An euphausia superba oil gel, a method for preparing the same and use thereof in heat-processed meat products

Abstract

The application discloses a kind of euphausia superba oil gel and its preparation method and application in hot-processed meat products.The method comprises: under salt-containing conditions, natural pea protein is subjected to acid heat treatment to prepare pea protein fiber solution; iota-carrageenan solution is prepared; the two solutions are mixed in proportion and pH is adjusted, and composite hydrogel is formed under heating conditions; the obtained hydrogel is pre-frozen and freeze-dried to obtain porous aerogel template; the aerogel template is immersed in liquid euphausia superba oil to obtain high-oil-loaded composite oil gel.The oil gel can partially or completely replace animal fat when applied in emulsified sausage and other hot-processed meat products, maintains the texture stability of the products under high-salt and high-temperature processing conditions, imparts uniform and long-lasting orange-red color to the products using natural astaxanthin in euphausia superba oil, and improves the nutritional value and sensory quality.The method does not require organic solvents, and the process is safe and controllable, suitable for industrialization and popularization.

Description

TECHNICAL FIELD

[0001] The present application relates to an Antarctic krill oil gel, a preparation method thereof and an application thereof in hot-processed meat products, and belongs to the technical field of biological industry. BACKGROUND

[0002] With the continuous improvement of people's health awareness, the research on the application of functional lipids in food has gradually attracted widespread attention. Antarctic krill oil, as a natural marine source of functional oil, is rich in active ingredients such as omega-3 polyunsaturated fatty acids (such as EPA and DHA), phospholipids and astaxanthin. It not only has good cardiovascular protection, anti-inflammatory, antioxidant and other physiological functions, but also can give meat products a natural orange-red color, enhancing visual appeal and sensory acceptance. However, Antarctic krill oil also has certain application limitations, including strong fluidity, difficulty in controlling structure, and other problems, making it difficult to meet the comprehensive requirements of fat raw materials in texture and other aspects in hot-processed food systems such as cooked meat products.

[0003] In recent years, oleogel, as a means of structuring liquid oil into a solid-like fat, has gradually become an important strategy for functional regulation of lipids. By constructing a three-dimensional network structure composed of proteins, polysaccharides, fatty acids or waxes, liquid oil can be given good stability, heat processing adaptability and flavor release control ability. In traditional hot-processed meat products, animal fat is an important component of texture, flavor and appearance, but high intake of saturated fatty acids is associated with health risks such as cardiovascular disease. In order to reduce the proportion of saturated fatty acids and improve the nutritional value of products, oleogel technology is used to replace traditional animal fat in hot-processed meat products. However, the replacement fat needs to meet the requirements of heat processing adaptability, texture stability and sensory quality, and the existing technology still has deficiencies in simultaneously considering these properties.

[0004] Patent No. CN202211253529.5, Publication No. CN115500502A discloses a method for constructing Antarctic krill oil high internal phase emulsion, and applies it to surimi products, aiming to improve the nutritional value and texture performance of the products. This technical solution realizes the structural embedding of Antarctic krill oil by constructing a high internal phase emulsion, which has certain potential for functional oil loading. However, the stability of this system is sensitive to salt concentration, and it is easy to cause emulsion aggregation or structure destruction under high salt conditions, which limits its wide application in some meat products, especially in medium-high salt emulsified meat products.

[0005] The article "Substitution of animal fat with canola oil-based bigels in meat matrices: a functional and healthier approach" uses canola oil-bee wax oil gel and κ-carrageenan-potato starch hydrogel to construct bigel to replace pig back fat. The results show that in the model meat product system, the cooking loss is as high as 30.8%~32.7%, and in the hamburger type meat product system, it also reaches 11.2%~12.8%. Although the hardness, chewiness and other indicators can be reduced with the increase of the replacement ratio, the high cooking loss exposes the structural defects of the bigel network that is easy to break and oil-water co-analysis under high temperature shear.

[0006] As described above, the structured processing research of Antarctic krill oil is still relatively scarce, especially the key technical path of its application as a fat replacement component in hot-processed meat product systems has not been clearly defined. Therefore, it is urgent to explore a construction strategy of Antarctic krill oil oil gel suitable for hot-processed meat products, and realize its efficient loading and stable application in complex food systems such as emulsified sausages, which has important significance for promoting its functional application and industrialization. SUMMARY

[0007] The purpose of the present application is to provide an Antarctic krill oil gel and a preparation method thereof, by loading Antarctic krill oil on a protein fiber-polysaccharide composite template to form a three-dimensional network structure with high oil holding rate, strong stability and solid-like fat characteristics, thereby realizing partial or complete replacement of animal fat and simultaneously achieving conditioning and color enhancement effects in hot-processed meat products.

