A water-in-oil-in-water double emulsion for regulating perception of NaCl saltiness and a preparation method and application thereof

Abstract

The present application relates to the technical field of food processing, salt-reduced food and flavor delivery, and particularly relates to a water-in-oil-in-water double emulsion for regulating NaCl salty taste perception and a preparation method and application thereof. The double emulsion comprises an inner water phase, an oil phase and an outer water phase; the inner water phase comprises water and sodium chloride; the oil phase comprises oil and polyglycerol ricinoleate; and the outer water phase comprises water, sodium chloride and an octenyl succinic anhydride (OSA) modified starch-WPI compound; the degree of substitution of the OSA modified starch is 0.002-0.020; the concentration of sodium chloride in the inner water phase is 7-8 times that of sodium chloride in the outer water phase; and the total concentration of sodium chloride in the double emulsion is not higher than 40 mM. The present application can take into account the storage stability and oral release efficiency, and can flexibly select different release modes such as salty taste peak intensification or salty taste duration extension in the same emulsion system according to the sensory needs of different low-salt foods, and particularly significantly improves the salty taste peak intensity under low sodium content.

Description

Technical Field

[0001] This invention relates to the fields of food processing, low-sodium foods, and flavor delivery technology, specifically to a water-in-oil-in-water dual emulsion stabilized by a whey protein isolate and an octenyl succinic anhydride (OSA) modified starch complex, as well as the preparation method of the dual emulsion and its application in regulating the perception of sodium chloride saltiness. Background Technology

[0002] Sodium chloride (NaCl), the main component of table salt, is the most commonly used salty substance in food processing. Reducing the amount of sodium chloride added is an important direction for the development of low-sodium foods. However, directly reducing the amount of sodium chloride may lead to a decrease in the intensity of saltiness, affecting the sensory quality of the food. Therefore, under the condition of controlling the total amount of sodium chloride used, regulating the release behavior of sodium chloride during oral processing through food structure design is a technical approach to the development of low-sodium foods.

[0003] Water-in-oil-in-water (W1 / O / W2) double emulsions have a multi-compartment structure consisting of an inner aqueous phase, an oil phase, and an outer aqueous phase. This is achieved by embedding NaCl within the inner aqueous phase and dispersing the oil phase containing droplets of the inner aqueous phase in the outer aqueous phase, forming a NaCl emulsion. + The non-uniform spatial distribution of the emulsion. During oral processing, the structure of the emulsion is disrupted, rapidly releasing the high concentration of sodium chloride embedded within, creating a localized high concentration of salt stimulation in the oral cavity, achieving "reduced salt without reducing saltiness." For example, patent document CN121196138A discloses a water-in-oil-in-water double emulsion for enhancing the perception of saltiness. The inner aqueous phase of this double emulsion consists of sodium salt and polysaccharide gelling agent, the oil phase contains edible oil and polyglycerol ricinoleate, and the outer aqueous phase contains sodium salt and quinoa starch Pickering-type emulsifier. Adjusting the structural changes of the emulsion in the oral cavity provides a technical approach to regulate the spatiotemporal distribution of sodium chloride in the oral cavity and improve sodium salt utilization efficiency.

[0004] Existing research has employed OSA-modified starch to stabilize salt-containing W1 / O / W2 dual emulsions. The hydrolysis of starch components by salivary α-amylase promotes structural changes in the emulsion and the release of embedded salts in the oral environment. The level of starch modification can simultaneously affect emulsion stability and oral salt release performance. Furthermore, some studies have used whey protein isolate (WPI) to form a complex with OSA-modified starch to stabilize oil-in-water (O / W) emulsions, investigating the effect of OSA substitution degree on the complex structure and emulsion stability. The results showed that the OSA substitution degree is not only related to the properties of the starch itself but also affects the complex structure formed with the protein and the stability of the corresponding emulsion.

[0005] For dual emulsions used for sodium chloride delivery, it is necessary to balance the embedding and retention capabilities during storage with the release performance during oral processing. Premature migration of sodium chloride from the inner aqueous phase to the outer aqueous phase during storage can alter the salt distribution before consumption; conversely, overly stable embedding structures under oral conditions may limit sodium chloride release within the effective perception time. For starch-stabilized systems, simply adjusting oral enzyme responsiveness by changing the starch modification level requires evaluating the impact of this change on the composite structure, emulsion stability, and salt retention capacity. Furthermore, regulating salty taste perception requires considering not only the amount of sodium chloride released but also the changes in its release process and sensory response over time. Increasing peak salty taste intensity and prolonging salty taste duration are different sensory modulation objectives and cannot be judged solely based on salt release results at a single time point.

[0006] Therefore, for OSA-modified starch-protein complex-stabilized salt-containing dual emulsions, it is still necessary to determine the relationship between their structural parameters and oral salt release behavior, and to evaluate the corresponding storage and retention performance, taking into account the specific formulation, phase ratio, and spatial distribution of sodium chloride. The technical problem this invention aims to solve is how to balance salt retention during storage and oral salt release at a relatively low total sodium chloride dosage, and how to adjust the release time distribution through the selection of structural parameters to adapt to different salty taste perception needs. Summary of the Invention

[0007] This invention provides a W1 / O / W2 dual emulsion for regulating the perception of sodium chloride saltiness. The complex formed by OSA-modified starch and whey protein isolate participates in stabilizing the outer oil-water interface. The degree of substitution of OSA-modified starch is coordinated with the sodium chloride concentration distribution in the inner and outer aqueous phases and the total sodium chloride concentration in the emulsion to regulate the sodium chloride release time distribution during oral processing under the condition of lower total NaCl usage.

[0008] The present invention also provides a method for preparing the dual emulsion and its application in the regulation of saltiness perception in food, so as to meet the target requirements of enhancing the peak saltiness or extending the duration of saltiness by selecting different formulations while maintaining the encapsulation performance under the corresponding storage conditions.

[0009] The technical solution to the problem solved by this invention is:

[0010] In a first aspect, a water-in-oil-in-water dual emulsion (W1 / O / W2 dual emulsion) for regulating the perception of sodium chloride saltiness is provided, comprising an inner aqueous phase (W1), an oil phase (O), and an outer aqueous phase (W2); the inner aqueous phase comprises water and sodium chloride; the oil phase comprises oil and polyglycerol ricinoleate; the outer aqueous phase comprises water, sodium chloride, and an OSA-modified starch-WPI complex; the OSA-modified starch-WPI complex is a complex formed by whey protein isolate and octenyl succinic anhydride-modified starch, wherein the degree of substitution of the octenyl succinic anhydride-modified starch is 0.002–0.020; the concentration of sodium chloride in the inner aqueous phase is 7–8 times the concentration of sodium chloride in the outer aqueous phase; and the total concentration of sodium chloride in the dual emulsion is not higher than 40 mM.

