Preparation method of oyster mushroom protein-based gel and application of oyster mushroom protein-based gel in preparation of low-fat high-protein cheese sticks

Abstract

The invention discloses a preparation method of oyster mushroom protein-based gel and application of the oyster mushroom protein-based gel in preparation of low-fat high-protein cheese sticks. The oyster mushroom protein-based gel is obtained through pH adjustment and thermal induction. Cheese bars prepared by replacing traditional cream cheese with the oyster mushroom protein-based gel prepared by the method have good texture characteristics, water binding capacity, dehydration contractility and sensory characteristics compared with full-fat cheese bars, and have the characteristics of low fat and high protein compared with commercially available cheese bars. The protein content is higher than that of commercially available cheese sticks, the fat content is lower than that of commercially available cheese sticks, and the cheese stick is a novel low-fat high-protein cheese stick product and provides a theoretical basis for development of other dairy products.

Description

Technical Field

[0001] The present invention relates to a preparation method of a Pleurotus ostreatus protein-based gel and its application in the preparation of low-fat and high-protein cheese sticks, belonging to the technical field of food processing. Background Art

[0002] In recent years, issues such as the increase in the global population, consumers' dietary needs, and environmental problems have triggered world food supply problems. There is an urgent need to find new proteins to replace animal and plant proteins to relieve resource pressure. As an important part of the global healthy food industry, the edible mushroom industry has an expanding market scale year by year. As an important new alternative protein in the future food field, edible mushroom protein, with its unique advantages such as sustainable production and high nutritional value, meets the core needs of the concept of great health.

[0003] As a bulk edible mushroom, Pleurotus ostreatus has achieved industrial-scale production. It not only has a low price and a delicious taste, but also contains various nutrients such as carbohydrates, proteins, fats, vitamins, minerals, and dietary fiber, with a protein content as high as 36.4%. Pleurotus ostreatus protein is composed of various essential amino acids such as lysine, threonine, and valine, belonging to high-quality protein, and also has functional characteristics such as unique gel and flavor-binding properties, and has been gradually applied to the production and processing of various foods. Research shows that single-protein gels mostly present a loose and porous three-dimensional network structure, are easily affected by processing conditions, and it is difficult to obtain an ideal gel structure. Konjac glucomannan has excellent physical and chemical properties and has attracted much attention in the industry. Utilizing its functional characteristics to improve the gel structure of Pleurotus ostreatus protein-based gels is of great significance for the development of new protein gel products.

[0004] Due to its rich flavor levels, stable physical properties, and portability advantages, cheese sticks have become a popular category in the dairy consumption market. However, the fat content of traditional cheese sticks generally reaches 20% - 30%, which cannot meet the current consumers' healthy dietary needs of low fat and high protein. Moreover, the reduction of the fat content will, to a certain extent, affect the texture and unique flavor of cheese sticks. Protein-based gels have a special three-dimensional network structure and can simulate the relevant characteristics of traditional cream cheese. They are excellent fat substitutes, which can enable dairy products to still maintain a good taste under low-fat conditions, perfectly fitting the current dietary concept and health concept, and have received extensive attention. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide a preparation method of a Pleurotus ostreatus protein-based gel, its product, and its application in replacing traditional cream cheese to prepare low-fat and high-protein cheese sticks, so that the cheese sticks have good texture characteristics, water-holding capacity, syneresis, and sensory characteristics; and enable the cheese sticks to have the characteristics of low fat and high protein.

[0006] Technical solution: The present invention provides a method for preparing Pleurotus ostreatus protein-based gel, which comprises the following steps:

[0007] 1) Mix the freeze-dried powder of Pleurotus ostreatus evenly with deionized water, perform the first pH adjustment with NaOH, carry out alkali extraction, centrifuge, take the supernatant, perform the second pH adjustment with citric acid for acid precipitation, take the precipitate after centrifugation, redissolve it with water, then perform the third pH adjustment with NaOH solution and dialysis, and freeze-dry to obtain Pleurotus ostreatus protein;

[0008] 2) Compound the Pleurotus ostreatus protein obtained in step 1) with konjac glucomannan, add deionized water to prepare a Pleurotus ostreatus protein-based protein solution, adjust the pH with NaOH solution and citric acid solution, and then perform magnetic stirring to obtain the treated Pleurotus ostreatus protein-based protein solution;

[0009] 3) Heat the treated Pleurotus ostreatus protein-based protein solution obtained in step 2) in a water bath, then cool it to room temperature in an ice-water bath, and after equilibration, it is the Pleurotus ostreatus protein-based gel.

