Highland barley bran protein and its application in improving meat product quality and preparing meat product improver

Abstract

The present invention discloses highland barley bran protein and its application in improving the quality of meat products and preparing meat product improvers, belonging to the field of food technology. Highland barley bran protein and its modified products are added to meat products to improve the color, water holding capacity, cooking loss rate, texture, and sensory properties of the meat products to varying degrees. Therefore, applying highland barley bran protein and its modified bran protein in meat processing not only allows the use of discarded highland barley bran but also improves the quality of meat products. Furthermore, using highland barley bran protein and its modified bran protein as meat product improvers also has the characteristics of being green, nutritious, and safe. Therefore, the present invention can provide new ideas for the utilization of highland barley bran protein and increase the economic benefits of highland barley bran.

Description

Technical Field

[0001] The present invention relates to the field of food technology, in particular to highland barley bran protein and its application in improving the quality of meat products and preparing a meat product improver. Background Art

[0002] Highland barley ( Hordeum vulgare Var. coeleste Linnaeus, also known as highland barley, hullless barley, or naked barley, is a unique barley variety. Rich in various bioactive compounds, it is considered a health food with potential for preventing or treating cancer, cardiovascular disease, and metabolic syndrome, making it an economically promising crop.

[0003] Highland barley has a thick seed coat, requiring dehulling during processing. This process produces a significant amount of highland barley bran as a byproduct, accounting for over 30% of the total barley production. Due to its rough texture and poor palatability, most of the bran is still used as animal feed or simply discarded, resulting in a wasteful resource. However, the content of natural active substances such as protein and cellulose in highland barley bran is higher than that of the raw barley and higher than that of other grains.

[0004] Compared to research on other active ingredients, relatively little research has been conducted on highland barley bran protein. However, highland barley bran has a higher protein content than whole grain highland barley. Currently, research on plant proteins has received widespread attention, so studying the properties and uses of highland barley bran protein is essential. This will not only provide more high-quality plant protein sources, but also provide more ideas for the development of more highland barley bran protein products and increase the economic benefits of highland barley bran.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose highland barley bran protein and its application in meat products.

[0007] The present invention is achieved in that:

[0008] In one aspect, the present invention provides the use of highland barley bran protein in improving the quality of meat products.

[0009] In some embodiments, the above qualities include: color, water holding capacity, cooking loss, texture and sensory properties.

[0010] In some embodiments, the meat products include meatballs, specifically, meatballs include pork meatballs, beef meatballs, mutton meatballs, chicken meatballs and fish meatballs.

[0011] In some embodiments, the above-mentioned highland barley bran protein includes white highland barley bran protein and black highland barley bran protein.

[0012] In some embodiments, the highland barley bran protein comprises modified highland barley bran protein, wherein the modified highland barley bran protein comprises modified black highland barley bran protein and modified white highland barley bran protein.

[0013] Since highland barley bran protein is often hindered in food applications due to its poor functional properties including ductility, solubility, foaming activity and stability, and water and oil retention, the utilization of highland barley bran is relatively low. To overcome this problem, the present invention modifies the obtained highland barley bran protein so that the obtained modified bran protein can be better utilized.

[0014] As a modification method, the present invention selects pH shift and / or ultrasonic treatment. Among them, ultrasonic treatment is to destroy the spatial structure of the protein through the action of ultrasound, making the molecules more easily combined with other substances, thereby improving the functionality of the protein.

[0015] pH shift modification occurs when a protein is exposed to extremely alkaline or acidic pH conditions far from its isoelectric point. Increased repulsive forces between proteins lead to partial unfolding of the protein molecules. Adjusting the solution back to pH 7 allows the protein to refold, resulting in a more flexible structure known as the "molten state." This unfolding and refolding process significantly alters the protein's structural and functional properties.

[0016] In some embodiments, the modified highland barley bran protein is obtained by modifying the crude product of highland barley bran protein by pH shift and / or ultrasound.

[0017] Since the nutrient content in bran of different colors is different, studies have shown that the total phenol content of fiber, protein, flavonoids and anthocyanins in colored bran is higher than that in white bran. Based on this, the present invention studies highland barley with different bran colors and finds that white highland barley bran and black highland barley bran not only have certain differences in protein content, but also have differences in properties between the two proteins: when the black / white highland barley bran protein is subjected to the same modification treatment conditions, the two bran proteins have different effects. From the perspective of overall properties, the white highland barley bran protein is more suitable for alkaline treatment when carrying out pH shift treatment, while the black highland barley bran protein is more suitable for acidic treatment when carrying out pH shift treatment.

[0018] In some embodiments, the pH shift treatment of the white highland barley bran protein comprises: adding an alkaline solution to the crude product of the white highland barley bran protein, adjusting the pH thereof to 9-12, and then adjusting the pH thereof to neutral after the reaction.

[0019] In some embodiments, the pH shift treatment of black barley bran protein comprises: adding an acidic solution to the crude product of black barley bran protein to adjust its pH to 2-5, and then adjusting it to neutral after the reaction.

[0020] In some embodiments, the conditions for ultrasonic treatment of highland barley bran protein are: ultrasonic power of 100-300W, and ultrasonic time of 10-20min.

[0021] On the other hand, the present invention provides a meat product improver, which includes the above-mentioned highland barley bran protein.

[0022] In some embodiments, the added mass of highland barley bran protein in the meat product is 1%-10%.