[0011] The ratio of sodium chloride concentration in the internal and external aqueous phases referred to in this paper refers to the ratio of the sodium chloride concentrations prepared in the two aqueous phases during the preparation process; the total sodium chloride concentration in the double emulsion referred to in this paper refers to the concentration calculated based on the prepared sodium chloride concentration in each phase and the volume ratio of each phase in the double emulsion.

[0012] In this invention, OSA-modified starch is not used independently as an external aqueous phase interface stabilizer, but rather forms an OSA-modified starch-WPI complex with whey protein isolate. This complex participates in the formation of the outer oil-water interface of the double emulsion. Therefore, changes in the degree of OSA-modified starch substitution not only affect the sensitivity of the starch component itself to α-amylase activity, but also influence the complex state between WPI and OSA-modified starch, as well as the structure of the interface layer formed by the two. This, in turn, alters the structural evolution of the complex interface under the combined effects of enzymatic hydrolysis, shearing, and dilution in oral processing. Experimental results show that, with similar starch hydrolysis rates, OSA-modified starch-WPI complex systems with different OSA modification levels exhibit significantly different sodium chloride release rates. This indicates that the release behavior is not solely determined by the degree of starch enzymatic hydrolysis, but is closely related to the structural evolution characteristics of the interface membrane under oral conditions. The actual sodium chloride release behavior cannot be predicted solely based on the degree of starch hydrolysis. Moreover, this difference in responsiveness is not significant in conventional indicators such as particle size, zeta potential, and microstructure, but it is significantly reflected in oral release rate and salty taste perception, making it unpredictable.

[0013] Furthermore, this invention does not utilize the aforementioned composite interface response characteristics in isolation, but rather matches them with the spatial distribution of sodium chloride in the dual emulsion, ensuring that the sodium chloride concentration in the inner aqueous phase is 7-8 times that in the outer aqueous phase, and controlling the total sodium chloride concentration in the dual emulsion to no higher than 40 mM. The concentration gradient is the Na+ concentration after structural damage to the emulsion interface. + Migration provides the driving force, while a lower total sodium chloride concentration makes the perception of saltiness more dependent on Na. + Release time distribution.

[0014] In summary, this invention uses the degree of OSA substitution as a structural adjustment parameter for the OSA-modified starch-WPI composite interface, and matches the oral response characteristics of the composite interface with a sodium chloride concentration gradient of 7 to 8 times between the inner and outer aqueous phases and a low total salt condition of no more than 40 mM. Thus, the release time distribution of a limited amount of sodium chloride can be controlled in the same dual emulsion platform to achieve the regulation of the peak saltiness enhancement and the saltiness persistence process.

[0015] In some embodiments, when it is necessary to increase the peak intensity of the salty taste, the degree of substitution of the OSA-modified starch is 0.002 to 0.005, preferably 0.002 to 0.003, more preferably 0.002 to 0.0025, and even more preferably 0.0024.

[0016] The peak intensity of saltiness is not directly determined by the total amount of sodium chloride in the emulsion, but mainly depends on the sodium content on the tongue surface during oral processing. + The rate of increase and peak concentration. In this invention, although the total sodium chloride concentration is low, a sufficient concentration of Na is achieved within an extremely narrow time window. + The release of sodium chloride in the aqueous phase produces a peak salty flavor intensity that is comparable to or even stronger than that in the oral cavity. Specifically, using a low-substituted OSA-modified starch-WPI complex as the external aqueous phase provides rapid interfacial deconstruction and demulsification release in the oral cavity environment. Simultaneously, at the moment of interfacial rupture, the high concentration of sodium chloride in the internal aqueous phase, significantly higher than that in the external aqueous phase, creates a reasonable concentration gradient, promoting the release of sodium chloride in the internal aqueous phase. + It is rapidly released outwards, thus forming a localized high concentration on the tongue surface.

[0017] In some embodiments, when it is necessary to prolong the duration of the salty taste, the degree of substitution of the OSA-modified starch is 0.005 to 0.020, preferably 0.005 to 0.010, more preferably 0.007 to 0.008, and even more preferably 0.0075.

[0018] The duration of saltiness depends primarily on Na. + The duration of release and the rate of decay of the release rate. In this invention, although the total sodium chloride concentration is low, Na... + It releases sodium at a low rate over a longer period of time, maintaining its concentration on the tongue surface. + Concentrations exceeding the perception threshold prolong the duration of salty stimulation. Specifically, the interfacial film formed by the highly substituted OSA-modified starch-WPI complex exhibits strong overall tolerance to α-amylase hydrolysis, shearing, and dilution in the oral cavity, with a slower interfacial deconstruction rate, and better double emulsion demulsification and Na+ absorption. + The release process was significantly prolonged. Simultaneously, the uniform concentration difference between the internal and external aqueous phases was gradually consumed over a longer period, resulting in Na+. + The continued release provides a stable driving force.

[0019] In summary, the present invention can still significantly improve the peak intensity of saltiness or prolong the duration of saltiness even when the total sodium content is significantly lower than that of the prior art.

[0020] As a preferred embodiment of the present invention, this application focuses on low-substituted OSA-modified starch-WPI complexes to achieve a significant enhancement of the salty taste peak under low sodium conditions with a total sodium chloride content not exceeding 40 mM.

[0021] external water phase

[0022] In the external aqueous phase, the OSA-modified starch-WPI complex is used to stabilize the dual emulsion interface, maintain sodium chloride encapsulation capacity during storage, and regulate the emulsion structural instability process in the oral environment.

[0023] The OSA-modified starch-WPI complex is a composite formed by WPI and OSA-modified starch. Whey protein isolate is amphiphilic and can adsorb at the oil-water interface; octenyl succinic anhydride-modified starch, through hydrophobic modification, possesses certain interfacial activity; the combination of the two forms a protein-polysaccharide complex interfacial film. During storage, this interfacial film, together with the oil film, inhibits sodium chloride leakage and maintains a high encapsulation efficiency. During oral processing, the interfacial film undergoes structural changes under the influence of salivary α-amylase, shearing, and dilution, causing instability of the double emulsion and releasing the inner aqueous phase sodium chloride. The release behavior depends on the overall tolerance of the interfacial film to the above-mentioned effects, and this tolerance can be regulated by the degree of substitution of OSA starch.

[0024] The degree of substitution of octenyl succinic anhydride modified starch ranges from 0.002 to 0.020, for example, it can be 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.015, or 0.020. The degree of substitution is a key structural parameter of OSA-modified starch. As mentioned above, by selecting OSA-modified starch with different degrees of substitution, different interfacial response characteristics can be imparted to the dual emulsion, thereby allowing for differentiated control of the peak intensity and duration of saltiness within the same emulsion food system.

