Preparation method of switch type W / O type high internal phase emulsion-based sodium salt delivery carrier

Abstract

The invention discloses a preparation method of a switch type W / O type high internal phase emulsion-based sodium salt delivery carrier, and belongs to the field of food processing. The OSA starch is added into the inner water phase, the interface characteristics of the W / O type high internal phase emulsion are regulated and controlled, the stability of the shelf life is achieved, meanwhile, the salivary amylase mediated targeted oral instability is improved, and switch type delivery of sodium salt in the W / O type high internal phase emulsion is achieved by adding the OSA starch. The switch type sodium salt delivery W / O type high internal phase emulsion comprises polyglycerol ricinoleate, an OSA starch solution, sodium salt and edible oil, the mass concentration of the OSA starch solution is 0.1-6 mg / mL, the volume ratio of a water phase to an oil phase is (70-80): (20-30), and the volume fraction of the oil phase in the emulsion is 20%-30%. The switch type sodium salt delivery W / O type high internal phase emulsion is prepared, and the application of the switch type sodium salt delivery W / O type high internal phase emulsion as a fat-reducing salad dressing substitute is widened.

Description

Technical Field

[0001] The invention relates to a method for preparing a switchable W / O type high internal phase emulsion-based sodium salt delivery carrier, and belongs to the field of food processing. Background Art

[0002] With the integration of global food culture, salad dressing has become an indispensable part of consumers' daily diet. It is an O / W emulsion with a high oil content (40% to 64%) and is generally considered a high-fat, high-calorie product. However, excessive fat intake can cause a variety of health problems, such as obesity, cardiovascular disease, and hypertension. As the public's awareness of the health risks associated with fat intake continues to increase, low-fat salad dressings are becoming more and more popular.

[0003] W / O emulsion is an emulsion formed by the water phase being dispersed in the oil phase in the form of droplets. When the water phase accounts for more than 74%, W / O high internal phase emulsions (W / O HIPEs) are formed. They have high viscosity and are paste-like. Increasing the amount of water can reduce the fat content of salad dressings, so they have many potential applications in the production of low-fat salad dressing substitutes.

[0004] Sodium salt plays an important role in increasing the flavor and mouthfeel of food and is widely used in the production of foods such as salad dressings. O / W emulsions and W / O emulsions have different salty perception mechanisms. For O / W emulsions, sodium salts are present in the external water phase. When taken orally, they directly contact the taste receptors on the tongue, thereby producing salty perception. In W / O emulsions, sodium salts are encapsulated in the internal water phase. The phase change (demulsification) during oral processing promotes the explosive release of sodium salts, which helps to further obtain salty perception. Studies have shown that this oral instability of W / O emulsions is a key factor in determining their saltiness perception. At the same time, excellent shelf life stability is also essential for W / O HIPEs as salad dressing substitutes.

[0005] Therefore, it is very necessary to develop a preparation method for a W / O HIPEs-based sodium salt switchable (switchable) delivery carrier that can be used as a low-fat salad dressing substitute, which has good application prospects. Summary of the invention

[0006] In order to achieve the switchable delivery of sodium salt in W / O HIPEs, the present invention regulates the interfacial properties of W / O HIPEs by adding octenyl succinate starch (OSA starch) to the internal water phase, in order to achieve switchable delivery through salivary amylase-mediated targeted oral instability. The present invention adopts the characteristics of OSA starch in regulating interfacial properties to prepare a switchable W / O HIPEs-based sodium salt delivery carrier, improves its shelf life stability, and enhances its saltiness perception during oral processing. The present invention not only prepares a switchable W / O HIPEs-based sodium salt delivery carrier, but also can broaden their application as a substitute for fat-reduced salad dressing.

[0007] The present invention provides a switchable sodium salt delivery W / O HIPEs, comprising an oil phase, an aqueous phase and an emulsifier, wherein the switchable mode means that the shelf life stability and oral instability of the W / O HIPEs are achieved by controlling the addition amount of OSA starch;

[0008] The oil phase contains an emulsifier, the emulsifier is 1.5% to 2.5% by mass of polyglycerol polyricinoleate (PGPR), and the volume fraction of the oil phase in the emulsion is 20% to 30%;

[0009] The aqueous phase is a mixture of OSA starch solution and sodium salt;

[0010] The water phase is added to the oil phase to prepare switchable sodium salt delivery W / O HIPEs; the volume ratio of the water phase to the oil phase is 70-80:20-30.

[0011] In one embodiment, the oil phase is edible oil; the edible oil includes but is not limited to: sunflower oil, lard, corn oil, soybean oil, medium chain triglycerides.

[0012] In one embodiment, the mass fraction of sodium salt in the aqueous phase is 1.46% to 2.63%; preferably, the addition amount of OSA starch is 0.1 to 6 mg / mL.

[0013] The present invention also provides a method for preparing a switchable sodium salt delivery W / O HIPEs, wherein the switchable method refers to achieving shelf life stability and oral instability of the W / O HIPEs by controlling the amount of OSA starch added, and the method is specifically as follows:

[0014] (1) Preparation of aqueous phase:

[0015] Solution A is obtained by adding sodium chloride to an OSA starch solution; the mass fraction of the sodium salt is 1.46% to 2.63%; the amount of OSA starch added is 0.1 to 6 mg / mL;

[0016] (2) Preparation of oil phase containing emulsifier:

[0017] Mixing oil and PGPR to obtain solution B; the mass fraction of PGPR is 1.5% to 2.5%;

[0018] (3) Solution A is added to solution B to obtain W / O HIPEs colostrum, and the colostrum is further emulsified to obtain W / O HIPEs.