[0023] The present invention has the following beneficial effects:

[0024] The present invention extracts bran protein from highland barley bran of different bran colors and modifies it. The obtained product is improved in terms of water holding capacity, oil holding capacity, solubility, emulsification, starting capacity, foam retention, and gel properties. The modified bran protein is added to meat products to improve the color, water holding capacity, cooking loss rate, texture, and sensory properties of the meat products to varying degrees. Therefore, applying highland barley bran protein and its modified bran protein to meat product processing not only enables the utilization of discarded highland barley bran, but also improves the quality of meat products. At the same time, using highland barley bran protein and its modified bran protein as meat product improvers also has the characteristics of being green, nutritious, and safe. Therefore, the present invention can provide a new approach for the utilization of highland barley bran protein and increase the economic benefits of highland barley bran. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 The effect of ultrasound combined with pH treatment on the water holding capacity of black barley bran protein (A) / white barley bran protein (B) in Experimental Example 1; different letters in the figure indicate significant differences (P<0.05), the same below;

[0027] Figure 2 The effect of ultrasound combined with pH treatment on the oil retention of black barley bran protein (A) / white barley bran protein (B) in Experimental Example 1;

[0028] Figure 3The effect of ultrasound combined with pH treatment on the solubility of black barley bran protein (A) / white barley bran protein (B) in Experimental Example 1;

[0029] Figure 4 The effect of ultrasound combined with pH treatment on the emulsifying activity of black barley bran protein (A) / white barley bran protein (B) in Experimental Example 1;

[0030] Figure 5 Microscopic observation of black / white barley bran protein emulsion treated with ultrasound combined with pH in Experimental Example 1;

[0031] Figure 6 The effect of ultrasound combined with pH on the foaming and retention of black barley bran protein (A) / white barley bran protein (B) in Experimental Example 1;

[0032] Figure 7 Effects of ultrasound combined with pH treatment on the temperature sweep storage modulus and loss modulus of black / white barley bran protein in Experimental Example 1; (A) and (B) are the storage modulus and loss modulus of black barley bran protein, (C) and (D) are the storage modulus and loss modulus of white barley bran protein;

[0033] Figure 8 Effects of ultrasound combined with pH treatment on the frequency sweep storage modulus and loss modulus of black / white barley bran protein in Experimental Example 1; (A) and (B) are the storage modulus and loss modulus of black barley bran protein, (C) and (D) are the storage modulus and loss modulus of white barley bran protein;

[0034] Figure 9 The effect of ultrasound combined with pH treatment on the UV scanning spectra of black barley bran protein (A) / white barley bran protein (B) in Experimental Example 1;

[0035] Figure 10 The effect of ultrasound combined with pH treatment on the fluorescence scanning spectra of black barley bran protein (A) / white barley bran protein (B) in Experimental Example 1;

[0036] Figure 11 This is the effect of adding different highland barley bran proteins on the color of pork meatballs in Experimental Example 2;

[0037] Figure 12 This is the effect of different highland barley bran protein additions on the cooking loss rate of pork meatballs in Experimental Example 2;

[0038] Figure 13 This is the effect of adding different highland barley bran proteins on the texture of pork meatballs in Experimental Example 2;

[0039] Figure 14 This is the effect of adding different highland barley bran proteins on the cross section of pork meatballs in Experimental Example 2;

[0040] Figure 15 Black / white barley bran protein color;

[0041] Figure 16 The results of the juice loss rate of meatballs thawing in Experimental Example 3;

[0042] Figure 17 The cooking loss results of meatballs in Experimental Example 3;

[0043] Figure 18 The results of the meatball cooking loss rate in Experimental Example 4 are as follows;

[0044] Figure 19 This is the meatball texture result in Experimental Example 4;

[0045] Figure 20 The results of the thawing juice loss rate of meatballs in Experimental Example 4;

[0046] Figure 21 This is the meatball color result in Experimental Example 4. DETAILED DESCRIPTION

[0047] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0048] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0049] Example 1

[0050] This embodiment is the extraction of highland barley bran protein, and the method of alkali dissolution and acid precipitation is adopted to extract black highland barley bran protein and white highland barley bran protein respectively. The specific steps are as follows:

[0051] (1) Black barley bran powder and white barley bran powder are sieved through 80 mesh sieves respectively;

[0052] (2) bran powder and distilled water were mixed in a ratio of 1:15 (mass ratio) to obtain a mixed solution;

[0053] (3) Use 1 mol / L sodium hydroxide solution to adjust the pH of the mixed solution to 11.5;

[0054] (4) Extraction in a 30°C water bath for 90 min;

[0055] (5) Centrifuge at 8000 rpm for 10 min and collect the supernatant;

[0056] (6) Use 1 mol / L hydrochloric acid solution to adjust the pH of the supernatant to the isoelectric point of 4.5;

[0057] (7) Centrifuge at 8000 rpm for 10 min to obtain the precipitate;

[0058] (8) Use 1 mol / L sodium hydroxide solution to adjust the pH of the precipitate to neutral;

[0059] (9) Protein powder is obtained after freeze-drying.

[0060] Example 2

[0061] This example is about obtaining modified black barley bran protein, and the specific steps are as follows:

[0062] (1) The protein powder obtained by freeze-drying in Example 1 was mixed with distilled water in a ratio of 1:20 (protein powder mass: water mass) to form a solution, and stirred on a magnetic stirrer for 20 minutes to fully blend;

[0063] (2) Take an appropriate amount of the prepared protein solution, adjust the pH of the protein solution to 2 using 1 mol / L hydrochloric acid solution, and allow to react for 1 hour;

[0064] (3) Then use 1 mol / L sodium hydroxide solution to adjust the protein solution to neutrality;

[0065] (4) The cells were then treated with a cell disruptor at an ultrasonic power of 300 W for 10 min. To prevent the temperature from rising during the treatment process, the beaker containing the protein solution was placed in crushed ice. The protein solution obtained by the treatment was freeze-dried to obtain the co-modified protein.

[0066] Example 3

[0067] This example is about obtaining modified white highland barley bran protein, and the specific steps are as follows:

[0068] (1) The protein powder obtained by freeze-drying in Example 1 was mixed with distilled water in a ratio of 1:20 (protein powder mass: water mass) to form a solution, and stirred on a magnetic stirrer for 20 minutes to fully blend;

[0069] (2) Take an appropriate amount of the prepared protein solution, adjust the pH of the protein solution to 11 with 1 mol / L sodium hydroxide solution, and let it react for 1 hour;

[0070] (3) Then use 1 mol / L hydrochloric acid solution to adjust the protein solution to neutrality;

[0071] (4) The cells were then treated with a cell disruptor at an ultrasonic power of 300 W for 10 min. To prevent the temperature from rising during the treatment process, the beaker containing the protein solution was placed in crushed ice. The protein solution obtained by the treatment was freeze-dried to obtain the co-modified protein.

