Surface-active natural saponins. Properties, safety, and efficacy.

In the future, cleaning products must fulfil the principles of green chemistry while maintaining efficacy against bacteria. This study aims to evaluate the detergent properties, ecotoxicity, and anti-biofilm potential of natural saponins compared to synthetic surfactants. We tested sodium dodecyl sulphate, quillaja saponin, escin, and sapogenin for emulsifying capacity, critical micelle concentration, ecotoxicity to yeast, and antibacterial and anti-biofilm potential against bacteria. The results show that the emulsifying capacities of quillaja saponin and sodium dodecyl sulphate are similar, while the critical micelle concentration for quillaja saponin is much lower . Furthermore, the antibacterial and antibiofilm potentials are much higher for quillaja saponin than for synthetic sodium dodecyl sulphate . Moreover, we have shown that natural saponins are less toxic to the S. cerevisiae than synthetic saponin is. All these facts indicate that quillaja is a suitable candidate to replace synthetic products as it meets the requirements of efficacy and safety.

Recent Advances and Applications of Plant-Based Bioactive Saponins in Colloidal Multiphase Food Systems.

The naturally occurring saponins exhibit remarkable interfacial activity and also possess many biological activities linking to human health benefits, which make them particularly attractive as bifunctional building blocks for formulation of colloidal multiphase food systems. This review focuses on two commonly used food-grade saponins, Quillaja saponins (QS) and glycyrrhizic acid (GA), with the aim of clarifying the relationship between the structural features of saponin molecules and their subsequent self-assembly and interfacial properties. The recent applications of these two saponins in various colloidal multiphase systems, including liquid emulsions, gel emulsions, aqueous foams and complex emulsion foams, are then discussed. A particular emphasis is on the unique use of GA and GA nanofibrils as sole stabilizers for fabricating various multiphase food systems with many advanced qualities including simplicity, ultrastability, stimulability, structural viscoelasticity and processability. These natural saponin and saponin-based colloids are expected to be used as sustainable, plant-based ingredients for designing future foods, cosmetics and pharmaceuticals.

Saponins from Quillaja saponaria and Quillaja brasiliensis: Particular Chemical Characteristics and Biological Activities.

Quillaja saponaria Molina represents the main source of saponins for industrial applications. Q. saponaria triterpenoids have been studied for more than four decades and their relevance is due to their biological activities, especially as a vaccine adjuvant and immunostimulant, which have led to important research in the field of vaccine development. These saponins, alone or incorporated into immunostimulating complexes (ISCOMs), are able to modulate immunity by increasing antigen uptake, stimulating cytotoxic T lymphocyte production (Th1) and cytokines (Th2) in response to different antigens. Furthermore, antiviral, antifungal, antibacterial, antiparasitic, and antitumor activities are also reported as important biological properties of Quillaja triterpenoids. Recently, other saponins from Q. brasiliensis (A. St.-Hill. & Tul.) Mart. were successfully tested and showed similar chemical and biological properties to those of Q. saponaria barks. The aim of this manuscript is to summarize the current advances in phytochemical and pharmacological knowledge of saponins from Quillaja plants, including the particular chemical characteristics of these triterpenoids. The potential applications of Quillaja saponins to stimulate further drug discovery research will be provided.

Saponin Adsorption at the Air-Water Interface-Neutron Reflectivity and Surface Tension Study.

Saponins are a large group of glycosides present in many plant species. They exhibit high surface activity, which arises from a hydrophobic scaffold of triterpenoid or steroid groups and attached hydrophilic saccharide chains. The diversity of molecular structures, present in various plants, gives rise to a rich variety of physicochemical properties and biological activity and results in a wide range of applications in foods, cosmetics, medicine, and several other industrial sectors. Saponin surface activity is a key property in such applications and here the adsorption of three triterpenoid saponins, escin, tea saponins, and Quillaja saponin, is studied at the air-water interface by neutron reflectivity and surface tension. All these saponins form adsorption layers with very high surface visco-elasticity. The structure of the adsorbed layers has been determined from the neutron reflectivity data and is related to the molecular structure of the saponins. The results indicate that the structure of the saturated adsorption layers is governed by densely packed hydrophilic saccharide groups. The tight molecular packing and the strong hydrogen bonds between the neighboring saccharide groups are the main reasons for the unusual rheological properties of the saponin adsorption layers.

Functionalized PHB granules provide the basis for the efficient side-chain cleavage of cholesterol and analogs in recombinant Bacillus megaterium.

