A chickpea protein-based high internal phase emulsion with high freeze-thaw stability based on interface regulation, and its preparation method and application

Abstract

The present invention relates to a chickpea protein high internal phase emulsion with high freeze-thaw stability based on interface regulation and its preparation method and application, which belongs to the technical field of emulsion preparation. The preparation of the high internal phase emulsion of the present invention includes: adjusting the pH of the chickpea protein solution to 8-9, ultrasonic treatment, then adding a polysaccharide solution and uniformly mixing, heating the reaction in a water bath, centrifuging the reaction product after the reaction is completed, taking the supernatant and freeze-drying to obtain a protein-polysaccharide conjugate; dissolving the obtained protein-polysaccharide conjugate in water as an aqueous phase; mixing flavor oil and vegetable oil, stirring evenly, as an oil phase; mixing the aqueous phase and the oil phase, and shearing at high speed to obtain a high internal phase emulsion with high freeze-thaw stability. The chickpea protein high internal phase emulsion not only has good freeze-thaw stability, but also has the characteristics of significant gelation, can give fish paste products good freeze-thaw stability, and has broad application prospects.

Description

Technical Field

[0001] The invention relates to a chickpea protein-based high internal phase emulsion with high freeze-thaw stability based on interface regulation, a preparation method and application thereof, and belongs to the technical field of emulsion preparation. Background Art

[0002] Currently, freezing is an effective method for extending the shelf life and maintaining the quality of fish surimi products, such as fish balls, fish cakes, and fish intestines. However, the inevitable repeated freeze-thaw cycles during transportation and processing can severely damage the quality of emulsified surimi products. Therefore, determining how to add liquid oil to surimi gel without affecting the gel's quality and improving freeze-thaw stability is an urgent problem.

[0003] The direct introduction of liquid oil will adversely affect the gel strength and texture of surimi gel through interaction with myofibrillar proteins. The pre-emulsions currently used have a low main oil content and strong fluidity, which cannot provide sufficient oil. High internal phase emulsions are emulsions with an oil phase volume fraction of ≥74% (v / v) and a semi-solid form. They have the advantages of strong anti-caking ability, low water activity, and high microbial stability. Therefore, due to their high stability, high lipid load, small oil droplet size and low oxidative sensitivity, high internal phase emulsions are ideal carriers for lipid fortification in surimi products, which can reduce the damage of lipid addition to the myofibrillar protein gel network structure.

[0004] As a two-phase system, freeze-thaw instability has always been a major problem in the application of high internal phase emulsions (HIPEs). The freeze-thaw instability of HIPEs may cause the layer around individual oil droplets to rupture and allow the oil droplets to quickly coalesce, resulting in the separation of HIPEs into the original water phase and oil phase, which greatly destroys the encapsulation of flavor substances.

[0005] Flavor is one of the most important characteristics of food, and desirable flavor profiles can enhance consumer purchasing power. Essential oils and spices are primarily composed of volatile components, such as monoterpenes, sesquiterpenes, and oxygenated terpenes. Most of these components not only provide a pleasant aroma but also possess biological activity, but are often difficult to preserve in food additives. Summary of the Invention

[0006] In response to the defects and shortcomings of the existing technology, the present invention provides a chickpea protein-based high internal phase emulsion with high freeze-thaw stability based on interface regulation, as well as a preparation method and application thereof. The chickpea protein high internal phase emulsion not only has good freeze-thaw stability, but also has significant gelling properties, which can give fish paste products good freeze-thaw stability.

[0007] The first object of the present invention is to provide a method for preparing a chickpea protein-based high internal phase emulsion with high freeze-thaw stability based on interface regulation, the method comprising the following steps:

[0008] (1) adjusting the pH of the chickpea protein solution to 8-9, ultrasonically treating the solution, then adding the polysaccharide solution and uniformly mixing the solution, heating the solution in a water bath for reaction, centrifuging the reaction product after the reaction, and freeze-drying the supernatant to obtain a protein-polysaccharide conjugate; and dissolving the obtained protein-polysaccharide conjugate in water as the aqueous phase;

[0009] (2) Mixing flavor oil and vegetable oil and stirring evenly to form the oil phase;

[0010] (3) The aqueous phase prepared in step (1) and the oil phase prepared in step (2) are mixed and sheared at high speed to obtain a high internal phase emulsion with high freeze-thaw stability.