[0019] In one embodiment, the amount of OSA starch added to the solution A in step (1) is 0.1 to 6 mg / mL. Preferably, the amount of OSA starch added to the solution A in step (1) can be 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL. Experimental verification shows that adding more than 0.1 mg / mL and less than 6 mg / mL of OSA starch in the reaction system of the present invention can achieve the technical effect to be achieved by the present invention: preparing a W / O HIPEs as a salad dressing substitute, and at the same time making the W / O HIPEs obtained by the present invention have a strong salty taste perception, high stability, and the advantage of being low in fat.

[0020] In one embodiment, in the mixed solution A of step (1), the amount of sodium salt added is 250-450 mmol / L, preferably 300 mmol / L.

[0021] In one embodiment, the mass fraction of PGPR in the solution B in step (2) is 1.5% to 2.5%, preferably 2%.

[0022] In one embodiment, the oil in the solution B in step (2) is sunflower oil, and the volume fraction of the sunflower oil containing PGPR is 20% to 30%, preferably 25%.

[0023] In one embodiment, the amount of solution A in step (3) is 2 to 4 times that of solution B, preferably 3 times.

[0024] In one embodiment, the method specifically comprises the following steps:

[0025] (1) Weigh 0.5 g PGPR and 25 mL sunflower oil, stir and dissolve them thoroughly to prepare an oil phase containing an emulsifier;

[0026] (2) dissolving an appropriate amount of OSA starch in deionized water, heating in a constant temperature water bath at 90° C. for 30 min, and cooling to room temperature to prepare an OSA starch solution;

[0027] (3) adding 1.75 g of sodium chloride (the amount of sodium chloride used here is 1.75 g, which is equivalent to the standard sodium content in commercial salad dressing) to 75 mL of the OSA starch solution obtained in step (2), and stirring well to obtain an inner aqueous phase solution;

[0028] (4) slowly adding the internal aqueous phase solution obtained in step (3) dropwise into 25 mL of the oil phase containing the emulsifier obtained in step (1) to prepare a W / O type high internal phase colostrum;

[0029] (5) The W / O high internal phase colostrum obtained in step (4) was subjected to high-speed shearing at 12000 r / min for 3 min to obtain W / O HIPEs with an internal water phase volume fraction of 75%.

[0030] The present invention also provides a low-fat salad dressing, which contains the switchable sodium salt delivery W / O HIPEs prepared by the above method; preferably, the salad dressing also contains one or more of honey, lemon juice, vegetable juice, chopped celery, white pepper, vanilla, mustard, and low-fat yogurt.

[0031] The present invention also provides an application of switchable sodium salt delivery W / O HIPEs in the preparation of fat-reducing food.

[0032] Beneficial Effects

[0033] (1) OSA starch is used in the present invention to regulate the interfacial properties of W / O HIPEs to achieve switchable delivery of sodium salt in W / O HIPEs;

[0034] (2) The amount of OSA starch added in the present invention is crucial to achieve the switchable delivery of sodium salt in W / O HIPEs. 2 mg / mL OSA starch and PGPR have a synergistic effect, while 4 mg / mL and 6 mg / mL OSA starch and PGPR have a competitive effect;

[0035] (3) The addition of 2 mg / mL OSA starch in the present invention improves the stability of W / O HIPEs. At the same time, its targeted oral instability promotes the release of sodium salt in the internal aqueous phase and enhances the salty taste perception. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The physical stability of W / O HIPEs (oil phase is sunflower oil) with different OSA starch addition amounts, including: (A) 0 mg / mL; (B) 2 mg / mL; (C) 4 mg / mL; (D) 6 mg / mL.

[0037] Figure 2The apparent properties of W / O HIPEs with different OSA starch addition amounts, including: (A) 0 mg / mL; (B) 2 mg / mL; (C) 4 mg / mL; (D) 6 mg / mL.

[0038] Figure 3 The microstructure and particle size of W / O HIPEs with different OSA starch addition amounts, including (A) 0 mg / mL; (B) 2 mg / mL; (C) 4 mg / mL; (D) 6 mg / mL.

[0039] Figure 4 The bulk rheological properties of W / O HIPEs with different OSA starch addition amounts, where (A) apparent viscosity and shear rate (0.1-100s -1 ); (B) The relationship between G', G" and frequency (0.01~10Hz).

[0040] Figure 5 Time scan and dynamic frequency scan of the interfacial modulus at different OSA starch addition amounts, including: (A) elastic modulus (G'); (B) viscous modulus (G"); (C) dynamic frequency scan.

[0041] Figure 6 The physical stability of W / O HIPEs (oil phase is MCT) with different OSA starch addition amounts, including: (A) 0 mg / mL; (B) 2 mg / mL; (C) 4 mg / mL; (D) 6 mg / mL.

[0042] Figure 7 The microstructure of the emulsion stabilized by glyceryl monostearate (OSA starch addition amount is 0 mg / mL).