[0008] To achieve the above purpose, the present application provides a preparation method of an Antarctic krill oil gel, comprising the following steps:

[0009] 1) A certain amount of natural pea protein is dispersed in deionized water containing 150 mM NaCl, and stirred at 600 rpm for 1 h to completely dissolve it. The pH value of the solution is adjusted to 2, and it is placed in a 4°C refrigerator for 12 h to completely hydrate it. The solution is heated in an oil bath at 87°C for 20 h, and then quickly cooled to room temperature. The solution is subjected to desalting treatment using a dialysis bag with a molecular weight cut-off of 3500 Da to obtain a pea protein fiber solution. The concentration of the pea protein fiber is 14%~18% (w / v). A certain amount of ι-carrageenan is dissolved in deionized water, and stirred at 600 rpm for 6 h to completely dissolve it. The concentration of the ι-carrageenan is 0.1%~5% (w / v). The above pea protein fiber solution and ι-carrageenan solution are mixed uniformly, and the pH of the solution is adjusted to 5 to obtain a pea protein fiber-ι-carrageenan mixed solution.

[0010] 2) The mixed solution of step 1) is preheated by magnetic stirring at 55°C for 10 min, and then heated at 95°C for 30 min, and taken out and poured into a mold. The sample is cooled to room temperature in an ice bath and stored in a 4°C refrigerator overnight to form a hydrogel.

[0011] 3) The hydrogel of step 2) is pre-frozen at -20°C for 24 h, and then subjected to freeze-drying treatment, and the freeze-dried conditions are -40°C for 48 h to obtain an aerogel template.

[0012] 4) The aerogel template of step 3) is soaked in liquid oil for 4 h to obtain an Euphausia superba oil gel.

[0013] Preferably, in an embodiment of the present application, the concentration of the pea protein fiber in the solution of step 1) is 16% (w / v).

[0014] Preferably, in an embodiment of the present application, the concentration of the iota-carrageenan in the solution of step 1) is 1.25% (w / v).

[0015] The present application also provides an Euphausia superba oil gel prepared by the preparation method described in the above scheme. The oil gel is a food-grade protein fiber-polysaccharide composite template loaded oil gel, which has a solid-like fatty three-dimensional network structure, and the oil phase content is ≥ 96.7% (w / w) and the oil holding rate is ≥ 85%.

[0016] The present application also provides the use of the Euphausia superba oil gel described in the above scheme in a heat-processed meat product, in particular, in the aspects of conditioning and color enhancement.

[0017] The present application also provides an emulsified sausage, and the preparation raw materials include the Euphausia superba oil gel described in the above scheme.

[0018] The present application also provides a preparation method of an emulsified sausage, which includes the following steps:

[0019] 1) Pig lean meat is mixed with sodium chloride, sodium tripolyphosphate, and half of the ice water, and is properly chopped and stirred in a meat grinder.

[0020] 2) Pig back fat or Euphausia superba oil gel, and the remaining half of the ice water are added, and are chopped and stirred again until uniform.

[0021] 3) The meat paste obtained after chopping and stirring is filled, and then is heated and cooked, and cooled to obtain an emulsified sausage.

[0022] In an embodiment of the present application, the amount of sodium chloride added in step 1) is 2% of the mass of the emulsified sausage.

[0023] In one embodiment of the present invention, the amount of Antarctic krill oil gel added in step 2) is 4 to 10% of the mass of the emulsified sausage.

[0024] In one embodiment of the present invention, the filling in step 3) is carried out at 4°C to obtain emulsified sausage.

[0025] In one embodiment of the present invention, the heating and cooking in step 3) is heating at 85°C for 20 to 30 minutes.

[0026] In one embodiment of the present invention, the cooling in step 3) is cooling in water at 4°C for 20 to 40 minutes.

[0027] Unless otherwise specified, the room temperature described in this invention is 15–25°C.

[0028] Compared with the prior art, the beneficial effects and advantages of the present invention are:

[0029] (1) The Antarctic krill oil gel constructed in this invention uses a food-grade protein fiber-polysaccharide composite template as a carrier and combines freeze-drying and oil exchange technology to realize the solid-like structure of Antarctic krill oil. The preparation process does not involve organic solvents or chemical cross-linking agents. The process is green and safe, with a high molding rate. It is suitable for application in heat-processed meat product systems and has good industrial scalability.

[0030] (2) The Antarctic krill oil gel prepared by the present invention exhibits a stable three-dimensional lipid network structure and has the plastic rheological properties of animal fat. It can be used as a structural lipid in emulsified sausages, either partially or completely replacing pork back fat. Without significantly affecting the emulsification performance, cooking loss and yield of the product, it achieves healthy fat substitution, optimizes fatty acid composition, and meets the demand for low-saturated and high-unsaturated fats.

