A low-fat high-protein blueberry emulsion, and a preparation method and application thereof

Abstract

The application discloses a low-fat high-protein emulsion of aronia melanocarpa and a preparation method and application thereof. The low-fat high-protein emulsion of aronia melanocarpa is of a core-shell structure, and the preparation method comprises the following steps: (1) infrared heating pretreatment of aronia melanocarpa with shells; (2) preparation of aronia melanocarpa oil bodies; (3) preparation of aronia melanocarpa oil body dispersion system; shear homogenization, so as to obtain the aronia melanocarpa oil body dispersion system; and (4) formation of the low-fat high-protein emulsion: slowly adding a calcium chloride solution into the aronia melanocarpa oil body dispersion system, and stirring, so as to obtain the aronia melanocarpa low-fat high-protein emulsion stabilized by oil body protein@XG. The emulsion preparation method can effectively retain the nutritional components of the oil body raw material while reducing the oil content, provides high-quality intermediate raw materials for preparing healthy low-fat beverages and functional foods, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of health food processing, and particularly relates to a low-fat, high-protein pecan emulsion based on infrared pretreatment and oil protein @XG stabilization, its preparation method, and its application. Background Technology

[0002] Oil bodies are widely present in the seed cells of oilseed plants. Their structure consists of a neutral lipid core and a phospholipid-protein complex membrane, forming a natural oil-in-water pre-emulsion structure. In recent years, they have attracted widespread attention and have been applied in emulsion systems in food, cosmetics, and pharmaceuticals. In the food industry, oil bodies can serve as a natural oil phase for constructing oil-in-water emulsion systems, meeting the development needs of naturalized products and showing promising application prospects. However, as a natural pre-emulsion system, oil bodies are susceptible to aggregation, flocculation, or structural rearrangement during actual processing and storage due to factors such as ionic strength, pH value, and changes in system composition. This leads to a decrease in the physical stability of the emulsion, limiting its further application in plant-based milk beverages and other products.

[0003] To improve the physical stability of oils in emulsions, some studies have attempted to introduce polysaccharides, such as xanthan gum (XG), to inhibit flocculation by enhancing the viscosity of the continuous phase or creating steric hindrance between oil droplets. However, in practical applications, while adding xanthan gum alone can increase the viscosity of the system and delay oil droplet migration to some extent, its binding force with the oil interface is limited due to its non-adsorbent anionic polysaccharide nature. It mainly relies on the thickening effect of the continuous phase and is difficult to form a stable interfacial structure on the oil droplet surface. Therefore, it is still prone to stratification or structural instability during long-term storage.

[0004] Pecans (Carya illinoinensis) are rich in 17 amino acids, including 8 essential amino acids such as tryptophan. Lysine is the first limiting amino acid, and essential amino acids account for about 30% of the total, conforming to the FAO / WHO recommended essential amino acid pattern for adults, thus possessing high nutritional value. Furthermore, pecan protein is rich in functional amino acids such as tryptophan and glutamic acid. Tryptophan, as a precursor to serotonin, plays a positive role in mood regulation, stress relief, and sleep improvement in the nervous system. Pecans are also rich in unsaturated fatty acids, dietary fiber, and minerals, and are widely used in snack foods, baked goods, and vegetable oil processing. However, traditional utilization methods mainly focus on high-fat products, resulting in relatively limited product forms. In recent years, with consumers' increasing focus on healthy eating and the concept of holistic health, low-fat, natural, and clean-label plant-based milk beverages have gradually become a research hotspot. Against this backdrop, developing stable low-fat plant-based milk beverages based on the endogenous lipid structure of pecans not only aligns with the trend of healthy consumption but also has promising market prospects. Currently, low-fat plant-based beverages often use methods such as pressing, solvent extraction, or physical centrifugation to reduce the fat content of raw materials. These methods have certain limitations: pressing or solvent extraction often damages the original lipid microstructure, easily leading to the loss of fat-soluble nutrients and potentially causing solvent residue; simple centrifugation mainly relies on density differences to remove oil, making it difficult to precisely control the degree of lipid removal and easily causing the synergistic loss of proteins and functional components in the system. Furthermore, while traditional high-pressure homogenization or strong mechanical shearing can improve dispersibility, it consumes a lot of energy and may cause irreversible damage to the natural interface structure, affecting the stability of subsequent emulsions.