[0043] Figure 8 The physical stability of W / O HIPEs (OSA starch addition amount is 0 mg / mL) under different PGPR addition amounts, including: (A) 2%; (B) 4%; (C) 12%; (D) 20%. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0045] The detection method used in the embodiment is as follows:

[0046] 1. Sensory quality assessment method

[0047] The evaluators were selected and trained according to the international standard method for the selection, training and monitoring of evaluators (ISO-8586:2023). First, 42 evaluators were recruited and preliminarily screened from the School of Food Science and Engineering of Jiangnan University through an online questionnaire. The online questionnaire survey was used to understand the evaluators' interests, motivations, whether they had taken drugs that impaired sensory functions, and whether they had sufficient time. Then, 25 evaluators were screened through sensory sensitivity tests, basic taste identification and basic taste ranking tests. Among them, the basic taste ranking requires the evaluators to taste NaCl solutions of different concentrations and correctly identify the concentration gradient of NaCl solutions. The 25 selected evaluators were trained four times, including the introduction of experimental samples, understanding of sensory attributes, and familiarity with sensory evaluation methods (such as paired tests, ranking tests, scale training, time-intensity methods, etc.). Finally, a sensory evaluation team consisting of 12 selected evaluators (4 males and 8 females, with an average age of 24) was formed.

[0048] According to the Standard Guide for Time-Intensity Evaluation of Sensory Attributes (ASTM E1909-13, 2017), the real-time saltiness intensity felt during chewing was scored using a 10-point system (0 = no feeling, 10 = very strong). Before each sensory evaluation experiment, the experimenter provided the evaluators with 0.2g / 100mL, 0.5g / 100mL and 0.8g / 100mL NaCl standard solutions, and defined these three concentrations of standards as "2 points", "5 points" and "8 points" respectively, which were used as reference samples for sensory evaluation to score the real-time saltiness intensity felt during chewing. The samples were placed in three randomly coded tasting cups and presented to the evaluators in a random order. When the sample (0.5mL) was placed in the mouth, the start button of the TI software was clicked, and each sample was stirred and rubbed by the tongue and palate in the mouth for 12s before being spit out, and then the scoring continued until the saltiness could no longer be perceived. SensoMaker was used for sample evaluation and data collection. A 10-point rating scale was displayed on the screen. The evaluator moved the mouse along the scale line to score, and intensity data was collected every 4 seconds. Based on the results of the pre-experiment, the total duration of TI was set to 60s. All sensory tests were conducted in a sensory laboratory that meets ISO international standards. Between the evaluation of different samples, the evaluator was required to rinse his mouth with pure water and chew unsalted biscuits, and then rinse his mouth again and breathe evenly for 30s to restore his taste.

[0049] 2. Physical stability analysis method

[0050] The dispersion analyzer (LUMiSizer 651, LUM, Germany) was used to reflect the stability of W / OHIPEs at different OSA starch addition amounts.

[0051] Specifically: inject 1.8mL of sample into a polycarbonate tube (PC tube) sample dish with a light path of 2mm, place it flat in the instrument, and measure its transmittance. Analyze the centrifugal stability of the sample through the sample transmission curve at different times. Accelerate the movement rate of particles in the emulsion by centrifugation to predict the physical stability of the sample under long-term storage conditions. The experimental parameters are set as follows: the test light source is a red light source of 865nm, the light factor is 1, the centrifugal speed is 4000r / min, the contour line is 450, the test time interval is 20s, and the total test time is 2.5h. The stability of the sample can be reflected by observing the changes in transmittance at different positions of the same sample.

[0052] 3. Long-term storage stability analysis method

[0053] Freshly prepared W / O HIPEs were placed in glass bottles and stored at 4°C and 25°C for 30 days. The appearance of the samples was measured regularly to evaluate the storage stability of the samples.

[0054] 4. Microstructure observation and particle size analysis method

[0055] The W / O HIPEs were stained with 1 mg / mL Nile red. The microstructure of the emulsion was observed using a fluorescence microscope (Axio Vert A1, Zeiss, Germany) at a magnification of 400 times, and the images were obtained by processing with LSM 710ZEN software. The particle size of at least 100 particles was analyzed using Image J software to determine the average particle size of the W / O HIPEs.

[0056] 5. Analysis method of water status

[0057] A low-field nuclear magnetic resonance analyzer (PQ001, Shanghai Newmai Electronic Technology Co., Ltd.) was used to analyze the moisture state of W / O HIPEs with different OSA starch addition amounts.

[0058] Specifically, 3g of the emulsion sample to be tested was placed in a 25mm diameter NMR tube, and the signal was collected using the CPMG pulse sequence. The main parameters were set as follows: waiting time was 8500ms, echo time was 1ms, echo number was 18000, and scan number was 2. The CPMG decay curve was fitted using MultiExp Inv analysis software, multi-exponential fitting and SRIT algorithm to obtain the transverse relaxation time (T2) curve and the corresponding NMR parameters.

[0059] 6. Rheological properties analysis method

[0060] A rotational rheometer (DHR-3, TA Company, USA) was used to analyze the rheological properties of W / O HIPEs with different OSA starch addition amounts.

