Processing technology for regulating the gel structure of soy protein by stepwise induction of salt ions

Abstract

The present invention provides a processing technology for regulating the gel structure of soybean protein based on salt ion step-by-step induction. First, soybean protein isolate is uniformly dispersed in distilled water to obtain a protein solution; then oxidized dextran is added to the protein solution, fully stirred to obtain a mixed solution, and cold plasma treatment is performed to obtain a pretreated protein solution; then salt and a coagulant are sequentially added to the pretreated protein solution, ultrasonic oscillation treatment is performed for the first time, and finally fibrous soybean protein is added, ultrasonic oscillation treatment is performed for the second time, and the solution is allowed to stand to obtain a gel product. The present invention combines appropriate pretreatment, based on salt ion step-by-step induction, fibrous soybean protein is further induced, and the structure of soybean protein gel is regulated. The obtained gel product has good taste and flavor, does not involve the addition of other chemical reagents, and has good safety.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and particularly to a processing technology for regulating the gel structure of soybean protein by stepwise induction of salt ions. Background Art

[0002] Soybean protein is a complete protein with high nutritional value, low raw material cost, and good functional properties such as emulsification, gelation, and foaming properties, and is widely used in the processing and production of various foods.

[0003] Gelation is one of the important functional properties of proteins. Protein solutions form a three-dimensional network structure with a certain order through "solidification", that is, covalent or non-covalent interactions, so that protein gels have unique texture properties. Protein gels have many advantages such as edibility, renewability, low cost, high biocompatibility, and biodegradability, and have been widely used in fields such as food intelligent packaging, intelligent fresh-keeping, nutrient delivery, flavor adsorption and retention, and satiety product development. Reasonable design of food gels can not only improve food quality, but also improve the nutritional and bioavailability characteristics of foods, such as constructing foods with ideal sensory structures, maintaining metastable food structures, extending shelf life, replacing fats, and reducing salt and sugar intake, and plays an extremely important role in promoting the development of the modern food industry.

[0004] In traditional research and processing, people usually control the protein gel structure by methods such as controlling the acidification rate, adding other components (such as polysaccharides), and pH-shifting. However, these methods have disadvantages such as complex operation, difficult control, and introduction of exogenous additives, and may bring adverse taste, flavor, and even application safety problems while achieving the purpose, restricting their application in food processing and related fields. Summary of the Invention

[0005] The purpose of the present invention is to provide a processing technology for regulating the gel structure of soybean protein by stepwise induction of salt ions to solve the technical problems such as affecting the taste, flavor, or bringing safety of the existing technology.

[0006] To achieve the above purpose, the present invention provides a processing technology for regulating the gel structure of soybean protein by stepwise induction of salt ions, and the specific steps are as follows:

[0007] (1) First, uniformly disperse soy protein isolate in distilled water to obtain a protein solution;

[0008] (2) Then add dextran oxide to the protein solution, stir well to obtain a mixed solution, and perform cold plasma treatment to obtain a pretreated protein solution;

[0009] (3) Then, add salt and a coagulant to the pretreated protein solution in sequence, perform the first ultrasonic oscillation treatment, finally add fibrillar soy protein, perform the second ultrasonic oscillation treatment, and let it stand to obtain a gel product.

[0010] Preferably, in step (1), the mass ratio of soy protein isolate to distilled water is 1:8 - 10.

[0011] Preferably, in step (2), the dosage of oxidized dextran is 2 - 3% of the mass of the protein solution.

[0012] Preferably, in step (2), by weight, the oxidized dextran is prepared by the following method: Stir and disperse 1 part of dextran in 40 - 50 parts of distilled water, then add 0.5 - 0.7 part of sodium periodate under light - shielding conditions, stir at room temperature in the dark for 4 - 5 hours, dialyze with a dialysis bag with a cut - off molecular weight of 14000, and freeze - dry to obtain it.

[0013] Preferably, in step (2), the process conditions for sufficient stirring are: Stir at 300 - 400 r / min for 30 - 40 minutes.

[0014] Preferably, in step (2), the process conditions for cold plasma treatment are: The gas source uses a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20 - 25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40 - 45 mm, and the treatment time is 3 - 4 minutes.

[0015] Preferably, in step (3), the salt is selected from any one of CaSO4, MgSO4, CaCl2, and MgCl2, the concentration of this salt in the system is 1 - 5 mmol / L, and stir at room temperature for 30 - 40 minutes after adding.