[0011] In one embodiment, the ultrasonic conditions in step (1) are: power of 300-500W, and time of 20-40min.

[0012] In one embodiment, the polysaccharide solution in step (1) is one or more of a carrageenan solution, a linseed gum solution, and a low acyl gellan gum solution.

[0013] In one embodiment, the mass concentration of the polysaccharide solution in step (1) is 2-6 mg / mL; the mass concentration of the chickpea protein solution is 40-60 mg / mL; and the volume ratio of the polysaccharide solution to the chickpea protein solution is 1:1.

[0014] In one embodiment, the heating reaction conditions in step (1) are: temperature of 70 to 90° C., and time of 18 to 24 hours.

[0015] In one embodiment, the centrifugation conditions in step (1) are: 8000-10000 g, and the time is 10-20 min.

[0016] In one embodiment, the freeze-drying conditions of step (1) are: first freezing in a -18 to -40°C refrigerator for 12 to 24 hours, and then freeze-drying in a vacuum of 200 Pa at -40 to -80°C for 24 to 48 hours.

[0017] In one embodiment, the concentration of the protein-polysaccharide conjugate in the aqueous phase in step (1) is 20 to 40 mg / mL.

[0018] In one embodiment, the flavor oil in step (2) is one or more of Litsea cubeba oil, Zanthoxylum bungeanum oil, and Sichuan peppercorn oil.

[0019] In one embodiment, the vegetable oil in step (2) is one or more of corn oil, rapeseed oil, peanut oil, soybean oil, and sunflower oil.

[0020] In one embodiment, the volume ratio of the flavor oil to the vegetable oil in step (2) is 1:4.

[0021] In one embodiment, the stirring rate in step (2) is 300-500 rpm.

[0022] In one embodiment, the volume ratio of the water phase to the oil phase in step (3) is 1:4.

[0023] In one embodiment, the high-speed shearing conditions in step (3) are: a rate of 10,000-12,000 rpm, and a time of 3 to 5 minutes.

[0024] The second object of the present invention is to provide a high internal phase emulsion with high freeze-thaw stability prepared by the above method.

[0025] The third object of the present invention is to provide an application of the high internal phase emulsion with high freeze-thaw stability described above in the field of food preparation.

[0026] A fourth object of the present invention is to provide a method for improving the gel properties and freeze-thaw stability of an emulsified surimi product, the method comprising the following steps:

[0027] 1) Thaw the frozen surimi, cut it into small pieces, add salt and blend, and then adjust the moisture content to 75-80% to form surimi paste;

[0028] 2) Adding 5-15% of the high internal phase emulsion with high freeze-thaw stability prepared above to the surimi paste prepared in step 1) based on the total mass of the surimi paste, continuing to chop and blend, and then stuffing into sausage casings, gelling, heating and maturing.

[0029] In one embodiment, the amount of salt added in step 1) is 1-2.5% based on the mass of the surimi.

[0030] In one embodiment, the high internal phase emulsion with high freeze-thaw stability in step 2) is added to the surimi paste in 3-6 portions, and the mixture is chopped and stirred for 30 seconds and then rested for 30 seconds.

[0031] In one embodiment, the amount of the high internal phase emulsion with high freeze-thaw stability added in step 2) is 5% based on the total mass of the surimi paste.

[0032] In one embodiment, the gelation conditions in step 2) are: temperature 40-45° C., time 20-40 min.

[0033] In one embodiment, the heating and aging conditions in step 2) are: 90-100° C., and the time is 20-40 min.

[0034] The fifth object of the present invention is to provide a surimi product obtained by the above-mentioned method for improving the gel properties and freeze-thaw stability of emulsified surimi products.

