Pickering emulsion loaded with monascus pigment as well as preparation method and application of Pickering emulsion

Abstract

The invention provides a monascus pigment-loaded Pickering emulsion as well as a preparation method and application thereof. Specifically, the invention provides an emulsion, which comprises: a monascus pigment-loaded whey protein-OSA pectin compound, which is formed by crosslinking octenyl succinic anhydride (OSA) modified pectin, thermally denatured whey protein and monascus pigment under the action of calcium ions; and vegetable oil and water. The emulsion disclosed by the invention is a healthy fat substitute capable of endowing meat products with good color performance.

Description

Technical Field

[0001] The invention relates to the field of food chemistry, and in particular to a Pickering emulsion loaded with monascus pigment, and a preparation method and application thereof. Background Art

[0002] Meat products are one of the main sources of various nutrients for the human body. Existing studies have shown that excessive intake of meat products will bring certain health risks. First, nitrites are often added in the production of traditional meat products to give the products good color performance and a longer shelf life. Excessive intake of nitrites can lead to tissue poisoning and increase the risk of cancer. Secondly, a large amount of animal fat in meat products can induce a variety of cardiovascular and cerebrovascular diseases, such as hyperlipidemia and coronary heart disease. At present, with people's pursuit of a healthy life, the development of low-fat and low-nitrite meat products has received more and more attention.

[0003] Reducing the nitrite content while maintaining the color and shelf life of meat products is one of the concerns. Monascus pigment is a natural pigment produced by Monascus purpurogenum, which has multiple physiological functions such as antibacterial, hypolipidemic, and antioxidant. It is often used as a dye in the food industry in Asian countries such as China and Japan, such as a colorant for meat products. The antibacterial activity enables Monascus pigment to inhibit the growth of some microorganisms and give meat products a brighter color. Therefore, Monascus pigment has the potential to be a substitute for nitrite. However, Monascus pigment has poor stability and is prone to fading under light and high temperature conditions, which limits its further application. Reducing fat content is another focus of the development of healthy meat products. The use of Pickering emulsion as a fat substitute is one of the hot topics. Pickering emulsion uses macromolecular polymers as emulsifiers, which can simulate the texture of lipid tissue and avoid food safety issues that may be caused by the use of small molecule emulsifiers.

[0004] Therefore, there is a need in the art to provide a fat substitute that is healthier and more conducive to industrial application. Summary of the invention

[0005] The purpose of the present invention is to provide a fat substitute which is healthier and more conducive to industrial application.

[0006] The first aspect of the present invention provides an emulsion comprising:

[0007] A whey protein-OSA pectin complex loaded with monascus pigment, which is formed by cross-linking octenyl succinic anhydride (OSA)-modified pectin, heat-denatured whey protein and monascus pigment under the action of calcium ions; and

[0008] Vegetable oil and water.

[0009] In another preferred embodiment, the emulsion is obtained by emulsifying a mixture of an aqueous solution containing a whey protein-OSA pectin complex loaded with monascus pigment and vegetable oil.

[0010] In another preferred embodiment, in the whey protein-OSA pectin complex loaded with monascus pigment, the mass ratio of octenyl succinic anhydride (OSA) modified pectin to heat-denatured whey protein is 1:1-3, preferably 1:1.5-2.5, and more preferably 1:2.

[0011] In another preferred embodiment, the content of monascus pigment in the whey protein-OSA pectin complex loaded with monascus pigment (based on dry weight) is 1-10wt%, preferably 2-8wt%, more preferably 4-7wt%, such as 3wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6.5wt%, 7wt% or 7.5wt%.

[0012] In another preferred embodiment, in the aqueous solution containing the whey protein-OSA pectin complex loaded with monascus pigment, the concentration of the complex is 0.1-5g / 100mL, preferably 0.5-3g / 100mL, such as 1g / 100mL, 1.5g / 100mL, 1.6g / 100mL, 1.8g / 100mL, 2.0g / 100mL or 2.5g / 100mL.

[0013] In another preferred embodiment, in the emulsion, the volume ratio of water to vegetable oil is 1:1-2, preferably 1:1.2-1.8, such as 1:1.3, 1:1.4, 1:1.5, 1:1.6 or 1:1.7.