[0061] Specifically, the strain scan was performed at a frequency of 1 Hz in the range of 0.01% to 10% to determine the linear viscoelastic region (LVE region) of the sample. Then, the frequency scan was performed at a strain of 0.1% (in the LVE region) in the range of 0.01 to 10 Hz to record and analyze the curves of the storage modulus G' and loss modulus G" changing with frequency; and the shear rate was 0.1 to 100 s -1 The curve of apparent viscosity changing with shear rate was measured in the range.

[0062] 7. Analysis method of interface shear rheological properties

[0063] A stress-controlled rotational rheometer (DHR-3, TA Company, USA) equipped with a Du noüy ring was used to analyze the shear rheological properties of the interfacial film at different OSA starch addition amounts.

[0064] Specifically: OSA starch is poured into a PTFE cup, and then the Du noüy ring is placed at the air-water interface, and PGPR-rich sunflower oil is slowly added on top. First, a strain scan is performed at a frequency of 1 Hz in the range of 0.01% to 10% to determine the LVE region of the sample. Then, a dynamic frequency scan is performed at a strain of 0.5% (in the LVE region) in the frequency range of 0.01 to 10 Hz, and the curves of the interfacial elastic modulus (G') and interfacial viscous modulus (G") of the sample varying with frequency are recorded and analyzed. Finally, a dynamic time scan is performed at a frequency of 1 Hz for 1800 s at a strain of 0.5% (in the LVE region) until the sample forms a stable interfacial film on the interface, and the curves of G' and G" varying with time are recorded and analyzed.

[0065] 8. Sources

[0066] OSA starch was purchased from Shanghai Songqin Food Co., Ltd.

[0067] 1408K polyglycerol ricinoleate, medium chain triglyceride (MCT), lecithin, and glyceryl monostearate were all purchased from Shanghai Youchuang Industrial Co., Ltd.

[0068] Sunflower oil was purchased from COFCO Corporation.

[0069] Waxy corn starch was purchased from Ingredion.

[0070] Example 1: Preparation of W / O HIPEs

[0071] The specific implementation is as follows:

[0072] (1) Oil phase preparation:

[0073] Weigh 0.5 g PGPR and 25 mL sunflower oil respectively, and stir at 300 r / min for 20 min to make the mixture uniform;

[0074] (2) Weighing 0 g, 0.2 g, 0.4 g, and 0.6 g of OSA starch (octenyl succinate starch ester) respectively, dissolving them in water, stirring at 90 ° C at a rate of 350 r / min for 30 min, and preparing OSA starch aqueous solutions with mass concentrations of 0 mg / mL, 2 mg / mL, 4 mg / mL, and 6 mg / mL respectively;

[0075] (3) 75 mL of the OSA starch aqueous solution of different mass concentrations in step (2) were measured respectively, and 1.75 g of sodium chloride was added, and the mixture was stirred at 350 r / min for 3 min to ensure uniform mixing, and then added dropwise to the sunflower oil dissolved with PGPR obtained in step (1), and stirred at 600 r / min for 10 min to obtain W / O type high internal phase colostrum. The prepared colostrum was high-speed sheared at 12000 r / min for 3 min to prepare W / O HIPEs containing OSA starch with mass concentrations of 0 mg / mL, 2 mg / mL, 4 mg / mL, and 6 mg / mL, respectively.

[0076] Example 2: Sensory Quality Evaluation

[0077] The W / O HIPEs prepared in Example 1 were respectively taken, and the saltiness of the W / O HIPEs with different OSA starch addition amounts was dynamically evaluated using time-intensity sensory analysis. The results are shown in Table 1.

[0078] I max , AUC, and Plateau 90% represent the maximum stimulus intensity perceived during the evaluation period, the total area under the curve during the entire evaluation process (i.e., the overall salty taste perception intensity), and the stimulus intensity ≥ 90% I max duration.

[0079] Table 1 Saltiness index of W / O HIPEs with different OSA starch addition amounts

[0080]

[0081] The results show:

[0082] Compared with W / O HIPEs without OSA starch, with the increase of OSA starch addition, I max The values, AUC values ​​and Plateau 90% values ​​increased gradually, indicating that the addition of OSA starch enhanced the intensity and duration of salty taste perception in W / O HIPEs.

[0083] It can be seen that during the oral processing, the OSA starch adsorbed on the oil-water interface was enzymatically hydrolyzed by salivary amylase, the barrier effect of the interfacial layer was weakened, the release of sodium salt in the inner water phase was promoted, and the intensity and duration of salty taste perception in W / O HIPEs were enhanced.

[0084] Example 3: Physical stability

[0085] The W / O HIPEs prepared in Example 1 were centrifuged using a dispersion analyzer to accelerate the occurrence of instability, thereby analyzing the stabilizing effect of the W / O HIPEs under different OSA starch addition amounts.

[0086] Figure 1 This is a graph showing the evolution of the transmittance curve over time. The horizontal axis represents the top (110mm) and bottom (130mm) of the sample tube, and the vertical axis represents the transmittance of the sample to the incident light. As the analysis time increases, the contour line will change from the initial red to green. By observing the changes in transmittance at different positions of the same sample, the stability of the sample can be reflected. The results show:

[0087] Figure 1 In (A), in W / O HIPEs without OSA starch addition, the creaming layer height is about 4 mm, and the final overall transmittance is about 90%;

[0088] Figure 1 In (B), when the addition amount of OSA starch was 2 mg / mL, the overall transmittance of W / O HIPEs dropped below 60%, and the height of the emulsion layer dropped to about 2 mm, indicating that the addition of 2 mg / mL OSA starch can improve the physical stability of W / O HIPEs;

[0089] Figure 1 (C) Figure 1 In (D), as the amount of OSA starch added further increased to 4 mg / mL and 6 mg / mL, the overall transmittance of W / O HIPEs increased to about 90%, and the height of the creaming layer gradually increased to 7-10 mm.