[0072] Comparative Example 1

[0073] The difference from Example 2 is that the modification treatment only involves pH shift, without ultrasonic treatment.

[0074] Comparative Example 2

[0075] The difference from Example 2 is that the modification treatment only involves ultrasonic treatment and no pH shift is performed.

[0076] Comparative Example 3

[0077] The difference from Example 3 is that the modification treatment only involves pH shift, without ultrasonic treatment.

[0078] Comparative Example 4

[0079] The difference from Example 3 is that the modification treatment only involves ultrasonic treatment and no pH shift is performed.

[0080] Experimental Example 1

[0081] The modified protein powders obtained in Examples 2-3 and Comparative Examples 1-4 were tested for functional properties, including water holding capacity, oil holding capacity, solubility, emulsification, foaming properties, foam retention, gel properties, UV scanning spectrum and fluorescence scanning spectrum.

[0082] 1. Water holding capacity

[0083] Weigh protein powder (accurate to four decimal places) at a mass of M0 and place it in a test tube. The total weight of the powder and test tube is recorded as M1. Add 5 mL of purified water to the test tube, mix on a vortex for 10 minutes, and let it sit at room temperature for 40 minutes. Centrifuge at 8000 rpm for 10 minutes, discard the supernatant, and invert the test tube on filter paper for 10 minutes. Wipe off any remaining water on the inner wall and weigh the total weight of the precipitate and test tube, M2. The calculation formula is as follows:

[0084] Water holding capacity (g / g) = (M2-M1) / M0

[0085] Where M0 is the mass of protein powder weighed (g), M1 is the total mass of powder and test tube (g), and M2 is the total mass of the precipitate and test tube after centrifugation with water (g).

[0086] Test results such as Figure 1 As shown, Figure 1 It can be seen from A that the water holding capacity of black barley bran protein after ultrasonic treatment is better than that after pH shift treatment alone; however, the water holding capacity of protein after pH shift combined with ultrasonic treatment was not significantly improved. Figure 1B shows that the water holding capacity of white highland barley bran protein after pH shift treatment alone is significantly lower than that of ultrasonically treated and untreated proteins, but the water holding capacity of protein after pH shift combined with ultrasonic treatment is lower than that of untreated protein. This may be due to the influence of pH shift treatment, which reduces the water holding capacity of the combined treated protein.

[0087] 2. Oil retention

[0088] Weigh protein powder (N0) to four decimal places and place it in a test tube. The total weight of the powder and test tube is recorded as N1. Add 5 mL of soybean oil to the test tube, mix thoroughly on a vortexer for 10 minutes, and let it sit at room temperature for 40 minutes. Then, centrifuge at 8,000 rpm for 10 minutes, discard the supernatant, and invert the test tube onto filter paper for 10 minutes. Wipe off any remaining soybean oil on the inner wall, and weigh the total weight of the precipitate and test tube, N2. The calculation formula is as follows:

[0089] Oil retention (g / g) = (N2-N1) / N0

[0090] Where N0 is the mass of protein powder weighed (g), N1 is the total mass of powder and test tube (g), and N2 is the total mass of the precipitate and test tube after centrifugation with soybean oil (g).

[0091] Test results such as Figure 2 As shown. Figure 2 A shows that the oil retention of black barley bran protein after ultrasound treatment alone was 1.44 times that of protein after pH shift treatment alone and 3.47 times that of untreated protein. The oil retention of protein after combined treatment increased by 3.28 times compared to the control group and 1.36 times compared to ultrasound treatment alone. The results show that the oil retention of protein after combined treatment was significantly improved (P<0.05), and the effect was significantly higher than that of pH shift treatment alone (P<0.05), which is consistent with the effect of ultrasound treatment.

[0092] Figure 2 B shows that the oil retention of white highland barley bran protein after ultrasound treatment alone was 1.27 times that of pH shift treatment alone and 2.07 times that of untreated protein. The oil retention of protein after pH shift combined with ultrasound treatment was significantly higher than that after pH shift treatment alone or ultrasound treatment alone, increasing by 1.41 times (pH shift treatment) and 1.11 times (ultrasound treatment), respectively. The results showed that the oil retention of white highland barley bran protein was significantly improved after combined treatment (P<0.05), and the degree of improvement was significantly higher than that after pH shift treatment alone or ultrasound treatment alone (P<0.05).

[0093] 3. Solubility

[0094] Weigh appropriate protein powder to make a 0.1 mg / mL solution. Mix on a vortex for 10 minutes. Centrifuge at 4000 rpm for 10 minutes. Add 0.5 mL of the supernatant to 2.5 mL of Coomassie Brilliant Blue solution and allow to react for 5 minutes. Measure the absorbance of the reaction solution at 595 nm and substitute it into the Coomassie Brilliant Blue standard curve to calculate the solubility. The calculation formula is as follows:

[0095] Solubility (%) = 100% ∗ protein concentration in supernatant / total protein concentration

[0096] Figure 3 A shows that the solubility of black barley bran protein increased significantly after combined treatment (P < 0.05), but decreased slightly compared to either treatment alone, from 46.06% (pH shift treatment) and 51.12% (ultrasound treatment) to 30.31%. This suggests that the combined treatment was less effective than either treatment alone in terms of black barley bran protein solubility. This may be because the turbulent forces generated by ultrasound during treatment accelerated collisions and aggregation between protein molecules, leading to a certain degree of protein aggregation. Furthermore, when the pH was adjusted back to neutral after treatment (pH 2), the protein folded and aggregated as it passed the isoelectric point, resulting in a decrease in protein solubility after combined treatment compared to either treatment alone.

[0097] Depend on Figure 3 B shows that the solubility of white highland barley bran protein increased significantly after the combined treatment (P<0.05), from 29.66% to 43.54%. There was no significant difference in protein solubility between the combined treatment and the pH shift treatment alone or the ultrasound treatment alone. The results show that the combined treatment can significantly improve protein solubility (P<0.05), but there is no significant difference in the effect of improving protein solubility compared with either treatment alone.