[0005] Therefore, it is necessary to establish a technical solution that combines lipid-lowering effects, physical stability, and nutritional health properties from the perspective of oil body structure regulation and interface construction. This invention first pre-treats pecans using infrared spectroscopy to partially disrupt the oil body structure under controlled conditions, promoting the release of some oils and thus regulating and reducing fat content. Subsequently, combining pulping, enzymatic hydrolysis, and centrifugation processes, some free oils are removed and the system components are reconstructed, forming a low-fat oil body dispersion system while preserving as many beneficial interfacial components as possible. Based on this, xanthan gum and calcium ions are introduced. Calcium ions construct an ionic bridging structure between negatively charged xanthan gum molecules and the oil body interface, forming a stable "calcium bridge" network. This coats the oil body surface with a layer of xanthan gum, constructing a core-shell structure (oil body protein@XG), enhancing the interfacial layer structural strength and the three-dimensional support of the system, and improving the emulsion's anti-flocculation and anti-stratification capabilities. In addition to meeting stability requirements, the resulting emulsion can also serve as a dietary calcium source, helping to supplement the body's daily mineral needs. The xanthan gum in the emulsion can be gradually added to the diet as a prebiotic to improve gut microbiota, enhancing the product's health benefits. This technology achieves a synergistic improvement in low-fat content and long-term stability while preserving the natural nutrients of pecans, providing a new technology for the preparation of low-fat, high-protein plant-based milk beverages. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention employs mid-infrared radiation treatment to pretreat pecans, partially disrupting the oil structure and promoting the release of some oils. Subsequently, through pulping, enzymatic hydrolysis, and centrifugation, free oils and insoluble residues are removed, while the aqueous phase and relatively intact oil components are retained to construct a low-fat emulsion system. Furthermore, xanthan gum and calcium ions are introduced. Calcium ions form ionic bridges between negatively charged xanthan gum molecules and the oil interface, creating a "calcium bridge" network that enhances the interfacial layer strength and the three-dimensional support of the system, improving the emulsion's dispersion uniformity and storage stability. Through this technical solution, this invention achieves synergistic regulation of gentle infrared deoiling, natural nutrient retention, and emulsion stability, providing a novel method combining structural regulation and interfacial strengthening for the preparation of low-fat pecan milk beverages.

[0007] To achieve the above and other related objectives, the present invention provides the following technical solution: a method for preparing a low-fat, high-protein pecan emulsion, characterized by comprising the following steps:

[0008] Step 1: Infrared pretreatment of pecans

[0009] Fresh pecans with shells are heated at a mid-infrared power of 600-700W for 3.0-4.5 minutes to remove the shells and obtain pecan kernels.

[0010] Step 2: Preparation of pecan oil

[0011] Take pecan kernels, mix them with water at a mass ratio of 1:8-9 and grind them for 2-3 minutes to obtain pecan pulp; add 0.05-0.15 w / v % neutral protease to the pecan pulp, and enzymatically hydrolyze it for 1.5-2.5 hours at a pH of 6.5-7.0 and a temperature of 50-55 ℃, then inactivate the enzyme, and subsequently collect the aqueous phase and pecan oil body separately;

[0012] Step 3: Preparation of Pecan Oil Dispersion System

[0013] A portion of the aqueous phase and the pecan oil are mixed at a ratio of 3-5:1 to form an oil dispersion. Simultaneously, xanthan gum is added to the remaining aqueous phase at a concentration of 0.06-0.1 w / v %, and the mixture is stirred evenly at 50-55°C to obtain a xanthan gum solution. Under stirring conditions, the oil dispersion is added to the xanthan gum solution and mixed evenly. The mixture is then sheared at a speed of 12000-15000 rpm for 2-4 min to obtain the pecan oil dispersion system.

[0014] Step 4: Formation of low-fat, high-protein emulsion

[0015] Prepare a 50-100 mM calcium chloride solution using deionized water; add the calcium chloride solution to the pecan oil dispersion system under magnetic stirring and room temperature conditions, so that the concentration of calcium ions in the system is 1.8-2.2 mM, and continue stirring for 30-40 minutes to obtain a low-fat, high-protein pecan emulsion.

[0016] The preferred technical solution is that the color of the pecan meets the numerical ranges of brightness, red-green difference, and yellow-blue difference of 40-60, -5-10, and 20-30, respectively.

[0017] The preferred technical solution is that, in step 2, the centrifugation process conditions are: centrifugation at 8000-12000 rpm for 20-30 min.

[0018] The preferred technical solution is characterized in that, in step 1, the mid-infrared power is 700 W and the heating treatment time is 3.5 min.

[0019] The preferred technical solution is characterized in that, in step 2, the centrifugation process conditions are: centrifugation at 8000-12000 rpm for 20-30 min.

[0020] The preferred technical solution is characterized in that, in step 3, the concentration of xanthan gum is 0.08 w / v.

[0021] The preferred technical solution is characterized in that, in step 4, the concentration of calcium ions is 2.0 mM.

[0022] To achieve the above and other related objectives, the present invention provides the following technical solution: The pecan low-fat high-protein emulsion prepared by the method described above is characterized in that the emulsion has a core-shell structure, wherein the core is an oil body, the shell is coated with xanthan gum molecules, and the core and shell are connected by Ca²⁺ ions to form a stable interface.

[0023] To achieve the above and other related objectives, the present invention provides the following technical solution: the application of the pecan low-fat high-protein emulsion prepared by the method described above, characterized in that: the pecan low-fat high-protein emulsion remains stable under pH 5-9 and temperature 4-50℃ conditions, and is used as a base material for low-fat dairy beverages, plant-based functional beverages, and flavored dairy products.