[0090] This shows that the large-scale addition of OSA starch (4 mg / mL, 6 mg / mL) significantly reduced the physical stability of W / O HIPEs. Under the action of centrifugal force, more and more internal water phase precipitated from W / O HIPEs and existed at the bottom of the sample tube, thereby increasing the height of the emulsion layer. In addition, the changes in the two adjacent red transmission curves became more and more obvious, indicating that the time required for W / O HIPEs to demulsify became shorter and shorter.

[0091] Example 4: Long-term storage stability

[0092] The W / O HIPEs freshly prepared in Example 1 were placed in glass bottles and stored at 4°C and 25°C for 30 days. The appearance of the samples was measured regularly to evaluate the storage stability of the samples. The results are as follows: Figure 2 As shown in the figure, we can see that:

[0093] (1) Storage at 4°C for 30 days:

[0094] The W / O HIPEs without OSA starch addition remained stable and showed no phase separation;

[0095] The W / O HIPEs with 2 mg / mL OSA starch also remained stable, with no phase separation observed within 30 days, until 160 days of storage, when phase separation occurred;

[0096] When the addition amount of OSA starch was further increased to 4 mg / mL and 6 mg / mL, obvious phase separation occurred in W / O HIPEs within 30 days.

[0097] (2) Storage at 25°C for 30 days:

[0098] W / O HIPEs without OSA starch showed obvious phase separation after storage at 25°C for 30 days;

[0099] No obvious phase separation was found in the W / O HIPEs with 2 mg / mL OSA starch added until 40 days of storage, when phase separation occurred;

[0100] When the addition amount of OSA starch was further increased to 4 mg / mL and 6 mg / mL, obvious phase separation occurred in W / O HIPEs within 30 days.

[0101] It can be seen that the storage stability of W / O HIPEs with the addition of 2 mg / mL OSA starch is better, while the storage stability of W / O HIPEs with the addition of 4 mg / mL and 6 mg / mL OSA starch is poor.

[0102] Example 5: Microstructure Observation

[0103] The W / O HIPEs prepared in Example 1 were taken and the microstructure of the emulsion was observed using a fluorescence microscope. The particle sizes of at least 100 particles were analyzed using Image J software to determine the average particle size of the W / O HIPEs. The results are as follows: Figure 3 shown.

[0104] By observing the microstructure at a magnification of 400×, it can be found that in the emulsions prepared by adding four different amounts of OSA starch, the sunflower oil continuous phase (red) labeled by Nile red surrounds the dispersed water droplets (black), thus having the characteristics of a typical W / O emulsion and forming W / O HIPEs.

[0105] The droplet size of W / O HIPEs without OSA starch was small and evenly distributed, and no droplet aggregation was observed;

[0106] The droplet size of W / O HIPEs with 2 mg / mL OSA starch increased, and its distribution was more uniform, and no droplet aggregation was observed;

[0107] The droplet size of W / O HIPEs added with 4 mg / mL and 6 mg / mL OSA starch continued to increase, and droplet aggregation was observed.

[0108] It can be seen that the droplet size distribution of W / O HIPEs with 2 mg / mL OSA starch is uniform, and there is no droplet aggregation phenomenon, while the droplet aggregation phenomenon exists in W / O HIPEs with 4 mg / mL and 6 mg / mL OSA starch.

[0109] Example 6: Rheological properties

[0110] The W / O HIPEs prepared in Example 1 were analyzed for their rheological properties using a rheometer. The results are as follows: Figure 4 shown.

[0111] Depend on Figure 4 (A) It can be seen that as the shear rate increases from 0.1s -1 Increase to 100s -1 , the apparent viscosity of W / OHIPEs gradually decreased with different OSA starch addition amounts, indicating that all samples exhibited shear thinning behavior and were typical non-Newtonian pseudoplastic fluids.

[0112] The apparent viscosity of W / O HIPEs decreases with the increase of OSA starch addition, indicating that the fluidity of the emulsion gradually improves. Lower apparent viscosity can increase the movement rate and collision probability of droplets, thereby reducing the stability of W / O HIPEs. It can be seen from the results of Examples 3 and 4 that the addition of 2 mg / mL OSA starch improves the stability of W / O HIPEs, indicating that the change in apparent viscosity is not the main factor in regulating its stability.

[0113] from Figure 4The frequency scan of (B) shows that in W / O HIPEs with different OSA starch addition amounts, the G” value is always greater than G’, indicating the formation of a viscous liquid structure. At the same time, G’ and G” increase with increasing frequency, indicating that the modulus has a strong frequency dependence.