[0010] Further, in step 1), the material-liquid ratio of the freeze-dried powder of Pleurotus ostreatus to deionized water is 1:50 g / mL; the first pH adjustment is to 12, the second pH adjustment is to 4, and the third pH adjustment is to 7; the centrifugation conditions are 4000 r / min and the centrifugation time is 20 min; the alkali extraction is for 3 h; the dialysis is for 48 h.

[0011] Further, in step 2), the mass ratio of the Pleurotus ostreatus protein to konjac glucomannan is 20:0.2 - 1.0; the mass fraction of the Pleurotus ostreatus protein-based protein solution is 20%; the pH is adjusted to 4 - 8; the magnetic stirring is for 3 h.

[0012] Further, in step 3), the water bath heating temperature is 90 °C and the time is 30 min; the equilibration conditions are 4 °C and 12 h.

[0013] The present invention also provides the Pleurotus ostreatus protein-based gel prepared by the above method.

[0014] The present invention also provides the application of the above Pleurotus ostreatus protein-based gel in the preparation of low-fat and high-protein cheese sticks.

[0015] Further, the cheese sticks are prepared by mixing whole milk powder, the mixture of Pleurotus ostreatus protein-based gel and traditional cream cheese, granulated sugar, gelatin and cocoa powder.

[0016] Further, the mass ratio of the whole milk powder, the mixture of Pleurotus ostreatus protein-based gel and traditional cream cheese, granulated sugar, gelatin and cocoa powder is 35 - 50:35:5 - 9.5:5 - 5.5:0.5 - 1.

[0017] Furthermore, the mass percentage of the Pleurotus ostreatus protein-based gel in the mixture of the Pleurotus ostreatus protein-based gel and traditional cream cheese is 10-50%.

[0018] Furthermore, the mass percentage of the Pleurotus ostreatus protein-based gel in the mixture of the Pleurotus ostreatus protein-based gel and traditional cream cheese is 10-20%.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: The Pleurotus ostreatus protein-based gel prepared by the present invention can replace traditional cream cheese to prepare low-fat and high-protein cheese sticks, which have good texture properties, water-holding capacity, syneresis and sensory properties, and are a kind of cheese sticks with good evaluation; Compared with commercially available cheese sticks, its protein content is higher than that of commercially available cheese sticks, and its fat content is lower than that of commercially available cheese sticks. It is a new type of low-fat and high-protein cheese stick product, providing a theoretical basis for the development of other dairy products. Description of the Drawings

[0020] Att Figure 1 : Comparison chart of water-holding capacity and gel strength of Pleurotus ostreatus protein-based gels prepared under different pH conditions;

[0021] Att Figure 2 : Comparison chart of hardness and elasticity of Pleurotus ostreatus protein-based gels prepared under different pH conditions;

[0022] Att Figure 3 : Surface and cross-sectional views of cheese sticks with different Pleurotus ostreatus protein-based gel contents;

[0023] Att Figure 4 : Comparison chart of texture properties of cheese sticks with different Pleurotus ostreatus protein-based gel contents;

[0024] Att Figure 5 : Comparison chart of water-holding capacity of cheese sticks with different Pleurotus ostreatus protein-based gel contents;

[0025] Att Figure 6 : Comparison chart of syneresis of cheese sticks with different Pleurotus ostreatus protein-based gel contents;

[0026] Att Figure 7 : Comparison chart of sensory evaluation of cheese sticks obtained in Examples 1-6 of the present invention;

[0027] Att Figure 8 : Comparison chart of fat and protein contents of cheese sticks with 20% Pleurotus ostreatus protein-based gel content and commercially available cheese sticks. Detailed Embodiments

[0028] The technical solutions of the present invention will be further described below with reference to the drawings.