[0031] (3) The structured lipid system of the present invention has good emulsifying and dispersing ability and compatibility with meat matrix, and can be stably distributed in the continuous phase during the processing of emulsified sausage, effectively maintaining the fat network structure. Its hardness, chewiness and gel strength can be adjusted by controlling the template composition and the oil loading ratio, providing technical support for the development of emulsified sausages with different texture types.

[0032] (4) The Antarctic krill oil gel constructed in this invention exhibits excellent thermal processing adaptability. It can effectively maintain structural integrity during the cooking process of emulsified sausage, significantly reduce oil migration and fat precipitation, significantly reduce cooking loss, and improve product yield and production stability.

[0033] (5) The astaxanthin component in the gel system constructed in this invention significantly improves the color performance of meat products, making the finished product present a natural and full orange-red tone, enhancing the product's appearance appeal and market competitiveness, and meeting consumers' visual needs for high-quality meat products.

[0034] (5) This invention achieves functional delivery of structured lipids in emulsified sausage system, which not only maintains the texture and processing stability of the product, but also successfully introduces Antarctic krill oil as a functional fat into meat products, providing a new path for the nutritional upgrade of functional meat products, and has good health value and market potential. Attached Figure Description

[0035] Figure 1 This is a graph showing the effect of pea protein fiber and ι-carrageenan concentrations on hydrogel formation in Examples 1 to 15.

[0036] Figure 2 These are appearance diagrams of the hydrogels at different ι-carrageenan concentrations in Examples 16 to 19.

[0037] Figure 3 These are hardness and elasticity graphs of hydrogels with different ι-carrageenan concentrations in Examples 16 to 19.

[0038] Figure 4 These are microstructure diagrams of aerogels with different ι-carrageenan concentrations in Examples 16 to 19.

[0039] Figure 5 These are infrared spectra of aerogels and raw materials pea protein fiber and 1-carrageenan at different 1-carrageenan concentrations in Examples 16 to 19.

[0040] Figure 6 These are polarized light microscope images of oleogels at different ι-carrageenan concentrations in Examples 16 to 19.

[0041] Figure 7 The graphs show the oil absorption and oil retention capacity of the oleogels at different ι-carrageenan concentrations in Examples 16 to 19.

[0042] Figure 8 These are strain scan and frequency scan curves of oleogels at different ι-carrageenan concentrations in Examples 16 to 19.

[0043] Figure 9 Appearance of the emulsified sausage in Example 19 and Comparative Example 1.

[0044] Figure 10 These are color feature diagrams of the emulsified sausages in Example 19 and Comparative Example 1.

[0045] Figure 11 This refers to the cooking loss rate of the emulsified sausage in Example 19 and Comparative Example 1. Detailed Implementation

[0046] The present invention will be further described below with reference to embodiments. It should be noted that these descriptions of embodiments are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] Unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the materials and reagents used, unless otherwise specified, are commercially available.

[0048] Example 1:

[0049] A certain amount of natural pea protein was weighed and dispersed in deionized water containing 150 mM NaCl, and stirred at 600 rpm for 1 h to ensure complete dissolution. The pH of the solution was adjusted to 2, and the solution was placed in a refrigerator at 4°C for 12 h to allow for complete hydration. The solution was then heated in an oil bath at 87°C for 20 h, and then rapidly cooled to room temperature. The solution was desalted using a dialysis bag with a molecular cutoff of 3500 Da to obtain a pea protein fiber solution. The concentration of pea protein fiber was 14% (w / v).

[0050] A certain amount of ι-carrageenan was weighed and dissolved in deionized water, and stirred at 600 rpm for 6 h until completely dissolved. The concentration of ι-carrageenan was 0.1% (w / v). The above pea protein fiber solution was mixed evenly with the ι-carrageenan solution, and the pH of the solution was adjusted to 5 to obtain a pea protein fiber-ι-carrageenan mixed solution. The mixed solution was preheated at 55°C with magnetic stirring for 10 min, and then heated at 95°C for 30 min. The solution was then poured into a mold. It was cooled to room temperature in an ice bath and stored overnight in a 4°C refrigerator to form a hydrogel.

[0051] Example 2:

[0052] The difference from Example 1 is that the concentration of ι-carrageenan is 0.2% (w / v).

[0053] Example 3:

[0054] The difference from Example 1 is that the concentration of ι-carrageenan is 0.3% (w / v).

[0055] Example 4:

[0056] The difference from Example 1 is that the concentration of ι-carrageenan is 0.4% (w / v).

[0057] Example 5:

[0058] The difference from Example 1 is that the concentration of ι-carrageenan is 0.5% (w / v).

[0059] Example 6:

[0060] The difference from Example 1 is that the concentration of pea protein fiber is 16% (w / v).

