiobarbituric reactive substances—TBARS value, while for NEs, lipid hydroperoxides and TBARS values were monitored. Both synthetic (butylated hydroxytoluene—BHT and ethylenediaminetetraacetic acid—EDTA), and natural (oregano essential oil—ORE and oak fruit extract—OAK) antioxidants were used. Pure RO and RO with BHT or ORE were stable at 5 °C and 25 °C, but at 40 °C BHT showed only moderate protection, while ORE was prooxidant. NEs prepared with new biodegradable polyglycerol esters-based surfactants, with droplet sizes of < 50 nm and narrow size distribution, showed improved physicochemical stability at room temperature, and especially at 40 °C, compared to NEs with polysorbate 80, which required the addition of antioxidants to preserve their stability. Natural antioxidants ORE and OAK were compatible with all NEs; therefore, their use is proposed as an effective alternative to synthetic antioxidants.

Nanoscale Delivery Systems of Lutein: An Updated Review from a Pharmaceutical Perspective

Carotenoids are natural lipid-soluble pigments that produce yellow to red colors in plants as well as providing bright coloration in vegetables and fruits. Lutein belongs to the xanthophyll subgroup of the carotenoid family, which plays an essential role in photosynthesis and photoprotection in nature. In the human body, lutein, together with its isomer zeaxanthin and its metabolite meso-zeaxanthin, accumulates in the macula of the eye retina, which is responsible for central, high-resolution, and color vision. As a bioactive phytochemical, lutein has essential physiological functions, providing photoprotection against damaging blue light, along with the neutralization of oxidants and the preservation of the structural and functional integrity of cellular membranes. As a potent antioxidant and anti-inflammatory agent, lutein unfortunately has a low bioavailability because of its lipophilicity and a low stability as a result of its conjugated double bonds. In order to enhance lutein stability and bioavailability and achieve its controlled delivery to a target, nanoscale delivery systems, which have great potential for the delivery of bioactive compounds, are starting to be employed. The current review highlights the advantages and innovations associated with incorporating lutein within promising nanoscale delivery systems, such as liposomes, nanoemulsions, polymer nanoparticles, and polymer–lipid hybrid nanoparticles, as well as their unique physiochemical properties.

Saponins as Natural Emulsifiers for Nanoemulsions

The awareness of sustainability approaches has focused attention on replacing synthetic emulsifiers with natural alternatives when formulating nanoemulsions. In this context, a comprehensive review of the different types of saponins being successfully used to form and stabilize nanoemulsions is presented, highlighting the most common natural sources and biosynthetic routes. Processes for their extraction and purification are also reviewed altogether with the recent advances for their characterization. Concerning the preparation of the nanoemulsions containing saponins, the focus has been initially given to screening methods, lipid phase used, and production procedures, but their characterization and delivery systems explored are also discussed. Most experimental outcomes showed that the saponins present high performance, but the challenges associated with the saponins' broader application, mainly the standardization for industrial use, are identified. Future perspectives report, among others, the emerging biotechnological processes and the use of byproducts in a circular economy context.

Resveratrol Stabilization and Loss by Sodium Caseinate, Whey and Soy Protein Isolates: Loading, Antioxidant Activity, Oxidability

The interaction of protein carrier and polyphenol is variable due to their environmental sensitivity. In this study, the interaction between resveratrol and whey protein isolate (WPI), sodium caseinate (SC) and soy protein isolate (SPI) during storage were systematically investigated from the aspects of polyphenol loading, antioxidant activity and oxidability. It was revealed that resveratrol loaded more in the SPI core and existed both in the core of SC micelles and on the particle surface, while WPI and resveratrol mainly formed in complexes. The loading capacity of the three proteins ranked in order SC > SPI > WPI. ABTS assay showed that the antioxidant activity of the protein carriers in the initial state was SC > SPI > WPI. The results of sulfhydryl, carbonyl and amino acid analysis showed that protein oxidability was SPI > SC > WPI. WPI, with the least oxidation, improved the storage stability of resveratrol, and the impact of SC on resveratrol stability changed from a protective to a pro-degradation effect. Co-oxidation occurred between SPI and resveratrol during storage, which refers to covalent interactions. The data gathered here suggested that the transition between the antioxidant and pro-oxidative properties of the carrier is the primary factor to investigate its protective effect on the delivered polyphenol.