[0024] To achieve the above and other related objectives, the present invention provides the following technical solution: The pecan low-fat high-protein emulsion prepared by the method described above is characterized in that the emulsion has a core-shell structure, wherein the core is an oil body, the shell is coated with xanthan gum molecules, and the core and shell are connected by Ca²⁺ ions to form a stable interface.

[0025] To achieve the above and other related objectives, the present invention provides the following technical solution: the application of the pecan low-fat high-protein emulsion prepared by the method described above, characterized in that: the pecan low-fat high-protein emulsion remains stable under pH 5-9 and temperature 4-50℃ conditions, and is used as a base material for low-fat dairy beverages, plant-based functional beverages, and flavored dairy products.

[0026] Beneficial effects

[0027] (1) This invention achieves controlled partial destruction of pecan oil through mid-infrared treatment, releasing some of the oil which is then removed by subsequent separation, thereby achieving gentle lipid reduction without solvent extraction or high-intensity mechanical degreasing. This method avoids the excessive damage to lipid microstructure and fat-soluble nutrients caused by traditional pressing or solvent degreasing, and is conducive to preserving unsaturated fatty acids, proteins and other active ingredients in pecans, achieving a synergistic effect of lipid reduction and nutrient retention;

[0028] (2) In constructing the emulsion system, the present invention introduces xanthan gum and calcium ions. Through the formation of ion bridging structure between negatively charged xanthan gum molecules and oil body proteins by calcium ions, a stable "calcium bridge" network is constructed. A layer of xanthan gum is coated on the surface of the oil body to construct a core-shell structure (oil body protein@XG). This structure not only enhances the structural strength of the oil body interface layer, but also improves the overall three-dimensional support of the system, significantly improves the dispersion uniformity and anti-flocculation and anti-stratification ability of the emulsion, and enables the emulsion to maintain a stable state during long-term storage.

[0029] (3) This invention combines infrared mild degreasing technology with ion bridging stabilization mechanism to achieve synergistic design of lipid regulation and interface enhancement, which not only reduces the oil content of the emulsion system, but also avoids the problem of insufficient stability caused by simply relying on thickeners. The resulting low-fat pecan emulsion has a stable structure, a relatively simple process, and does not require the addition of synthetic emulsifiers. It is in line with the development trend of naturalization and clean labeling, and has good industrial application prospects and promotion value. Attached Figure Description

[0030] Figure 1 Laser confocal microscopy images of the pecan oil emulsions prepared in Examples 1-3 and Comparative Example 1.

[0031] Figure 2 The rheological properties of pecan oil emulsions prepared in Examples 1 and 4-7 and Comparative Examples 2-4.

[0032] Figure 3 The contact angle of the pecan oil emulsions prepared in Example 1 and Comparative Examples 2-4 is shown.

[0033] Figure 4 Laser confocal microscopy images of the pecan oil emulsions prepared in Example 1 and Comparative Examples 2-4.

[0034] Figure 5 Atomic force microscopy images of the pecan oil emulsions prepared in Example 1 and Comparative Examples 2-4.

[0035] Figure 6 Fourier transform infrared (a) and XPS spectra (full spectrum (b), C1s fine spectrum (c), O1s fine spectrum (d)) of pecan oil emulsions prepared in Examples 1 and Comparative Examples 2-4.

[0036] Figure 7 Comparison of appearance during storage of the low-fat, high-protein pecan beverage prepared for Test Example 1.

[0037] Figure 8 The structure of the pecan low-fat, high-protein emulsion of the present invention is shown below.

[0038] Figure 9 This is a process flow diagram of the present invention. Detailed Implementation

[0039] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand other advantages and effects of the present invention from the content disclosed in these embodiments.

[0040] Please see Figures 1-7It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effectiveness or purpose of the invention, should fall within the scope of the disclosed technical content. The following embodiments are provided to better understand the invention, but are not intended to limit it. Unless otherwise specified, the experimental materials used in the following embodiments were purchased from conventional consumables and biochemical reagent stores.

[0041] Example 1: A low-fat, high-protein pecan emulsion based on infrared pretreatment and oil body protein@XG stabilization, its preparation method, and its application.

[0042] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0043] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0044] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them at a ratio of 4:1 to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.08% (w / v) to the remaining aqueous phase, and stir evenly at 50-55 ℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0045] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.0 mM, and continue stirring for 30-40 minutes to obtain an oil protein@XG stabilized pecan low-fat, high-protein emulsion.

[0046] The technical solution adopted in this invention is as follows: Pecans are heated with mid-infrared radiation, shelled, mixed with water, and ground to obtain pecan pulp; the pecan pulp is enzymatically hydrolyzed and centrifuged to obtain an aqueous phase and pecan oil; a portion of the aqueous phase is mixed with the pecan oil to form an oil dispersion; xanthan gum is added to the remaining aqueous phase to prepare a xanthan gum solution; under magnetic stirring and room temperature conditions, the oil dispersion is added to the xanthan gum solution, mixed evenly, and sheared to obtain a pecan oil emulsion; an appropriate amount of anhydrous calcium chloride is weighed and mixed with deionized water to prepare a calcium chloride solution; under magnetic stirring and room temperature conditions, the calcium chloride solution is slowly added to the pecan oil emulsion to construct a "calcium bridge" between the xanthan gum and the oil, and stirring is continued for 35 minutes to obtain a low-fat, high-protein pecan oil emulsion stabilized by oil protein @XG.