[0098] 4. Emulsification

[0099] (1) Emulsifying activity

[0100] The protein powder obtained by freeze-drying was prepared into a 10 mg / mL solution. The protein solution and soybean oil were mixed in a ratio of 3:1. The solution was homogenized at 20,000 rpm for 2 minutes. 50 μL of the emulsion was quickly collected from the bottom and added to 5 mL of SDS solution with a mass fraction of 0.1%. The solution was mixed and the absorbance A0 of the emulsion was measured at a wavelength of 500 nm. The emulsifying activity was calculated as follows:

[0101]

[0102] Where T is a constant 2.303; A0 represents the absorbance of the obtained emulsion; and Φ is the volume fraction of the oil phase.

[0103] (2) Emulsion turbidity

[0104] Immediately take 50 μL from the bottom of the emulsion homogenized by the homogenizer and add it to 5 mL of pure water, shake and mix, measure the absorbance A1 at 600 nm, and use the value of A1 as the reference for the turbidity of the emulsion.

[0105] Figure 4 The results showed that the emulsifying activity and emulsion turbidity of black / white barley bran protein after pH shift combined with ultrasonic treatment were significantly improved compared with those treated with ultrasonic alone (P<0.05). The emulsifying activity of black / white barley bran protein increased from 26.42m 2 / g and 25.1m 2 / g rises to 31.43m 2 / g and 31.52m 2 / g. The dominant role here is played by pH shift treatment. It can be seen that ultrasonic treatment cannot significantly improve the emulsifying activity of protein. However, after combined pH treatment, pH shift increases protein solubility and enhances the exposure of hydrophobic groups, thereby enhancing the emulsifying property of protein.

[0106] (3) Emulsion microscopic observation

[0107] Immediately draw 100uL of the prepared emulsion from the bottom and add it to 1mL of pure water for dilution. After mixing, draw a small amount of the emulsion and place it on a glass slide, and observe it under magnification on an inverted microscope.

[0108] Depend on Figure 5 It can be seen that when untreated, the particle size distribution of the two protein emulsions is uneven, with a large number of aggregates. After pH shift modification alone, the distribution of the emulsion particles is more dispersed, and the emulsion droplets become significantly smaller and more uniform. Compared with the unmodified treatment, the phenomenon of large aggregation and uneven distribution of emulsion particles after ultrasonic treatment has improved. This may be because the increased electrostatic repulsion and hydrophobicity between proteins after ultrasonic treatment prevent the aggregation of the emulsion. After pH shift combined with ultrasonic treatment, the emulsion particles are the smallest and most evenly distributed. This result shows that the emulsification effect of highland barley protein after pH shift combined with ultrasonic modification has improved, confirming the results of emulsification activity and emulsion turbidity. This may be because when ultrasonic treatment and pH shift are combined for treatment, the protein is fully unfolded to form a stable structure, promoting the formation of protein membrane and increasing the interaction between protein and oil.

[0109] 5. Foaming and foam retention

[0110] Prepare a 10mg / mL solution of protein powder, mix and react for 20 minutes, take 10mL of the mixed solution and place it in a centrifuge tube. Use a homogenizer at 10,000 rpm for 2 minutes, then immediately pour it into a 25mL graduated cylinder. After stabilizing for 2 minutes, record the foam volume V0, and then record the foam volume V1 every 30 minutes. The formulas for calculating foaming and foam retention are as follows:

[0111] Foaming property (%) = 100 × V0 / 10

[0112] Foam retention (%) = 100 × V1 / V0

[0113] Where V0 represents the volume of protein foam at the end of homogenization (mL); V1 represents the residual volume of protein foam after standing for 30 minutes (mL).

[0114] Depend on Figure 6 As shown in Figure 1, the foaming properties of black barley bran protein were significantly improved (P<0.05) after pH shift and ultrasound treatment alone, with similar improvements, increasing by 1.37-fold and 1.35-fold, respectively, compared to the control. The combined treatment showed the greatest improvement in foaming properties (P<0.05), increasing by 2.59-fold compared to the control, and by 1.89-fold (pH shift) and 1.91-fold (ultrasound) compared to either treatment alone. Foam retention was significantly reduced under all treatments (P<0.05), particularly after the combined treatment, where foam retention decreased from 59.24% (control), 37.34% (pH shift), and 39.88% (ultrasound) to 24.34% (ultrasound).

[0115] Figure 6 Figure B shows that pH shift and ultrasound treatment alone did not significantly improve the foaming properties of highland barley bran protein compared to the control. However, combined treatment significantly improved the foaming properties of highland barley bran protein, increasing from 60.67% to 116.67%, a 1.92-fold increase. The combined treatment significantly decreased the protein's foam retention, lower than the effects of either modification alone, and also lower than the control, from 55.48% (control), 36.93% (pH shift), and 47.57% (ultrasound treatment) to 32.60%. Ultrasound causes protein molecules to unfold at the air-liquid interface, increasing their ability to diffuse and entrain air at the air-water interface, resulting in improved foaming. Simultaneously, the pH shift exposes hydrophobic protein groups. Combined treatment increases surface hydrophobicity, resulting in better protein solubility and smaller particle size, all of which contribute to improved foaming properties. Combined treatment significantly improved the foaming properties of both proteins, with the improvement significantly greater than that achieved by individual treatments (P < 0.05).

[0116] 6. Gel properties

[0117] Dynamic rheological measurements were performed using a rheometer in the linear viscoelastic region using a 12% protein powder solution. The mixed solution was equilibrated for 60 seconds before each measurement. Glycerol was added to the edge of the equilibration plate during the measurement to prevent water evaporation from the sample during gelation. A temperature sweep was first performed at a fixed frequency of 1 Hz and a constant strain of 1%. The protein sample solution was heated from 25°C to 95°C at a rate of 5°C / min, then held at 95°C for 30 minutes, and then cooled from 95°C to 25°C at a rate of 5°C / min. The storage modulus G' and loss modulus G'' were recorded for each sample. After the temperature sweep, a frequency sweep was performed by applying an angular frequency of 0.1-100 rad / s and a fixed strain of 1%. The rheological parameters G' and G'' of the mixed gel were recorded.