Interaction of ovalbumin with lutein dipalmitate and their effects on the color stability of marigold lutein esters extracts

In this study, the interaction of ovalbumin with lutein dipalmitate and the effect of ovalbumin on marigold lutein esters extracts were investigated. Lutein dipalmitate quenched the fluorescence of ovalbumin by static quenching. Binding and thermodynamic parameters proved that lutein dipalmitate bound to ovalbumin spontaneously by van der Waals force and hydrogen bond, and the complex stoichiometry was 1:1. Through three-dimensional fluorescence spectroscopy, Fourier transform infrared spectroscopy and circular dichroism experiments, the conformation of ovalbumin was unfolded, and alteration in the ovalbumin secondary structure induced by lutein dipalmitate was observed. The results of transmission electron microscopy and particle size revealed that there were spherical and nano-sized aggregates in the ovalbumin-lutein dipalmitate system, indicating the lutein dipalmitate not only could bind to ovalbumin at molecular level, but also promote the aggregation of ovalbumin. Additionally, the addition of ovalbumin had a positive effect on the stability of marigold lutein esters extracts.

High Internal Phase Emulsions Stabilized with Polyphenol-Amyloid Fibril Supramolecules for Encapsulation and Protection of Lutein

High internal phase emulsions (HIPEs), also called highly concentrated emulsions with a minimal internal phase volume fraction of 74%, have been paid increasing attention in the development of functional foods due to their high potential in loading with large amounts of hydrophobic nutriceuticals. In the present study, HIPEs stabilized by polyphenol-amyloid supramolecular filaments were prepared for encapsulation of olive oil and loading with lutein. Binding and stacking of the green tea polyphenol epigallocatechin gallate (EGCG) on the surface of amyloid fibrils fabricated from hen egg lysozyme resulted in the hybrid supramolecules, which assembled to form hydrogels. The amyloid fibril clusters shrouded by EGCG were observed in the microstructure of the hydrogels characterized by atomic force microscopy (AFM). HIPEs stabilized by the EGCG-amyloid fibril supramolecules showed the typical microstructure of highly packed polyhedral geometric oil droplets. The gel strength of the HIPEs stabilized by the hybrid supramolecules was greater than that of HIPEs stabilized by pure amyloid fibrils. The droplet size of the HIPEs first decreased and then increased with the increase of EGCG contents in the hybrid supramolecules, which was consistent with the corresponding emulsion morphologies obtained from the images of confocal laser scanning microscopy (CLSM). Aggregation of the protein-based nanofibrils appeared in the continuous phase at higher EGCG contents. The droplet size of the HIPEs decreased with the increase of the amyloid fibril concentration, accompanied by more packed and homogenously dispersed lipid droplets, as shown in the CLSM images. A high loading content of lutein of up to 10 mg/mL in the prepared HIPEs was realized, and the stability of lutein against ultraviolet irradiation, heat, iron, and hydrogen peroxide was promoted significantly. In addition, encapsulation with the HIPEs prevented the oxidization of olive oil, and this effect was enhanced with the increase of the EGCG content in the hybrid supramolecules ranging from 0 to 0.25 wt %. The protection function of the HIPEs might be ascribed to the membrane of interfacial amyloid fibrils and the crowded oil droplet environment, both of which could shield the pro-oxidation factors.

Effect of the emulsifier type on the physicochemical stability and in vitro digestibility of a lutein/zeaxanthin-enriched emulsion

Lutein (L) and zeaxanthin (Z), as macular pigments, are water-insoluble, chemically unstable, and have low bioaccessibilities; they are often emulsified to overcome these limitations. This study investigated the impact of various emulsifiers (ethyl lauroyl arginate (LAE); Tween 80; and sodium dodecyl sulfate (SDS)) on the physicochemical properties and in vitro digestibilities of L/Z-fortified oil-in-water emulsions. Droplet aggregation and creaming extents were dependent on the emulsifier type. The ζ-potentials of emulsions stabilized by LAE, Tween 80, and SDS were + 87, - 26, and - 95 mV, respectively. SDS-stabilized emulsion had the smallest particles, while the particle sizes for the LAE- and Tween 80-stabilized emulsions were larger and not significantly different. The rates of L/Z degradation were sensitive to the emulsifier type and to heat, not to light. The L/Z bioaccessibility was the highest for the Tween 80 emulsion. Surfactants should therefore be carefully selected to optimize L/Z physicochemical stability and bioaccessibility in emulsions.