[0047] The structure of the pecan low-fat, high-protein emulsion of the present invention is as follows: Figure 8 As shown.

[0048] Example 2: A low-fat, high-protein pecan emulsion based on infrared pretreatment and oil body protein@XG stabilization, its preparation method, and its application.

[0049] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.0 min, and remove the shells to obtain pecan kernels.

[0050] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0051] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them at a ratio of 4:1 to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.08% (w / v) to the remaining aqueous phase, and stir evenly at 50-55 ℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0052] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.0 mM, and continue stirring for 30-40 minutes to obtain an oil protein@XG stabilized pecan low-fat, high-protein emulsion.

[0053] Example 3: A low-fat, high-protein pecan emulsion based on infrared pretreatment and oil body protein@XG stabilization, its preparation method, and its application.

[0054] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 4.0 min, and remove the shells to obtain pecan kernels.

[0055] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0056] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them at a ratio of 4:1 to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.08% (w / v) to the remaining aqueous phase, and stir evenly at 50-55 ℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0057] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.0 mM, and continue stirring for 30-40 minutes to obtain an oil protein@XG stabilized pecan low-fat, high-protein emulsion.

[0058] Example 4: A low-fat, high-protein pecan emulsion based on infrared pretreatment and oil body protein@XG stabilization, its preparation method, and its application.

[0059] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0060] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0061] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them in a 4:1 ratio to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.06% (w / v) to the remaining aqueous phase, and stir evenly at 50-55 ℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0062] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.0 mM, and continue stirring for 30-40 minutes to obtain an oil protein@XG stabilized pecan low-fat, high-protein emulsion.

[0063] Example 5: A low-fat, high-protein pecan emulsion based on infrared pretreatment and oil body protein@XG stabilization, its preparation method, and its application.

[0064] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0065] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0066] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them in a 4:1 ratio to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.1% (w / v) to the remaining aqueous phase, and stir evenly at 50-55℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0067] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.0 mM, and continue stirring for 30-40 minutes to obtain an oil protein@XG stabilized pecan low-fat, high-protein emulsion.

[0068] Example 6: A low-fat, high-protein pecan emulsion based on infrared pretreatment and oil body protein@XG stabilization, its preparation method, and its application.

[0069] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0070] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0071] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them at a ratio of 4:1 to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.08% (w / v) to the remaining aqueous phase, and stir evenly at 50-55 ℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0072] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 1.8 mM, and continue stirring for 30-40 minutes to obtain a low-fat, high-protein pecan emulsion with oil protein@XG stability.

[0073] Example 7: A low-fat, high-protein pecan emulsion based on infrared pretreatment and oil body protein@XG stabilization, its preparation method, and its application.

[0074] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0075] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0076] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them at a ratio of 4:1 to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.08% (w / v) to the remaining aqueous phase, and stir evenly at 50-55 ℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0077] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.2 mM, and continue stirring for 30-40 minutes to obtain a low-fat, high-protein pecan emulsion with oil protein@XG stability.

[0078] Comparative Example 1

[0079] The only difference between this comparative example and Example 1 is that mid-infrared treatment is not performed. The preparation method of the pecan oil emulsion in this comparative example includes the following steps:

[0080] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30 respectively, and remove the shells to obtain pecan kernels.

[0081] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0082] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them at a ratio of 4:1 to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.08% (w / v) to the remaining aqueous phase, and stir evenly at 50-55 ℃ to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0083] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.0 mM, and continue stirring for 30-40 minutes to obtain an oil protein@XG stabilized pecan low-fat, high-protein emulsion.

[0084] Comparative Example 2

[0085] The only difference between this comparative example and Example 1 is that calcium ions and xanthan gum are not added. The preparation method of the pecan oil emulsion in this comparative example includes the following steps:

[0086] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0087] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0088] Step 3: Formation of low-fat, high-protein emulsion: Take a portion of the aqueous phase and the pecan oil body, mix them in a 4:1 ratio to form an oil dispersion; under stirring conditions, add the oil dispersion to the remaining aqueous phase and mix evenly, and shear at 13000 rpm for 3.0 min to obtain a low-fat, high-protein emulsion.

[0089] Comparative Example 3

[0090] The only difference between this comparative example and Example 1 is that xanthan gum is not added. The preparation method of the pecan oil emulsion in this comparative example includes the following steps:

[0091] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0092] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0093] Step 3: Preparation of pecan oil dispersion: Take a portion of the aqueous phase and the pecan oil, mix them in a ratio of 4:1 to form an oil dispersion; under stirring conditions, add the oil dispersion to the remaining aqueous phase and mix evenly, and shear at 13000 rpm for 3.0 min to obtain the pecan oil dispersion.