[0118] The gel point, the temperature at which the storage modulus and loss modulus intersect during protein gelation, is defined as the onset of gelation. The gel point of untreated black barley bran protein is 86.28°C. A pH shift of 2 did not reduce the gel point, but ultrasound treatment lowered the gel point to 79.48°C. However, combined treatment reduced the gel point to 56.43°C. The gel point of untreated white barley bran protein is 93.04°C. A pH shift of 11 also failed to reduce the gel point, but combined treatment reduced the gel point to 58.47°C. Ultrasonic treatment can increase a protein's sensitivity to heat, causing it to aggregate and gel. Tong Xing et al. demonstrated that ultrasound treatment reduced the gel point of chicken protein from 65°C to between 55.30 and 54.50°C. After the combined treatment, the gel point temperature of the protein dropped more than that of the single ultrasonic treatment. The possible reasons are: on the one hand, cavitation causes rapid molecular movement, and the shear force generated by ultrasonic cavitation is sufficient to destroy weak protein binding and break protein chains, causing protein dissociation and partial unfolding, exposing hydrophobic groups and disulfide bonds. Under the action of continuously increasing temperature, these unfolded proteins re-aggregate into a new protein network; on the other hand, pH shift treatment causes the subunits in the protein to denature, and the sulfhydryl groups are oxidized to form disulfide bonds. The new disulfide bonds further strengthen the covalent interaction between protein molecules and reinforce the gel network structure of the protein.

[0119] Figure 7A-7B shows that the gel storage modulus value of black barley bran protein increased significantly after the combined treatment of pH shift and ultrasound, and the degree of improvement was greater than that of single pH shift treatment and single ultrasound treatment. It can be seen that the storage modulus of the protein obtained by the combined treatment was 625.77Pa at the end of the cooling stage, and the storage modulus after single pH shift treatment and single ultrasound treatment was 371.74Pa and 330.82Pa, respectively. The gel elasticity of the protein after the combined treatment increased by 1.68 times and 1.89 times compared with the single treatment. In addition, during the constant temperature cooling stage, the storage modulus of the combined treated protein was always higher than that of the single treatment and the untreated protein, indicating that the gel properties of the protein after the combined treatment were higher than those of the single modification treatment. After 56.43°C, the storage modulus of the combined treated protein was always higher than the loss modulus, indicating that the protein gel obtained by the combined treatment has strong solid properties and is a strong gel.

[0120] Depend on Figure 7 C-7D shows that the storage modulus of the white highland barley bran protein after combined treatment is higher than that of the single ultrasound and single pH shift treatments. After the cooling stage, the storage modulus of the white highland barley bran protein treated with the combined treatment was 1157.66Pa, while the storage moduli of the white highland barley bran after pH11 shift treatment and ultrasound treatment were 317.32Pa and 1113.70Pa, respectively. The gel elasticity of the combined treatment was 3.65 times higher than that of the single pH shift treatment, significantly improving the gel properties of the protein. After the heating and cooling stages, the storage modulus and loss modulus of the combined treatment protein were always higher than those of the single pH shift treatment, indicating that the gel properties after the combined treatment were much greater than those of the single pH shift treatment. In this process, the storage modulus of the protein was always greater than the loss modulus, indicating that the gel formed by the white highland barley bran protein after the combined treatment was a strong gel, showing strong solid properties. The change in storage modulus at the end point shows that the combined action can maximize the elasticity and strength of the gel and the density of the network structure.

[0121] Figure 8 The changes in the storage modulus and loss modulus of black and white barley bran proteins as a function of angular frequency after the cooling stage are shown. At the same angular frequency, the storage modulus of all treated black and white barley bran proteins was significantly higher than the loss modulus of the untreated proteins, indicating that the treated black and white barley bran proteins possess strong solid gel-like properties. Furthermore, as the angular frequency increases, the storage modulus and loss modulus of the black and white barley bran proteins before and after treatment also increase. Both the storage modulus and loss modulus show a strong angular frequency dependence, indicating that the gel structure is primarily maintained by non-covalent bonds and that the gels are physical gels rather than covalent gels.

[0122] After pH2 shift combined with ultrasonic treatment, the storage modulus and loss modulus of black barley bran protein increased from 54.87Pa and 86.16Pa to 1072.53Pa and 359.80Pa, respectively ( Figure 8 A-8B), the storage modulus of the protein at any angular frequency after combined treatment is significantly higher than that of the single treatment, indicating that the protein gel strength is the strongest after combined treatment. The storage modulus of the untreated black barley bran protein is lower than the loss modulus, and it is a weak gel in a liquid state. After the combined treatment, the storage modulus of the black barley bran protein is higher than the loss modulus, achieving the strengthening of the black barley bran protein gel and transforming it into a solid state, which is a strong gel. After pH11 shift combined with ultrasonic treatment, the storage modulus and loss modulus of the white barley bran protein increased from 369.38Pa and 213.17Pa to 2141.41Pa and 785.90Pa, respectively ( Figure 8 C-8D), which is higher than the storage modulus of either treatment alone, indicating that the combined treatment enhances protein gel strength. The storage modulus of the combined protein is consistently greater than the loss modulus, indicating strong gel properties. Combined treatment further enhances the gel strength and gel properties of white highland barley bran protein compared to pH shift treatment alone.

[0123] 7. UV scanning spectrum

[0124] Prepare a 0.4 mg / mL solution of protein powder, mix thoroughly, and centrifuge at 2500 rpm for 5 minutes. Take an appropriate amount of the supernatant and perform a spectral scan in the 200-400 nm band using a UV spectrophotometer.