Comparison of Lutein Bioaccessibility from Dietary Supplement-Excipient Nanoemulsions and Nanoemulsion-Based Delivery Systems

The impact of lutein-loaded nanoemulsions and excipient nanoemulsions mixed with lutein-based dietary supplements (capsules and soft gels) on the bioaccessibility of lutein was explored using a simulated gastrointestinal tract (GIT). The particle size, particle size distribution, ζ-potential, microstructure, lipid digestibility, and lutein bioaccessibility of all the samples were measured after they were exposed to different environments (stomach and small intestine environments) within a simulated GIT. As expected, the bioaccessibility of lutein from the capsules (1.5%) and soft gels (3.2%) was relatively low when they were administered alone. However, the co-administration of excipient nanoemulsions significantly increased the bioaccessibility of lutein from both the capsules (35.2%) and soft gels (28.7%). This phenomenon was attributed to the fast digestion of the small oil droplets in the excipient nanoemulsions and the further formation of mixed micelles to solubilize any lutein molecules released from the supplements. The lutein-loaded nanoemulsions exhibited a much higher lutein bioaccessibility (86.8%) than any of the supplements, which was attributed to the rapid release and solubilization of lutein when the lipid droplets were rapidly and extensively digested within the small intestine. This study indicates that the bioaccessibility of lutein is much higher in nanoemulsion droplets than that in dietary supplements. However, consuming dietary supplements in the presence of nanoemulsion droplets can greatly increase lutein bioavailability. The results of this study have important guiding significance for the design of more effective lutein supplements.

Enzymatic acylation of lutein with a series of saturated fatty acid vinyl esters and the thermal stability and anti-lipid oxidation properties of the acylated derivatives

Lutein was enzymatically acylated with saturated fatty acid vinyl esters of different lengths of carbon chain (C₆ -C₁₄ ) under the action of Candida antarctica lipase B (Novozyme 435). The acylation reaction was optimized by considering substrate molar ratio, reaction solvent, type of enzyme, and reaction time. The highest yield (88%) was obtained using the Novozyme 435 to catalyze the acylation reaction of lutein and vinyl decanoate (lutein/vinyl decanoate molar ratio of 1/10) for 16 h in methyl tert-butyl ether. Ten lutein esters were synthesized, isolated, and purified, which were characterized by Fourier-transform infrared spectroscopy, high-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy. We found that the acylation of lutein improved its antioxidant capacity in lipid system and thermal stability. Our study extended the potential application of lutein in lipophilic food, cosmetic, and pharmaceutical industries. Practical Application: Enzyme acylation of lutein improved its antioxidant capacity in lipid system and thermal stability, extended its potential application in food, cosmetic, and pharmaceutical industries. In addition, our study also provided a new perspective and cognition for the further development and utilization of lutein.

Microencapsulation of carotenoid-rich materials: A review

Carotenoids are natural pigments that present several bioactive properties, including antioxidant, anticarcinogenic and provitamin A activities. However, these compounds are susceptible to degradation when exposed to a number of conditions (e.g. light, heat, oxygen), leading to loss of benefits and hampering their application in food products. Their hydrophobicity also makes incorporation into water-based foods more difficult. Microencapsulation techniques have been applied for decades to provide stability to carotenoid-rich extracts under typical conditions of processing and storage of foods, besides offering several other advantages to the use and application of these materials. This work reviews the recent advances in the microencapsulation of carotenoid-rich extracts, oils and oleoresins from varying sources, evidencing the technologies applied to encapsulate these materials, the effects of encapsulation on the obtained particles, and the impact of such processes on the bioaccessibility and release profile of carotenoids from microparticles. Moreover, recent applications of carotenoid-rich microparticles in food products are discussed. Most of the applied processes were effective in improving different aspects of the encapsulated materials, especially the stability of carotenoids during storage, resulting in microparticles with promising properties for future applications in food products. However, the lack of information about the effects of microencapsulation on carotenoids during processing of model foods, the sensory acceptance of enriched food products and the bioaccessibility and bioavailability of microencapsulated carotenoids reveals gaps that should be explored in the future.