BACKGROUND: Cholesterol, the precursor of all steroid hormones, is the most abundant steroid in vertebrates and exhibits highly hydrophobic properties, rendering it a difficult substrate for aqueous microbial biotransformations. In the present study, we developed a Bacillus megaterium based whole-cell system that allows the side-chain cleavage of this sterol and investigated the underlying physiological basis of the biocatalysis. RESULTS: CYP11A1, the side-chain cleaving cytochrome P450, was recombinantly expressed in the Gram-positive soil bacterium B. megaterium combined with the required electron transfer proteins. By applying a mixture of 2-hydroxypropyl-ß-cyclodextrin and Quillaja saponin as solubilizing agents, the zoosterols cholesterol and 7-dehydrocholesterol, as well as the phytosterol ß-sitosterol could be efficiently converted to pregnenolone or 7-dehydropregnenolone. Fluorescence-microscopic analysis revealed that cholesterol accumulates in the carbon and energy storage-serving poly(3-hydroxybutyrate) (PHB) bodies and that the membrane proteins CYP11A1 and its redox partner adrenodoxin reductase (AdR) are likewise localized to their surrounding phospholipid/protein monolayer. The capacity to store cholesterol was absent in a mutant strain devoid of the PHB-producing polymerase subunit PhaC, resulting in a drastically decreased cholesterol conversion rate, while no effect on the expression of the recombinant proteins could be observed. CONCLUSION: We established a whole-cell system based on B. megaterium, which enables the conversion of the steroid hormone precursor cholesterol to pregnenolone in substantial quantities. We demonstrate that the microorganism's PHB granules, aggregates of bioplastic coated with a protein/phospholipid monolayer, are crucial for the high conversion rate by serving as substrate storage. This microbial system opens the way for an industrial conversion of the abundantly available cholesterol to any type of steroid hormones, which represent one of the biggest groups of drugs for the treatment of a wide variety of diseases.

Surface shear rheology of saponin adsorption layers.

Saponins are a wide class of natural surfactants, with molecules containing a rigid hydrophobic group (triterpenoid or steroid), connected via glycoside bonds to hydrophilic oligosaccharide chains. These surfactants are very good foam stabiliziers and emulsifiers, and show a range of nontrivial biological activities. The molecular mechanisms behind these unusual properties are unknown, and, therefore, the saponins have attracted significant research interest in recent years. In our previous study (Stanimirova et al. Langmuir 2011, 27, 12486-12498), we showed that the triterpenoid saponins extracted from Quillaja saponaria plant (Quillaja saponins) formed adsorption layers with unusually high surface dilatational elasticity, 280 ± 30 mN/m. In this Article, we study the shear rheological properties of the adsorption layers of Quillaja saponins. In addition, we study the surface shear rheological properties of Yucca saponins, which are of steroid type. The experimental results show that the adsorption layers of Yucca saponins exhibit purely viscous rheological response, even at the lowest shear stress applied, whereas the adsorption layers of Quillaja saponins behave like a viscoelastic two-dimensional body. For Quillaja saponins, a single master curve describes the data for the viscoelastic creep compliance versus deformation time, up to a certain critical value of the applied shear stress. Above this value, the layer compliance increases, and the adsorption layers eventually transform into viscous ones. The experimental creep-recovery curves for the viscoelastic layers are fitted very well by compound Voigt rheological model. The obtained results are discussed from the viewpoint of the layer structure and the possible molecular mechanisms, governing the rheological response of the saponin adsorption layers.

Formulation and physicochemical stability of oil-in-water nanoemulsion loaded with α-terpineol as flavor oil using Quillaja saponins as natural emulsifier.

Alpha-terpineol (α-TOH) is a promising monoterpenoid detaining several biological activities. However, as a volatile molecule, the incorporation of α-TOH within formulated products poses several challenges related to its stability. In this sense, nanoencapsulation works as a key technology to protect the bioactivity of low molecular weight oils, like α-TOH, against environmental stresses (heat, light, and moisture), mitigating their susceptibility to degradation (oxidation and volatilization). Physical properties of encapsulated flavor/essential oil have been extensively reported, whereas there is a lack in the literature regarding their chemical stability, which is usually the main purpose of encapsulation. Thus, in this study, the physicochemical stability of the formulated oil-in-water nanoemulsion loaded with α-TOH stabilized with Quillaja saponins (QSs) as a natural emulsifier (α-TOH-QSs-NE) were tracked in a long-term (up to 280th day). Along with time, mean droplet diameter (MDD) and turbidity were used as a reference for physical parameters; while the chemical stability was monitored using gas chromatography analysis to quantify the mark content of α-TOH into the NE. Results indicated that α-TOH-QSs-NE was successfully formulated with a high-load amount of α-TOH (90 mg mL-1). α-TOH-QSs-NE showed great physicochemical stability regardless the storage-temperature (5 °C or 25 °C) up to 280th day, with no significant alterations in the MDD or turbidity, where c.a. 79% of the initial amount of the nanoemulsified α-TOH remained detectable in α-TOH-QSs-NEs, with no finding of degradation products. Thus, the data here disclosure may be useful for innovative application of α-TOH in foodstuffs.