[0029] Example 1 Preparation of Pleurotus ostreatus Protein-Based Gel

[0030] 1) Preparation of Pleurotus ostreatus protein: Mix the freeze-dried Pleurotus ostreatus powder with deionized water at a solid-liquid ratio of 1:50 g / mL, adjust the pH to 12.0 with food-grade NaOH solution for alkali extraction for 3 h, then centrifuge at 4000 r / min for 20 min, take the supernatant, adjust the pH of the supernatant to 4.0 with food-grade citric acid solution for acid precipitation, centrifuge at 4000 r / min for 20 min, take the precipitate, redissolve it in water, then adjust the pH value to 7.0 with food-grade NaOH solution and dialyze for 48 h, and freeze-dry to obtain Pleurotus ostreatus protein;

[0031] 2) Preparation of Pleurotus ostreatus protein-based protein solution: Compound the Pleurotus ostreatus protein obtained in step 1) and konjac glucomannan at a mass ratio of 20:0.6, add deionized water to prepare a Pleurotus ostreatus protein-based protein solution with a mass fraction of 20%, then adjust the pH to 6.0 with food-grade NaOH and citric acid solutions and stir magnetically for 3 h to obtain the treated Pleurotus ostreatus protein-based protein solution;

[0032] 3) Preparation of Pleurotus ostreatus protein-based gel: Heat the Pleurotus ostreatus protein-based protein solution obtained in step 2) in a water bath at 90 °C for 30 min, cool it to room temperature in an ice-water bath, and then equilibrate at 4 °C for 12 h to obtain Pleurotus ostreatus protein-based gel.

[0033] Comparative Example 1

[0034] Steps 1) and 3) are the same as in Example 1.

[0035] 2) Preparation of Pleurotus ostreatus protein-based protein solution: Compound the Pleurotus ostreatus protein obtained in step 1) and konjac glucomannan at a mass ratio of 20:0.6, add deionized water to prepare a Pleurotus ostreatus protein-based protein solution with a mass fraction of 20%, then adjust the pH to 4.0 with food-grade NaOH and citric acid solutions and stir magnetically for 3 h to obtain the treated Pleurotus ostreatus protein-based protein solution.

[0036] Comparative Example 2

[0037] Steps 1) and 3) are the same as in Example 1.

[0038] 2) Preparation of Pleurotus ostreatus protein-based protein solution: Compound the Pleurotus ostreatus protein obtained in step 1) and konjac glucomannan at a mass ratio of 20:0.6, add deionized water to prepare a Pleurotus ostreatus protein-based protein solution with a mass fraction of 20%, then adjust the pH to 5.0 with food-grade NaOH and citric acid solutions and stir magnetically for 3 h to obtain the treated Pleurotus ostreatus protein-based protein solution;

[0039] Comparative Example 3

[0040] Steps 1) and 3) are the same as in Example 1.

[0041] 2) Preparation of Pleurotus ostreatus protein-based protein solution: The Pleurotus ostreatus protein obtained in step 1) and konjac glucomannan were compounded at a mass ratio of 20:0.6, and deionized water was added to prepare a Pleurotus ostreatus protein-based protein solution with a mass fraction of 20%. Then, the pH was adjusted to 7.0 with food-grade NaOH and citric acid solution and magnetically stirred for 3 h to obtain the treated Pleurotus ostreatus protein-based protein solution.

[0042] Comparative Example 4

[0043] Steps 1) and 3) are the same as in Example 1.

[0044] 2) Preparation of Pleurotus ostreatus protein-based protein solution: The Pleurotus ostreatus protein obtained in step 1) and konjac glucomannan were compounded at a mass ratio of 20:0.6, and deionized water was added to prepare a Pleurotus ostreatus protein-based protein solution with a mass fraction of 20%. Then, the pH was adjusted to 8.0 with food-grade NaOH and citric acid solution and magnetically stirred for 3 h to obtain the treated Pleurotus ostreatus protein-based protein solution.

[0045] The water-holding capacity, gel strength, hardness, and elasticity of the Pleurotus ostreatus protein-based gels prepared in Example 1 and Comparative Examples 1-4 were tested:

[0046] Water-holding capacity: Weigh 2 g of the Pleurotus ostreatus protein-based gel into a 10 mL centrifuge tube, and record the mass of the centrifuge tube as m0, and the mass of the initial sample and the centrifuge tube as m1. Centrifuge at 10000×g for 15 min at 4°C. After centrifugation, remove the supernatant and weigh the mass of the centrifuge tube and the precipitate, denoted as m2. The test was repeated three times.

[0047]

[0048] Gel strength: Place the Pleurotus ostreatus protein-based gel stored at 4°C in a room temperature environment for 1 h. Use a texture analyzer model TA-XT Plus. The program is set to a gel strength of 50 N, the probe is P / 0.5. During the probe pressing process, the trigger force is 0.1 N, the deformation amount is 40%, the puncture distance is 3 mm, and the detection speed is 1.0 mm / s. The test was repeated 3 times.