[0014] In another preferred embodiment, the volume ratio of the aqueous solution containing the whey protein-OSA pectin complex loaded with monascus pigment to the vegetable oil is 1:1-2, preferably 1:1.2-1.8, such as 1:1.3, 1:1.4, 1:1.5, 1:1.6 or 1:1.7.

[0015] In another preferred embodiment, in the emulsion, the calcium ion concentration is 0.8-1.6 mmol / L, such as 1 mmol / L, 1.2 mmol / L, 1.5 mmol / L or 1.6 mmol / L.

[0016] In another preferred embodiment, the emulsion comprises:

[0017] 0.1-1 parts by weight (e.g., 0.2, 0.4, 0.5, 0.6, 0.7 or 0.8 parts by weight) of a whey protein-OSA pectin complex loaded with monascus pigment;

[0018] 30-50 parts by weight (e.g., 35, 38, 40, 42 or 48 parts by weight) of water; and

[0019] 45-75 parts by weight (e.g., 50, 55, 60, 65 or 70 parts by weight) of vegetable oil.

[0020] In another preferred embodiment, the emulsion comprises:

[0021] 0.1-1 wt% (e.g., 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt% or 0.8 wt%) of a whey protein-OSA pectin complex loaded with monascus pigment;

[0022] Water 30-50 wt% (e.g. 35 wt%, 38 wt%, 40 wt%, 42 wt% or 48 wt%); and

[0023] Vegetable oil 45-75wt% (such as 50wt%, 55wt%, 60wt%, 65wt% or 70wt%).

[0024] In another preferred embodiment, in the emulsion, the content of Monascus pigment is 0.01-0.1wt%, preferably 0.02-0.08wt%, such as 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt% or 0.07wt%.

[0025] In another preferred embodiment, in the octenyl succinic anhydride (OSA) modified pectin, the degree of substitution of OSA is 0.02-0.06, preferably 0.03-0.05, and more preferably 0.035-0.045.

[0026] In another preferred embodiment, the octenyl succinic anhydride (OSA) modified pectin is prepared by a method comprising the following steps:

[0027] Add the OSA anhydrous ethanol solution dropwise into the pectin solution, and stir at 50±5°C for 0.5-4h at pH 8.5±0.5.

[0028] In another preferred embodiment, the concentration of the OSA anhydrous ethanol solution is (20±5) w / v%, preferably (20±2) w / v%.

[0029] In another preferred embodiment, the concentration of the pectin solution is 0.05-0.15 g / ml, preferably 0.08-0.12 g / ml, such as 0.1 g / mL.

[0030] In another preferred embodiment, the heat-denatured whey protein is obtained by heating and denaturing a whey protein aqueous solution. Preferably, the whey protein content in the aqueous solution is 5-50 g / L, preferably 10-30 g / L, such as 15 g / L, 18 g / L, 20 g / L, 25 g / L.

[0031] In another preferred embodiment, the heat denaturation is heat denaturation at 80-100°C, preferably heat denaturation at 90±5°C.

[0032] In another preferred embodiment, the heating time for heat denaturation is 5-30 min, preferably 15±5 min.

[0033] In another preferred embodiment, the monascus pigment is selected from the following group: monascus red pigment, monascus yellow pigment, monascus orange pigment, or a combination thereof.

[0034] The second aspect of the present invention provides a method for preparing the emulsion according to the first aspect of the present invention, comprising the steps of:

[0035] (i) providing a mixed aqueous solution of octenyl succinic anhydride (OSA)-modified pectin, heat-denatured whey protein and monascus pigment;

[0036] (ii) adding a calcium salt solution to the mixed aqueous solution for cross-linking reaction, thereby obtaining an aqueous solution containing a whey protein-OSA pectin complex loaded with monascus pigment;

[0037] (iii) mixing the aqueous solution of the whey protein-OSA pectin complex loaded with monascus pigment with vegetable oil and emulsifying to form the emulsion.

[0038] In another preferred embodiment, the emulsification comprises homogenizing at 16000±2000 rpm for 1-10 min.