Formation and stability of emulsions stabilized by Quillaja saponin-egg lecithin mixtures.

Knowledge of binary emulsifiers' influence on the formation and stability of emulsion-based products is still limited. The aim of this study was to investigate the emulsifying properties of Quillaja saponin-egg lecithin mixtures at different concentration ratios (r = 5:0, 4:1, 3:2, 2:3, 1:4, and 0:5) with total emulsifier concentration set to 0.5% or 1.0% (w/w). For this, oil-in-water emulsions (10% oil, pH 7) were prepared via high-pressure homogenization. Furthermore, emulsion stability against different environmental stresses was tested. All the binary emulsifier mixtures formed submicron sized emulsions upon homogenization. The most stable emulsions among the mixed emulsifiers were obtained at low Quillaja saponin concentration at r = 1:4 that showed similar physical stability over time to emulsions stabilized by Quillaja saponins and egg lecithin alone. The data suggested that the mixtures of Quillaja saponins and egg lecithins built mixed interfacial layers that were prone to changes over time. Emulsions stabilized by the binary mixtures were in general less stable against changes in pH and ionic strength than the emulsions stabilized by the individual emulsifiers. An exception were the emulsions at r = 1:4 that showed improved stability at pH 2 over the phase separated Quillaja saponin-stabilized emulsions at the same pH. Moreover, all the emulsions were heat stable up to 90 °C. On the other hand, none of the emulsions were stable upon freeze-thawing. These results increase our understanding of technofunctionality of binary emulsifier systems. PRACTICAL APPLICATION: Food-grade and natural emulsifier mixtures composed of Quillaja saponins and egg lecithin may be used in selected emulsion-based food or personal care product applications to replace synthetic surfactants due to issues with consumer acceptance and regulatory restrictions.

Quillaja Saponin Characteristics and Functional Properties.

Consumer concerns about synthetically derived food additives have increased current research efforts to find naturally occurring alternatives. This review focuses on a group of natural surfactants, the Quillaja saponins, that can be extracted from the Quillaja saponaria Molina tree. Quillaja saponins are triterpenoid saponins comprising a hydrophobic quillaic acid backbone and hydrophilic sugar moieties. Commercially available Quillaja saponin products and their composition and properties are described, and the technofunctionality of Quillaja saponins in a variety of food, cosmetic, and pharmaceutical product applications is discussed. These applications make use of the biological and interfacial activities of Quillaja saponins and their ability to form and stabilize colloidal structures such as emulsions, foams, crystallized lipid particles, heteroaggregates, and micelles. Further emphasis is given to the complexation and functional properties of Quillaja saponins with other cosurfactants to create mixed surfactant systems, an approach that has the potential to facilitate new interfacial structures and novel functionalities.

Fabrication and characterization of nanostructured lipid carriers (NLC) using a plant-based emulsifier: Quillaja saponin.

Nanostructured lipid carriers (NLCs) are a type of colloidal delivery system that was developed in the pharmaceutical industry to combine the advantages and eliminate the shortcomings of oil-in-water (O/W) nanoemulsions and solid lipid nanoparticles (SLNs). The hydrophobic core of the particles within NLCs consists of a solidified fat phase with a partially disorganized structure, which inhibits morphological changes and bioactive expulsion. In the present study, we formulated NLCs using a hot-homogenization approach using fully hydrogenated soybean oil (HSO) as the lipid phase and quillaja saponins as a natural surfactant. The NLCs formed had a low viscosity and milky white appearance similar to that of O/W nanoemulsions. The fabrication conditions were optimized, including the number of passes through the microfluidizer, stirring conditions, cooling rate, and emulsifier level. Unlike bulk HSO, the emulsified form had to be supercooled substantially to promote crystallization of the lipid droplets, which was attributed to differences in nucleation behavior. The crystallization temperature decreased with increasing saponin concentration, which was probably because smaller droplets were formed at higher emulsifier levels. For instance, at 3, 6, 9, and 12 wt% saponin, the degree of supercooling was 10, 15, 18, and 18 °C, while the mean particle diameter was 0.82, 0.53, 0.41, and 0.44 µm, respectively. The melting and crystallization behavior of the NLCs was characterized using an optical microscope and differential scanning calorimetry (DSC), while the morphology of the NLCs was characterized using transmission electron microscopy (TEM). This analysis showed that the NLCs contained spherical particles with a crystallization temperature around 31 °C. This information may be useful for formulating NLC from natural ingredients for application in the food and beverage industry.