[0035] Beneficial effects of the present invention:

[0036] (1) During the preparation of the high internal phase emulsion of the present invention, ultrasonic treatment can change the secondary and tertiary structures of the protein and expose more free amino groups for glycosylation with polysaccharides, thereby increasing the degree of saccharification and improving the interfacial activity of the saccharified protein while avoiding the high temperature / time required for classical wet heating; and the covalent bond between the protein and polysaccharide components can prevent denaturation or aggregation, thereby increasing the overall stability of the conjugate.

[0037] (2) The present invention improves the freeze-thaw stability of chickpea protein high internal phase emulsions primarily by adjusting the interfacial structure of the aqueous and oil phases. Glycosylated chickpea modified protein exhibits improved interfacial adsorption, and the introduction of flavor oil into vegetable oil further reduces the interfacial tension of protein at the oil / water interface, facilitating rapid adsorption of protein to the interface. Furthermore, the combination of protein and flavor substances in the flavor oil increases the viscoelasticity of the interfacial film to resist freeze-thaw damage.

[0038] (3) The freeze-thaw stability and flavor of the glycosylated chickpea protein high internal phase emulsion prepared by the present invention have significant gelling characteristics, which overcomes the adverse effects of directly adding oil on the gel properties of surimi products and gives surimi products good freeze-thaw stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a process flow chart for preparing the surimi product of the present invention;

[0040] Figure 2 The oil / water interfacial tension diagrams of the proteins of Example 1 and Comparative Examples 1, 3 and 4 are shown;

[0041] Figure 3 Graph showing the oil droplet distribution of the high internal phase emulsions of Example 1 and Comparative Examples 1-3. DETAILED DESCRIPTION

[0042] The content of the present invention is further illustrated below with reference to the following embodiments and comparative examples, but the content protected by the present invention is not limited to the following embodiments.

[0043] The measuring method involved in the present invention is as follows:

[0044] 1. Method for determining protein tension at the oil / water interface

[0045] The dynamic interfacial tension of a protein solution was recorded using a video optical contact angle meter. A 20 μL drop of protein solution was injected into the oil to form a drop, and the dynamic interfacial tension of the protein solution was monitored over time.

[0046] 2. Method for determining droplet distribution of high internal phase emulsion

[0047] The high internal phase emulsion was placed on a glass slide, covered with a cover glass, and gently compacted. Its structure and droplet distribution were observed using an inverted optical microscope.

[0048] 3. Determination of freeze-thaw stability of high internal phase emulsion

[0049] Place the high internal phase emulsion in a 30 mL glass vial, freeze it at -22°C for 24 hours, then thaw it at 25°C for 4 hours. Repeat this cycle three times. Weigh the mass of the emulsion (m0 g), and the mass of the emulsion and centrifuge tube (m1 g). Centrifuge the emulsion at 10,000 g for 10 minutes. After removing the leaked oil, the total mass of the emulsion and centrifuge tube is m2 g. Oil loss (%) = (m2 - m1) / m0 × 100%.

[0050] 4. Determination of retention rate of citral content in high internal phase emulsion

[0051] To measure the citral concentration in the emulsions, approximately 2 mL of emulsion sample was mixed with four volumes of n-hexane, vortexed at 1000 rpm / min for 30 minutes, and then allowed to stand for an additional 30 minutes. The supernatant from each test tube was collected, filtered using a syringe-driven filter unit (polytetrafluoroethylene, 0.22 μm), diluted with n-hexane to a citral concentration range of 20–100 μg / mL, and then analyzed by gas chromatography. An Agilent 6890 Series gas chromatograph was used, equipped with a flame ionization detector (FID) and a fused silica capillary column (30 m × 0.25 mm × 0.25 μm film thickness; temperature range: 35–280°C). The temperature settings were as follows: initial temperature 60°C (hold for 1 minute), then increased to 240°C at 8°C / min and held for 1 minute; the injector and detector temperatures were 250°C. The carrier gas was helium (2.0 mL / min). A sample (1.0 μL) was injected into a gas chromatograph for analysis. The two isomers of citral were identified by comparing their retention times with those of a Sigma citral analytical standard. Citral concentration was determined by measuring the peak areas of lactone and geraniol in the GC-FID spectrum and comparing these peaks to a calibration curve of the citral standard. Citral concentration was expressed as the sum of the two isomers.