[0039] In another preferred embodiment, in step (iii), the aqueous solution of the whey protein-OSA pectin complex loaded with monascus pigment can be obtained directly from step (ii) or after adjusting the concentration.

[0040] In another preferred embodiment, in the calcium salt solution, Ca 2+ The concentration is 50-70mM, such as 55, 50 or 65mM.

[0041] In another preferred embodiment, the volume ratio of the calcium salt solution to the mixed aqueous solution is 1:10-25, such as 1:15-20.

[0042] In another preferred embodiment, in the reaction solution of step (ii), Ca 2+ The concentration is 1-5mM, such as 2mM, 2.5mM, 3mM, 3.5mM, 4mM or 4.5mM.

[0043] In another preferred embodiment, the calcium ions come from CaCl2, Ca(OH)2, or a combination thereof.

[0044] In another preferred embodiment, the vegetable oil is selected from the group consisting of soybean oil, peanut oil, corn oil, rapeseed oil, sunflower oil, olive oil, coconut oil, sesame oil, or a combination thereof.

[0045] The third aspect of the present invention provides use of the emulsion described in the first aspect of the present invention in preparing a fat substitute.

[0046] In another preferred embodiment, the fat substitute can be used to prepare low-fat foods, especially low-fat meat products.

[0047] According to a fourth aspect of the present invention, a low-fat meat product is provided, comprising the emulsion according to the first aspect of the present invention, and minced lean meat.

[0048] In another preferred embodiment, the low-fat meat product contains 2-30wt% of the emulsion, preferably 5-20wt%, such as 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt% or 25wt%.

[0049] In another preferred embodiment, the lean minced meat comes from pigs, cattle, sheep, chickens, ducks or geese.

[0050] The fifth aspect of the present invention provides a method for preparing the low-fat meat product according to the fourth aspect of the present invention, comprising the steps of:

[0051] The low-fat meat product is obtained by mixing the emulsion of claim 1 with lean minced meat.

[0052] In another preferred embodiment, the method further comprises the step of further processing the low-fat meat to obtain the final product, such as heating at 80±5°C for 20-60 minutes.

[0053] In another preferred embodiment, the heating time is 30±5 min.

[0054] In another preferred embodiment, the step of centrifugation to remove bubbles is further included after mixing.

[0055] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The microstructures of HWP, HWP-OP, HWP-OP-Ca, and HWP-OP-Ca-MPs are shown;

[0057] Figure 2 The three-phase contact angles of HWP, HWP-OP, HWP-OP-Ca, and HWP-OP-Ca-MPs are shown;

[0058] Figure 3 The improvement effect of the complex carrier on the photostability of MPs was shown;

[0059] Figure 4 It shows that the composite carrier improves the thermal stability of MPs;

[0060] Figure 5 The microstructures of H-PE, HO-PE, HOC-PE and HOCM-PE are shown. (A) Optical microscopy observation; (B) Oil phase fluorescence; (C) Protein fluorescence; (D) OSA pectin fluorescence; (E) Overlay of B, C and D.

[0061] Figure 6 The storage stability and centrifugal stability of Pickering emulsions are shown;

[0062] Figure 7 A physical picture showing the low-fat meat patties in the minced meat state and in the finished heated product;

[0063] Figure 8 The textural parameters of the low-fat patties are shown. DETAILED DESCRIPTION

[0064] After extensive and in-depth research, a large number of screenings and tests, the inventors have provided a Pickering emulsion loaded with red pigment, and a preparation method and application thereof. The present invention uses a complex obtained by cross-linking heat-denatured whey protein and OSA-modified pectin (OSA pectin) as a carrier to load red pigment, thereby protecting the red pigment and improving its stability in light, heat, etc. On the other hand, the complex of the present invention can also be used as an ideal emulsifier for Pickering emulsion. They have excellent biocompatibility and exhibit good interfacial stability, thereby preparing Pickering emulsions that can give meat products good color performance as fat substitutes. The present invention was completed on this basis.