[0025] The ratio of WPI to OSA-modified starch affects the composition of the complex, the interfacial membrane structure, and the sensitivity to oral environmental changes, thereby influencing the storage stability and release rate of the dual emulsion. Preferably, the OSA-modified starch-WPI complex is formed by OSA-modified starch and whey protein isolate at a mass ratio of 1:(0.8–1.2); for example, the mass ratio can be 1:0.8, 1:0.9, 1:1, 1:1.1, or 1:1.2; preferably 1:1. If the WPI content is too high, there will be too much protein component at the complex interface, reducing the sensitivity of the interfacial membrane to enzymatic hydrolysis and shearing in the oral cavity, delaying emulsion instability, and widening the release time window. This may weaken the effectiveness in applications requiring rapid release and a high peak saltiness; on the other hand, excessive stability may also result in a low release rate, making it difficult to achieve the desired saltiness intensity within a reasonable time. Conversely, if the proportion of OSA-modified starch is too high, there will be too much enzymatically hydrolyzable starch component at the interface, potentially leading to premature defects in the interfacial film during storage, a decrease in sodium chloride encapsulation efficiency, and impact on the structural integrity of the dual emulsion during storage. Simultaneously, a high starch proportion may result in an excessively thick interfacial film or increased viscosity of the continuous phase, hindering the release of Na+. + Impaired outward diffusion is detrimental to both rapid and slow release modes. Therefore, limiting the mass ratio of WPI to OSA-modified starch to 1:1 achieves a balance between interfacial integrity during storage and controllable release during the oral cavity, providing a stable interfacial basis for subsequent selection of different release modes through degree of substitution.

[0026] The concentration of the OSA-modified starch-WPI complex in the aqueous phase affects the coverage of the emulsion interface, the viscosity of the continuous phase, and the oral release behavior, and is a fundamental parameter to ensure that the dual emulsion has good performance under different release modes. Preferably, the mass concentration of the OSA-modified starch-WPI complex in the aqueous phase is 1% to 2%; for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%; preferably 1%. If the complex concentration is too low, it is difficult to form a complete and effective interfacial film on the oil droplet surface, leading to aggregation and demulsification of the emulsion during preparation or storage, a decrease in sodium chloride encapsulation efficiency, and premature leakage of some sodium chloride into the aqueous phase, causing the dual emulsion to lose its structural basis for controllable release in the oral cavity. If the concentration of the complex is too high, on the one hand, the viscosity of the external aqueous phase will increase, which is not conducive to shear emulsification and high-pressure homogenization, and may cause the emulsion particle size to increase and the distribution to become wider; on the other hand, excessive complex will form an excessively thick interfacial film on the surface of oil droplets, which will slow down the rate of instability of the emulsion in the oral environment, and the release time window will be excessively widened, making it difficult to achieve high-intensity release in a short time window, and also making it difficult to obtain clear distinction of release modes.

[0027] Sodium chloride in the external aqueous phase is mainly used to adjust the osmotic pressure environment of the emulsion system and provide a basic salty taste. In this scheme, sodium chloride is mainly embedded in the internal aqueous phase, and only a low concentration of sodium chloride is needed in the external aqueous phase.

[0028] Preferably, the concentration of sodium chloride in the external aqueous phase does not exceed 32 mM; for example, it can be 32 mM, 31 mM, 30 mM, 29 mM, 28 mM, 27 mM, 26 mM, or 25 mM. This invention differs from existing technologies, which often require external aqueous phase salt to provide the initial saltiness, thus the external aqueous phase typically has a certain concentration of sodium chloride. This solution significantly reduces the external aqueous phase salt concentration to no more than 32 mM, resulting in a significant reduction in total sodium content. At this low external aqueous phase salt concentration, the maintenance or enhancement of saltiness perception mainly relies on the controlled release of sodium chloride from the internal aqueous phase. Through OSA-WPI complex interface regulation, when it is necessary to increase the peak saltiness, a low-substitution complex can be selected to rapidly release sodium chloride from the internal aqueous phase and form a localized high concentration; when it is necessary to prolong the duration of saltiness, a high-substitution complex can be selected to slowly release sodium chloride from the internal aqueous phase. Therefore, the lower external aqueous phase salt concentration not only reduces the total sodium content but also provides greater design space for the regulation of the release mode.

[0029] As a preferred embodiment of the present invention, the external aqueous phase is composed of water, sodium chloride, and OSA-modified starch-WPI complex.

[0030] oil phase

[0031] The oil in the oil phase is used to physically isolate the internal aqueous phase from the external aqueous phase, serving as a source of Na. + One of the barriers to sodium chloride release from the aqueous phase to the oral cavity. Its integrity, along with the interfacial membrane, determines the timing of sodium chloride release in the oral cavity. During storage, the oil film and the OSA-modified starch-WPI complex interface jointly prevent sodium chloride leakage. During the oral cavity phase, the oil film ruptures due to the overall structural disruption of the dual emulsion under shearing and enzymatic hydrolysis, ensuring that sodium chloride from the aqueous phase can enter the oral cavity liquid phase according to the preset release pattern. Whether rapid release is needed to increase peak value or slow release is needed to prolong duration, the oil film must rupture in a timely manner in synergy with the interfacial membrane in the oral cavity environment to avoid becoming an uncontrollable release obstacle.

[0032] The oil in the oil phase is a food-grade edible oil; for example, it may be selected from at least one of soybean oil, corn oil, sunflower oil, rapeseed oil, and peanut oil; soybean oil is preferred. Soybean oil is widely available, has low cost, good oxidative stability, and good compatibility with polyglycerol ricinoleate.

[0033] Polyglycerol ricinoleate (PGPR) in the oil phase is a lipophilic emulsifier used to reduce the oil-water interfacial tension, promote the formation of the W1 / O primary emulsion, stabilize the W1 / O primary emulsion, prevent the aggregation of droplets in the aqueous phase, and improve the encapsulation efficiency of sodium chloride. Its stabilizing effect keeps sodium chloride embedded during storage. However, when the double emulsion becomes unstable in the oral cavity, the oil film can rupture along with the structural damage, releasing the aqueous sodium chloride.

[0034] The selection of PGPR dosage must ensure the stability of the W1 / O colostrum while not hindering timely release in the oral cavity, providing a structural basis for different release modes. Preferably, the mass concentration of polyglycerol ricinoleate in the oil phase is 2%–4%; for example, it can be 2%, 2.5%, 3%, 3.5%, or 4%; preferably 3%. If the PGPR dosage is too low, insufficient interfacial film coverage may occur, leading to easy aggregation of droplets in the inner aqueous phase, instability of the W1 / O colostrum, and leakage of the inner aqueous phase during subsequent secondary emulsification. This reduces the sodium chloride encapsulation rate, preventing the dual emulsion from maintaining a complete encapsulation structure during storage, thus affecting the controllability of oral release. If the PGPR dosage is too high, it may affect the compatibility of the W1 / O colostrum with the external aqueous phase of the OSA-WPI complex; simultaneously, excessive PGPR may make the oil film difficult to break in the oral cavity or result in excessive emulsion viscosity, which is detrimental to shearing and homogenization, delaying sodium chloride release or making the release rhythm difficult to control, thus hindering the realization of different release modes under low sodium conditions.