[0052] 5. Determination of gel properties of surimi products

[0053] Gel strength test conditions: pre-test speed 1 mm / s, test speed 1 mm / s, return speed 10 mm / s; downward distance 20 mm.

[0054] 6. Determination of water holding capacity of surimi products

[0055] Cut the gel into small pieces approximately 5 x 5 x 5 mm. Weigh m1 (approximately 3 g) of gel, wrap it in two layers of filter paper, place it in a centrifuge tube, and centrifuge it at 10,000 rpm for 10 minutes. Remove the gel and weigh it. The mass of the gel after centrifugation is m2. The water holding capacity of the gel is calculated as follows: Water holding capacity (%) = m2 / m1 x 100%.

[0056] 7. Determination of juice loss during freeze-thaw of surimi products

[0057] Weigh the unfrozen-thawed surimi gel sample and record it as m1 g. After three freeze-thaw cycles, wipe the surface moisture of the sample with filter paper and record the sample mass as m2 g. Calculate the juice loss rate using the following formula: Juice loss rate (%) = (m1 - m2) / m1 × 100%.

[0058] Example 1

[0059] A method for preparing a high internal phase emulsion with good stability comprises the following steps:

[0060] (1) Preparation of aqueous phase: The pH of a 40 mg / mL chickpea protein solution was adjusted to 8, ultrasonicated at 400 W for 30 min, and then a 4 mg / mL carrageenan solution was added at a volume ratio of 1:1 and uniformly mixed. The mixture was heated in an 80°C water bath for 20 h. After the reaction was completed, the mixture was cooled to room temperature in an ice-water mixture. The cooled reaction product was centrifuged at 8500 g for 20 min to remove insoluble and unreacted aggregates. The supernatant was collected and frozen in a -22°C refrigerator for 24 h, and then vacuum freeze-dried (-80°C, 200 Pa) for 48 h to obtain a protein-polysaccharide conjugate. 20 mg / mL of the protein-polysaccharide conjugate was dissolved in deionized water as the aqueous phase.

[0061] (2) Preparation of composite oil phase: Litsea cubeba oil and rapeseed oil were mixed in a volume ratio of 1:4 and stirred at a rate of 300-500 rpm until fully mixed to obtain a mixed oil as the oil phase;

[0062] (3) Preparation of high internal phase emulsion: The aqueous phase prepared in step (1) and the oil phase prepared in step (2) were mixed in a volume ratio of 1:4 and high-speed sheared at 12000 rpm for 3 min to obtain a stable high internal phase emulsion.

[0063] Example 2

[0064] A method for preparing a high internal phase emulsion with good stability comprises the following steps:

[0065] (1) Preparation of aqueous phase: The pH of a 40 mg / mL chickpea protein solution was adjusted to 8, ultrasonicated at 400 W for 30 min, and then a 4 mg / mL flaxseed gum solution was added at a volume ratio of 1:1 and uniformly mixed. The mixture was heated in an 80°C water bath for 20 h. After the reaction was completed, the mixture was cooled to room temperature in an ice-water mixture. The cooled reaction product was centrifuged at 8500 g for 20 min to remove insoluble and unreacted aggregates. The supernatant was collected and frozen in a -22°C refrigerator for 24 h, and then vacuum freeze-dried (-80°C, 200 Pa) for 48 h to obtain a protein-polysaccharide conjugate. 20 mg / mL of the protein-polysaccharide conjugate was dissolved in deionized water as the aqueous phase.