[0016] Preferably, in step (3), the salt is selected from any two of CaSO4, MgSO4, CaCl2, and MgCl2, add them step by step, the concentration of this salt in the system is 1 - 5 mmol / L, and stir at room temperature for 30 - 40 minutes after each addition.

[0017] Preferably, in step (3), the coagulant is CaSO4, and after adding, the total concentration of all salt ions in the system is 35 mmol / L.

[0018] Preferably, in step (3), the process conditions for the first ultrasonic oscillation treatment are: The ultrasonic frequency is 30 kHz, the power density is 100 - 120 W / L, the pulse working time is 10 s, the pulse interval time is 5 s, and the treatment time is 30 - 40 minutes.

[0019] Preferably, in step (3), the dosage of fibrillar soy protein is 0.8 - 1% of the mass of the pretreated protein solution.

[0020] Preferably, in step (3), the fibrous soy protein is prepared by the following method, measured by weight: first, 1 part of soy protein isolate is uniformly dispersed in 20-25 parts of distilled water, the pH is adjusted to 12 using 1-2 mol / L sodium hydroxide solution, heated at 80-85°C for 10-12 minutes, centrifuged to obtain the supernatant, added with an equal volume of 0.5-0.7 mol / L tartaric acid solution to the supernatant, stirred at 65-75°C for 40-50 minutes, centrifuged to obtain the precipitate, and freeze-dried to obtain the product.

[0021] Preferably, in step (3), the process conditions for the second ultrasonic oscillation treatment are: ultrasonic frequency 30 kHz, power density 100-120 W / L, pulse working time 10 s, pulse interval time 5 s, and treatment time 10-15 minutes.

[0022] Preferably, in step (3), the standing process conditions are: standing at 0-4°C for 12-15 hours.

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

[0024] The present invention firstly disperses soybean protein isolate uniformly in distilled water to obtain a protein solution; then adds oxidized dextran to the protein solution, fully stirs to obtain a mixed solution, and performs cold plasma treatment to obtain a pretreated protein solution; then adds salt and a coagulant to the pretreated protein solution in sequence, performs a first ultrasonic oscillation treatment, and finally adds fibrous soybean protein, performs a second ultrasonic oscillation treatment, and stands to obtain a gel product. The present invention combines appropriate pretreatment, based on the step-by-step induction of salt ions, further induces fibrous soybean protein, and regulates the structure of soybean protein gel. The obtained gel product has good taste and flavor, does not involve the addition of other chemical reagents, and has good safety.

[0025] Oxidized dextran is obtained by oxidizing the hydroxyl groups on dextran to aldehyde groups, which promotes interaction with soy protein isolate and promotes gelation.

[0026] Cold plasma treatment can appropriately destroy protein peptide bonds, reduce protein particle size, and then fully modify the protein to promote the formation of gel structure.

[0027] After the introduction of oxidized dextran and cold plasma treatment, the obtained pretreated protein solution has better reactivity and provides a good basis for gelation.

[0028] The present invention introduces salt ions into the system in one or two steps for step-by-step induction, and adds fibrous soybean protein to strengthen the induction effect, promote protein aggregation and gelation, and then ultrasonic oscillation treatment and standing are sufficient, heating is not required, the cost is low, the process is easy to control, the taste and flavor of the product will not be affected, and the product is suitable for industrial production.

[0029] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. Description of the Drawings

[0030] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0031] Figure 1 is the gel structure diagram of the comparative example and the embodiment of the present invention. Detailed Embodiments

[0032] The following will describe in detail the embodiments of the present invention with reference to the drawings. However, the present invention can be implemented in many different ways defined and covered by the claims.

[0033] Comparative Example ( Figure 1 A in

[0034] A preparation method of a protein gel product, the specific steps are as follows: First, uniformly disperse soy protein isolate in 9 times its mass of distilled water, stir at 95 °C for 15 minutes, add calcium sulfate so that the concentration of calcium sulfate is 35 mmol / L, stir at 80 °C for 30 minutes, and naturally cool to room temperature to obtain the gel product.

[0035] Example 1 ( Figure 1 B in

[0036] A processing technology for regulating the gel structure of soy protein by stepwise induction of salt ions, the specific steps are as follows:

[0037] (1) First, uniformly disperse 1 kg of soy protein isolate in 8 - 10 kg of distilled water to obtain a protein solution;

[0038] (2) Then add 2 - 3% by mass of dextran oxide to the protein solution, stir well to obtain a mixed solution, and perform cold plasma treatment to obtain a pretreated protein solution;

[0039] (3) Then add 2 mmol / L CaSO4 to the pretreated protein solution, stir at room temperature for 30 minutes, add 33 mmol / L CaSO4, perform the first ultrasonic oscillation treatment, and finally add fibrillar soy protein (the dosage is 0.8 - 1% of the mass of the pretreated protein solution), perform the second ultrasonic oscillation treatment, and let it stand to obtain the gel product.