[0035] As a preferred embodiment of the present invention, the oil phase consists of oil and PGPR, i.e., no other emulsifiers or stabilizers are added. This ensures the controllability of the W1 / O primary emulsion interface properties, avoids additional influences from other components on the timing of oil film rupture and sodium chloride release behavior, and makes the release behavior mainly controlled by the OSA-WPI complex interface and the concentration gradient between the internal and external aqueous phases.

[0036] Internal water phase

[0037] Sodium chloride in the internal aqueous phase is used for concentration gradient-based release during dual emulsion instability, providing a salt reserve for different release modes.

[0038] The concentration of sodium chloride in the inner aqueous phase is 7 to 8 times that in the outer aqueous phase. If the concentration difference between the inner and outer phases is too low, it will be difficult to form a sufficient concentration gradient after demulsification, making it difficult to establish an effective sodium chloride concentration in the oral cavity, regardless of whether the release is rapid or slow. + Concentration reduces the saltiness enhancement effect. If the concentration difference between the inside and outside is too high, it will lead to an excessive osmotic pressure difference between the inside and outside aqueous phases, causing aqueous phase migration and emulsion structure instability, affecting the sodium chloride encapsulation rate, and may cause the release to be too rapid, the saltiness peak to be too high but the duration to be too short, or the emulsion to leak during storage, destroying the stability of the two release modes.

[0039] As a preferred embodiment of the present invention, the sodium chloride concentration in the internal aqueous phase is 150–250 mM; for example, it can be 150 mM, 160 mM, 170 mM, 180 mM, 190 mM, 200 mM, 210 mM, 220 mM, 230 mM, 240 mM, or 250 mM; preferably 240 mM.

[0040] Preferably, the inner aqueous phase of this invention consists of an aqueous solution of sodium chloride. Compared to the gelled inner aqueous phase in the prior art, the liquid sodium chloride aqueous solution, after the double emulsion demulsification, [contains sodium chloride in a more concentrated form]. + It can rapidly diffuse and enter the oral liquid phase, which is beneficial for forming a high local concentration in the rapid release mode; at the same time, in the slow release mode, the aqueous phase in the liquid can also continuously provide Na. + To avoid the gel network affecting Na + Diffusion is hindered. Therefore, the interface between the aqueous phase in the liquid state and the OSA-modified starch-WPI complex works synergistically to better adapt to the needs of different release modes.

[0041] Double emulsion

[0042] The volume ratio of the internal aqueous phase to the oil phase affects the droplet size, stability, and sodium chloride encapsulation capacity of the W1 / O pre-emulsion, as well as the subsequent double emulsion. Preferably, the volume ratio of the internal aqueous phase to the oil phase is 1:(3-5); for example, it can be 1:3, 1:3.5, 1:4, 1:4.5, or 1:5. If the oil phase ratio is too high, although the W1 / O pre-emulsion may be more stable, the volume proportion of the internal aqueous phase in the overall emulsion is too small, resulting in insufficient total NaCl encapsulation. Regardless of the release mode, it will be difficult to form a sufficient salty flavor intensity. If the internal aqueous phase ratio is too high, the internal aqueous phase droplets in the W1 / O pre-emulsion are dense, easily colliding and coalescing, increasing the pre-emulsion viscosity, worsening the emulsification effect, and making it easier for the internal aqueous phase to leak into the external aqueous phase during secondary emulsification, thus reducing the encapsulation rate and affecting storage stability and release controllability. Within the range of 1:(3~5), the internal aqueous phase can maintain a high sodium chloride encapsulation amount under the protection of the oil film and provide sufficient salt reserves for release in the oral cavity, supporting the realization of different release modes.

[0043] The volume ratio of the W1 / O pre-emulsion to the external aqueous phase affects the dispersion, stability, and sodium chloride distribution of the dual emulsion. Preferably, the volume ratio of the pre-emulsion formed by the internal aqueous and oil phases to the external aqueous phase is 1:(2-3); examples include 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, and 1:3. If the external aqueous phase ratio is too low, the system viscosity is high, emulsification is difficult, the dual emulsion is prone to aggregation, and the unstable behavior is uncontrollable, which is detrimental to the selective control of the release mode. If the external aqueous phase ratio is too high, the proportion of the W1 / O pre-emulsion in the overall composition decreases, the internal aqueous and oil phases decrease accordingly, the total amount of encapsulated sodium chloride decreases, and even if completely released, it is difficult to form a sufficient release concentration gradient, weakening the saltiness enhancement effect. Within the range of 1:(2~3), the external aqueous phase can provide a stable continuous phase for the dual emulsion and retain a sufficient proportion of W1 / O promulgated emulsion, so that the sodium chloride in the internal aqueous phase can achieve the preset release mode in the oral cavity through interface regulation.

[0044] Secondly, another objective of this invention is to provide a method for preparing the OSA-modified starch-WPI dual emulsion for regulating the perception of sodium chloride saltiness, comprising the following steps:

[0045] S1. Prepare a W1 / O primary emulsion by combining the internal aqueous phase and oil phase;

[0046] S2. Prepare a W1 / O / W2 double emulsion by mixing the W1 / O colostrum with an aqueous solution of the OSA-modified starch-WPI complex;

[0047] S3. Add sodium chloride to the W1 / O / W2 double emulsion to obtain the desired double emulsion.

[0048] This invention adds sodium chloride to the external aqueous phase after the formation of the double emulsion, rather than before emulsification. This salt addition sequence separates the formation of the composite interface from the establishment of the final sodium chloride concentration gradient. On one hand, it reduces the interference of high ionic strength on the formation of the OSA-modified starch-WPI composite and its interface assembly process; on the other hand, it reduces sodium chloride migration during emulsification caused by a pre-existing large sodium chloride concentration difference between the internal and external aqueous phases, allowing the predetermined sodium chloride concentration relationship between the internal and external aqueous phases to be established after emulsion formation. Simultaneously, the post-salt addition method allows for more precise control of the sodium chloride concentration in the external aqueous phase and the total sodium content of the system, meeting the requirements of low-salt formulations for precise sodium content control.

[0049] In step S1, when preparing the W1 / O primary emulsion from the internal aqueous phase and oil phase, preferably according to the present invention, the internal aqueous phase and oil phase are mixed in a certain proportion and sheared and emulsified at 14,000-18,000 rpm for 1-3 min to obtain the W1 / O primary emulsion. Preferably, the shearing speed is 16,000 rpm and the shearing time is 2 min.