Improvement of stability and bioaccessibility of β-carotene by curcumin in pea protein isolate-based complexes-stabilized emulsions: Effect of protein complexation by pectin and small molecular surfactants

The impact of different complexes on the properties of β-carotene-loaded emulsions was investigated by measuring the droplet size, encapsulation efficiency, droplet morphology, and physical stability. The photo and thermal stability of β-carotene and its bioaccessibility during digestion were also analyzed. Comparing to the emulsions stabilized by other complexes, the emulsion stabilized by the high methoxyl pectin-rhamnolipid-pea protein isolate-curcumin (HMP-Rha-PPI-Cur) complex had the smallest droplet size (17.53 ± 0.15 μm) and the maximum encapsulation efficiency for curcumin (90.33 ± 0.03 %) and β-carotene (92.16 ± 0.01 %). The emulsion stabilized by the HMP-Rha-PPI-Cur complex exhibited better physical stability against creaming. The retention rate of β-carotene in the HMP-Rha-PPI-Cur complex-stabilized emulsion was 17.75 ± 0.02 and 33.64 ± 0.02 % after UV irradiation and thermal treatment. The HMP-Rha-PPI-Cur complex-stabilized emulsion also had a higher level of free fatty acid released (43.67 %) and higher bioaccessibility of β-carotene (32.35 ± 0.02 %).

Color and composition of beauty products formulated with lemongrass essential oil: Cosmetics formulation with lemongrass essential oil

Diversification of products that are derived from essential oils carries important implications in reducing agricultural waste and promoting the medicinal materials industry. In this study, we formulated a shampoo and a body wash product incorporated with lemongrass (Cymbopogon citratus) essential oils (LEOs) and evaluated their color stability and the LEO compositional change. We first determined the color change and chemical composition of bare LEO under different storage conditions. Afterward, the washing product base was formulated, and its formulation process was optimized to minimize the color change by varying a wide range of parameters including pH, the inclusion of preservatives and antioxidants, LEO/antioxidant ratio, and emulsification temperature. The base product was then used in body wash and shampoo formulation following our previously reported procedure. The results indicated that direct incorporation of the LEO into the cosmetic products resulted in better color stability and citral retention in comparison with emulsion formation. In addition, shampoo and body wash products showed no detectible presence of compounds resulting from citral decomposition such as 3,7-dimethyl-1,3,6-octatriene, p-mentha-1,5-dien-8-ol, and p-cymene-8-ol. The current findings are expected to aid in diversifying LEO-derived commodities and justifying scalability of the cosmetics production process with a focus on the incorporation of naturally derived ingredients.

The interfacial covalent bonding of whey protein hydrolysate and pectin under high temperature sterilization: Effect on emulsion stability

In this study, the effect of high-pressure steam sterilization (121 °C for 15 min) on whey protein hydrolysate-pectin solutions and emulsions was studied. The interaction and emulsification characteristics of pectin and whey protein concentrate (WPC) were evaluated from the solution system to the emulsion system. Enzymatic hydrolysis of WPC (WPH, 2 % and 8 % degree of hydrolysis) increased the covalent binding with pectin, which reduced the heat-induced aggregation of protein and improved emulsification. The thermodynamic incompatibility between WPC and pectin was not conducive to the covalent bonding under high temperature sterilization and produced serious aggregates, which also made a rapid increase in particle size (up to ∼3 μm), compared to WPH-pectin emulsion (∼ 400 nm). In addition, if emulsion was stirred during the sterilization, the creaming and protein aggregation could be avoided. By comparing low methoxy pectin (LMP) and high methoxy pectin (HMP), it was found that the whey protein-HMP complex had better emulsification stability, and the steric stabilization played a more important role in emulsion stability than the electrostatic repulsion. The changes of whey protein and pectin at the oil-water interface of the emulsion during the sterilization process may provide a reference for the sterilized bioactive ingredient delivery system.

Study on the bioavailability of stevioside-encapsulized lutein and its mechanism

This study aims to develop novel lutein nanoparticles encapsulized by stevioside (LUT-STE, 165 ± 2 nm average particles size) and systematically evaluate its bioavailability. Multiple spectroscopy and NMR analyses showed lutein and stevioside could interact through hydrogen bonds, CHπ interaction and van der Waals forces. Molecular docking simulation showed lutein was well distributed in the hydrophobic cavity of stevioside. Analyzed by Caco-2 cellular models, the transported amount of LUT-STE was 2.39 times that of lutein in 120 min with a P_app (B → A)/P_app (A → B) value of 0.63 ± 0.04. Nystatin and dynasore significantly reduced the cellular uptake of LUT-STE by 41.3% and 57.7%, respectively. Compared with free lutein, LUT-STE increased the C_max in mice plasma by 5.01-fold and promoted the accumulation in multiple organs. LUT-STE promoted the protein expressions of CD36, NPC1L1 and PPARγ in both cell and animal models. In conclusion, stevioside entrapment significantly promote the bioavailability of lutein through multiple transmembrane pathways.