[0094] Step 4: Formation of low-fat, high-protein emulsion: Weigh anhydrous calcium chloride and prepare a 100 mM calcium chloride solution with deionized water; under magnetic stirring and room temperature conditions, slowly add the calcium chloride solution to the pecan oil dispersion system to make the calcium ion concentration in the system 2.0 mM, and continue stirring for 30-40 minutes to obtain a low-fat, high-protein pecan emulsion.

[0095] Comparative Example 4

[0096] The only difference between this comparative example and Example 1 is that calcium ions are not added. The preparation method of the pecan oil emulsion in this comparative example includes the following steps:

[0097] Step 1: Infrared pretreatment of pecans: Select fresh pecans with shells whose color matches the range of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) values ​​of 40-60, -5-10, and 20-30, respectively. Heat the pecans at a mid-infrared power of 700W for 3.5 min, and remove the shells to obtain pecan kernels.

[0098] Step 2: Preparation of pecan oil: Take pecan kernels, mix them with water at a mass ratio of 1:9 and grind for 2.5 min to obtain pecan pulp; add 0.1% (w / v) neutral protease to the pecan pulp, and enzymatically hydrolyze for 2 hours at pH 6.5-7.0 and temperature 50-55 ℃, then inactivate the enzyme in a water bath at 95 ℃ for 20 min, and then centrifuge at 10000 rpm for 25 min to collect the aqueous phase and pecan oil separately;

[0099] Step 3: Formation of low-fat, high-protein emulsion: Take a portion of the aqueous phase and the pecan oil, mix them in a 4:1 ratio to form an oil dispersion; simultaneously, add xanthan gum at a concentration of 0.08% (w / v) to the remaining aqueous phase, and stir evenly at 50-55°C to obtain a xanthan gum solution; under stirring conditions, add the oil dispersion to the xanthan gum solution and mix evenly, and shear at 13000 rpm for 3.0 min to obtain a low-fat, high-protein emulsion;

[0100] 1. The emulsions prepared in Examples 1-7 and Comparative Examples 1-4 were diluted with phosphate buffer (0.01 M, pH 7.0) at a volume ratio of 1:100, and their particle size and zeta potential were determined using a Zetasizer Nano-ZSE (Malvern Panalytical Ltd., Worcestershire, UK). The protein content and fat content of the emulsions were determined according to the Kjeldahl method specified in GB 5009.5-2025 "National Food Safety Standard - Determination of Protein in Food" and the Soxhlet extraction method specified in GB 5009.6-2025 "National Food Safety Standard - Determination of Fat in Food". The results are shown in Table 1.

[0101] Table 1. Particle size, potential, PDI, protein content, and oil content of pecan oil emulsions obtained in Examples 1-12 and Comparative Examples 1-4.

[0102]

[0103] As shown in Table 1, the low-fat, high-protein pecan emulsions prepared in Examples 1-7 of this invention exhibited good uniformity and dispersibility in terms of particle size, electrostatic potential, and PDI. The particle size of the emulsions in these examples was all within the range of 4.40–6.0 μm, with generally low PDI values ​​and electrostatic potentials ranging from -34.60 to -43.78 mV, indicating good electrostatic stability. The protein content was maintained at 3.04–4.38 wt%, and the fat content at 2.65–5.95 wt%. In contrast, Comparative Examples 1-4 exhibited larger particle sizes, higher PDI values, and lower electrostatic potentials, indicating lower emulsion stability. Furthermore, compared to Comparative Example 1, the fat content of the other samples was significantly reduced, indicating that infrared treatment can effectively control the fat content of the emulsion.

[0104] 2. Samples of the low-fat, high-protein pecan oil emulsions prepared in Examples 1-3 were taken and stained with 0.1% (w / v) Nile Red and fluorescein isothiocyanate (FITC). The microstructure of the oils was observed using a laser confocal microscope (Leica TCSSP8, Germany), and compared with Comparative Example 1. The results are shown in [Figure 1]. Figure 1 .

[0105] Depend on Figure 1 Laser confocal microscopy images of emulsions under different infrared treatment times (red represents lipid phase, green represents protein) show that lipid particles are more densely distributed in Comparative Example 1, with obvious aggregation in some areas. As the infrared treatment time increases, the number of lipid particles in the system gradually decreases, indicating that infrared treatment promotes the release and removal of some oils, reduces the lipid content of the system, and improves the spatial distribution of oil bodies.

[0106] 3. Rheological properties of the low-fat, high-protein pecan oil emulsion samples prepared in Examples 2 and 4-7 were determined. Two ml of the sample was spread evenly on the test platform of the rheometer. A clamp with a diameter of 40 mm was selected, and the gap between the test platform and the clamp was set to 1000 μm. Frequency scanning tests were conducted under the conditions of a strain of 0.5% and a frequency range of 0.1-10 Hz, with a duration of 0.01-100 s⁻¹. −1 Apparent viscosity was measured within the shear rate range and compared with Comparative Examples 2-4. The results are shown in [Figure number missing]. Figure 2 .