[0050] In step S2, when preparing the W1 / O / W2 dual emulsion from the aqueous solution of the W1 / O promulgated emulsion and the OSA-modified starch-WPI complex, preferably according to the present invention, after mixing, the mixture is first sheared and emulsified at 8000–12000 rpm for 1–3 min, and then homogenized under high pressure at 250–350 bar for 1–3 cycles to obtain the W1 / O / W2 dual emulsion. Preferably, the shearing rate is 10000 rpm, the shearing time is 2 min, the high-pressure homogenization pressure is 300 bar, and the number of high-pressure homogenization cycles is 2.

[0051] Thirdly, another objective of this invention is to provide the application of the water-in-oil-in-water dual emulsion described above, which regulates the perception of sodium chloride saltiness, in the preparation of low-salt foods, sodium chloride delivery systems, saltiness-enhancing formulations, or salt-reducing formulations.

[0052] The beneficial effects of this invention are:

[0053] 1. This invention provides a water-in-oil-in-water dual emulsion, in which an OSA-modified starch-WPI complex is used to construct the outer oil-water interface of the dual emulsion. The degree of substitution of OSA-modified starch is used as a structural parameter to regulate the oral response characteristics of the complex interface, so that the sodium chloride release behavior is no longer solely determined by the degree of enzymatic hydrolysis of OSA-modified starch, providing a new dimension for regulating sodium chloride release kinetics. Furthermore, the response characteristics of the OSA-modified starch-WPI complex interface are matched with the spatial distribution of sodium chloride, ensuring that the sodium chloride concentration in the inner aqueous phase is 7-8 times that in the outer aqueous phase, while controlling the total sodium chloride concentration in the system to no more than 40 mM. Thus, under conditions of lower total sodium chloride usage, the saltiness perception efficiency is improved by adjusting the release time distribution of sodium chloride during oral processing.

[0054] 2. In some embodiments, an OSA-modified starch-WPI complex with a lower OSA modification level is used, combined with appropriate sodium chloride concentrations in the internal and external aqueous phases, based on a dual emulsion structure, interfacial membrane response, and Na+. + Synergistic regulation of release rate and oral retention behavior to achieve sufficient Na concentration within an extremely narrow time window. + The release of [something] significantly increases the peak intensity of saltiness and produces a comparable or even stronger saltiness perception at low total sodium chloride concentrations.

[0055] 3. This double emulsion exhibits good structural stability and sodium chloride encapsulation ability: its initial particle size distribution is unimodal, and the droplet size is concentrated; the sodium chloride encapsulation rate can reach 74% to 84%; and it can still maintain the overall emulsion structure stability after being stored at 4℃ for 21 days, providing a stable basis for its application in low-sodium foods.

[0056] 4. The technology of this invention can improve the perceived saltiness while maintaining a low sodium level, providing a technical basis for the formulation design of low-sodium seasonings, low-sodium sauces, low-sodium emulsified foods, low-sodium meat products and other reduced-sodium foods. Attached Figure Description

[0057] Figure 1 The particle size distribution, zeta potential, apparent viscosity, and microstructure of the dual emulsions obtained in the examples and comparative examples are shown.

[0058] Figure 2 The sodium chloride encapsulation efficiency of the dual emulsions obtained in the examples and comparative examples;

[0059] Figure 3 The storage appearance of the dual emulsions obtained in the examples and comparative examples;

[0060] Figure 4 The particle size distribution and Zeta potential of the dual emulsions obtained in the examples and comparative examples under different oral digestion times are shown.

[0061] Figure 5 The sodium chloride oral release rate and starch hydrolysis rate of the dual emulsions obtained in the examples and comparative examples;

[0062] Figure 6 These are the static salty taste characteristics evaluation results of the dual emulsions obtained in the examples and comparative examples;

[0063] Figure 7 These are the evaluation results of the dynamic salty taste characteristics of the dual emulsions obtained in the examples and comparative examples. Detailed Implementation

[0064] The following are specific embodiments of the present invention, and the technical solution of the present invention will be further described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0065] The testing method involved in this invention is as follows:

[0066] Particle size and Zeta potential analysis: The emulsion samples were diluted 100-fold, and the average particle size and Zeta potential of the samples were measured using a Zeta potential-nanoparticle size analyzer. The test temperature was 25℃, the scattering angle was set to 173°, and the measurement began after the samples had equilibrated for 120 s. During the measurement, the refractive index of the sample and the refractive index of the dispersion medium were set to 1.456 and 1.333, respectively. All samples were measured in triplicate, and the results are expressed as mean ± standard deviation.

[0067] Microstructure analysis: The emulsion sample was diluted 30 times, and 10 μL of the sample was dropped onto a glass slide. The coverslip was slowly covered to avoid the formation of air bubbles. After equilibration for 2 minutes, the sample was placed on the stage of an optical microscope. The distribution of the droplets was observed using a 100x oil immersion lens. Multiple areas were selected for observation, and multiple parallel studies were set up.

[0068] Apparent viscosity determination: Before testing, the sample was equilibrated at room temperature for 10 min. Then, an appropriate amount of sample was loaded between the parallel plates of the rotational rheometer using an aluminum parallel plate clamp with a diameter of 40 mm and a measurement gap of 1 mm. The test temperature was controlled at 25 ℃, and the sample was allowed to stand for 60 s before each measurement to eliminate stress introduced during loading and allow the sample to reach a stable state. The shear rate range was set to 0.1–100 s⁻¹. -1 The relationship between the apparent viscosity of the sample and the shear rate was determined.

[0069] NaCl encapsulation efficiency determination: The prepared emulsion was diluted 8 times and centrifuged at 10,000 rpm for 20 min at 4 ℃. The supernatant was aspirated with a syringe; centrifugation was repeated three times. Residual proteins and soybean oil in the supernatant were separated using dilute nitric acid and filtered through a 0.45 μm filter membrane. NaCl encapsulation efficiency was determined at 589 nm using an Agilent 720 ES (OES) inductively coupled plasma optical emission spectrometer. + content.

[0070] Storage stability evaluation: During the W1 / O emulsion preparation parameter optimization stage, the prepared emulsion samples were placed at 4℃ and 25℃ for 14 days, respectively, and photographed and observed at 0, 1, 7, and 14 days. During the W1 / O / W2 dual emulsion property characterization stage, the prepared emulsion samples were placed at 4℃ for 21 days, and their appearance changes were observed. If the appearance of the emulsion remained basically unchanged, it indicated that the emulsion stability was good; if phenomena such as oil separation or demulsification occurred, it indicated that the emulsion stability was poor.

[0071] In vitro oral digestion: After conducting an in vitro oral digestion experiment on the double emulsion, the particle size distribution and zeta potential of the emulsion were measured.