[0061] Example 7:

[0062] The difference from Example 1 is that the concentration of pea protein fiber is 16% (w / v) and the concentration of 1-carrageenan is 0.2% (w / v).

[0063] Example 8:

[0064] The difference from Example 1 is that the concentration of pea protein fiber is 16% (w / v) and the concentration of 1-carrageenan is 0.3%.

[0065] Example 9:

[0066] The difference from Example 1 is that the concentration of pea protein fiber is 16% (w / v) and the concentration of 1-carrageenan is 0.4%.

[0067] Example 10:

[0068] The difference from Example 1 is that the concentration of pea protein fiber is 16% (w / v) and the concentration of 1-carrageenan is 0.5% (w / v).

[0069] Example 11:

[0070] The difference from Example 1 is that the concentration of pea protein fiber is 18% (w / v).

[0071] Example 13:

[0072] The difference from Example 1 is that the concentration of pea protein fiber is 18% (w / v) and the concentration of 1-carrageenan is 0.2% (w / v).

[0073] Example 14:

[0074] The difference from Example 1 is that the concentration of pea protein fiber is 18% (w / v) and the concentration of 1-carrageenan is 0.3% (w / v).

[0075] Example 15:

[0076] The difference from Example 1 is that the concentration of pea protein fiber is 18% (w / v) and the concentration of 1-carrageenan is 0.4% (w / v).

[0077] Example 16:

[0078] A certain amount of natural pea protein was weighed and dispersed in deionized water containing 150 mM NaCl, and stirred at 600 rpm for 1 h to completely dissolve it. The pH of the solution was adjusted to 2, and the solution was placed in a refrigerator at 4°C for 12 h to allow it to fully hydrate. The solution was heated in an oil bath at 87°C for 20 h, and then rapidly cooled to room temperature. The solution was desalted using a dialysis bag with a molecular cutoff of 3500 Da to obtain a pea protein fiber solution. The concentration of pea protein fiber was 14% (w / v). A certain amount of ι-carrageenan was weighed and dissolved in deionized water, and stirred at 600 rpm for 6 h to completely dissolve it. The concentration of ι-carrageenan was 0.5%. The above pea protein fiber solution and ι-carrageenan solution were mixed evenly, and the pH of the solution was adjusted to 5 to obtain a pea protein fiber-ι-carrageenan mixed solution. The mixture was preheated at 55°C with magnetic stirring for 10 min, then heated at 95°C for 30 min, and poured into a mold. It was cooled to room temperature in an ice bath and stored overnight at 4°C to form a hydrogel. The hydrogel was pre-frozen at -20°C for 24 h, then freeze-dried at -40°C for 48 h to obtain an aerogel template. The aerogel template was then immersed in liquid oil for 4 h to obtain Antarctic krill oil gel.

[0079] Example 17:

[0080] The difference from Example 16 is that the concentration of ι-carrageenan is 0.75% (w / v).

[0081] Example 18:

[0082] The difference from Example 16 is that the concentration of ι-carrageenan is 1.0% (w / v).

[0083] Example 19:

[0084] A certain amount of natural pea protein was weighed and dispersed in deionized water containing 150 mM NaCl, and stirred at 600 rpm for 1 h to completely dissolve it. The pH of the solution was adjusted to 2, and the solution was placed in a refrigerator at 4°C for 12 h to allow it to fully hydrate. The solution was heated in an oil bath at 87°C for 20 h, and then rapidly cooled to room temperature. The solution was desalted using a dialysis bag with a molecular cutoff of 3500 Da to obtain a pea protein fiber solution. The concentration of pea protein fiber was 16% (w / v). A certain amount of ι-carrageenan was weighed and dissolved in deionized water, and stirred at 600 rpm for 6 h to completely dissolve it. The concentration of ι-carrageenan was 1.25%. The above pea protein fiber solution and ι-carrageenan solution were mixed evenly, and the pH of the solution was adjusted to 5 to obtain a pea protein fiber-ι-carrageenan mixed solution. The mixture was preheated at 55°C with magnetic stirring for 10 min, then heated at 95°C for 30 min, and poured into a mold. It was cooled to room temperature in an ice bath and stored overnight at 4°C to form a hydrogel. The hydrogel was pre-frozen at -20°C for 24 h, then freeze-dried at -40°C for 48 h to obtain an aerogel template. The aerogel template was then immersed in liquid oil for 4 h to obtain Antarctic krill oil gel.

[0085] Emulsified sausages were prepared using Antarctic krill oil gel as a raw material. The specific component formula of the emulsified sausage is shown in Table 1. First, the raw materials of each component were weighed according to the formula table and refrigerated at 4°C for later use. Lean pork was mixed with sodium chloride, sodium tripolyphosphate, and half of the ice water, and then chopped appropriately in a meat grinder. Pork back fat, Antarctic krill oil gel, and the remaining half of the ice water were added, and the mixture was chopped again until homogeneous. The resulting meat paste was then filled into containers, heated at 85°C for 20–30 min, and cooled in water at 4°C for 20–40 min to obtain the emulsified sausage.