[0107] like Figure 2 As shown in Figure a, the pecan oil emulsion of this invention exhibits typical pseudoplastic fluid characteristics, i.e., its viscosity gradually decreases with increasing shear rate. The pecan oil emulsions of Comparative Examples 2, 3, and 4 have low low-shear viscosity, poor dispersibility, and are prone to stratification; however, after introducing xanthan gum and calcium ions in the examples, the low-shear viscosity of the emulsions is significantly higher than that of the comparative examples, with Example 1 showing the highest viscosity, indicating the successful formation of "calcium bridges" and a significant improvement in the structural stability and anti-stratification properties of the emulsion. Figure 2 As shown in b and c of 2, the pecan oil emulsions of Comparative Examples 2 and 3 have low storage modulus (G') and loss modulus (G''), indicating that the system is predominantly viscous and lacks a stable network structure. Comparative Example 4 shows a slight improvement, but it is still weak, indicating that the gel structure formed by xanthan gum alone has limited strength. In contrast, the emulsions of Examples 1–7 all show an increase in modulus and exhibit elastic gel characteristics (G' > G'') across the entire frequency range, indicating that the system has transformed from a viscous-dominant liquid state to an elastically-dominant gel state, significantly enhancing the stability of the emulsion network structure.

[0108] 4. Contact angle measurements were performed on the low-fat, high-protein pecan oil emulsion samples prepared in Example 1 and Comparative Examples 2-4, respectively. After lyophilizing the emulsion samples, the powder was compressed into tablets using an MP-1 micro tablet press, and the results were measured using a contact angle meter (Model: Dataphysics OCA15EC, Germany). A 2 μL droplet of water was suspended at the tip of a syringe needle, adjusted downwards to contact the dry tablet surface, and an image was captured using a camera. The results are shown in [Figure number missing]. Figure 3 .

[0109] like Figure 3 As shown, the water contact angle of Comparative Example 2 was 87.4°, close to the hydrophobic threshold, indicating that the oil surface was mainly composed of hydrophobic proteins; the contact angle of Comparative Example 3 decreased slightly to 84.5°, with limited improvement in hydrophilicity; the contact angle of Comparative Example 4 decreased significantly to 73.6°, indicating that xanthan gum adsorption enhanced surface hydrophilicity. The contact angle of Example 6 further decreased to 66.0°, showing that calcium bridge crosslinking promoted the dense arrangement of xanthan gum on the oil surface, forming a surface layer rich in hydrophilic groups, which significantly improved interfacial wettability.

[0110] 5. Low-fat, high-protein pecan oil emulsion samples prepared in Example 1 and Comparative Examples 2-4 were observed using a laser confocal microscope (model: Leica TCS SP8, Germany). The samples were stained with 0.1% (w / v) Nile Red and fluorescent brightener 28. The microstructure of the emulsions was observed using a laser confocal microscope. The results are shown in [Figure number missing]. Figure 4 .

[0111] like Figure 4 As shown, red fluorescence represents the oil phase, and blue fluorescence represents xanthan gum. In Comparative Example 2, the oil droplets are unevenly distributed, with some droplets being larger, resulting in an unstable interfacial structure. After the addition of Ca²⁺, the oil droplets significantly aggregated, exhibiting an irregular flocculated structure, and the emulsion stability decreased. In Comparative Example 4, the oil droplet size decreased and the distribution became more uniform. Xanthan gum formed a spatial network at the oil interface, providing effective steric hindrance. In the examples, when xanthan gum and Ca²⁺ were present simultaneously, the oil droplet distribution was the most uniform, and the fluorescence highly overlapped, indicating that calcium bridges promote polysaccharide cross-linking, forming a dense and stable three-dimensional network at the oil interface, effectively inhibiting droplet aggregation and stratification.

[0112] 6. The low-fat, high-protein pecan oil emulsion samples prepared in Example 1 and Comparative Examples 2-4 were observed using an atomic force microscope (AFM) (model: Bruker Dimension Icon, USA). The emulsion was dropped onto a mica sheet, rinsed with ultrapure water, and dried with nitrogen. Images of the samples were taken using an AFM; the results are shown in the figure. Figure 5 .

[0113] like Figure 5 As shown, atomic force microscopy (AFM) surface morphology analysis revealed the influence of calcium ions and xanthan gum on the interfacial structure of pecan oil emulsions at the nanoscale. Surface roughness (Ra) data showed that the Ra value of Comparative Example 2 was 0.860 nm, while the Ra value of Comparative Example 3 increased dramatically to 2.379 nm, with a height fluctuation range of 55 nm. The three-dimensional morphology image showed numerous aggregate protrusions, indicating disordered aggregation of the oil. The Ra value of Comparative Example 4 decreased to 0.301 nm, with a relatively smooth surface, indicating that xanthan gum partially inhibited oil aggregation through steric hindrance. Example 1 achieved the lowest Ra value of 0.138 nm, and the three-dimensional morphology image showed a smooth and uniform surface structure. The Ra value of Example 1 was significantly lower than that of the comparative examples, and this significant surface smoothing effect indicates the uniform dispersion and dense arrangement of oil particles.