[0065] the term

[0066] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0067] As used herein, when used in reference to a specific recited numerical value, the term "about" means that the value may vary by no more than 1% from the recited value. For example, as used herein, the expression "about 100" includes all values ​​between 99 and 101 (e.g., 99.1, 99.2, 99.3, 99.4, etc.).

[0068] As used herein, the term "comprising" or "including (comprising)" may be open, semi-closed and closed. In other words, the term also includes "consisting essentially of" or "consisting of".

[0069] As used herein, the term "room temperature" or "normal temperature" refers to a temperature of 4-40°C, preferably, 25±5°C.

[0070] Whey protein-OSA pectin complex loaded with monascus pigment

[0071] The invention provides a whey protein-OSA pectin complex loaded with monascus pigment, which is formed by cross-linking octenyl succinic anhydride (OSA)-modified pectin, heat-denatured whey protein and monascus pigment under the action of calcium ions.

[0072] The octenyl succinic anhydride (OSA) modified pectin can be obtained by reacting octenyl succinic anhydride and pectin under alkaline conditions (such as pH 8.5±0.5). Preferably, in the octenyl succinic anhydride (OSA) modified pectin, the degree of substitution of OSA is 0.02-0.06, preferably 0.03-0.05, and more preferably 0.035-0.045.

[0073] As used in the present invention, the structure of the octenyl succinic anhydride (OSA) is:

[0074] Octenyl succinic anhydride (OSA).

[0075] In the present invention, the pectin can be commonly used food-grade pectin, and pectin can form gel when combined with divalent ions such as calcium and magnesium. Preferably, the relative molecular mass of the pectin is 20,000 to 400,000, the degree of esterification is 65±5%, and the galacturonic acid content is >74%.

[0076] As used in the present invention, heat-denatured whey protein can be obtained by denaturing a whey protein aqueous solution by heating.

[0077] The composite can be formed by adding a calcium salt solution to a mixed aqueous solution of octenyl succinic anhydride (OSA) modified pectin, heat-denatured whey protein and monascus pigment to carry out a cross-linking reaction. The composite of the present invention is soluble in water.

[0078] In the present invention, a complex obtained by cross-linking heat-denatured whey protein and OSA modified pectin (OSA pectin) is used as a carrier to load the red pigment, thereby protecting the red pigment and improving its stability in light, heat, etc. On the other hand, the complex of the present invention can also serve as an ideal emulsifier for Pickering emulsion. They have excellent biocompatibility and exhibit good interfacial stability, thereby preparing a Pickering emulsion that can give meat products good color performance as a fat substitute.

[0079] Emulsion and its application

[0080] The present invention also provides an emulsion that can be used as a fat substitute, which comprises the whey protein-OSA pectin complex loaded with monascus pigment, vegetable oil and water.

[0081] Generally, the emulsion can be obtained by emulsifying a mixture of an aqueous solution of the whey protein-OSA pectin complex loaded with monascus pigment and vegetable oil.

[0082] The emulsion of the present invention is a Pickering emulsion. Pickering refers to an emulsion obtained by using ultrafine solid particles as an emulsifier. Surprisingly, the complex of the present invention has excellent biocompatibility and exhibits good interfacial stability. It is an ideal emulsifier, which enables the emulsion of the present invention to be stably stored, easy to use and prolong the shelf life of the product.

[0083] Preferably, the emulsion comprises:

[0084] 0.1-1 parts by weight (e.g., 0.2, 0.4, 0.5, 0.6, 0.7 or 0.8 parts by weight) of a whey protein-OSA pectin complex loaded with monascus pigment;

[0085] 30-50 parts by weight (e.g., 35, 38, 40, 42 or 48 parts by weight) of water; and

[0086] 45-75 parts by weight (e.g., 50, 55, 60, 65 or 70 parts by weight) of vegetable oil.

[0087] In the present invention, the vegetable oil can be an edible vegetable oil commonly used in the art, such as but not limited to: soybean oil, peanut oil, corn oil, rapeseed oil, sunflower oil, olive oil, coconut oil, sesame oil, or a combination thereof.

[0088] The invention also provides use of the emulsion in preparing a fat substitute.