[0086] Table 1. Sausage Composition Formula for Example 19

[0087]

[0088] Comparative Example 1:

[0089] The specific component formula for emulsified sausage is shown in Table 2. First, weigh out each component according to the formula and refrigerate at 4°C for later use. Mix lean pork with sodium chloride, sodium tripolyphosphate, and half of the ice water, and chop appropriately in a meat grinder. Add pork back fat and the remaining half of the ice water, and chop again until well combined. Pack the resulting meat mixture into containers, then heat at 85°C for 20–30 minutes, and cool in 4°C water for 20–40 minutes to obtain emulsified sausage.

[0090] Table 2 Comparative Example 1 Sausage Composition Formula

[0091]

[0092] Experimental Example 1: Observation of Gel Formation

[0093] The hydrogels prepared in Examples 1 to 15 were inverted to observe whether the gel was successfully formed.

[0094] See results Figure 1 Pea protein fiber (PPF) alone failed to form hydrogels within a concentration range of 14%–18%, possibly due to the low albumin content in pea protein or the purification and extraction process, which weakened the protein's gelation ability. When ι-carrageenan (CG) concentration was below 0.5%, the combination of PPF and CG concentrations could not form a heat-induced gel; however, when the CG concentration reached 0.5%, hydrogels could form across the entire PPF concentration range.

[0095] The effect of CG concentration on PPF thermally induced hydrogel was further investigated, and the results are as follows: Figure 2 When PPF and CG are present simultaneously, a composite hydrogel can be formed only when the CG concentration is 0.5%, while neither PPF (14%) nor CG (0.5%) in a single system can form a thermally induced hydrogel at this concentration. This may be due to the following reasons: First, the hydrogels in Examples 1 to 15 were prepared under pH conditions far from the isoelectric point of proteins (pH=7). Both CG and PPF are negatively charged, and the electrostatic repulsion between them is strong. The incompatibility between the two polymers leads to a reduction in the space occupied by the protein, an increase in the apparent protein concentration, and thus promotes protein interaction, forming a phase-separated gel. Second, the protein fibers formed by acid heat treatment expose more hydrophobic residues. Polysaccharides participate in the formation of the protein fiber gel network through hydrophobic interactions with the protein fibers, thereby enhancing the network structure of the gel.

[0096] Experiment Example 2: Hydrogel Texture Behavior Test

[0097] Using the hydrogels obtained in Examples 16, 17, 18 and 19 as samples, the samples were compressed to 75% of the maximum deformation using a P30 probe at a speed of 6 mm / min. The human oral chewing process was simulated by two compression tests, and the hardness and elasticity of the hydrogels were calculated by the force-time curve during the compression process.

[0098] The results are as follows Figure 3As the CG concentration increased, the hardness and elasticity of the composite hydrogel continuously improved, indicating that the addition of CG enhanced the mechanical strength of the gel and formed a more elastic gel structure. This result suggests that the presence of CG in the composite gel system may contribute to the formation of a denser and more uniform gel structure, thereby improving the gel strength of the composite gel.

[0099] Experimental Example 3: Microstructure of Aerogels

[0100] Using the aerogels obtained in Examples 16, 17, 18 and 19 as samples, the aerogel samples were cut into thin slices with cross-sections and fixed on the observation platform. Then, gold was sprayed onto the surface, and the microstructure of the cryogels was observed by field emission scanning electron microscopy (SEM).

[0101] The results are as follows Figure 4 All four aerogels exhibited a porous network structure. The aerogel in Example 16 had the largest pore size and most disordered pores, indicating structural instability. The aerogel in Example 17 showed a more uniform pore distribution and more micropores. In summary, as the CG concentration increased, the pore structure of the aerogel became denser and the pore distribution more uniform. This result may be due to two main reasons: firstly, the effect of solution viscosity on ice crystal growth; the addition of CG increases the viscosity of the composite solution, and high fluid viscosity hinders ice layer growth, leading to differences in microstructure among different aerogel samples. Secondly, this phenomenon may be due to the intermolecular interaction between PPF and CG, where CG can enhance the gel network of protein fibers through non-covalent interactions and stabilize the connection of PPF protein network chains, thus contributing to the formation of a dense network structure in the aerogel. In addition to changes in pore size, the pore wall sheets also became thicker with increasing polysaccharide concentration. This may be because as the total concentration of biopolymers increases, the volume of protein-polysaccharide aggregates in the hydrogel network increases, and the porous network of the cryogel is inherited from the gel network of its precursor hydrogel, thus forming a network backbone with a larger volume proportion after freeze-drying to remove the aqueous phase.