[0125] Depend on Figure 9 A It can be seen that after pH shift combined with ultrasonic treatment, the absorption peak of black barley bran protein at 280nm is much larger than that of the single-treated and untreated proteins. This may be because the ultrasonic cavitation after the combined treatment causes the protein conformation to change, and the unfolding and renaturation of the protein after pH shift treatment may destroy the hydrophobic interaction and van der Waals force between protein molecules, causing the protein structure to unfold. The combined treatment opens the protein structure to a greater extent, enhances the exposure of protein residues, and enhances the absorption peak. After the combined treatment, the absorption peak of white barley bran protein decreases and is lower than the absorption peak when it is not treated ( Figure 9 B). This may be because the temperature rises during ultrasonic treatment, causing the white highland barley bran protein to aggregate and wrap the amino acid residues, resulting in a decrease in the absorption peak.

[0126] 8. Fluorescence scanning spectroscopy

[0127] Prepare a 0.4 mg / mL solution of protein powder, mix thoroughly, and centrifuge at 2500 rpm for 5 minutes. Collect an appropriate amount of the supernatant and record the fluorescence spectrum using an RF-6000 fluorescence spectrometer with an excitation wavelength of 280 nm and an emission wavelength of 300-500 nm at a minimum scan rate of 2000 nm.

[0128] Figure 10 The results showed that after combined treatment, the maximum absorption waves of black and white highland barley bran proteins underwent a 1-2nm red shift, and the fluorescence intensity decreased. The red shift indicates that the polarity of the solution in which the protein is located has changed, that is, the protein structure has been affected. The reduction in fluorescence intensity at this time is likely due to the exposure of tryptophan residues when the combined treatment returns the protein to neutrality and causes it to unfold. In addition, since heat is generated during the ultrasonic treatment, the heating forms larger insoluble aggregates through hydrophobic bonds, which enhances the interaction between exposed hydrophobic amino acid residues and leads to fluorescence quenching. Yizhou Sun et al. also found that the fluorescence intensity of coconut milk protein obtained by acid pH shift combined with ultrasonic treatment was lower than that of coconut milk protein obtained by acid pH shift alone. They believe that the cavitation generated by ultrasound accelerates the formation of large aggregates and promotes the oxidation of sulfhydryl groups to form disulfide bonds, thereby reducing the exposed chromophores and fluorescence intensity.

[0129] Combined treatment effectively improves the effects of pH shift on oil retention, foaming, and gelling properties, while also enhancing the effects of ultrasound treatment on protein emulsification, foaming, and gelling properties. Furthermore, after combined treatment, the foaming and gelling properties of the protein were significantly enhanced compared to either pH shift or ultrasound treatment alone.

[0130] Experimental Example 2

[0131] The black and white highland barley bran protein obtained in Example 1 and the modified highland barley bran protein in Examples 2-3 were added to pork balls respectively to test their effects on the properties of the pork balls, as follows:

[0132] Pork lean meat and pork fat were mixed and minced in a mass ratio of 3:1, and 30% ice water and an appropriate amount of salt, five-spice powder, and other seasonings were added and mixed evenly to obtain a mixed meat paste. Then, the black and white barley bran protein obtained in Example 1 and the modified barley bran protein in Examples 2-3 were added to the mixed meat paste in a mass ratio of 5%, and meatballs of a certain size were formed and cooked at 95°C for 30 minutes to obtain formed meatballs. Wherein, BHBBP represents unmodified black barley bran protein, WHBBP represents unmodified white barley bran protein, UpH-BHBBP represents modified black barley bran protein, and UpH-WHBBP represents modified white barley bran protein.

[0133] 1. Changes in meatball color

[0134] Cut the meatballs flat and measure the colorimetry of the cut surface using a colorimeter. Calibrate with a white board before measurement and record the brightness (L*), redness (a*), and yellowness (b*) values.

[0135] Color is closely linked to the appearance and acceptability of meat products. Meat color is crucial for evaluating meat freshness, with lightness (L*) and redness (a*) being key indicators of meat color. A higher myoglobin content, meaning a greater lean meat content, results in a brighter red color.

[0136] Depend on Figure 11 The addition of protein significantly decreased the brightness and yellowness of the meatballs, while the redness significantly increased (P < 0.05). Excessively high L* values ​​are due to poor water retention and increased internal water migration. Untreated meatballs exhibited the highest brightness, while those with protein significantly decreased (P < 0.05). Combined with the results of the cooking loss rate, the untreated meatballs exhibited poor water retention and a high cooking loss rate, which resulted in water loss and increased brightness. However, the addition of protein reduced the cooking loss rate, suggesting that the addition of protein enhances water retention and reduces water loss, leading to a decrease in surface gloss. Furthermore, the meatballs treated with white barley bran protein before and after modification exhibited lower brightness than those treated with black barley bran protein before and after modification. This is likely due to the color of the protein itself; black barley bran protein is brighter in comparison. After adding protein, the redness value of the meatballs increased significantly, especially when the modified white barley bran protein group was added, the redness value reached the highest. The reason is that the reddish-brown color of the white barley bran protein itself changed the color of the meatballs, and the increase in redness value made it easier to attract consumers' attention.

[0137] 2. Meatball cooking loss rate

[0138] Each portion of minced meat is weighed before cooking and recorded as W1. After cooking, the meatballs are picked up and cooled to room temperature, the surface moisture is wiped off, and the weight is recorded as W2. The cooking loss rate of the meatballs is calculated as follows:

[0139] Cooking loss rate (%) = (W1-W2) / W1

[0140] Where W1 is the mass of uncooked pork meatballs (g), and W2 is the mass of cooked pork meatballs (g).

[0141] Cooking yield is usually measured by the ability of protein to fix water and fat. It is an important indicator used to determine the loss of meat when cooked at high temperatures. Higher cooking loss will reduce the taste, flavor and nutrition of the meat. Figure 12As can be seen from the data, the cooking loss rate of the meatballs in the control group without protein addition was the highest at 25.87%. The cooking loss rates of the meatballs in the groups with unmodified black barley bran protein and white barley bran protein were significantly reduced from 25.87% to 18.52% and 22.72% (P<0.05). The cooking loss rate of the meatballs in the group with black barley bran protein was significantly lower than that in the group with white barley bran protein (P<0.05). Compared with the cooking loss rates of the meatballs in the control and untreated protein groups, the cooking loss rates of the meatballs in the groups with combined modified protein addition reached the lowest values ​​at 10.13% (combined black barley bran protein) and 11.34% (combined white barley bran protein), respectively. The addition of the two combined modified barley bran proteins improved the cooking loss rate of the meatballs to the same extent. After adding protein, the protein exerts its water and oil-holding properties during the cooking process. The gel formed during the heating process also locks in the juices in the meatballs, preventing moisture loss. Compared to unmodified protein, the modified protein has higher water and oil holding capacity and stronger gel properties. During the heating process, it forms a tight gel network, enhancing the binding properties of the pork meatballs with water, locking in moisture and oil, reducing the loss of juice from the meatballs and improving cooking loss.