Emulsion-based control of flavor release profiles: Impact of oil droplet characteristics on garlic aroma release during simulated cooking.

The objective of this research was to elucidate the main factors influencing flavor retention in oil-in-water emulsions during simulated cooking, including oil droplet concentration, oil type, droplet size, and emulsifier type. Allyl methyl disulfide (AMDS), a hydrophobic flavor in garlic that is easily lost from foods during processing, storage, and preparation, was used as a model aroma compound. The impact of droplet characteristics on the flavor retention profile of AMDS-loaded emulsions subjected to simulated cooking conditions was determined, which involved heating from them from room temperature to boiling and then holding them for 30 min. The flavor retention half-time (FT1/2) was calculated from the retention-time curves, i.e., the time for the flavor concentration to decrease to half its initial value. Based on FT1/2, the flavor retention during cooking depended on oil type: palm oil > corn oil > mineral oil. However, the mineral oil emulsions were also the most unstable to droplet coalescence during cooking. Increasing the oil droplet concentration in the emulsions increased flavor retention during cooking, but also decreased their physical stability. Based on FT1/2, the type of emulsifier used to formulate the emulsions also influenced flavor retention: quillaja saponin > Tween 80 > sodium caseinate > whey protein isolate. The emulsions that were most unstable to coalescence during cooking, and therefore had the largest droplet sizes, tended to have better flavor retention (longer FT1/2). The observed differences in flavor retention were mainly attributed to differences in the size and location of the oil droplets during cooking. These results have important implications for the design of food matrices that can control flavor retention and release during food preparation.

Production of thymol nanoemulsions stabilized using Quillaja Saponin as a biosurfactant: Antioxidant activity enhancement.

Thymol oil-in-water nanoemulsions as a potential natural alternative for synthetic antioxidant agents were developed. The nanoemulsions were formulated using Quillaja Saponin bio-surfactant and green solvents including high oleic sunflower oil (HOSO), tricaprylin (TC), and cinnamaldehyde (CA). The 4% thymol nanoemulsions containing TC and HOSO remained stable during long-term storage (at least 30 d). The antioxidant activity (AA) of free thymol and thymol nanoemulsions was compared with butylated hydroxytoluene (BHT) and ascorbic acid. The results obtained from DPPH, FRAP, and CUPRAC antioxidant assays showed a substantial improvement (p < 0.05) of the AA of free thymol through emulsification. The outcomes from the AA of the nanoemulsions in raw chicken breast meat measured by the TBARS assay revealed a significant improvement (p < 0.05) of the AA when thymol was encapsulated. These nanoemulsions may be applicable in the food industry as well as in cosmetic and health care products.

Stabilization and Rheology of Concentrated Emulsions Using the Natural Emulsifiers Quillaja Saponins and Rhamnolipids.

Concentrated emulsions are widely used in the cosmetic, personal-care, and food industries to reduce storage and transportation costs and to provide desirable characteristics. The current study aimed to produce concentrated emulsions (50 wt % oil) using two natural emulsifiers, quillaja saponins and rhamnolipids. The impacts of emulsifier concentrations on the particle sizes, rheological properties, and stabilities of concentrated emulsions were evaluated. Emulsion particle sizes were negatively correlated with the concentrations of both quillaja saponins and rhamnolipids, and rhamnolipids were more effective in producing smaller droplets. Both emulsifiers formed stable concentrated emulsions against a series of environmental stresses, including various temperatures (30-90 °C), salt concentrations (≤200 mM NaCl), and pHs (pH 5-8). The rheology tests suggested that concentrated emulsions stabilized by quillaja saponins or rhamnolipids presented shear-thinning behaviors and had relatively low consistency coefficients.