[0066] (2) Preparation of composite oil phase: Litsea cubeba oil and rapeseed oil were mixed in a volume ratio of 1:4 and stirred at a rate of 300-500 rpm until fully mixed to obtain a mixed oil as the oil phase;

[0067] (3) Preparation of high internal phase emulsion: The aqueous phase prepared in step (1) and the oil phase prepared in step (2) were mixed in a volume ratio of 1:4 and high-speed sheared at 12000 rpm for 3 min to obtain a stable high internal phase emulsion.

[0068] Example 3

[0069] A method for preparing a high internal phase emulsion with good stability comprises the following steps:

[0070] (1) Preparation of aqueous phase: The pH of a 40 mg / mL chickpea protein solution was adjusted to 8, ultrasonicated at 400 W for 30 min, and then a 4 mg / mL low acyl gellan gum solution was added at a volume ratio of 1:1 and uniformly mixed. The mixture was heated in an 80°C water bath for 20 h. After the reaction was completed, the mixture was cooled to room temperature in an ice-water mixture. The cooled reaction product was centrifuged at 8500 g for 20 min to remove insoluble and unreacted aggregates. The supernatant was collected and frozen in a -22°C refrigerator for 24 h, and then vacuum freeze-dried (-80°C, 200 Pa) for 48 h to obtain a protein-polysaccharide conjugate. 20 mg / mL of the protein-polysaccharide conjugate was dissolved in deionized water as the aqueous phase.

[0071] (2) Preparation of composite oil phase: Litsea cubeba oil and rapeseed oil were mixed in a volume ratio of 1:4 and stirred at a rate of 200-250 rpm until fully mixed to obtain a mixed oil as the oil phase;

[0072] (3) Preparation of high internal phase emulsion: The aqueous phase prepared in step (1) and the oil phase prepared in step (2) were mixed in a volume ratio of 1:4 and high-speed sheared at 12000 rpm for 3 min to obtain a stable high internal phase emulsion.

[0073] Example 4

[0074] A method for preparing a high internal phase emulsion with good stability comprises the following steps:

[0075] (1) Preparation of aqueous phase: The pH of a 40 mg / mL chickpea protein solution was adjusted to 8, ultrasonicated at 400 W for 30 min, and then a 4 mg / mL carrageenan solution was added at a volume ratio of 1:1 and uniformly mixed. The mixture was heated in an 80°C water bath for 20 h. After the reaction was completed, the mixture was cooled to room temperature in an ice-water mixture. The cooled reaction product was centrifuged at 8500 g for 20 min to remove insoluble and unreacted aggregates. The supernatant was collected and frozen in a -22°C refrigerator for 24 h, and then vacuum freeze-dried (-80°C, 200 Pa) for 48 h to obtain a protein-polysaccharide conjugate. 20 mg / mL of the protein-polysaccharide conjugate was dissolved in deionized water as the aqueous phase.

[0076] (2) Preparation of composite oil phase: Peppercorn oil and rapeseed oil were mixed in a volume ratio of 1:4 and stirred at a rate of 200-250 rpm until fully mixed to obtain a mixed oil as the oil phase;

[0077] (3) Preparation of high internal phase emulsion: The aqueous phase prepared in step (1) and the oil phase prepared in step (2) were mixed in a volume ratio of 1:4 and high-speed sheared at 12000 rpm for 3 min to obtain a stable high internal phase emulsion.

[0078] Example 5

[0079] A method for preparing a high internal phase emulsion with good stability comprises the following steps:

[0080] (1) Preparation of aqueous phase: The pH of a 40 mg / mL chickpea protein solution was adjusted to 8, ultrasonicated at 400 W for 30 min, and then a 4 mg / mL carrageenan solution was added at a volume ratio of 1:1 and uniformly mixed. The mixture was heated in an 80°C water bath for 20 h. After the reaction was completed, the mixture was cooled to room temperature in an ice-water mixture. The cooled reaction product was centrifuged at 8500 g for 20 min to remove insoluble and unreacted aggregates. The supernatant was collected and frozen in a -22°C refrigerator for 24 h, and then vacuum freeze-dried (-80°C, 200 Pa) for 48 h to obtain a protein-polysaccharide conjugate. 20 mg / mL of the protein-polysaccharide conjugate was dissolved in deionized water as the aqueous phase.