[0142] 3. Meatball texture

[0143] The cooled pork meatballs were cut into samples of the same size and height and measured using a texture analyzer. Each group was measured three times. Before the measurement, the instrument was calibrated for height force. The test mode was TPA; the test rate was 5 mm / s; the deformation was 40%; the time interval between the two presses was 5 s; the trigger type was automatic; and the trigger force was 5 g.

[0144] Depend on Figure 13It can be seen that the addition of both proteins significantly improved the firmness of the pork meatballs. The meatballs supplemented with unmodified black barley bran protein exhibited a firmer firmness than those supplemented with unmodified white barley bran protein. The meatballs supplemented with the combined modified black and white barley bran proteins significantly increased in firmness from 471.12 to 1049.38 and 982.49, respectively (P < 0.05). The addition of protein increased the protein content of the pork meatballs, and during cooking, the proteins were fully denatured, forming a more stable structure and improving the firmness and chewiness of the meatballs. While the addition of the unmodified proteins did not significantly improve the meatballs' elasticity, the addition of the combined modified proteins significantly increased their elasticity (P < 0.05), increasing it from 0.82 (control group) to 0.95 (modified black barley bran protein group) and 0.92 (modified white barley bran protein group), respectively. This may be because the modified protein has better gel properties, forming a gel during the cooking process, thereby enhancing the elasticity of the meatballs. Compared with the control, the addition of protein can significantly improve the chewiness of the meatballs (P < 0.05). The chewiness of the meatballs with the addition of two unmodified proteins increased significantly from 232.39 to 419.99 (black barley bran protein) and 356.58 (white barley bran protein). The chewiness of the meatballs with the addition of modified proteins increased to 740.18 (black barley bran protein) and 716.29 (white barley bran protein), respectively, which are 3.19 and 3.08 times higher than the control group.

[0145] 4. Observation of the cross section of meatballs

[0146] After cooking and cooling, cut the pork meatballs and take photos to record and observe the changes in the cross-section.

[0147] By cross section Figure 14 It can be seen that the addition of two proteins makes the meatballs appear different colors. The addition of black barley bran protein makes the meatballs appear dark brown, which looks similar to beef balls to the naked eye. The addition of white barley bran protein makes the meatballs appear light red, similar to the appearance of red sausage. In contrast, the meatballs without added protein are lighter in color, and the addition of protein makes the meatballs more attractive. The color change of the meatballs after adding protein is due to the color of the protein itself. Black barley bran protein appears dark gray and white barley bran protein appears reddish brown ( Figure 15 The addition of protein not only makes the meatballs more appealing, but also improves their texture and chewiness. The addition of black and white barley bran protein improves the appearance of the meatballs, making them more appealing and appealing to consumers.

[0148] 5. Sensory evaluation of meatballs

[0149] Find 10 students from the School of Food Science to taste and rate the meatballs. Rinse your mouth with water before tasting. The rating criteria are as follows:

[0150] Table 1 Sensory scoring criteria

[0151]

[0152] The evaluation results are shown in Table 2:

[0153] Table 2 Sensory evaluation results of meatballs

[0154]

[0155] Note: Different letters in the same column indicate significant differences (P<0.05).

[0156] As shown in Table 2, the addition of protein before and after modification can significantly improve the color score of meatballs, especially the addition of protein after modification, which increased by 2.27 times and 2.33 times respectively (P<0.05); the addition of modified protein can significantly improve the taste of meatballs (P<0.05), increasing by 1.59 times and 1.5 times respectively. This may be because the special smell of plant protein itself masks the fishy smell of some meatballs; the taste of meatballs in the group with unmodified protein is not much different from that of meatballs in the control group. It may be that the unmodified protein does not improve the elasticity of the meatballs enough, resulting in little difference in taste, while the combined modified protein can significantly improve the elasticity of the meatballs in terms of texture. The hardness and chewiness (P<0.05) gave the meatballs a better taste. After adding protein, the tissue state score of the meatballs was higher, especially the group with combined modified protein. This may be because the modified protein significantly enhanced the gel strength of the meatballs, making the meatballs tighter and less likely to fall apart when cut. It can be seen that the group with combined modified protein had the highest overall score, which increased by 2.31 times and 2.13 times compared with the control group, and increased by 1.42 times compared with the respective unmodified protein groups. The addition of combined modified protein significantly enhanced the taste, appearance and flavor of the meatballs, and can significantly increase consumers' preference for meatballs.

[0157] Experimental Example 3

[0158] The method of Experimental Example 2 was used to verify the effect of the addition of white barley bran protein on the texture characteristics of beef balls and mutton balls. The texture test results are shown in Table 3:

[0159] Table 3 Results of the texture of beef and mutton meatballs

[0160]

[0161] As shown in Table 3, an appropriate amount of white barley bran protein can improve the lubricity of meatballs, making them more flavorful. However, excessive addition can lead to a rough texture, reduced lubricity, and a poor overall taste. In summary, different addition amounts of white barley bran protein affect the texture, lubricity, and taste of meatballs. An appropriate addition can improve the taste and texture of meatballs, enhancing the eating experience.

[0162] Figure 16 The results show that adding an appropriate amount of white barley bran protein can improve the water retention of meatballs, making the meatballs more tender and juicy. However, when the addition amount is too high, it may cause the meatballs to be too moist, affecting the taste and texture.