[0040] Among them, in step (2), the oxidized dextran is prepared by the following method: 0.1 kg of dextran is stirred and dispersed in 4 - 5 kg of distilled water, then 0.05 - 0.07 kg of sodium periodate is added under dark conditions, and stirred at room temperature for 4 - 5 hours in the dark, dialyzed with a dialysis bag with a cut-off molecular weight of 14,000, and freeze-dried to obtain it.

[0041] In step (2), the process conditions for sufficient stirring are: stirring at 300 - 400 r / min for 30 - 40 minutes.

[0042] In step (2), the process conditions for cold plasma treatment are: the gas source uses a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20 - 25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40 - 45 mm, and the treatment time is 3 - 4 minutes.

[0043] In step (3), the process conditions for the first ultrasonic oscillation treatment are: ultrasonic frequency 30 kHz, power density 100 - 120 W / L, pulse working time 10 s, pulse intermittent time 5 s, and treatment time 30 - 40 minutes.

[0044] In step (3), the fibrillar soy protein is prepared by the following method: first, 0.1 kg of soy protein isolate is evenly dispersed in 2 - 2.5 kg of distilled water, the pH is adjusted to 12 with 1 - 2 mol / L sodium hydroxide solution, heated at 80 - 85 °C for 10 - 12 minutes, centrifuged to take the supernatant, added with 0.5 - 0.7 mol / L tartaric acid solution with the same volume as the supernatant, stirred at 65 - 75 °C for 40 - 50 minutes, centrifuged to take the precipitate, and freeze-dried to obtain it.

[0045] In step (3), the process conditions for the second ultrasonic oscillation treatment are: ultrasonic frequency 30 kHz, power density 100 - 120 W / L, pulse working time 10 s, pulse intermittent time 5 s, and treatment time 10 - 15 minutes.

[0046] In step (3), the process conditions for standing are: standing at 0 - 4 °C for 12 - 15 hours.

[0047] Example 2( Figure 1 in C)

[0048] The processing technology based on step-by-step induction and regulation of the soybean protein gel structure by salt ions is as follows:

[0049] (1) First, 1 kg of soy protein isolate is evenly dispersed in 8 - 10 kg of distilled water to obtain a protein solution;

[0050] (2) Then, add dextran oxide with a mass of 2-3% of the protein solution thereto, stir well to obtain a mixed solution, and perform cold plasma treatment to obtain a pretreated protein solution;

[0051] (3) Next, add 5 mmol / L CaSO4 to the pretreated protein solution, stir at room temperature for 30 minutes, add 30 mmol / L CaSO4, perform the first ultrasonic oscillation treatment, and finally add fibrillar soy protein (the dosage is 0.8-1% of the mass of the pretreated protein solution), perform the second ultrasonic oscillation treatment, and let it stand to obtain a gel product.

[0052] Among them, in step (2), the dextran oxide is prepared by the following method: Stir and disperse 0.1 kg of dextran in 4-5 kg of distilled water, then add 0.05-0.07 kg of sodium periodate under light-shielded conditions, stir at room temperature in the dark for 4-5 hours, dialyze with a dialysis bag with a cut-off molecular weight of 14,000, and freeze-dry to obtain it.

[0053] In step (2), the process conditions for sufficient stirring are: Stir at 300-400 r / min for 30-40 minutes.

[0054] In step (2), the process conditions for cold plasma treatment are: The gas source uses a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20-25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40-45 mm, and the treatment time is 3-4 minutes.

[0055] In step (3), the process conditions for the first ultrasonic oscillation treatment are: The ultrasonic frequency is 30 kHz, the power density is 100-120 W / L, the pulse working time is 10 s, the pulse interval time is 5 s, and the treatment time is 30-40 minutes.

[0056] In step (3), the fibrillar soy protein is prepared by the following method: First, uniformly disperse 0.1 kg of soy protein isolate in 2-2.5 kg of distilled water, adjust the pH = 12 with 1-2 mol / L sodium hydroxide solution, heat at 80-85 °C for 10-12 minutes, centrifuge to take the supernatant, add a 0.5-0.7 mol / L tartaric acid solution with the same volume as the supernatant, stir and treat at 65-75 °C for 40-50 minutes, centrifuge to take the precipitate, and freeze-dry to obtain it.