[0072] Starch hydrolysis rate determination: An appropriate amount of digestive emulsion was mixed with 2 mL of anhydrous ethanol to inactivate the enzyme. After centrifugation at 1800 g for 10 min, 0.1 mL of the supernatant was added to 0.5 mL of acetate buffer solution containing amyloglucosidase and invertase. The mixture was incubated at 37℃ and pH 5.2 for 10 min to completely digest the soluble dextrin. The glucose concentration was determined using a glucose kit. The starch hydrolysis rate was calculated using the following formula: %SH = S W / S i = 0.9 × G P / S i In the formula, S W 0.9 represents the amount of starch hydrolyzed; 0.9 represents the ratio of starch monomer molecular weight to glucose molecular weight; G P To the amount of glucose produced; S i This represents the initial amount of starch.

[0073] Sodium chloride oral release rate determination: After collecting in vitro oral digestion products, the sodium content in the digestion products was determined according to the sodium chloride encapsulation rate determination method. + The content was determined, and the oral release rate of sodium chloride was calculated.

[0074] Salty Sensory Evaluation: Evaluators were screened and trained according to GB / T 10220 "General Methods of Sensory Analysis", GB / T 14195 "Guidelines for Selection and Training of Sensory Evaluators", and GB / T 16291 "Guidelines for Selection, Training and Management of Sensory Analysis Experts". Their abilities in basic food sensory attributes, odor and taste recognition, scale application, and sensory analysis methods were assessed. After initial training of the 40 recruited evaluators, 8 were selected to form the emulsion salty sensory evaluation team, and they underwent a 2-month training program. The training frequency was 3 to 5 times per week, with each session lasting 1 to 2 hours. The training content included understanding attribute definitions, familiarity with reference samples, consistency in using the 15 cm linear scale and time-intensity evaluation method.

[0075] Static saltiness evaluation was conducted using a 15 cm linear scale. The pH of the solution was adjusted using food-grade phosphoric acid. Quantitative samples were placed in 50 mL volumetric beakers, randomly coded with three digits, and presented to sensory evaluators in random order. Evaluators scored the saltiness intensity using a 15 cm linear scale. After evaluating each sample, evaluators rinsed their mouths with unsalted crackers and purified water to alleviate taste fatigue. Each sample underwent three rounds of parallel evaluation, and the competence of the sensory evaluation team members was assessed using PanelCheck 1.4.2 software.

[0076] Dynamic saltiness evaluation was conducted using the time-intensity method. Quantitative samples were placed in 50 mL volumetric flasks, randomly coded with three digits, and presented to sensory evaluators in random order. Evaluators used SugarRuler software, written in Java script, to perform dynamic time-intensity sensory evaluation of the emulsion. Samples were ingested and then spat out after 10 seconds, and evaluation continued until the saltiness disappeared. The software recorded the cursor's position from the origin every 0.01 seconds as the instantaneous taste intensity at that time point, and plotted a TI curve with time on the x-axis and intensity on the y-axis using Matlab. After evaluating each sample, the mouth was rinsed with unsalted biscuits and purified water. Each sample underwent three rounds of parallel evaluation.

[0077] The main sources of materials involved in this invention are as follows:

[0078] Soybean oil was purchased from COFCO Fortune Food Marketing Co., Ltd.; PGPR 90 was purchased from IFF International Flavors & Fragrances, Inc. (USA); sodium hydroxide was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; anhydrous ethanol was purchased from Xilong Scientific Co., Ltd.; hydrochloric acid was purchased from Sinopharm Chemical Reagent Co., Ltd.; glucose reagent kit was purchased from Nanjing Jiancheng Bioengineering Research Institute Co., Ltd.; glucosidase and invertase were purchased from Megazyme International Inc.; potassium chloride, potassium dihydrogen phosphate, magnesium chloride hexahydrate, calcium chloride dihydrate, and Bis-Tris were purchased from Shanghai Maclean Biotechnology Co., Ltd.; α-amylase was purchased from Sigma-Aldrich Reagents, Inc. (USA); acetate buffer was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; and sodium chloride was purchased from Zhejiang Tianhe Food Biotechnology Co., Ltd.

[0079] Example 1

[0080] A water-in-oil-in-water dual emulsion for modulating the perception of saltiness from sodium chloride, used to enhance the peak intensity of saltiness.

[0081] Prepared by the following steps:

[0082] (1) Preparation of OSA-modified starch-WPI complex with low OSA modification level (Low OSA-WPI)

[0083] Whey protein isolate powder was dissolved in deionized water and magnetically stirred at room temperature for 2 h until completely dissolved. The solution was then hydrated overnight at 4 °C to obtain WPI stock solution.

[0084] Low-substituted OSA-modified starch (DS=0.0024) was dispersed in deionized water, magnetically heated and stirred at 95 °C for 20 min, cooled to room temperature, and then hydrated overnight at 4 °C to obtain OSA-modified starch stock solution.

[0085] The WPI stock solution and OSA-modified starch stock solution were mixed at a WPI to OSA-modified starch mass ratio of 1:1 and magnetically stirred for 30 min to make the total biopolymer concentration in the resulting system 1% (w / w). The pH of the system was adjusted to 5.0 and magnetically stirred for another 30 min to obtain an OSA-modified starch-WPI complex solution, denoted as Low OSAS-WPI.

[0086] (2) Preparation of double emulsion

[0087] S1. A 240 mM sodium chloride aqueous solution was used as the internal aqueous phase W1. 3% PGPR was weighed and dissolved in soybean oil. The mixture was magnetically heated and stirred at 65°C for 15 min, then cooled to room temperature to allow the PGPR to dissolve completely, yielding the oil phase O. The internal aqueous phase W1 and the oil phase O were mixed at a volume ratio of 2:8 and sheared at 16000 rpm for 2 min using a shear mill to obtain the W1 / O primary emulsion.

[0088] S2. Using a 1% (w / w) Low OSAS-WPI aqueous solution as the external aqueous phase W2, the W1 / O primary emulsion and the external aqueous phase W2 were mixed at a volume ratio of 3:7, sheared at 10000 rpm for 2 min, and then subjected to two cycles at 300 bar using a high-pressure homogenizer to obtain the W1 / O / W2 double emulsion.

[0089] S3. Add sodium chloride to the obtained W1 / O / W2 double emulsion and mix thoroughly to make the sodium chloride concentration in the external aqueous phase W2 30.8 mM, thus obtaining the W1 / O / W2 double emulsion with improved sodium chloride saltiness perception.