Impact of oil droplet concentration on the optical, rheological, and stability characteristics of O/W emulsions stabilized with plant-based surfactant: Potential application as non-dairy creamers.

The development of plant-based foods and beverages is becoming increasingly popular because of growing consumer concerns about perceived ethical, health, and environmental issues. The current study examined the influence of oil droplet concentration on the physicochemical properties of oil-in-water (O/W) emulsions stabilized with a plant-based surfactant. Emulsions were utilized as model creamers, which consisted of medium chain triglycerides (MCT) as the oil phase and quillaja saponin as a plant-based surfactant. The optical, rheological and stability properties of these model creamers were measured at varied oil content from 0 to 15%, at a constant surfactant-to-oil ratio (1:15). The model creamers had an appearance similar to that of commercial non-dairy creamers, and their whiteness increased with increasing droplet concentration due to enhanced light scattering: L* from 77 to 91 for creamer and L* from 5 to 55 for white coffee. The quillaja saponin-coated lipid droplets were stable to aggregation and gravitational separation when added to hot acidic coffee solutions (85°C, pH4.9), which was attributed to strong steric and electrostatic repulsions. The apparent viscosity of the model creamers increased with increasing droplet concentration due to increased frictional losses associated with the presence of the droplets. This study provides valuable information into the impact of oil content on the physicochemical properties of liquid creamers using plant based surfactants, which is important for the formulation of healthier products.

Emulsions as delivery systems for gamma and delta tocotrienols: Formation, properties and simulated gastrointestinal fate.

Tocotrienols have been reported to have stronger bioactivities than tocopherols, and may therefore be suitable as a potent source of vitamin E in functional foods, supplements, and pharmaceuticals. However, their inclusion into new products is hindered by their low water-solubility and oral bioavailability. Oil-in-water emulsions (O/W) could provide an adequate delivery system for these bioactive compounds. Tocotrienols were tested in bulk oil and within O/W conventional emulsions (>10µm) and nanoemulsions (<350nm). The emulsions were prepared with medium chain triglycerides (MCT) as an oil phase (5 to 40% wt) and quillaja saponins as a natural surfactant. The gastrointestinal fate of the emulsion-based delivery systems was investigated using a simulated gastrointestinal tract (GIT). The physical properties of the emulsions (color, apparent viscosity) were affected with increased droplet concentration. The lipid phase composition (emulsion type and particle size) had a pronounced impact on the microstructure of the emulsions in different regions of the GIT. At simulated small intestine conditions, the rate of lipid digestion and tocotrienol bioaccessibility decreased in the following order: nanoemulsions>emulsions>bulk oil. These results suggest that emulsions containing small lipid droplets are particularly suitable for delivering tocotrienols.

Quillaja saponin-based hollow salt particles as solid carriers for enhancing sensory aroma with reduced sodium intake.

Dietary salt is a vital ingredient associated with sensory performance in processed foods, while reduced salt intake linked to public health is highly desired by consumers and food manufacturers. In this paper, quillaja saponin (QS) based hollow salt particles (∼10 µm) were fabricated by simple spray drying, and utilized as solid carriers to enhance sensory aromas with reduced sodium intake. QS-coated nanodroplets were firstly prepared as a reservoir for flavor oils (lemon and garlic oil), and then served as frameworks to construct hollow salt particles via general spray drying. Headspace gas chromatography-mass spectrometry (DHS-GC-MS) and panel sensory analysis conclude that the hollow salt particles loaded with flavor oils enhance typical aroma attributes and saltiness perception in comparison with their mixture control. The QS-based hollow salt particles could be developed into novel vehicles for improving flavor performance with reduced sodium intake, and furthermore used for delivery of hydrophobic bioactives in food systems.

Stabilization and functionalization of aqueous foams by Quillaja saponin-coated nanodroplets.

We report evidence for stabilization and functionalization of aqueous foams stabilized by Quillaja saponin (QS)-coated nanodroplets. In contrast to foams stabilized by QS, stabilized the foams of QS-coated nanodroplets showed superior foamability, stability and multi-functional characteristics. Specifically, the half-life time of the foam stabilized by nanodroplets was approximately 4 times that of saponin. The microstructure observation indicates the nanodroplets from assembly of saponin around oil droplet were strong attachment at the gas-liquid interface and stabling a large gas-liquid interfacial area in a hierarchical structure. The surface dynamic adsorption and large deformation rheology were performed, revealed that QS nanodroplets were almost irreversibly adsorbed at air-liquid interface and exhibited less surface desorption and high elastic-viscous response to a large mechanical deformation. These nanodroplets stabilized foams presented a large capacity for loading hydrophobic flavors and nutrients (e.g., ß-carotene and curcumin), which could be used to create a new class of foam food products with sustained release of flavors and/or health benefit functionality.