[0102] Experiment Example 4: Infrared Spectroscopy Analysis

[0103] Using the aerogels obtained in Examples 16, 17, 18, and 19 as samples, the aerogel samples were mixed with potassium bromide at a mass ratio of 1:100 and pressed into thin sheets using a grinding tool. The infrared spectra of the samples were obtained using a Fourier transform infrared spectrometer at 500 cm⁻¹. -1 ~4000 cm -1 Scan within the wavenumber range, with a resolution set to 4cm. -1 .

[0104] The results are as follows Figure 5Examples 16, 17, 18, and 19 all contain characteristic peaks of PPF and CG: 3425 cm⁻¹ -1 (O–H stretching vibration), 1650 cm -1 (Amide I tape), 1538 cm -1 (Amide ІІ tape), 1271 cm -1 (O=S=O symmetric stretching vibration), and exhibits similar infrared spectra. At 3200 cm⁻¹ -1 ~3600 cm -1 The broad peaks within this range are mainly related to hydrogen bonding; the absorption peaks of the two raw materials are at 3425 cm⁻¹. -l (PPF) and 3411cm -l (CG), while the absorption peak at this location in the aerogel sample shows a certain shift, which is related to the formation of hydrogen bonds.

[0105] Experimental Example 5: Polarized Light Microscopy Analysis

[0106] Using the oleogels obtained in Examples 16, 17, 18, and 19 as samples, an appropriate amount of oleogel was applied to a glass slide and covered with a coverslip. The microstructure of the oleogel samples was observed under a 10x objective lens using a polarizing microscope, and microscopic images of the samples were captured and collected.

[0107] The results are as follows Figure 6 All olegels possess a protein filament-polysaccharide crystalline network, and the crystalline network framework of the olegel becomes denser as the CG concentration increases from 0.5% to 1.25%. The dense network structure of the aerogel is retained after the formation of the olegel and serves as the network framework that determines the microstructure of the olegel.

[0108] Experimental Example 6: Analysis of Oil Absorption and Retention Capacity

[0109] The oleogels obtained in Examples 16, 17, 18, and 19 were used as samples. Fresh oleogels formed immediately after the aerogels had fully absorbed oil were weighed, and the oil absorption capacity of the aerogels was calculated according to the following formula, where... m 1 refers to the quality of freshly prepared oleogel. m 0 represents the mass of the original aerogel.

[0110]

[0111] The freshly prepared olegel was centrifuged at 12,000 rpm for 20 min to remove the floating oil on the surface of the olegel. The mass of the olegel before and after centrifugation was measured and recorded as follows: m 1 and m 2. Calculate the oil-holding capacity of the structured lipid using the following formula:

[0112]

[0113] The results are as follows Figure 7 The aerogel of Example 16 exhibited the highest oil absorption capacity (69.59), while the aerogel of Example 19 had the lowest (29.33), and the oil absorption capacity of the aerogels was negatively correlated with the polysaccharide concentration. This result is mainly due to the difference in the pore structure of the aerogels; lower pore size and pore volume limit the oil absorption and storage capacity of the aerogels. Furthermore, with increasing polysaccharide concentration, aerogels with lower porosity and smaller pore size exhibited higher oil retention capacity. The aerogel of Example 19 achieved an oil retention capacity of 96.15%, demonstrating very high centrifugal stability and oil droplet binding ability.

[0114] Experiment Example 7: Rheological Behavior Analysis

[0115] The oleogels obtained in Examples 16, 17, 18, and 19 were used as samples. The rheological properties of the samples were characterized at 25°C using a rheometer equipped with a CP-50 flat plate probe. A certain amount of oleogel sample was transferred to the test platform of the rheometer. Initially, strain scan tests were performed at a fixed frequency of 1 Hz within the range of 0.01% to 100%. Then, frequency scan tests were performed from 1 Hz to 25 Hz on the samples under a fixed strain condition of 0.05% (within the linear viscoelastic region). The curves of storage modulus (G') and loss modulus (G") as a function of strain or frequency were recorded and analyzed.