Stabilisation of Lutein and Lutein Esters with Polyoxyethylene Sorbitan Monooleate, Medium-Chain Triglyceride Oil and Lecithin

Lutein is a challenging compound to incorporate into food, as it is poorly soluble and unstable in aqueous solutions. In this study, the aim was to prepare stable encapsulates of lutein and lutein esters using feasible and straightforward techniques. Fine suspensions based on polyoxyethylene sorbitan monooleate and medium-chain triglyceride oil micelle-like units with 3.45% lutein esters or 1.9% lutein equivalents provided high encapsulation efficiencies of 79% and 83%, respectively. Lutein encapsulated in fine suspensions showed superior stability, as 86% was retained within the formulation over 250 days at 25 °C in the dark. Under the same storage conditions, only 38% of lutein remained in corresponding formulations. Higher encapsulation efficiencies were achieved with lecithin emulsions, at up to 99.3% for formulations with lutein, and up to 91.4% with lutein esters. In lecithin emulsions that were stored for 250 days, 17% and 80% of lutein and lutein esters, respectively, were retained within the formulations.

Critical Review of Lipid-Based Nanoparticles as Carriers of Neuroprotective Drugs and Extracts

The biggest obstacle to the treatment of diseases that affect the central nervous system (CNS) is the passage of drugs across the blood-brain barrier (BBB), a physical barrier that regulates the entry of substances into the brain and ensures the homeostasis of the CNS. This review summarizes current research on lipid-based nanoparticles for the nanoencapsulation of neuroprotective compounds. A survey of studies on nanoemulsions (NEs), nanoliposomes/nanophytosomes and solid lipid nanoparticles (SLNs)/nanostructured lipid carriers (NLCs) was carried out and is discussed herein, with particular emphasis upon their unique characteristics, the most important parameters influencing the formulation of each one, and examples of neuroprotective compounds/extracts nanoencapsulated using these nanoparticles. Gastrointestinal absorption is also discussed, as it may pose some obstacles for the absorption of free and nanoencapsulated neuroprotective compounds into the bloodstream, consequently hampering drug concentration in the brain. The transport mechanisms through which compounds or nanoparticles may cross BBB into the brain parenchyma, and the potential to increase drug bioavailability, are also discussed. Additionally, factors contributing to BBB disruption and neurodegeneration are described. Finally, the advantages of, and obstacles to, conventional and unconventional routes of administration to deliver nanoencapsulated neuroprotective drugs to the brain are also discussed, taking into account the avoidance of first-pass metabolism, onset of action, ability to bypass the BBB and concentration of the drug in the brain.

Effect of environmental stresses on physicochemical properties of ALA oil-in-water nanoemulsion system prepared by emulsion phase inversion

To solve the stability and oxidation issues of alpha-linolenic acid (ALA), this study focused on developing ALA nanoemulsion system (ALA-NE, oil-in-water) and evaluating the effect of environmental conditions on physical stability and the effect of antioxidants on oxidative stability. The physicochemical properties of nanoemulsions were measured at different conditions, including particle diameter, zeta potential, retention rate and peroxidation value (POV). The particle diameter increased significantly and the retention rate decreased after 25 days storage under the conditions of high temperature and metal ions. However, the influence of ionic strength, pH and light was insignificant. As an antioxidant, Vitamin E was more effective at retarding lipid oxidation of nanoemulsions than that of vitamin C. These results provided reference information in preparing effective and stable ALA-NE systems and enlarging the application fields.

