Engineered Interface For The Microstructural Design Of Emulsion-based Food Colloids Of Quillaja Saponin With Controlled Flavor Release

Food is regarded as the complex material that is made up multi-scale hierarchical structure with multi-component.Clarifying the relevant between its hierarchical structure and its delivery of functionalities is the key factor for manipulating its quality and nutritional characteristics.Typical food emulsion system would be used as the research model.The effects of the structure in the hierarchical emulsions stabilized by natural small molecules quillaja saponin?QS?on delivery of flavors would be investigated,trying to elaborate the relationship between food hierarchical structure and its functionalities and optimizing the food quality and nutritional properties via modifying its structure.?1?The planar interfaces between two immiscible fluids are employed as an ideal template to produce self-assemblies.QS has gathered widespread interest within the scientific community as a result of its unique interfacial properties.Herein,the spontaneously self-assembly of QS at the oil-water interface was systematically studied by morphology and spectroscopy,and shown that a micrometer-scale network from helical fibrous by hydrogen-bonded self-assembly,in which are formed from one-dimensional fibrils into ribbons results in complex structures of higher dimensionality.We also observed the multilayer self-assembled fibrils on the surfaces of dispersed droplets and enhanced emulsion stability.Interfacial QS-based films on droplet surfaces are also shown to confine interfacial diffusion processes by serving as transport barriers,and more can be exploited to control the release of volatile small molecules from dispersed liquid phase droplets by regulating the interface film,which is shown by molecular dynamics to occur by a hydrogen-bonded mechanism.?2?A new facile route was developed to use QS-stabilized orange oil-in-water emulsion as a template for the preparation of flavor oil powders and oleogels obtained in a single step by tunable oil fraction and evaporation of water.The interfacial behavior showed a fibrosis network interfacial film at the oil-water interface from self-assembly of QS,which contributed to the formation of stable emulsions and subsequent oil powder and oleogels.An oil powder containing nearly 93%orange oil can be formed by spray-drying,resulting powder shows excellent stability,flowability and reconstitution ability with?colloidosomes?architecture.Upon medium evaporation of water by freeze-drying,porous structured solid products and followed oleogels by a simple shearing can be formed.Upon oven-drying,a translucent oleogels with oil content as high as 98 wt%can be achieved from a high internal phase emulsion template.Moreover,the resulting oleogels showed high gel strength,thixotropic recovery as well as reversibility to reconstituted emulsions.?3?In this chapter,we report for the first time to design the emulsion with hierarchical compartmentalization for controlled release of volatile molecules.The quillaja saponin self-assembly behavior is also facilitated QS-coated nanodroplets to adsorb and assemble at the liquid-liquid interface,and consequently acted as efficient stabilizers of oil-in-water emulsions with host-guest construction by a bottom-up approach.Fairly monodispersed nanodroplets were adsorbed at the oil-water interface to stabilize emulsions with hierarchical architecture.Moreover,locking nanodroplets assembling at interfaces leads to emulsion with nanometer-controlled permeability prescribed by the nanodroplets density.Real-time headspace gas chromatography revealed that the volatile release can be tuned by manipulating the inherently permeability.Furthermore,this emulsion showed an interesting spatial release behavior that the release of volatiles entrapped in nanodroplets covered the surface is dominated by the microscaled host core of emulsions according to their difference in the length scale sense?ca.100 times?.The resulting emulsion can easily convert into a transparent oleogel with very high oil content?99.7%?upon water evaporation,which was provided by a percolating 3D network of nanodroplets in oil phase.Firstly,we successfully tune the color performance of emulsions and following oleogels by manipulating the spatial locations of bio-colorants with different types and content in the hierarchy architecture.?4?Hierarchically multicompartmental multiple emulsions in highly stable was successfully developed by the emulsifying and assembling of QS-coated nanodroplets as outer layer stabilizer.The multiple emulsions had relatively homogeneous size distribution,high yield,and superior storage stability?180 d?.The interfacial assembly of QS-coated nanodroplets effectively protected the triple emulsion??O₁/W₁?/O₂/W₂?droplets against flocculation and coalescence and strongly prevented the osmotic-driven water diffusion from the internal water droplets to the external water phase,thus contributing to the highly emulsion stability.The effects of formulation parameters,including lipophilic emulsifier content,oil fraction and nanodroplets concentration,on the formation of multiple emulsions were systematically investigated.We show that these multi-compartmentalized emulsions can be used to encapsulate and controlled release,both lipophilic and hydrophilic volatiles by loading them into the reservoirs.?5?We report evidence for stabilization and functionalization of aqueous foams stabilized by QS-coated nanodroplets.In contrast to foams stabilized by QS,stabilized the foams of 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.,?-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.?6?QS based hollow salt microspheres?¹0?m?were fabricated by simple spray drying based on the aerosol-assisted technology and interface engineering,and utilized as solid carrier to enhance sensory of aromas with reduced sodium intake.QS-coated nanodroplets were firstly prepared as reservoir for flavor oils?lemon and garlic oil?,and then served as frameworks to construct hollow salt microspheres via general spray drying.Headspace gas chromatography-mass spectrometry?DHS-GC-MS?and panel sensory analysis conclude that the hollow salt particles loaded flavor oils enhance typical aroma attributes and saltiness perception in comparison with their mixture control.?7?We firstly achieved a one-pot ultrasound emulsification strategy?alternative heating-homogenization?to prepare phytosterols structured thermosensitive algae oil-in-water nanoemulsion templates stabilized by QS.After spray drying,the resulting algae oil powders from the structured nanoemulsion templates exhibit an excellent reconstructed behavior,even if after 30d storage.Further,an enhanced oxidative stability was obtained with reduced both the primary and secondary oxidation products formulated with?-sitosterol and?-oryzanol,which is a natural antioxidant.When the results of headspace volatiles by dynamic headspace-gas chromatography-mass spectrometer?DHS-GC-MS?,it was clear that structured algae oil-loaded nanoemulsion and powder had lower levels of fishy off-flavour?e.g.,?Z?-heptenal,decanal,ethanone,and hexadecenoic acid?,whereas the control emulsion and oil powder without structured performed worse.