[0116] The results are as follows Figure 8 In the initial stage of strain scanning, the storage modulus G' of the olegel was highest at 0.7 MPa and lowest at 0.1 MPa. The aerogel network structure was dense, exhibiting high mechanical strength. The olegel formed after the oil absorption process also possessed greater rigidity. With increasing strain, the G' and G" of all olegels initially showed a brief plateau region, and then decreased after exceeding 0.1% strain. Polarizing microscopy observation (…) Figure 7 The results showed that the aerogel-based olegel had a dense crystalline network framework, with a large number and volume of crystals, providing more crystalline framework support for the gel network and thus exhibiting higher resistance to elastic deformation. Furthermore, as the carrageenan concentration increased from 0.5% to 1.25%, the G and G" values ​​of the olegel also increased continuously. In the high strain range, both G' and G" of the olegel decreased with increasing strain, and a crossover point appeared, indicating that the olegel system became viscous at this point. In the frequency scan, the G' and G" values ​​of the aerogel template olegel showed very small frequency dependence, and G' was higher than G"; that is, olegels with different polysaccharide concentrations all exhibited a semi-solid state dominated by elasticity, proving the existence of a gelled network structure inside the olegel.

[0117] Experiment Example 8: Visual Observation

[0118] Digital photographs were taken of the cross-sections of the freshly prepared emulsified sausages in Example 19 and Comparative Example 1 to record the appearance and morphological characteristics of the emulsified sausages.

[0119] See results Figure 9 In Comparative Example 1, the freshly prepared emulsified sausage was light pink, which is related to the heat processing of myoglobin in pork. In contrast, the freshly prepared emulsified sausage in Example 19 was orange-red, because Antarctic krill oil itself is bright red, rather than the pale white of PPF. Further observation of the appearance of different sausage cross-sections revealed that the emulsified sausage in Example 19 had a uniform texture, similar in appearance to the emulsified sausage in Comparative Example 1. This indicates that although oil gel was used to replace some of the fat in Example 19, the resulting emulsified sausage still had a firm internal structure and good stability during processing.

[0120] Experimental Example 9: Colorimetric Measurement

[0121] A 50mm thick cross-section of sausage (Example 19 and Comparative Example 1) was taken for colorimetry testing. The colorimetry of Example 19 and Comparative Example 1 was measured using a colorimeter. L *、 a *、 b * and Δ E In short, first, calibrate the colorimeter using black and white boards. Place an appropriate amount of emulsified sausage sample in the center of a test dish, ensuring the dish surface is clean and free of stains. The color difference value is then measured using the air color difference (…). L 0*=0.24, a 0* = –0.11 b Using 0*=0.09 as a blank calibration standard, the total color difference (Δ) between Example 1 and Comparative Example 1 is calculated according to the following formula. E ).

[0122]

[0123] The color characteristics of the sausage were further characterized by measuring the colorimetric values ​​of the sausage samples. The results are shown in [Figure number missing]. Figure 10 Comparative Example 1: Emulsified sausage a *and b *The values ​​were 1.06±0.14 and 8.70±0.35, respectively, for the emulsified sausage (i.e., Example 19) substituted with Antarctic krill oil gel. a *、 bThe values ​​of * were significantly higher than those of Comparative Example 1, indicating that they exhibited more pronounced red and yellow hues compared to the original sausages, consistent with visual observations. Typically, color-enhancing agents such as nitrites or pigments are added during food processing to improve the color of sausages, achieving a more vibrant and appealing appearance. The sausages in Example 19, containing Antarctic krill oil, all exhibited a natural color-enhancing effect. This demonstrates that Antarctic krill oil gel not only acts as a fat substitute to reduce the proportion of saturated fatty acids in sausages but also enhances their color, giving them a superior sensory appeal. This is beneficial for increasing consumer purchasing desire and the commercial value of the sausages.

[0124] Experimental Example 10 Cooking Loss

[0125] The cooking loss of sausages is calculated by measuring their mass before and after cooking, using the following formula.

[0126]

[0127] in, M 1 represents the mass (g) of the emulsified sausage before cooking. M 2 represents the mass (g) of the emulsified sausage after cooking.

[0128] During the cooking process, the proteins in sausages undergo thermal denaturation and shrinkage, and the muscle fibers undergo longitudinal contraction, leading to the migration and loss of water, lipids, and some soluble substances. Consequently, the quality of the sausage decreases after cooking, resulting in cooking loss. Cooking loss reflects the water-holding capacity of the sausage and the stability of its internal network structure. Generally, lower cooking loss indicates better quality and stability of the sausage.

[0129] See results Figure 11 The cooking loss rates of the emulsified sausage in Example 19 and Comparative Example 1 were 2.73% and 3.77%, respectively. This shows that the sausage replaced with oil gel experienced greater oil and water loss after cooking compared to the emulsified sausage. This is because the oil gel undergoes gel network collapse and oil leakage under high-temperature treatment, thus resulting in additional oil loss compared to pork back fat. However, the difference in cooking loss rates is not significant. This is because the Antarctic krill oil gel in Example 19 contains PPF fibers. PPF fibers can act as emulsifiers to enhance the emulsification of salt-soluble proteins in the minced meat, more effectively encapsulating oil particles, thereby reducing the cooking loss in Example 19.