Comparative Encapsulation Efficiency of Lutein in Micelles Synthesized via Batch and High Throughput Methods

PURPOSE

Black raspberries (BRBs) and their anthocyanin-rich hydrophilic fractions (BRB-H) have exhibited significant chemopreventative activity across aerodigestive cancers. Lutein, the primary component of the BRB lipophilic fraction (BRB-L), also demonstrates bioactivity potential, but is less well characterized, in part because of its poor, innate bioavailability. For these lipophilic compounds to be accurately evaluated for anticancer efficacy, it is necessary to increase their functional bioavailability using delivery vehicles. Lutein has been delivered in commercial settings in emulsion form. However, emulsions are unstable, particularly in the gastrointestinal tract, which limit their use as an oral nutraceutical. Here, we evaluated lutein encapsulation and cellular uptake for nanoparticle (NP) delivery vehicles composed of three different materials synthesized via two different approaches.

METHODS

Specifically, NPs were synthesized via smaller scale batch interfacial instability (II) sonication and semi-continuous high throughput electrohydrodynamic-mediated mixing nanoprecipitation (EM-NP) methods using polystyrene-polyethylene oxide (PSPEO) or polycaprolactone-polyethylene glycol (PCLPEG) block copolymers and PHOSPHOLIPON 90G® (P90G, Lipoid GmbH) lipids. Size distribution, lutein encapsulation efficiency (EE), and cellular uptake and delivery were evaluated for each NP formulation.

RESULTS

NPs produced via high throughput EM-NP had higher EEs than NPs produced via batch II sonication, and P90G had the greatest EE (55%) and elicited faster cellular uptake in premalignant oral epithelial cells (SCC83) compared to other delivery systems.

CONCLUSION

These qualities suggest P90G could be a beneficial candidate for future lutein in vitro delivery research and clinical translation for oral cancer prevention.

Whey protein and maltodextrin-stabilized oil-in-water emulsions: Effects of dextrose equivalent

The aim of this work is to evaluate the effect of dextrose equivalent (DE) of maltodextrins (MD) on the stability of whey protein and maltodextrin stabilized oil-in-water (o/w) emulsions. Emulsions with DE 15 maltodextrin (MD 15) exhibited better stability under light acidic (pH 6), neutral and alkaline (pH 8-9) conditions, as well as during temperature ramps (20-60 °C). After 15-days of storage, MD 15 emulsion showed increase in polydispersity and decrease in the average droplet size. The apparent viscosity of the emulsions decreased with increasing DE. The shear stresses of all emulsions fitted well with the power law model (R² > 0.9), while MD 15 showed the most stable k and n indexes. The brightness and whiteness of emulsion decreased with increases in DE. In conclusion, emulsions with MD 15 exhibited better stability, which suggests their good potential for use in the preparation of energy drinks.

Comparison of legume and dairy proteins for the impact of Maillard conjugation on nanoemulsion formation, stability, and lutein color retention

While dairy proteins have traditionally been used to stabilize nanoemulsions, there is a trend towards plant-based formulations. Additionally, both types of protein are poorly soluble near their isoelectric point. The main goals of this research were to develop and characterize Maillard conjugates from pea protein (PPI) or caseinate and dextran, and to evaluate the physical stability of nanoemulsions made with such emulsifiers at various ionic strengths, pH = 4.6, and temperatures during storage, as well as lutein color retention over storage. Protein conjugates formed nanoemulsions with diameters of 125 ± 12 nm (PDI = 0.13 ± 0.00) and 269 ± 36 nm (PDI = 0.76 ± 0.42) (pH = 7) for caseinate and PPI, respectively. Conjugation improved the physical stability (droplet size) of emulsions at the isoelectric point, during storage at 4-55 °C, and in ionic solutions. Lutein color degradation was better associated with particle size than conjugation and was lowest for PPI-stabilized emulsions. This study suggests that Maillard conjugation could improve PPI emulsification properties.

Microemulsions as nano-reactors for the solubilization, separation, purification and encapsulation of bioactive compounds

Bioactive components possess various functionalities and are most interested for different food, nutraceutical and pharmaceutical formulations. The current review will discuss the preparation methods and fabrication techniques to design microemulsions (MEs) for the solubilization, separation, encapsulation and purification of various agro-food bioactive compounds. ME systems have shown suitable potential in enhancing oil recovery, protein extraction, and isolation of bioactive compounds. Moreover, the capability of ME based systems as drug and nutraceutical delivery cargos, and synthesis of various organic and inorganic nanoparticles, especially using biopolymers, will be investigated. ME liquid membranes are also developed as nano-extractor/nano-reactor vehicles, capable of simultaneous extraction, encapsulation or even synthesis of hydrophilic and lipophilic bioactive compounds for food, nutraceutical and drug applications.