[0081] (2) Preparation of composite oil phase: Peppercorn oil and rapeseed oil were mixed in a volume ratio of 1:4 and stirred at a rate of 200-250 rpm until fully mixed to obtain a mixed oil as the oil phase;

[0082] (3) Preparation of high internal phase emulsion: The aqueous phase prepared in step (1) and the oil phase prepared in step (2) were mixed in a volume ratio of 1:4 and high-speed sheared at 12000 rpm for 3 min to obtain a stable high internal phase emulsion.

[0083] Comparative Example 1

[0084] The only difference from Example 1 is that step (1) is adjusted as follows: the pH of the 40 mg / mL chickpea protein solution is adjusted to 8, and then a 4 mg / mL carrageenan solution is added in a volume ratio of 1:1 and evenly mixed, and heated in an 80°C water bath for 20 h. After the reaction is completed, the mixture is cooled to room temperature in an ice-water mixture; the cooled reaction product is centrifuged at 8500 g for 20 min to remove insoluble and unreacted aggregates, and the supernatant is frozen in a -22°C refrigerator for 24 h, and then vacuum freeze-dried (-80°C, 200 Pa) for 48 h to obtain a protein-polysaccharide conjugate; other parameters and conditions are the same as in Example 1.

[0085] Comparative Example 2

[0086] The only difference from Example 1 is that step (1) is adjusted as follows: 40 mg / mL chickpea protein solution and 4 mg / mL carrageenan solution are directly and evenly mixed in a volume ratio of 1:1, and the resulting solution is used as the aqueous phase; other parameters and conditions are the same as in Example 1.

[0087] Comparative Example 3

[0088] The only difference from Example 1 is that the pH of the 40 mg / mL chickpea protein solution is adjusted to 8, ultrasonicated at 400 W for 30 min, and directly used as the aqueous phase. Other parameters and conditions are the same as those in Example 1.

[0089] Comparative Example 4

[0090] The only difference from Example 1 is that the Litsea cubeba oil in step (2) is omitted, and other parameters and conditions are the same as those in Example 1.

[0091] Example 6

[0092] A method for improving the gel properties and freeze-thaw stability of an emulsified surimi product, comprising the following steps:

[0093] (1) Thawing the frozen surimi, cutting it into small pieces, and blending it for 3 minutes, adding 2.5% by weight of salt and blending it for 3 minutes, and adjusting the moisture content to 80% to form a surimi paste;

[0094] (2) Add the highly stable high internal phase emulsion prepared in Example 1 in 0%, 5%, 10% and 15% by mass (based on the total mass of the fish paste) to the fish paste prepared in step (1), continue chopping and blending for 5 minutes, then fill into sausage casings with a diameter of 25 mm, gel at 40°C for 30 minutes, and then heat and mature at 90°C for 20 minutes.

[0095] Comparative Example 5

[0096] The only difference from Example 6 is that the highly stable high internal phase emulsion in step (2) is replaced by adding 5%, 10% and 15% corn oil respectively. Other parameters and conditions are the same as those in Example 6.

[0097] Result determination

[0098] 1. The interfacial tension of the proteins prepared in Example 1 and Comparative Examples 1, 3 and 4 was measured. The results are as follows: Figure 2 As shown:

[0099] from Figure 2 It can be seen that compared with Comparative Example 3, the glycosylation with polysaccharides in Comparative Example 1 resulted in a significant decrease in the interfacial tension of the chickpea protein, and the interfacial tension of the modified protein prepared by ultrasonic-assisted wet heating in Example 1 was the smallest. After ultrasonic treatment, the dense areas of the chickpea protein were more expanded, the internal hydrophobic groups of the protein were more exposed, the protein and polysaccharide molecules were more easily grafted, and finally the yield of glycosylation increased. In addition, more anionic polysaccharides will adhere to the chickpea protein, which can increase the viscoelasticity of the interface layer and reduce the interfacial tension of the aqueous phase and oil phase interface. In addition, compared with Comparative Example 4, Example 1 proves that adding flavor oils to the oil phase can effectively reduce the oil / water interfacial tension of the protein.