[0114] 7. Fourier transform infrared spectroscopy (FTIR) was performed on the low-fat, high-protein pecan oil emulsion samples prepared in Examples 1 and Comparative Examples 2-4 (model: Thermo Nicolet iS50, USA). Attenuated total reflectance (ATR) technology was used for the measurement of the samples. The samples were dropped onto the surface of an ATR crystal, with a test range of 4000 cm⁻¹ to 400 cm⁻¹ and a resolution of 4 cm⁻¹. The results are shown in [Figure number missing]. Figure 6 .

[0115] The infrared spectra of Example 1 and Comparative Examples 2, 3, and 4 are as follows: Figure 6 As shown in Figure a, in the hydroxyl / amino stretching vibration region (3200-3500 cm⁻¹), compared to the comparative example, the characteristic peak of Example 1 blue-shifts to 3421.58 cm⁻¹. This significant blue shift indicates that the addition of xanthan gum and the formation of calcium bridges altered the hydrogen bond network structure in the system, weakening or rearranging some hydrogen bonds, resulting in OH and NH groups being in a more free vibrational state. In the amide I band / carboxyl asymmetric stretching vibration region (1630-1655 cm⁻¹), the characteristic peak of Example 1 red-shifts to 1631.51 cm⁻¹, indicating that calcium ions form coordination bonds with the carboxyl groups (aspartic acid and glutamic acid residues) of the oil body surface protein and the carboxyl groups on the xanthan gum molecular chain through electrostatic interactions, thereby constructing an oil body-Ca²⁺-xanthan gum calcium bridge cross-linking network. In the polysaccharide characteristic region (1000-1100 cm⁻¹), the characteristic peak of Example 1 was blue-shifted to 1026.43 cm⁻¹, indicating that the glycosidic bonds of xanthan gum molecules participated in the construction of the overall molecular network of the system.

[0116] 8. X-ray photoelectron spectroscopy (XPS) was performed on the low-fat, high-protein pecan oil emulsion samples prepared in Example 6 and Comparative Examples 2-4, respectively. The XPS spectra of the samples were measured using an XPS spectrometer (ThermoScientific K-Alpha, USA), with an operating voltage of 12.5 kV and a filament current of 16 mA. The XPS spectra were corrected using C1s = 284, and the data were processed using Advantage software. The results are shown in [Figure number missing]. Figure 6 .

[0117] XPS full-spectrum scans of Example 6 and Comparative Examples 2, 3, and 4 are as follows: Figure 6 As shown in b, C1s, O1s, and N1s characteristic peaks were detected in all samples, corresponding to carbon, oxygen, and nitrogen elements in the oil surface proteins and xanthan gum, respectively. Comparative Example 3 and Example 1 showed distinct Ca2p 3 / 2 and Ca2p 1 / 2 doublets near 347 eV and 351 eV, respectively, confirming the successful introduction and presence of calcium ions in the system. (C1s high-resolution spectrum) Figure 4The peak fitting results of c) show that Example 1 exhibits a new characteristic peak at 289.38 eV, attributed to a calcium carboxylate coordination structure (Ca-COO), while the OC=O peak (289.08 eV) at this position in Comparative Examples 2, 3, and 4 is weaker and shows no significant shift. This demonstrates that calcium ions have undergone coordination reactions with the carboxyl groups on the surface proteins and xanthan gum molecular chains of the oil body, forming a calcium bridge cross-linked structure. O1s high-resolution spectrum ( Figure 4 The peak fitting results (d) show that Example 1 exhibits a significantly enhanced Ca-O characteristic peak at 532.58 eV. The appearance and enhancement of this peak indicate the formation of a stable coordination bond between the calcium ion and the carboxyl oxygen atom. Furthermore, the intensity of the OC=O peak in Example 1 is relatively weaker than that in the comparative example, while the intensity of the Ca-O peak is enhanced. This shift in peak intensity further confirms that some free carboxyl groups are converted into a calcium carboxylate coordination structure.

[0118] Test Example 1: Application of Infrared Pretreatment and Oil-Body Protein@XG Stabilized Pecan Low-Fat High-Protein Emulsion in Low-Fat High-Protein Plant-Based Beverages

[0119] The oil-body protein@XG stabilized pecan low-fat, high-protein emulsion was used to prepare a pecan low-fat, high-protein beverage, denoted as XGCaOB. The oil-body emulsions prepared by the method described in Comparative Examples 2-4 were used to prepare pecan low-fat, high-protein beverages for comparison and were named OB, CaOB, and XGOB, respectively.