[0090] The obtained particle size distribution of the dual emulsion is as follows: Figure 1 As shown in Figure A, the particle size distribution of the dual emulsions is unimodal, indicating that the droplet size is relatively concentrated and the initial dispersion is good. The Zeta potential results are as follows: Figure 1 As shown in B, it remains at a high level. The apparent viscosity results are as follows: Figure 1 As shown in Figure C, the emulsion systems all exhibit shear-thinning behavior; and the viscosity decreases only slightly in the high shear rate region, demonstrating strong resistance to shear deformation. The microstructure results are as follows... Figure 1 As shown in Figure D, a relatively complete double emulsion coating structure was formed, and no obvious droplet aggregation or interface damage was observed, indicating that the OSA-modified starch-WPI complex can effectively stabilize the double emulsion interface. The particle size distribution after digestion is shown in Figure D. Figure 4 As shown in Figure A, after 10 minutes of digestion, the particle size distribution of the emulsion changed from a single peak to a double peak, indicating that the OSA-modified starch component underwent selective hydrolysis under the action of α-amylase, and some interfacial adsorption layers were locally degraded, resulting in damage to the integrity of the interfacial film.

[0091] The NaCl encapsulation efficiency results are as follows: Figure 2 As shown, the sodium chloride encapsulation efficiency of the dual emulsion in this embodiment reaches 74% to 84%, indicating that the constructed dual emulsion exhibits good structural integrity and internal phase encapsulation efficiency during the preparation process, which can meet the requirements of the interface barrier function for subsequent sodium chloride delivery.

[0092] Storage stability results are as follows Figure 3 As shown, after 7 days of storage at 4℃, the samples maintained good macroscopic homogeneity, with no obvious stratification, emulsification, or bottom aqueous phase precipitation. After 21 days of storage, a small amount of aqueous phase precipitation appeared at the bottom of the samples, but the overall emulsion structure remained largely stable, without large-scale demulsification or oil phase separation. This indicates that the OSA-modified starch-WPI complex can achieve a good balance between initial encapsulation capacity and structural stability during storage in sodium chloride-encapsulated double emulsions.

[0093] Sensory evaluation of saltiness, such as Figure 6 , 7 As shown, evaluators were screened and trained before the sensory evaluation, and the discrimination and repeatability of the evaluation team were examined. The results showed that the vast majority of evaluators achieved or approached the 1% significance level for most descriptive terms, indicating good sample discrimination ability; most MSE values ​​were below 4, indicating high stability and consistency in repeated measurements. Therefore, the data from this sensory evaluation team met the analytical requirements in terms of discrimination and repeatability, and have a reliable statistical basis. The static saltiness evaluation results are as follows... Figure 6 As shown, the dual emulsion in this embodiment has the highest saltiness intensity score, at 10.10 ± 1.85; the dynamic saltiness evaluation results are as follows. Figure 7 As shown, the maximum saltiness intensity Imax of the double emulsion is 11.33±1.42, demonstrating a significant saltiness enhancement effect.

[0094] Example 2

[0095] This embodiment is basically the same as Example 1, except that: a high OSA-modified starch-WPI complex (High OSAS-WPI) with a high OSA modification level is selected.

[0096] A water-in-oil-in-water dual emulsion that modulates the perception of saltiness from sodium chloride, used to prolong the duration of saltiness.

[0097] Prepared by the following steps:

[0098] (1) Preparation of OSA-modified starch-WPI complex with high OSA modification level (High OSA-WPI)

[0099] Whey protein isolate powder was dissolved in deionized water and magnetically stirred at room temperature for 2 h until completely dissolved. The solution was then hydrated overnight at 4 °C to obtain WPI stock solution.

[0100] Highly substituted OSA-modified starch (DS=0.0075) was dispersed in deionized water, magnetically heated and stirred at 95 °C for 20 min, cooled to room temperature, and then hydrated overnight at 4 °C to obtain OSA-modified starch stock solution.

[0101] The WPI stock solution and OSA-modified starch stock solution were mixed at a WPI to OSA-modified starch mass ratio of 1:1 and magnetically stirred for 30 min to make the total biopolymer concentration in the resulting system 1% (w / w). The pH of the system was adjusted to 5.0 and magnetic stirring was continued for 30 min to obtain an OSA-modified starch-WPI complex solution, denoted as High OSAS-WPI.

[0102] (2) Preparation of double emulsion

[0103] S1. A 240 mM sodium chloride aqueous solution was used as the internal aqueous phase W1. 3% PGPR was weighed and dissolved in soybean oil. The mixture was magnetically heated and stirred at 65°C for 15 min, then cooled to room temperature to allow the PGPR to dissolve completely, yielding the oil phase O. The internal aqueous phase W1 and the oil phase O were mixed at a volume ratio of 2:8 and sheared at 16000 rpm for 2 min using a shear mill to obtain the W1 / O primary emulsion.

[0104] S2. Using a 1% (w / w) High OSAS-WPI aqueous solution as the external aqueous phase W2, the W1 / O primary emulsion and the external aqueous phase W2 were mixed at a volume ratio of 3:7, sheared at 10000 rpm for 2 min, and then subjected to two cycles at 300 bar using a high-pressure homogenizer to obtain the W1 / O / W2 double emulsion.

[0105] S3. Add sodium chloride to the obtained W1 / O / W2 double emulsion and mix thoroughly to make the NaCl concentration in the external aqueous phase W2 30.8 mM, thus obtaining the W1 / O / W2 double emulsion used to prolong the duration of the salty taste of sodium chloride.

[0106] Comparative Example 1

[0107] This embodiment is basically the same as embodiment 1, except that Low OSAS-WPI is replaced with WPI of equal quality.

[0108] Prepared by the following steps:

[0109] (1) Dissolve whey protein isolate powder in deionized water, stir magnetically at room temperature for 2 h until completely dissolved, and hydrate overnight at 4℃ to obtain WPI stock solution; adjust pH to 6.8±0.2 with 0.1 mol / L NaOH or HCl.

[0110] (2) Preparation of double emulsion

[0111] S1. A 240 mM sodium chloride aqueous solution was used as the internal aqueous phase W1. 3% PGPR was weighed and dissolved in soybean oil. The mixture was magnetically heated and stirred at 65°C for 15 min, then cooled to room temperature to allow the PGPR to dissolve completely, yielding the oil phase O. The internal aqueous phase W1 and the oil phase O were mixed at a volume ratio of 2:8 and sheared at 16000 rpm for 2 min using a shear mill to obtain the W1 / O primary emulsion.

[0112] S2. Using a 1% WPI stock solution as the external aqueous phase W2, the W1 / O primary emulsion and the external aqueous phase W2 were mixed at a volume ratio of 3:7, sheared at 10000 rpm for 2 min, and then subjected to two cycles at 300 bar using a high-pressure homogenizer to obtain a W1 / O / W2 double emulsion.

[0113] S3. Add sodium chloride to the obtained W1 / O / W2 double emulsion and mix thoroughly to make the NaCl concentration in the external aqueous phase W2 30.8 mM.