[0049] Hardness and elasticity: (1) Use a texture analyzer to measure the texture properties of different Pleurotus ostreatus protein-based gels. The specific parameters are as follows: P / 0.5 probe, the pre-test speed is 1.0 mm / s, the test speed is 1.0 mm / s, the post-test speed is 1.0 mm / s, the deformation amount is 40%, the trigger force is 0.1 N, the number of pressing times is 2, and the test was repeated three times.

[0050] The test results are shown in Figure 1 and Figure 2 . The results show that as the pH value of the Pleurotus ostreatus protein-based gel increases to 6, the water-holding capacity, gel strength, hardness, and elasticity of the Pleurotus ostreatus protein-based gel are all significantly enhanced.

[0051] Example 2 Preparation of low-fat and high-protein cheese sticks using Pleurotus ostreatus protein-based gel to replace traditional cream cheese and evaluation of cheese sticks

[0052] 1. Preparation of cheese sticks:

[0053] Mix whole milk, the mixture of Pleurotus ostreatus protein-based gel and traditional cream cheese (Milkana cream cheese), granulated sugar, gelatin and cocoa powder according to the mass ratio of 50:35:9.5:5:0.5, stir at 90 °C until no particles are formed, sieve twice, then pour into molds, and let it form overnight in a 4 °C refrigerator. Demold the next day to prepare cheese sticks with different contents of Pleurotus ostreatus protein-based gel. Among them, the Pleurotus ostreatus protein-based gel accounts for 0%, 10%, 20%, 30%, 40% and 50% of the mixture respectively.

[0054] Cut the above-prepared cheese sticks into cylinders with a diameter of 1 cm and a height of 1 cm. The colors and cross-sections of each cheese stick are as Figure 3 shown.

[0055] 2. Evaluation of cheese sticks

[0056] (1) Use a texture analyzer to measure the texture properties of cheese sticks with different contents of Pleurotus ostreatus protein-based gel. The specific parameters are as follows: P / 0.5 probe, the pre-test speed is 1.0 mm / s, the test speed is 1.0 mm / s, the post-test speed is 1.0 mm / s, the deformation is 40%, the trigger force is 0.1 N, the number of downward presses is 2, and the test is repeated 3 times. The test results are shown in Figure 4 . The results show that with the increase of the replacement ratio of Pleurotus ostreatus protein-based gel, the hardness, elasticity, chewiness and cohesiveness of the cheese sticks are all significantly enhanced. Among them, when the replacement ratio is 20%, the cheese stick has good hardness and chewiness, which has a very high correlation with hardness. This shows that the Pleurotus ostreatus protein-based gel has a compact network structure, which can make the cheese stick have stronger texture properties.

[0057] (2) Put cheese sticks (1 g) with different contents of Pleurotus ostreatus protein-based gel into 2 mL centrifuge tubes respectively, then centrifuge at 10000 g for 15 minutes at 4 °C. After centrifugation, remove the supernatant and carefully remove the water on the surface of the cheese sticks with absorbent paper. Record the mass of the centrifuge tube and the cheese stick before centrifugation (W0) and after centrifugation (W1). The calculation formula for water-holding capacity (%) is as follows: water-holding capacity (%) = (W0 - W1) / W0 × 100%. The test results are shown in Figure 5 . The results show that when the replacement ratio of the Pleurotus ostreatus protein-based gel prepared by the present invention is 20%, the prepared cheese stick has the highest water-holding capacity.

[0058] (3) Cheese sticks with different Pleurotus ostreatus protein-based gel contents were sealed and stored at 4 °C for 4, 7, and 14 days. Record the initial weight (m0) of the sample before storage. After the storage period ended, carefully pour out all the drained liquid, and then weigh the remaining cheese stick (m1). The formula for syneresis (%) is as follows:

[0059] Syneresis (%) = (m0 - m1) / m0 × 100%. The test results are shown in Figure 6 . The results showed that when the substitution ratio of the Pleurotus ostreatus protein-based gel prepared in the present invention was 20%, the cheese stick prepared had the lowest syneresis.

[0060] (4) The sensory evaluation was carried out in the Food Nutrition and Chemistry Laboratory. The evaluation panel consisted of 10 sensory evaluation personnel aged 20 - 30 years old, including 5 male members and 5 female members. Before the sensory evaluation, the evaluation panel was appropriately trained according to the purpose, requirements, and standards of the sensory evaluation experiment. During the sensory evaluation, the cheese sticks with different Pleurotus ostreatus protein-based gel contents were randomly numbered, and the personnel of the evaluation panel independently and objectively evaluated the cheese sticks with different Pleurotus ostreatus protein-based gel contents respectively. During the evaluation process, there was a time interval between different samples, and they rinsed their mouths with water.