[0089] Furthermore, the present invention also provides a low-fat meat product, which comprises the emulsion of the present invention and minced lean meat.

[0090] In another preferred embodiment, the lean minced meat may come from various edible animals, such as pigs, cattle, sheep, chickens, ducks or geese.

[0091] The amount of the emulsion added can be selected according to the performance of the final product. Usually, the low-fat meat product contains 2-30wt% of the emulsion, preferably 5-20wt%, such as 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt% or 25wt%.

[0092] Typically, the low-fat meat product can be obtained by mixing the emulsion of the present invention with lean minced meat.

[0093] The low-fat meat product can be seasoned with various seasonings (such as salt, spices, etc.) as needed to prepare the desired product.

[0094] The low-fat meat product can be processed in various ways as required, such as heating, air-drying, smoking or baking.

[0095] The present invention has no limitation on the form of the low-fat meat product, and the low-fat meat product can be prepared into various forms such as sausage, roll, slice, block, etc. as required.

[0096] The main advantages of the present invention include:

[0097] 1. The whey protein-OSA pectin complex loaded with monascus pigment of the present invention significantly improves the stability of monascus pigment and can be used as an ideal emulsifier for Pickering emulsion, thereby providing Pickering emulsion as a fat substitute that can give meat products good color performance.

[0098] 2. The present invention provides a new fat substitute, which can not only prepare healthier low-fat meat products, but also extend the shelf life of the low-fat meat products.

[0099] The present invention will be further described below in conjunction with specific implementation. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0100] Example 1

[0101] (1) Preparation of OSA pectin: Dissolve 10 g of pectin in 100 mL of distilled water. Under stirring, slowly add a 20% OSA anhydrous ethanol solution to the pectin solution. Use 1 M NaOH to maintain the pH of the mixed solution at 8.5 and stir at 50°C for 2 h. Then adjust the pH of the mixed solution to 6.0 to terminate the reaction. Add 500 mL of 95% ethanol solution to the mixed solution, let it stand for 4 h, and collect the precipitate. Wash the residual OSA with anhydrous ethanol. Redissolve the precipitate and freeze-dry it to obtain OSA-modified pectin, called OSA pectin. The degree of substitution of OSA pectin is 0.0398±0.0032.

[0102] (2) Preparation of whey protein-OSA pectin complex loaded with Monascus pigment: 2 g of whey protein was dissolved in 100 mL of distilled water and stirred for 30 min to fully hydrate. The protein solution was heated in a 90°C water bath for 15 min to induce protein denaturation and aggregation. After heating, the WP solution was cooled to room temperature. 1 g of OSA pectin was added to 90 mL of distilled water and mixed with the above 100 mL of WP solution after it was fully dissolved. 200 mg of MPs was added to the mixed solution and stirred for 30 min. Subsequently, 10 mL of 60 mM CaCl2 solution was added to the mixed solution of the three and stirred for 2 h to allow OSA pectin and WPI to fully cross-link and load MPs. After stirring, the mixture was placed at 4°C overnight to obtain a WPI-OSA pectin complex loaded with MPs.

[0103] (3) Preparation of Pickering emulsion: 300 mL of sunflower oil was added to 200 mL of the complex solution prepared in step (2), and the mixture was stirred at 1000 rpm for 10 min. Subsequently, the mixture was homogenized at 16000 rpm for 3 min to prepare the Pickering emulsion.

[0104] (4) Preparation of low-fat meat (example): Fresh pork hind leg meat and pork fat with fat and fascia removed were minced. The emulsion was added to the lean minced meat and stirred to mix. Subsequently, the mixed minced meat was centrifuged at 2000 rpm for 5 minutes to remove excess bubbles. The mixed pork minced meat was heated in a water bath at 80°C for 30 minutes, cooled to room temperature, and then stored at 4°C.