[0100] 2. The properties of the emulsions prepared in Example 1 and Comparative Examples 1 to 3 were measured. Figure 3 As shown:

[0101] Figure 3 It is the droplet distribution diagram of the high internal phase emulsion of Example 1 and Comparative Examples 1-3. As can be seen from the results in the figure, the high internal phase emulsion (Comparative Example 3) stabilized by using only chickpea protein has the largest particle size, and directly adding carrageenan (Comparative Example 2) does not improve the particle size of the emulsion, and makes the particle size distribution more uneven. After ultrasonic-assisted heating and glycosylation, the structure of chickpea protein molecules at the interface is rearranged and its interfacial activity is improved, so the particle size of the high internal phase emulsion stabilized by the glycosylated modified protein is significantly reduced and distributed more evenly. In addition, the interfacial tension of the protein solution in the mixed oil / water of Litsea cubeba oil and rapeseed oil is small, so the particle size of the high internal phase emulsion prepared based on the mixed oil is significantly reduced.

[0102] 3. Freeze-thaw stability test of the high internal phase emulsions prepared in Examples 1 to 5 and Comparative Examples 1 to 4

[0103] Table 1. Oil loss rate of high internal phase emulsions of Examples 1-5 and Comparative Examples 1-4 after multiple freeze-thaw cycles

[0104]

[0105] As can be seen from the results in Table 1, the direct addition of carrageenan (Comparative Example 2) can improve the viscoelasticity of the high internal phase emulsion, but there is no significant improvement in the freeze-thaw stability because the properties of the protein at the interface are not changed, and the freeze-thaw stability of HIPEs is mainly related to the stability of the interfacial layer. Examples 1-3 and Comparative Example 1 illustrate that the freeze-thaw stability of the high internal phase emulsion stabilized by glycosylated chickpea protein is significantly improved because the glycosylated protein can form a thicker layer around the oil droplets, which can provide a smaller droplet size and minimize aggregation. The conjugate prepared with the assistance of ultrasound (Example 1) forms a thicker interfacial film around the oil droplets than the conjugate prepared by wet heat alone (Comparative Example 1), and provides them with better steric hindrance, thereby preventing the oil droplets from aggregating after freeze-thaw cycles. In addition, the addition of Litsea cubeba oil, Zanthoxylum bungeanum oil and Sichuan pepper oil (Examples 1, 3 and 4) further reduced the oil loss of the high internal phase emulsion during freeze-thaw, where the flavor compounds in the flavor oils can combine with the hydrophobic groups of the interfacial proteins to form a more stable interfacial layer, reducing the damage of ice crystals to the emulsion droplets during the freezing process.

[0106] Table 2. Retention rate of citral, the main flavoring substance in Litsea cubeba oil, after multiple freeze-thaw cycles

[0107]

[0108]

[0109] As can be seen from the results in Table 2, Example 1, which has better freeze-thaw stability, can effectively retain citral, because after the emulsion leaks oil, more citral comes into direct contact with oxygen, resulting in the loss of volatile substances.

[0110] 4. Freeze-thaw stability test of the surimi products prepared in Example 6 and Comparative Example 5

[0111] Table 3. Freeze-thaw stability of surimi products prepared in Example 6 and Comparative Example 5

[0112]

[0113] The results in Table 3 show that, compared with the direct addition of vegetable oil (Comparative Example 5), the addition of a high internal phase emulsion (Example 6) reduced the deterioration in gel strength of the surimi product. This is because the chickpea high internal phase emulsion produces evenly distributed small oil droplets that occupy the interstices of the surimi gel matrix. The chickpea protein cross-links with myosin during heating, and the oil droplets act as active fillers, enhancing the gelling properties of the surimi, thereby forming a denser gel network structure.