Catalase to demulsify oil-in-water fish oil-polysorbate emulsion and affect lipid oxidation

The physicochemical and oxidative stability of oil emulsion has been one of the major challenges in food industry. Factors influencing the emulsion stability have seemingly been exhaustedly elucidated, such as temperature, pH, salts, proteins, polysaccharides and digestive enzymes. Here we report the previously unrecognized influence of catalase on emulsion stability. Submicron oil-in-water fish oil emulsion was prepared by high speed homogenization in the presence of polysorbate 80. Influence of catalase on the emulsion's stability was investigated in comparison with its deactivated version and bovine serum albumin (BSA) by visual examination, turbidity and DLS measurement and TEM observation. Catalase demulsified the emulsion instantly in a concentration-responsive manner at concentrations higher than 0.8 μmol/L, resulting a decreased turbidity, oil flocculation and precipitation of the enzyme itself. Neither BSA nor the thermally inactivated CAT caused demulsification at the same speed, indicating that CAT's demulsification effect was attributed to its enzymatic activity rather than its general protein properties. The enlargement of oil-polysorbate droplets and precipitation of CAT were confirmed by both TEM and DLS. Furthermore, CAT's demulsification effect was found irrelevant of the lipid oxidation. This insight into catalase's influences on emulsion not only sheds lights on food processing and shelf-life, nutritional value and potential biological effects, but also presents an exciting challenge to elucidate the mechanism behind.

Nanostructured Lipid-Based Delivery Systems as a Strategy to Increase Functionality of Bioactive Compounds

Acquisition of a healthy lifestyle through diet has driven the food manufacturing industry to produce new food products with high nutritional quality. In this sense, consumption of bioactive compounds has been associated with a decreased risk of suffering chronic diseases. Nonetheless, due to their low solubility in aqueous matrices, high instability in food products during processing and preparation as well as poor bioavailability, the use of such compounds is sometimes limited. Recent advancements in encapsulation and protection of bioactive compounds has opened new possibilities for the development of novel food products. In this direction, the present review is attempting to describe encapsulation achievements, with special attention to nanostructured lipid-based delivery systems, i.e., nanoemulsions, multi-layer emulsions and liposomes. Functionality of bioactive compounds is directly associated with their bioavailability, which in turn is governed by several complex processes, including the passage through the gastrointestinal tract and transport to epithelial cells. Therefore, an overview of recent research on the properties of these nanostructured lipid-based delivery systems with a strong impact on the functionality of bioactive compounds will be also provided. Nanostructured lipid-based delivery systems might be used as a potential option to enhance the solubility, stability, absorption and, ultimately, functionality of bioactive compounds. Several studies have been performed in this line, modifying the composition of the nanostructures, such as the lipid-type or surfactants. Overall, influencing factors and strategies to improve the efficacy of encapsulated bioactive compounds within nanostructures have been successfully identified. This knowledge can be used to design effective targeted nanostructured lipid-based delivery systems for bioactive compounds. However, there is still a lack of information on food interactions, toxicity and long-term consumption of such nanostructures.

Penetratin-modified lutein nanoemulsion in-situ gel for the treatment of age-related macular degeneration

Background: Lutein is the primary macular pigment with an favorable effect on the treatment of age-related macular degeneration (AMD). However, the poor water solubility of lutein hinders its absorption and delivery. In this study, a penetratin-modified lutein nanoemulsion in-situ gel (GEL) was prepared for the treatment of AMD.Methods: A nanoemulsion (NE) was prepared and modified with penetratin (P-NE) to improve the penetration. The effect of penetratin was evaluated by cell uptake and intraocular distribution assays. A dry AMD model was induced using NaIO₃, and the therapeutic effect was evaluated by electroretinography, the number of apoptosis cells and the reactive oxygen species (ROS) level.Results: Lutein showed a good ability to protect ARPE-19 from the damage of H₂O₂ and the uptake rate of P-NE was significantly higher than NE. In the efficacy experiments, the structure of retina was significantly improved after treatment, the apoptosis rate decreased from 31.98% to 2.05%, and the level of ROS was significantly decreased (p < 0.0001).Conclusions: With the aid of penetratin, lutein could be delivered to the retina effectively. The P-NE GEL could evidently inhibit the apoptosis and ROS, demonstrating that the P-NE GEL has a good application prospect in the treatment of AMD.