[0114] In addition, as the addition amount of OSA starch increased from 0 mg / mL to 6 mg / mL, the G' and G" values ​​of W / O HIPEs decreased continuously, indicating that the viscoelasticity of the emulsion was decreasing, which may be related to the change in droplet size ( Figure 3 ). With the increase of OSA starch addition amount, the droplet size gradually increased, the average distance between droplets increased, and the amplitude of interaction between droplets decreased, thereby reducing the viscoelasticity of the emulsion.

[0115] It can be seen that in the W / O HIPEs with the addition of 4 mg / mL and 6 mg / mL OSA starch, the decrease in viscoelasticity will reduce its stability.

[0116] Example 7: Water Existence State

[0117] Moisture presence detection: relaxation peak between 0ms and 10ms (T 21 ) represents water tightly bound to macromolecules, i.e. bound water; the relaxation peak (T 22 ) corresponds to water and oil that are not easy to flow; and when the relaxation peak (T 23 ) is distributed between 500ms and 5000ms, it represents the freely mobile water in the emulsion, and its peak area accounts for more than 70% of the total peak area, which is the main relaxation peak in the emulsion.

[0118] The W / O HIPEs prepared in Example 1 were taken and the water content of the W / O HIPEs was analyzed using low-field nuclear magnetic resonance. The results are shown in Table 2.

[0119] Table 2 T2 relaxation time and T2 peak relative area of ​​W / O HIPEs with different OSA starch addition amounts

[0120]

[0121]

[0122] The results show:

[0123] Compared with W / O HIPEs without OSA starch, the addition of 2 mg / mL OSA starch increased the T 23The relaxation time shifted from (2437.613±0.186) ms to the left to (2025.519±0.021) ms, indicating that the addition of OSA starch can increase the binding force of hydrogen protons in the inner water phase and reduce their freedom. This may be because the hydrophilic groups (carboxyl and hydroxyl groups) of OSA starch extend into the inner water phase, and their steric hindrance restricts the movement of hydrogen protons in the water phase, thereby reducing the freedom and fluidity of water, and thus obtaining W / O HIPEs with good physical stability.

[0124] T of W / O HIPEs before and after adding OSA starch 22 The peaks appear as continuous double peaks, which are defined as T 22a and T 22b , refer to the relaxation peaks of oil and immobile water in W / O HIPEs, respectively.

[0125] When the addition amount of OSA starch was 4 mg / mL and 6 mg / mL, the T 22a The relaxation time shifted from (45.530±0.004) ms to (49.960±0.015) ms and (49.950±0.028) ms, with a longer T 22a The relaxation time indicates that the hydrogen protons of sunflower oil in W / O HIPEs are less restricted and have higher degrees of freedom.

[0126] This may be due to the competitive adsorption of OSA starch and PGPR at the oil-water interface. The more OSA starch is added, the stronger the competition is. More PGPR falls off from the oil-water interface, making W / O HIPEs in an "unstable state". The hydrogen protons in sunflower oil cannot be effectively captured, which increases the freedom and fluidity of sunflower oil, thereby increasing the relaxation time. The increase in the fluidity of sunflower oil increases the movement of emulsion droplets in W / O HIPEs and promotes the aggregation of droplets, thereby reducing the stability of W / O HIPEs.

[0127] It can be seen that the physical stability of W / O HIPEs with the addition of 2 mg / mL OSA starch is the best, while the stability of W / O HIPEs decreases when 4 mg / mL and 6 mg / mL OSA starch are added.

[0128] Example 8: Interfacial Shear Rheological Properties

[0129] The W / O HIPEs prepared in Example 1 were used to analyze the shear rheological properties of the interface film at different OSA starch addition amounts using a stress-controlled rotational rheometer equipped with a Du Noüy ring. The results are as follows: Figure 5 shown.

[0130] Depend on Figure 5(A) Figure 5 (B) It can be seen that G' and G" of all samples remain almost unchanged within the test time (1800s), indicating that they are not time-dependent, indicating that PGPR and OSA starch have fast formation kinetics and are easy to diffuse and adsorb at the oil-water interface. The G" of all samples is higher than G', indicating that the interfacial film formed by PGPR is mainly viscous, and the addition of OSA starch does not cause a change in the viscoelasticity of the interfacial film.

[0131] Compared with the PGPR interfacial layer without OSA starch, the addition of 2 mg / mL OSA starch increased G” and the interfacial layer showed a stronger viscous response. The formation of a viscous and more stable interfacial layer helps to improve the stability of W / O HIPEs.

[0132] When the addition amount of OSA starch was 4 mg / mL, G' decreased significantly, indicating that the elastic response of the interfacial layer decreased and the stability of W / OHIPEs decreased.

[0133] When the addition amount of OSA starch was 6 mg / mL, both G' and G" increased significantly and reached the maximum value. It is speculated that at this time, OSA starch was mainly adsorbed on the oil-water interface, thus helping to form an interfacial film with stronger viscoelasticity. However, this is not conducive to the stability of W / OHIPEs.

[0134] like Figure 5 As shown in (C), within the test frequency range of 0.1 to 10 Hz, G” and G' of all samples increase with increasing frequency, indicating that the modulus has a strong frequency dependence. In the low frequency range, G” is higher than G', indicating that the interface layer formed at this time is mainly viscous; with the increase of frequency, G” and G' have a crossover point, that is, G'>G”, indicating that the interface layer dominated by viscosity gradually transforms into an interface layer dominated by elasticity. In addition, the increase in the amount of OSA starch added will cause G' to first decrease and then increase, which is consistent with the results of the time scan test.