Influence of homogenization on physical properties of model coffee creamers stabilized by quillaja saponin.

There is a growing demand for use of natural ingredients in food manufacturing. This study utilized a natural emulsifier, quillaja saponin (1%) to fabricate non-dairy model creamer emulsions (containing 10% medium chain triglycerides oil). Varying homogenization conditions, ranging from a high-shear mixer to passing through a microfluidizer at 20,000psi, were applied to fabricate emulsions. The effect of particle size on the appearance, tristimulus color coordinates, and electrical characteristics of the model creamers and white coffee drinks were investigated. The average droplet size varied from 0.2 to 16µm. All model creamers had whitish milk-like appearance and the white coffee solutions had light brown color. All systems were physically stable except for the systems with largest oil droplets (1.8 and 16µm), which had creaming. The lightness, L* (whiteness) of the model creamer and the white coffee increased with decreasing oil droplet size, as smaller droplets scatter more light. Decreasing the oil droplet size led to lower zeta potential (from -73 to -54mV) due to lesser negative charge group accumulated on the interfacial layer of the droplets. The oil droplets were also found to be stable to aggregation in hot acidic coffee solutions prepared using model hard water. Overall, this study found that oil droplets stabilized with natural plant-based surfactant have potential for application in liquid coffee creamers and their stability and whitening power were dependent on the droplet size.

Emulsification efficacy of Quillaja saponins at very low concentration: Model development and role of alcohols.

The present study aims at quantifying interfacial coverage of a biosurfactant (Quillaja saponins) and understanding the impact of flavor and fragrance alcohols on emulsification efficacy of the biosurfactant in a surfactant-oil-matrix system. Emulsions were prepared using limonene, alkanes (C8, C12, and C16) or limonene ̶ alcohol (linalool and C6C10 alcohols) mixtures at different ratios as oil phase stabilized by Quillaja saponins at very low concentrations (0.005-0.05% w/w). Droplet size was measured and size distributions were numerized to determine surface and volume average droplet diameters of bimodal emulsions. Using a model developed in the present study, Quillaja saponins showed an interfacial coverage of 5.0×106cm2/g and a head surface of 1.37nm2 with a lay-on configuration at interface. The model proved to discriminate between surface active (alcohols) and non-active (alkanes) compounds. The apparent interfacial coverage of saponins increased linearly with increasing alcohol concentration. The type of alcohol (terpene alcohol vs. medium chain alcohols) and alcohol chain length (C6C10) showed little impact on emulsification efficacy of Quillaja saponins. The molar ratio of heptanol to saponin at interface increased from 0 to 8.6 corresponding to 0-30% w/w heptanol in limonene. This study revealed that the distribution of alcohol at interface was mainly driven by partitioning in the surfactant-oil-matrix system. The practical implication of the present study is to enhance emulsification efficacy of Quillaja Saponins at very low concentration by incorporating surface active compounds, i.e. flavor or fragrance alcohols.

Hierarchical high internal phase emulsions and transparent oleogels stabilized by quillaja saponin-coated nanodroplets for color performance.

Herein, we report novel high internal phase emulsions and transparent oleogels that exhibit a hierarchical configuration by manipulating the spatial assembly of a natural small molecular-weight quillaja saponin for color performance. Quillaja saponin (QS) is a natural triterpenoid bidesmosidic from the soapbark tree (Quillaja saponaria Molina). Fairly monodispersed QS-coated nanodroplets (∼154 nm) were prepared using the ultrasonic emulsification strategy, and then used as block stabilizers for the fabrication of stable oil-in-water high internal phase emulsions (HIPEs, ϕ = 0.75). The resulting HIPEs can be easily converted into transparent oleogels with a very high oil loading (99.7%) through oven drying (70 °C). The jelly-like oleogels exhibit weak elastic, shear thinning behavior, good thixotropic recovery, and thermostabilization properties, which might be provided by the percolating 3D network of QS fibrils in the oil phase. We spatially tuned the color performance of the HIPEs and subsequent oleogels by locating the compositions of food colorants in different sections of their hierarchal architecture. The design and construction of hierarchical HIPEs and oleogels provide a promising new route for multitask functional delivery applications in various fields including food, cosmetics, and medical applications.