[0061] Table 1 Sensory Evaluation Criteria

[0062]

[0063] The test results are as Figure 7 shown. The results showed that the 20% Pleurotus ostreatus protein-based gel cheese stick had good flavor, taste, color, texture, and overall acceptance, and there was little difference from the full-fat cheese stick. Therefore, the cheese stick with 20% Pleurotus ostreatus protein-based gel replacing traditional cream cheese was selected as the optimal formula.

[0064] (5) The 20% Pleurotus ostreatus protein-based gel cheese stick was compared with a commercially available cheese stick (Miaokelan Duo GB25192), and the protein and fat contents in the sample were measured with reference to GB 5009 - 2016. The results are as Figure 8 shown. The results showed that for the cheese stick prepared by using 20% Pleurotus ostreatus protein-based gel prepared in the present invention to replace traditional cream cheese, the fat content was significantly lower than that of the commercially available cheese stick, while the protein content was significantly higher than that of the conventional commercially available cheese stick.

Claims

1. A preparation method of a Pleurotus ostreatus protein-based gel, characterized in that, It includes the following steps: 1) Mix the freeze-dried Pleurotus ostreatus powder evenly with deionized water, conduct the first pH adjustment with NaOH solution, perform alkali leaching, centrifuge, take the supernatant, conduct the second pH adjustment with citric acid solution for acid precipitation, take the precipitate after centrifugation, redissolve it with water, conduct the third pH adjustment with NaOH solution and then dialyze, and freeze-dry to obtain Pleurotus ostreatus protein; 2) Compound the Pleurotus ostreatus protein obtained in step 1) with konjac glucomannan, add deionized water to prepare a Pleurotus ostreatus protein-based protein solution, adjust the pH with NaOH solution and citric acid solution, and then stir magnetically to obtain the treated Pleurotus ostreatus protein-based protein solution; 3) Heat the treated Pleurotus ostreatus protein-based protein solution obtained in step 2) in a water bath, cool it in an ice-water bath to room temperature, and after equilibration, it is the Pleurotus ostreatus protein-based gel.

2. The preparation method according to claim 1, wherein, In step 1), the material-liquid ratio of the freeze-dried Pleurotus ostreatus powder to deionized water is 1:50 g / mL; the first pH adjustment is to 12, the second pH adjustment is to 4, the third pH adjustment is to 7; the centrifugation conditions are 4000 r / min and the centrifugation time is 20 min; the alkali leaching is for 3 h; the dialysis is for 48 h.

3. The preparation method according to claim 1, characterized in that, In step 2), the mass ratio of the Pleurotus ostreatus protein to konjac glucomannan is 20:0.2 - 1.0; the mass fraction of the Pleurotus ostreatus protein-based protein solution is 20%; adjust the pH to 4 - 8; stir magnetically for 3 h.

4. The preparation method according to claim 1, wherein In step 3), the water bath heating temperature is 90 °C and the time is 30 min; the equilibration conditions are 4 °C and 12 h.

5. The Pleurotus ostreatus protein-based gel prepared by the method according to any one of claims 1 - 4.

6. The application of the Pleurotus ostreatus protein-based gel according to claim 5 in the preparation of low-fat and high-protein cheese sticks.

7. The application according to claim 6, wherein The cheese stick is prepared by mixing whole milk powder, the mixture of Pleurotus ostreatus protein-based gel and traditional cream cheese, granulated sugar, gelatin and cocoa powder.

8. The application according to claim 7, wherein The mass ratio of the whole milk powder, the mixture of Pleurotus ostreatus protein-based gel and traditional cream cheese, granulated sugar, gelatin and cocoa powder is 35 - 50:35:5 - 9.5:5 - 5.5:0.5 - 1.

9. The application according to claim 7, wherein In the mixture of the Pleurotus ostreatus protein-based gel and traditional cream cheese, the mass percentage of the Pleurotus ostreatus protein-based gel in the mixture is 10 - 50%.

10. The application according to claim 7, wherein In the mixture of the Pleurotus ostreatus protein-based gel and traditional cream cheese, the mass percentage of the Pleurotus ostreatus protein-based gel in the mixture is 10 - 20%.

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