[0114] Juice loss is an important indicator for evaluating the freeze-thaw stability of high-moisture emulsified surimi gels, directly impacting product quality and consumer acceptance. Table 3 shows the thaw loss of surimi products containing oil and chickpea-based high internal phase emulsions during freeze-thaw cycles. The water loss of all samples increased significantly with increasing freeze-thaw cycles (P < 0.05). This can be attributed to ice crystal formation and recrystallization, which stretches and squeezes the gel network, resulting in deformation that cannot be fully recovered during frozen storage. The larger the pore size of the gel, the less water can be reabsorbed by the gel matrix, resulting in a decrease in water holding capacity and, consequently, an increase in freeze-thaw loss. When the high internal phase emulsion was added at 5%, the surimi exhibited the lowest thaw water loss of all samples (1.40%), corresponding to the highest water holding capacity. Surimi products supplemented with 5% and 10% oil and HIP emulsion experienced juice losses of 2.78%, 3.18%, 1.40%, and 2.54% after three freeze-thaw cycles, respectively. This indicates that the HIP emulsion, which exhibits high freeze-thaw stability, improves the freeze-thaw stability of the surimi gel. Emulsions with high freeze-thaw stability have a lower freezing point than water. Therefore, surimi products supplemented with HIP emulsion exhibit fewer ice crystals and smaller particles during freezing. This reduces internal structural damage and minimizes changes in water distribution during freeze-thaw cycles, thus improving the freeze-thaw stability of the surimi.

[0115] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge are also within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a chickpea protein-based high internal phase emulsion with high freeze-thaw stability based on interface regulation, characterized in that: The method comprises the following steps: (1) adjusting the pH of a chickpea protein solution to 8-9, ultrasonically treating the solution, then adding a polysaccharide solution and uniformly mixing the solution, heating the solution in a water bath for reaction, centrifuging the reaction product after the reaction, and freeze-drying the supernatant to obtain a protein-polysaccharide conjugate; dissolving the obtained protein-polysaccharide conjugate in water as an aqueous phase; wherein the polysaccharide solution is one or more of a carrageenan solution, a flaxseed gum solution, and a low-acyl gellan gum solution; (2) Mixing flavor oil and vegetable oil and stirring evenly to form the oil phase; (3) The aqueous phase prepared in step (1) and the oil phase prepared in step (2) are mixed in a volume ratio of 1:4 and sheared at high speed to obtain a high internal phase emulsion with high freeze-thaw stability.

2. The method according to claim 1, characterized in that The ultrasonic conditions in step (1) are: power of 300-500W, and time of 20-40min.

3. The method according to claim 1, characterized in that The concentration of the protein-polysaccharide conjugate in the aqueous phase of step (1) is 20 to 40 mg / mL.

4. The method according to claim 1, wherein The flavor oil in step (2) is one or more of Litsea cubeba oil, Zanthoxylum bungeanum oil and Sichuan pepper oil.

5. The method according to claim 1, wherein The mass ratio of the flavor oil to the vegetable oil in step (2) is 1:

4.

6. A high internal phase emulsion with high freeze-thaw stability prepared by the method according to any one of claims 1 to 5.

7. Use of the high internal phase emulsion with high freeze-thaw stability according to claim 6 in the field of food preparation.

8. A method for improving the gel properties and freeze-thaw stability of emulsified surimi products, characterized in that: The method comprises the following steps: 1) Thaw the frozen surimi, cut it into small pieces, add salt and blend, and then adjust the moisture content to 75-80% to form surimi paste; 2) Adding 5-15% of the high freeze-thaw stability high internal phase emulsion prepared according to any one of claims 1 to 5 to the surimi paste prepared in step 1), based on the total mass of the surimi paste, continuing to chop and blend, and then filling into sausage casings, gelling, and heating and maturing.

9. The method according to claim 8, characterized in that In step 2), the amount of the high internal phase emulsion with high freeze-thaw stability added is 5% based on the total mass of the surimi paste.

10. A surimi product obtained by the method according to claim 8 or 9.

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