[0114] Comparative analysis

[0115] like Figures 1-7 This invention demonstrates, through in vitro simulated oral digestion experiments, static saltiness evaluation, and dynamic time-intensity evaluation, the saltiness enhancement effect and release regulation characteristics of the obtained W1 / O / W2 dual emulsion under low sodium conditions. The obtained data are as follows:

[0116] In terms of structural characterization, the stable dual emulsions of OSA-modified starch-WPI complexes with different degrees of substitution showed no significant differences in particle size distribution, Zeta potential, apparent viscosity, and microstructure. All exhibited unimodal particle size distribution, relatively high absolute potential values, shear-thinning behavior, and intact dual emulsion coating structures. This indicates that the macroscopic emulsion structure is not the determining factor for release regulation in this application.

[0117] In simulated oral digestion, the starch hydrolysis rates at 10 min were 7.02%, 33.65%, and 30.78% for the WPI group, Low OSAS-WPI group, and High OSAS-WPI group, respectively, with corresponding sodium chloride release rates of 30.41%, 44.52%, and 28.88%. These results indicate that there is no simple linear relationship between starch hydrolysis rate and sodium chloride release rate. Specifically, when the starch hydrolysis rates of Low OSAS-WPI and High OSAS-WPI were similar, the sodium chloride release rate differed by approximately 16 percentage points; however, at 0 min, the starch hydrolysis rate of High OSAS-WPI was slightly higher than that of Low OSAS-WPI, but its sodium chloride release rate was significantly lower. This suggests that sodium chloride release behavior is mainly controlled by the overall responsiveness of the OSAS-WPI complex interfacial membrane in the oral environment, rather than simply by the degree of starch enzymatic hydrolysis, and sodium chloride release behavior cannot be simply predicted by the degree of hydrolysis of OSA-modified starch.

[0118] It should be noted that the WPI group in Comparative Example 1 did not contain OSA-modified starch, yet a low apparent starch hydrolysis rate was still obtained using the above method. The starch hydrolysis rate in this application is not obtained by directly measuring the remaining starch content, but rather by measuring the glucose content in the digestion products and calculating it according to the corresponding formula. Therefore, background sugar signals or detection responses generated by the simulated oral digestive system, enzyme preparations, and sample matrix may all be included in the calculation results, causing a non-zero apparent hydrolysis value in the WPI group without OSA-modified starch. Therefore, the 7.02% in the WPI group should be understood as the apparent background value obtained under this assay method, and does not represent that starch hydrolysis occurred in the WPI itself.

[0119] Regarding sodium chloride encapsulation efficiency, the Low OSAS-WPI complex achieved a stable dual emulsion encapsulation efficiency of 75%, lower than the 80%–85% of the other groups. However, this system achieved the highest peak saltiness intensity, indicating that a higher encapsulation efficiency is not necessarily more beneficial for salt reduction. The balance between adequate encapsulation and rapid oral release is key to improving the efficiency of low-sodium saltiness perception.

[0120] It is evident that the saltiness control effect of this invention comes from the matching between the sodium chloride encapsulation state, the oral response of the composite interface, and the sodium chloride release process, rather than simply increasing the sodium chloride encapsulation rate or the degree of starch hydrolysis.

[0121] In terms of sensory evaluation, the saltiness intensity of all double emulsions was significantly higher than that of isoNa. +The low OSAS-WPI dual emulsion was compared with the control group in terms of the amount of WPI aqueous solution. The low OSAS-WPI dual emulsion showed the highest static saltiness score (10.10±1.85), significantly higher than the WPI group's 6.50±1.71. In dynamic evaluation, its maximum saltiness intensity (Imax) reached 11.33±1.42, and the dynamic saltiness curve of the dual emulsion exhibited a "transient surge-steady-state maintenance-long-lasting tail" characteristic, with both the duration of saltiness and the area under the curve significantly greater than the control group. These effects were achieved under low-sodium conditions with total sodium chloride not exceeding 40 mM.

[0122] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A water-in-oil-in-water dual emulsion for regulating the perception of the salty taste of sodium chloride, comprising an inner aqueous phase, an oil phase, and an outer aqueous phase; wherein the inner aqueous phase comprises water and sodium chloride, and the oil phase comprises oil and polyglycerol ricinoleate; characterized in that: The external aqueous phase includes water, sodium chloride, and OSA-modified starch-WPI complex; the OSA-modified starch-WPI complex is a complex formed by OSA-modified starch and whey protein isolate, and the degree of substitution of the OSA-modified starch is 0.002 to 0.

020. The concentration of sodium chloride in the inner aqueous phase is 7 to 8 times that in the outer aqueous phase; The total concentration of sodium chloride in the double emulsion is no higher than 40 mM.

2. The water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness according to claim 1, characterized in that: When the peak intensity of saltiness is increased, the degree of substitution of the OSA-modified starch is 0.002 to 0.

005.

3. The water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness according to claim 1, characterized in that: When the duration of saltiness is prolonged, the degree of substitution of the OSA-modified starch is 0.005 to 0.

020.

4. A water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness according to claim 1, 2, or 3, characterized in that: Sodium chloride in the external aqueous phase is used to adjust the osmotic pressure environment, and the concentration of sodium chloride in the external aqueous phase does not exceed 32 mM.

5. A water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness according to claim 1, 2, or 3, characterized in that: The OSA-modified starch-WPI complex is a complex formed by OSA-modified starch and whey protein isolate at a mass ratio of 1:(0.8-1.2).

6. A water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness according to claim 1, 2, or 3, characterized in that: The mass concentration of the OSA-modified starch-WPI complex in the external aqueous phase is 1% to 2%.

7. A water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness according to claim 4, characterized in that: The sodium chloride concentration in the internal aqueous phase is 150–250 mM.

8. A water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness according to claim 1, 2, or 3, characterized in that: The volume ratio of the inner aqueous phase to the oil phase is 1:(3-5), and the volume ratio of the W1 / O primary emulsion formed by the inner aqueous phase and the oil phase to the outer aqueous phase is 1:(2-3).

9. A method for preparing a water-in-oil-in-water dual emulsion for regulating the perception of sodium chloride saltiness as described in any one of claims 1 to 8, characterized in that: Includes the following steps: S1. Prepare a W1 / O primary emulsion by combining the internal aqueous phase and oil phase; S2. Prepare a W1 / O / W2 double emulsion by mixing the W1 / O colostrum with an aqueous solution of the OSA-modified starch-WPI complex; S3. Add sodium chloride to the W1 / O / W2 double emulsion to obtain the desired double emulsion.

10. The application of a water-in-oil-in-water dual emulsion as described in any one of claims 1 to 8 for regulating the perception of sodium chloride saltiness in the preparation of low-salt foods, sodium chloride delivery systems, saltiness-enhancing formulations, or salt-reducing formulations.

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