[0135] It can be seen that the W / O HIPEs with the addition of 2 mg / mL OSA starch have higher stability, while the W / O HIPEs with the addition of 4 mg / mL and 6 mg / mL OSA starch have lower stability.

[0136] Example 9: Effects of different types of oil as oil phase on high internal phase emulsion

[0137] The specific implementation is the same as Example 1, except that a different type of oil is used: MCT.

[0138] The saltiness of W / O HIPEs (MCT in oil phase) with different OSA addition amounts was evaluated by time-intensity sensory analysis, and the saltiness results are shown in Table 3. The stability of W / O HIPEs (MCT in oil phase) with different OSA addition amounts was analyzed by dispersion analyzer, and the results are shown in Table 3. Figure 6 shown.

[0139] Table 3 Saltiness index of W / O HIPEs (oil phase is MCT) with different OSA starch addition amounts

[0140]

[0141] The results show:

[0142] In W / O HIPEs with MCT as the oil phase, with the increase of OSA starch addition, I max The values, AUC values ​​and Plateau 90% values ​​all increased gradually, indicating that the increase in the amount of OSA starch added increased the intensity and duration of salty taste perception in W / O HIPEs (the oil phase was MCT).

[0143] Figure 6 In (A), in W / O HIPEs (oil phase is MCT) without OSA starch addition, the height of the emulsion layer is about 5 mm, and the final overall transmittance is about 95%;

[0144] Figure 6 In (B), when the addition amount of OSA starch was 2 mg / mL, the overall transmittance of W / O HIPEs (the oil phase was MCT) dropped below 70%, and the height of the emulsion layer dropped to about 3 mm, indicating that the addition of 2 mg / mL OSA starch can improve the physical stability of W / O HIPEs (the oil phase was MCT);

[0145] Figure 6 (C) Figure 6 In (D), as the amount of OSA starch added further increased to 4 mg / mL and 6 mg / mL, the overall transmittance of W / O HIPEs (oil phase is MCT) increased to about 90%, and the height of the emulsion layer gradually increased to 5-8 mm, indicating that the large amount of OSA starch added (4 mg / mL, 6 mg / mL) significantly reduced the physical stability of W / O HIPEs (oil phase is MCT).

[0146] This is consistent with the phenomena observed in Examples 2 and 3, indicating that the switchable delivery of sodium salt can be achieved through the regulation of OSA starch in W / O HIPEs composed of sunflower oil or MCT.

[0147] Example 10: Effects of different internal water phases on high internal phase emulsions

[0148] The specific implementation method is the same as Example 1, except that OSA starch is replaced by waxy corn starch.

[0149] The saltiness of W / O HIPEs with different starch addition amounts was evaluated using time-intensity sensory analysis, and the saltiness results are shown in Table 4.

[0150] Table 4 Salinity index of W / O HIPEs prepared with different internal water phases

[0151]

[0152] The results show:

[0153] With the increase of waxy corn starch addition, I max The values, AUC values ​​and Plateau 90% values ​​did not change significantly, indicating that the increase in the amount of waxy corn starch added did not change the intensity and duration of salty taste perception in W / O HIPEs.

[0154] Comparative Example 1: Effect of emulsifier type on high internal phase emulsion

[0155] (1) Specific implementation method The same as Example 1, except that OSA starch is not added and different types of emulsifiers are used: phospholipids and glyceryl monostearate.

[0156] The microstructure of the emulsion was observed using a fluorescence microscope. Figure 7 shown.

[0157] The results show:

[0158] a. Using lecithin as an emulsifier does not form stable W / O HIPEs, which separate into layers after standing for 30 minutes at room temperature.

[0159] b. By observing the microstructure of the emulsion stabilized by glyceryl monostearate at 400× magnification ( Figure 7 ), it can be found that the sunflower oil (red) marked by Nile red is distributed in droplets and is surrounded by the aqueous phase (black). Therefore, it can be determined that the formed emulsion is an O / W type, rather than the W / O type emulsion in Example 1.

[0160] These results indicate that neither type of emulsifier can be used to stabilize the formation of W / O HIPEs.

[0161] (2) The specific implementation method is the same as Example 1, except that different types of emulsifiers are used: phospholipids and glyceryl monostearate instead of PGPR.

[0162] The results showed that different types of emulsifiers, including phospholipids and glyceryl monostearate, could not form stable W / OHIPEs. The reason may be that OSA starch, as a traditional emulsifier for stabilizing O / W emulsions, did not help the transformation of O / W emulsions to W / O emulsions.

[0163] Comparative Example 2: Effect of different PGPR dosages on high internal phase emulsion

[0164] Specific implementation method The addition amount of OSA starch in Example 1 is 0 mg / mL, except that the 0.5 g PGPR in step (1) is adjusted to 1 g, 3 g, and 5 g, so that the amount of PGPR is adjusted to 2%, 4%, 12%, and 20%.

[0165] The saltiness of W / O HIPEs (OSA starch addition amount was 0 mg / mL) with different PGPR addition amounts was evaluated by time-intensity sensory analysis, and the saltiness results are shown in Table 5. The stability of W / OHIPEs (OSA starch addition amount was 0 mg / mL) with different PGPR addition amounts was analyzed by dispersion analyzer, and the results are shown in Table 5. Figure 8 shown.