[0105] Example 2 Characterization of whey protein-OSA pectin complex loaded with monascus pigment (HWP-OP-Ca-MPs)

[0106] To illustrate the results, heat-treated whey protein (HWP), a mixture of heat-treated whey protein and OSA pectin (HWP-OP), and Ca 2+ Cross-linked whey protein-OSA pectin complex (HWP-OP-Ca) was used as the control group. Figure 1 It can be seen from the TEM image that HWP is granular. The connection between OSA pectin and HWP particles in HWP-OP is relatively loose. In HWP-OP-Ca and HWP-OP-Ca-MPs, OSA pectin molecules form a relatively thick bundle structure and the fiber bundles are connected to each other to form a network structure, and HWP particles are embedded in the network structure. The addition of MPs did not have a significant effect on the cross-linking effect of Ca2+, and the microstructural characteristics of HWP-OP-Ca and HWP-OP-Ca-MPs were basically the same.

[0107] Figure 2The three-phase contact angles reflect the wettability of different samples. The contact angle of HWP is 39.37°, showing strong hydrophilicity. The addition of OSA enhances the hydrophobicity of HWP, and the contact angle of HWP-OP increases to 70.48°. The cross-linking effect produced by Ca2+ further enhances the amphiphilicity of the complex, and the contact angle of HWP-OP-Ca reaches 82.33°. After loading MPs, the composite still maintains good wettability.

[0108] Table 1 Photostability data of red pigment

[0109]

[0110] Table 2 Thermal stability data of monascus pigment

[0111]

[0112]

[0113] Figure 3 and Figure 4 The results showed that the composite carrier significantly improved the light stability and thermal stability of MPs. After continuous irradiation for 6 days at 7000 lx, the pigment retention rate of free MPs was 9.87%, and the pigment retention rate of HWP-OP-Ca-MPs reached 19.46%. After heating in a 100℃ water bath for 6 hours, the pigment retention rate of free MPs was 29.69, and the pigment retention rate of HWO-OP-Ca-MPs reached 42.80%. The barrier effect of macromolecular wall materials on adverse environmental factors is the main reason for the improvement of light and thermal stability.

[0114] Example 3 Characterization of the complex-stabilized Pickering emulsion

[0115] For the purpose of presenting the results, the emulsion stabilized by HWP was named H-PE, the emulsion stabilized by HWP-OP was named HO-PE, the emulsion stabilized by HWP-OP-Ca was named HOC-PE, and the emulsion stabilized by HWP-OP-Ca-MPs was named HOCM-PE. Figure 5 As shown, compared with other groups, H-PE has the largest droplet diameter and the fluorescence signal intensity of the protein at the edge of its droplet is weaker. This shows that the amount of protein particles adsorbed at the oil-water interface in HW-PE is less, and more particles are dispersed in the water phase. The oil-water interface of HO-PE is stabilized by OSA pectin and HWP. Their composite solution forms an ordered interface structure around the oil droplets. HOC-PE and HOCM-PE have the smallest droplet diameter and the most uniform distribution. In these two emulsions, the Ca content of OSA pectin and HWP is 2+ While forming an ordered interface structure, the cross-linked material also produces a three-dimensional network structure in the continuous phase that wraps the oil droplets, which is beneficial to hinder the aggregation of oil droplets.

[0116] like Figure 6 As shown in the figure, after being placed at 4°C for 5 days, the difference in oil-water density caused H-PE and HO-PE to show obvious stratification. As the storage time increased, the volume of their lower aqueous phase continued to increase. HOC-PE and HOCM-PE did not show oil-water stratification during the test time, showing good stability. The trend of centrifugal stability was the same as that of storage stability. Centrifugal treatment caused H-PE and HO-PE to produce turbid and clear water layers, respectively, but did not cause phase separation of HOC-PE and HOCM-PE.

[0117] Example 4 Characterization of low-fat meat patties prepared using the complex-stabilized Pickering emulsion as a fat substitute

[0118] like Figure 7 As shown in Table 3, CM is a control group with 20% pig fat added, and EM-15, EM-20 and EM-25 are added with 15%, 20% and 25% HOCM-PE, respectively. The color of meat products is a key factor affecting consumers' purchasing desire. Compared with CM, the redness values ​​a* and b* of EM-15, EM-20 and EM-25 increase with the increase of emulsion addition. The change in a* value is the most significant. The a* of the low-fat meat patty samples is more than twice that of CM, and they all show a brighter red color. For the b* value, the increase in the amount of emulsion oil phase (sunflower oil, yellow) added is the main reason for the significant increase in the yellowness value of the low-fat meat patty.