[0163] Table 4 shows the colorimetric test results of beef and mutton meatballs:

[0164] Table 4 Chromaticity results

[0165]

[0166] As can be seen from Table 4, the addition of white barley bran protein can make the surface of the meatballs more uniform in color, which is beneficial to improving the overall appearance and texture. Secondly, the appropriate addition of white barley bran protein can also increase the brightness of the meatballs, making them look more attractive and enhancing appetite. In addition, white barley bran protein can also improve the color stability of the meatballs, reduce color changes during heating or insulation, and maintain the aesthetics of the product. Moreover, the addition of white barley bran protein has a significant effect on the color of beef and mutton meatballs. After comparing the meatball samples of the experimental group and the control group, it was found that the meatballs with the addition of white barley bran protein showed a more uniform and brighter color, the overall color was brighter, and had a better visual effect than traditional meatballs.

[0167] from Figure 17 The results showed that meatballs containing white barley bran protein showed a lower loss rate during the cooking process compared to traditional meat products. The addition of white barley bran protein not only improved the taste and chewiness of the meatballs, but also reduced weight loss during the cooking process to a certain extent, maintaining the original delicious taste of the meat product. Overall, white barley bran protein, as a functional ingredient, has a significant impact on cooking loss in meatball production.

[0168] Table 5 shows the sensory quality test results of beef and mutton meatballs:

[0169] Table 5 Determination of sensory quality

[0170]

[0171] As the amount of white barley bran protein added increases, the taste of beef and mutton meatballs will change to a certain extent. A reasonable amount of addition can achieve a balance in taste, color, and aroma, improving the overall sensory quality and thus better satisfying the taste needs of a wider range of people.

[0172] In summary, when the white barley bran protein content is added at a rate of 2%, the thawing water loss rate of the beef balls is relatively small, which can well maintain the texture of the meatballs and show good softness and elasticity; while the mutton balls have a better texture when the white barley bran protein content is added at a rate of 4%.

[0173] Experimental Example 4

[0174] The method of Experimental Example 2 was used to verify the effect of the addition of black barley bran protein on the cooking loss rate of chicken and fish meatballs. The cooking loss rate, texture, thawing juice loss rate and color test results were as follows: Figure 18-21 As shown:

[0175] from Figure 18 It can be seen that the addition of black barley bran protein does help reduce the loss of water in meatballs during cooking, thereby improving the water retention of meatballs. Specifically, by comparing the changes in the cooking loss rate of fish and chicken meatballs, it can be found that although both benefit from the addition of black barley bran protein, the specific response patterns may be slightly different. The initial loss rate of chicken meatballs is low, and it shows a relatively steady downward trend as the amount of protein added increases. Fish meatballs, despite the high initial loss rate, achieve a greater improvement in water retention by adding black barley bran protein.

[0176] Figure 19 Figure A shows the texture results for fish meatballs, and Figure B shows the texture results for chicken meatballs. As can be seen from the figures, the addition of black barley bran protein has a positive impact on the textural properties of both fish and chicken meatballs. Adjusting the amount of protein added effectively improves the hardness, elasticity, and chewiness of the meatballs, providing consumers with a more delicious and nutritious meat product.

[0177] from Figure 20 It can be seen that the addition of black barley bran protein can significantly reduce the thawing juice loss rate of fish meatballs and chicken meatballs, and improve the quality and nutritional value of the meatballs.

[0178] Figure 21 Figure A shows the colorimetric results for fish balls, and Figure B shows the colorimetric results for chicken balls. As can be seen from the figures, the addition of black barley bran protein reduced the brightness of the fish and chicken balls, making the overall color of the balls slightly darker. However, the effect on the red-green and yellow-blue hues was not significant, and the basic color of the balls was maintained after the addition of protein.

[0179] Table 6 shows the sensory evaluation results of fish balls and chicken balls:

[0180] Table 6 Sensory evaluation results of fish balls and chicken balls

[0181]

[0182] As can be seen from the table, when added in appropriate amounts, black barley bran protein can significantly improve the color, flavor, texture, and organizational structure / elasticity of meatballs, thereby improving the overall quality of meatballs. However, excessive protein addition may cause the texture to become too firm, so the amount added should be strictly controlled in actual applications.

[0183] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. Application of modified highland barley bran protein in improving the quality of meat products, characterized in that: The modified highland barley bran protein is obtained by modifying a crude product of highland barley bran protein through pH shift and ultrasound; Said qualities include: color, water holding capacity, cooking loss, texture and sensory properties; The modified highland barley bran protein includes modified white highland barley bran protein and modified black highland barley bran protein; The pH shift treatment of the modified white highland barley bran protein comprises: adding an alkaline solution to the crude product of the white highland barley bran protein to adjust the pH thereof to 9-12, and then adjusting the pH thereof to neutral after the reaction; The pH shift treatment of the modified black barley bran protein comprises: adding an acidic solution to the crude product of the black barley bran protein to adjust the pH thereof to 2-5, and then adjusting the pH thereof to neutral after the reaction.

2. The use according to claim 1, characterized in that The conditions for ultrasonic treatment of the modified highland barley bran protein are: ultrasonic power of 100-300W, and ultrasonic time of 10-20min.

3. The application of modified highland barley bran protein in the preparation of a meat product improver is characterized in that: The modified highland barley bran protein is obtained by modifying a crude product of highland barley bran protein through pH shift and ultrasound; The meat product improver is used to improve the quality of meat products, including color, water holding capacity, cooking loss rate, texture and sensory properties; The modified highland barley bran protein includes modified white highland barley bran protein and modified black highland barley bran protein; The pH shift treatment of the modified white highland barley bran protein comprises: adding an alkaline solution to the crude product of the white highland barley bran protein to adjust the pH thereof to 9-12, and then adjusting the pH thereof to neutral after the reaction; The pH shift treatment of the modified black barley bran protein comprises: adding an acidic solution to the crude product of the black barley bran protein to adjust the pH thereof to 2-5, and then adjusting the pH thereof to neutral after the reaction.

4. The use according to claim 3, characterized in that The added mass of the modified highland barley bran protein in the meat product is 1%-10%.

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