[0166] Table 5 Saltiness index of W / O HIPEs with different PGPR addition amounts (OSA starch addition amount is 0 mg / mL, oil phase is sunflower oil)

[0167]

[0168] Note: - means the saltiness cannot be sensed

[0169] The results show:

[0170] With the increase of PGPR addition, I max The values, AUC values ​​and Plateau 90% values ​​all decreased gradually, indicating that the increase in the addition amount of PGPR reduced the intensity and duration of salty taste perception in W / O HIPEs (the addition amount of OSA starch was 0 mg / mL), which was closely related to the change in stability.

[0171] Figure 8 In (A), in the W / O HIPEs with 2% PGPR addition (OSA starch addition amount is 0 mg / mL), the height of the creaming layer is about 4 mm, and the final overall transmittance is about 90%. Figure 8 (B) Figure 8 (C) Figure 8In (D), as the PGPR addition amount increases to 4%, 12%, and 20%, the overall transmittance and creaming layer height of W / O HIPEs (the addition amount of OSA starch is 0 mg / mL) gradually decrease, indicating that with the increase of PGPR addition amount, the physical stability of W / O HIPEs (the addition amount of OSA starch is 0 mg / mL) gradually increases.

[0172] It can be seen that although the increase in the amount of PGPR added can improve the physical stability of W / O HIPEs (the amount of OSA starch added is 0 mg / mL), it also reduces the intensity and duration of salty taste perception during oral processing, and cannot achieve the switch-like delivery of sodium salt.

[0173] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A switchable sodium salt delivery W / O type high internal phase emulsion, characterized in that: The W / O type high internal phase emulsion comprises an oil phase, an aqueous phase and an emulsifier, and the switch mode means that the shelf life stability and oral instability of the W / O type high internal phase emulsion are achieved by controlling the addition amount of octenyl succinate starch ester (OSA starch); The oil phase contains an emulsifier, the emulsifier is 1.5% to 2.5% by mass of polyglycerol ricinoleate, and the volume fraction of the oil phase in the high internal phase emulsion is 20% to 30%; The aqueous phase is a mixture of OSA starch solution and sodium salt; The water phase is added to the oil phase to prepare a switchable sodium salt delivery W / O type high internal phase emulsion; the volume ratio of the water phase to the oil phase is 70-80:20-30.

2. The high internal phase emulsion according to claim 1, characterized in that The oil phase is edible oil; the edible oil includes but is not limited to: sunflower oil, lard, corn oil, soybean oil, and medium-chain triglycerides.

3. The high internal phase emulsion according to claim 1 or 2, characterized in that: In the aqueous phase, the mass fraction of sodium salt is 1.46% to 2.63%; preferably, the mass concentration of the OSA starch solution is 0.1 mg / mL to 6 mg / mL.

4. A method for preparing a switchable sodium salt delivery W / O type high internal phase emulsion, characterized in that: The switch type means that the shelf life stability and oral instability of the W / O type high internal phase emulsion are achieved by controlling the addition amount of octenyl succinate starch ester (OSA starch); the preparation method specifically includes: (1) Preparation of aqueous phase: Adding sodium salt to the OSA starch solution to obtain solution A; the mass fraction of the sodium salt is 1.46% to 2.63%; the mass concentration of the OSA starch solution is 0.1 mg / mL to 6 mg / mL; (2) Preparation of oil phase containing emulsifier: Mixing oil with polyglycerol ricinoleate to obtain solution B; the mass fraction of the polyglycerol ricinoleate is 1.5% to 2.5%; (3) adding solution A to solution B to obtain a W / O type high internal phase colostrum, and further emulsifying the W / O type high internal phase colostrum to obtain a W / O type high internal phase emulsion.

5. The preparation method according to claim 4, characterized in that: In step (2), the solution B is obtained by mixing oil and polyglycerol ricinoleate at 300 r / min for 20 min.

6. The preparation method according to claim 5, characterized in that: The volume fraction of the oil phase in the high internal phase emulsion is 20% to 30%.

7. The preparation method according to claim 6, characterized in that: In step (3), the oil in the oil phase is edible oil; preferably, the edible oil includes but is not limited to: sunflower oil, lard, corn oil, soybean oil, and medium-chain triglycerides.

8. The preparation method according to claim 7, characterized in that: In step (3), the W / O type high internal phase colostrum is subjected to high-speed shearing at 10,000 to 15,000 r / min for 1 to 5 minutes to fully emulsify the obtained W / O type high internal phase emulsion having an internal water phase volume fraction of 70% to 80%.

9. A low-fat salad dressing, characterized in that: The low-fat salad dressing contains the switchable sodium salt delivery W / O type high internal phase emulsion described in any one of claims 1 to 3 or the W / O type high internal phase emulsion prepared by the preparation method described in any one of claims 4 to 8; preferably, the salad dressing also contains one or more of honey, lemon juice, vegetable juice, chopped celery, white pepper, vanilla, mustard, and low-fat yogurt.

10. Use of the switchable sodium salt delivery W / O type high internal phase emulsion according to any one of claims 1 to 3 or the preparation method according to any one of claims 4 to 8 in the preparation of fat-reducing food.

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