[0120] Pecan low-fat, high-protein plant protein beverage was prepared according to the following process: "raw material selection → infrared pretreatment → grinding and pulping → enzymatic hydrolysis → enzyme inactivation → centrifugation → emulsion preparation → blending → homogenization → sterilization". Fresh, shelled pecans with color matching the ranges of lightness (L*), red-green difference (a*), and yellow-blue difference (b*) of 40-60, -5-10, and 20-30, respectively, were selected as raw materials. The pecans were heated at 700 W in the mid-infrared range for 3.5 min, shelled, and then mixed with water at a mass ratio of 1:9 and ground for 2.0 min to obtain pecan pulp. 0.1% (w / v) neutral protease was added to the pecan pulp, and the pH was adjusted to 6.5-7.0. Enzymatic hydrolysis was carried out at 50℃ for 2 h, followed by enzyme inactivation in a water bath at 95℃ for 20 min. Then, the mixture was centrifuged at 10000 rpm for 25 min to separate the aqueous phase and pecan oil. A portion of the aqueous phase was mixed with pecan oil at a ratio of 4:1 to obtain an oil dispersion. Xanthan gum was added to the remaining aqueous phase at a concentration of 0.8% (w / v), and stirred at 50-55℃ to obtain a xanthan gum solution. The oil dispersion was then added to the xanthan gum solution under stirring and mixed thoroughly. The mixture was sheared at 12000 rpm for 3.0 min to obtain a pecan oil emulsion. A 100 mM calcium chloride solution was slowly added to the pecan oil emulsion under stirring and at room temperature to achieve a Ca²⁺ concentration of 2.0 mM, thus obtaining a pecan oil emulsion stabilized by a "calcium bridge". 3% (w / v) white sugar, 0.15% (w / v) sodium carboxymethyl cellulose, and an appropriate amount of vanillin were added sequentially to the emulsion. Deionized water was added to the target volume, and the pH of the system was adjusted to 6.8-7.0. The mixture was stirred thoroughly to obtain a formulation. The preparation solution was preheated to 60-65 °C and then homogenized under a homogenization pressure of 25 MPa. The homogenized beverage was then pasteurized at 72 °C, cooled, and stored at low temperature.

[0121] from Figure 7 As can be seen, the XGCaOB sample maintained good homogeneity throughout the storage period, without significant stratification. In contrast, the OB and CaOB groups showed stratification after one day of storage, while the XGOB group began to show stratification on the third day, and the stratification became more pronounced with prolonged storage. This indicates that the oil-body protein@XG-stabilized pecan low-fat, high-protein emulsion prepared in this invention has excellent physical stability and can maintain uniform distribution in plant-based milk beverage applications, ensuring product quality and stability.

[0122] The above description is merely a preferred embodiment for explaining the present invention and is not intended to limit the present invention in any way. Therefore, any modifications or changes made to the present invention under the same inventive spirit should still be included within the scope of protection intended by the present invention.

Claims

1. A method for preparing a low-fat, high-protein pecan emulsion, characterized in that, Includes the following steps: Step 1: Infrared pretreatment of pecans Fresh pecans with shells are heated at a mid-infrared power of 600-700W for 3.0-4.5 minutes to remove the shells and obtain pecan kernels. Step 2: Preparation of pecan oil Take pecan kernels, mix them with water at a mass ratio of 1:8-9 and grind them for 2-3 minutes to obtain pecan pulp; add 0.05-0.15 w / v % neutral protease to the pecan pulp, and enzymatically hydrolyze it for 1.5-2.5 hours at a pH of 6.5-7.0 and a temperature of 50-55 ℃, then inactivate the enzyme, and subsequently collect the aqueous phase and pecan oil body separately; Step 3: Preparation of Pecan Oil Dispersion System A portion of the aqueous phase and the pecan oil are mixed at a ratio of 3-5:1 to form an oil dispersion. Simultaneously, xanthan gum is added to the remaining aqueous phase at a concentration of 0.06-0.1 w / v %, and the mixture is stirred evenly at 50-55°C to obtain a xanthan gum solution. Under stirring conditions, the oil dispersion is added to the xanthan gum solution and mixed evenly. The mixture is then sheared at a speed of 12000-15000 rpm for 2-4 min to obtain the pecan oil dispersion system. Step 4: Formation of low-fat, high-protein emulsion Prepare a 50-100 mM calcium chloride solution using deionized water; add the calcium chloride solution to the pecan oil dispersion system under magnetic stirring and room temperature conditions, so that the concentration of calcium ions in the system is 1.8-2.2 mM, and continue stirring for 30-40 minutes to obtain a low-fat, high-protein pecan emulsion.

2. The method for preparing the pecan low-fat, high-protein emulsion according to claim 1, characterized in that, The pecan color conforms to the numerical ranges of lightness, red-green difference, and yellow-blue difference of 40-60, -5-10, and 20-30, respectively.

3. The method for preparing the pecan low-fat, high-protein emulsion according to claim 1, characterized in that, In step 2, the centrifugation process conditions are: centrifugation at 8000-12000 rpm for 20-30 minutes.

4. The pecan low-fat, high-protein emulsion prepared by the method according to any one of claims 1-3 is characterized in that, The emulsion has a core-shell structure, wherein the core is an oil body and the shell is covered by xanthan gum molecules. The core and shell are connected by Ca²⁺ ions to form a stable interface.

5. The application of the pecan low-fat, high-protein emulsion prepared by the method described in any one of claims 1-3, characterized in that: The pecan low-fat, high-protein emulsion remains stable under conditions of pH 5-9 and temperature 4-50℃, and is used as a base for low-fat dairy beverages, plant-based functional beverages, and flavored dairy products.

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