[0119] Table 3 Color parameters of low-fat meat patties before and after heating

[0120]

[0121] like Figure 8 As shown in the figure, the hardness and chewiness of EM-15 and EM-25 are significantly lower than those of CM, while the texture parameters of EM-20 are not significantly different from those of CM. The content and distribution of fat and water in muscle protein gel are key factors affecting the texture properties. When the addition amount of HOCM-PE increases or decreases, the protein gel network structure and the oil-water ratio and distribution state therein change, resulting in a decrease in the hardness and chewiness of EM-15 and EM-25. When the addition amount of HOCM-PE is consistent with that of pig fat, it plays a filling effect similar to that of pig fat in the protein gel network structure, giving EM-20 similar texture properties to CM. This shows that HOCM-PE can be used as an ideal fat substitute in meat products.

[0122] All documents mentioned in the present invention are cited as references in this application, just as each document is cited as reference individually. In addition, it should be understood that after reading the above teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. An emulsion, characterized in that include: A whey protein-OSA pectin complex loaded with monascus pigment, which is formed by cross-linking of octenyl succinic anhydride (OSA)-modified pectin, heat-denatured whey protein and monascus pigment under the action of calcium ions; and Vegetable oil and water.

2. The emulsion according to claim 1, characterized in that In the whey protein-OSA pectin complex loaded with monascus pigment, the mass ratio of octenyl succinic anhydride (OSA) modified pectin to heat-denatured whey protein is 1:1-3, preferably 1:1.5-2.5, and more preferably 1:

2.

3. The emulsion according to claim 1, characterized in that The volume ratio of the aqueous solution containing the whey protein-OSA pectin complex loaded with monascus pigment to the vegetable oil is 1:1-2, preferably 1:1.2-1.8, such as 1:1.3, 1:1.4, 1:1.5, 1:1.6 or 1:1.

7.

4. The emulsion according to claim 1, characterized in that The emulsion comprises: 0.1-1 parts by weight (e.g., 0.2, 0.4, 0.5, 0.6, 0.7 or 0.8 parts by weight) of a whey protein-OSA pectin complex loaded with monascus pigment; 30-50 parts by weight (e.g., 35, 38, 40, 42 or 48 parts by weight) of water; and 45-75 parts by weight (e.g., 50, 55, 60, 65 or 70 parts by weight) of vegetable oil.

5. The emulsion according to claim 1, characterized in that The emulsion comprises: 0.1-1 wt% (e.g., 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt% or 0.8 wt%) of a whey protein-OSA pectin complex loaded with monascus pigment; Water 30-50 wt% (e.g. 35 wt%, 38 wt%, 40 wt%, 42 wt% or 48 wt%); and Vegetable oil 45-75wt% (such as 50wt%, 55wt%, 60wt%, 65wt% or 70wt%).

6. The emulsion according to claim 1, characterized in that In the emulsion, the content of monascus pigment is 0.01-0.1 wt%, preferably 0.02-0.08 wt%, such as 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt% or 0.07 wt%.

7. The method for preparing the emulsion according to claim 1, comprising the steps of: (i) providing a mixed aqueous solution of octenyl succinic anhydride (OSA)-modified pectin, heat-denatured whey protein and monascus pigment; (ii) adding a calcium salt solution to the mixed aqueous solution for cross-linking reaction, thereby obtaining an aqueous solution containing a whey protein-OSA pectin complex loaded with monascus pigment; (iii) mixing the aqueous solution of the whey protein-OSA pectin complex loaded with monascus pigment with vegetable oil and emulsifying to form the emulsion.

8. Use of the emulsion according to claim 1 in the preparation of a fat substitute.

9. A low-fat meat product comprising the emulsion according to claim 1, and lean minced meat.

10. The method for preparing low-fat meat according to claim 9, comprising the steps of: The low-fat meat product is obtained by mixing the emulsion of claim 1 with lean minced meat.

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