[0130] Experiment Example 11 Texture Behavior Test

[0131] The emulsified sausages from Example 19 and Comparative Example 1 were cut into cylinders with a diameter of 20 mm and a height of 10 mm. A full texture analysis of the emulsified sausages was performed using a texture analyzer in TPA mode. The samples were compressed to 75% of their maximum deformation using a P30 probe at a speed of 6 mm / min. Two compression tests were conducted to simulate the human oral chewing process. The basic TPA parameters (hardness, elasticity, adhesiveness, cohesiveness, chewiness, and stickiness) of the emulsified sausages were calculated using the force-time curve during compression.

[0132] The results are shown in Table 3. Compared with the emulsified sausage in Comparative Example 1, the emulsified sausage replaced by Antarctic krill oil gel (i.e., Example 19) showed significantly reduced hardness, cohesiveness, adhesiveness, and chewiness; elasticity and adhesion did not change significantly. The textural properties of sausage are mainly related to its moisture and lipid content, suggesting that the texture of fat has a significant impact on the overall textural properties of sausage. Hardness dominated among the various textural indicators, significantly affecting the changes in the secondary parameters of adhesiveness and chewiness. This is mainly because the hardness of the oil gel differs significantly from that of pork back fat itself.

[0133] Table 3. TPA index of emulsified sausage

[0134]

[0135] Overall, Antarctic krill oil gel can mimic the textural properties of animal fat to some extent. Using oil gel to replace fat will affect the texture of sausages, but it is still within an acceptable range.

Claims

1. A method for preparing Antarctic krill oil gel, characterized in that, Includes the following steps: 1) Weigh a certain amount of natural pea protein and disperse it in deionized water containing 150 mM NaCl. Stir at 600 rpm for 1 h to completely dissolve it. Adjust the pH of the solution to 2 and place it in a refrigerator at 4°C for 12 h to allow it to fully hydrate. Heat the solution in an oil bath at 87°C for 20 h, then rapidly cool it to room temperature. Desalinate the solution using a dialysis bag with a molecular cutoff of 3500 Da to obtain a pea protein fiber solution with a pea protein fiber concentration of 16% (w / v). Weigh a certain amount of ι-carrageenan and dissolve it in deionized water. Stir at 600 rpm for 6 h to completely dissolve it. The ι-carrageenan concentration is 1.25% (w / v). Mix the above pea protein fiber solution and ι-carrageenan solution evenly and adjust the pH of the solution to 5 to obtain a pea protein fiber-ι-carrageenan mixed solution. 2) Preheat the mixture from step 1) at 55°C with magnetic stirring for 10 min, then heat the mixture at 95°C for 30 min, remove and pour into a mold; cool the sample to room temperature in an ice bath and store it overnight in a 4°C refrigerator to form a hydrogel; 3) Pre-freeze the hydrogel obtained in step 2) at -20°C for 24 h, and then freeze-dry it at -40°C for 48 h to obtain an aerogel template; 4) Soak the aerogel template obtained in step 3) in liquid Antarctic krill oil for 4 h to obtain Antarctic krill oil gel.

2. The method according to claim 1, characterized in that, In step 4), Antarctic krill oil is replaced with a mixture of Antarctic krill oil and other liquid oils, with Antarctic krill oil accounting for more than 50% of the total mass of the oil phase.

3. An Antarctic krill oil gel, characterized in that, The Antarctic krill oil gel is prepared by the method according to any one of claims 1-2, wherein the oil gel is a food-grade protein fiber-polysaccharide composite template-supported oil gel, exhibiting a three-dimensional network structure resembling a solid fat, with an oil phase content ≥ 96.7% (w / w) and an oil holding capacity ≥ 85%.

4. The application of the Antarctic krill oil gel according to claim 3 in heat-processed meat products, characterized in that, The gel is used as a structural lipid to partially or completely replace animal fat, and imparts thermal processing adaptability, textural stability and a natural orange-red color to the product.

5. An emulsified sausage, characterized in that, The raw materials for preparation include the Antarctic krill oil gel as described in claim 3, wherein the mass of the gel accounts for 4% to 10% of the total mass of the emulsified sausage.

6. The method for preparing emulsified sausage according to claim 5, characterized in that, Includes the following steps: 1) Mix lean pork with sodium chloride, sodium tripolyphosphate, and half of the ice water and chop it. 2) Add pork back fat and / or the Antarctic krill oil gel as described in claim 5 and the remaining ice water, and chop and mix well; 3) After filling, operate at 4℃ and heat at 85℃ for 20-30 minutes, then cool in water at 4℃ for 20-40 minutes to obtain emulsified sausage.

7. The method according to claim 6, characterized in that, In step 1), the amount of sodium chloride added is 2% of the mass of the emulsified sausage, and the amount of sodium tripolyphosphate added is 0.3%.

Images