[0057] In step (3), the process conditions for the second ultrasonic oscillation treatment are: The ultrasonic frequency is 30 kHz, the power density is 100-120 W / L, the pulse working time is 10 s, the pulse interval time is 5 s, and the treatment time is 10-15 minutes.

[0058] In step (3), the process conditions for standing are: Stand at 0-4 °C for 12-15 hours.

[0059] Example 3( Figure 1 in D)

[0060] Processing technology for stepwise induction regulation of soybean protein gel structure based on salt ions, the specific steps are as follows:

[0061] (1) First, 1 kg of soy protein isolate is evenly dispersed in 8 - 10 kg of distilled water to obtain a protein solution;

[0062] (2) Then, dextran oxide with a mass of 2 - 3% of the protein solution is added to the protein solution, and after sufficient stirring to obtain a mixed solution, cold plasma treatment is carried out to obtain a pretreated protein solution;

[0063] (3) Then, 5 mmol / L CaCl2 is added to the pretreated protein solution, stirred at room temperature for 40 minutes, 30 mmol / L CaSO4 is added, the first ultrasonic oscillation treatment is carried out, and finally fibrillar soybean protein (with a dosage of 0.8 - 1% of the mass of the pretreated protein solution) is added, the second ultrasonic oscillation treatment is carried out, and then left standing to obtain a gel product.

[0064] Among them, in step (2), the dextran oxide is prepared by the following method: 0.1 kg of dextran is stirred and dispersed in 4 - 5 kg of distilled water, then 0.05 - 0.07 kg of sodium periodate is added under light - shielding conditions, stirred at room temperature in the dark for 4 - 5 hours, dialyzed with a dialysis bag with a cut - off molecular weight of 14000, and freeze - dried to obtain it.

[0065] In step (2), the process conditions for sufficient stirring are: stirring at 300 - 400 r / min for 30 - 40 minutes.

[0066] In step (2), the process conditions for cold plasma treatment are: the gas source uses a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20 - 25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40 - 45 mm, and the treatment time is 3 - 4 minutes.

[0067] In step (3), the process conditions for the first ultrasonic oscillation treatment are: ultrasonic frequency 30 kHz, power density 100 - 120 W / L, pulse working time 10 s, pulse intermittent time 5 s, and treatment time 30 - 40 minutes.

[0068] In step (3), the fibrous soy protein is prepared by the following method: first, 0.1 kg of soy protein isolate is uniformly dispersed in 2-2.5 kg of distilled water, the pH is adjusted to 12 using 1-2 mol / L sodium hydroxide solution, heated at 80-85° C. for 10-12 minutes, centrifuged to obtain the supernatant, an equal volume of 0.5-0.7 mol / L tartaric acid solution is added to the supernatant, stirred at 65-75° C. for 40-50 minutes, centrifuged to obtain the precipitate, and freeze-dried to obtain the fibrous soy protein.

[0069] In step (3), the process conditions for the second ultrasonic oscillation treatment are: ultrasonic frequency 30kHz, power density 100-120W / L, pulse working time 10s, pulse interval time 5s, and treatment time 10-15 minutes.

[0070] In step (3), the standing process conditions are: standing at 0-4° C. for 12-15 hours.

[0071] Example 4 Figure 1 Middle E)

[0072] The processing technology based on salt ion step-by-step induction and regulation of soy protein gel structure, the specific steps are as follows:

[0073] (1) First, 1 kg of soy protein isolate is uniformly dispersed in 8-10 kg of distilled water to obtain a protein solution;

[0074] (2) then adding 2-3% by weight of oxidized dextran to the protein solution, stirring thoroughly to obtain a mixed solution, and treating with cold plasma to obtain a pretreated protein solution;

[0075] (3) Add 5 mmol / L CaSO4 to the pretreated protein solution, stir at room temperature for 30 to 40 minutes, add 5 mmol / L MgSO4, stir at room temperature for 30 to 40 minutes, add 25 mmol / L CaSO4, perform the first ultrasonic oscillation treatment, and finally add fibrous soy protein (the amount is 0.8 to 1% of the mass of the pretreated protein solution), perform the second ultrasonic oscillation treatment, and let it stand to obtain a gel product.

[0076] Wherein, in step (1) and step (2), the oxidized dextran is prepared by the following method: 0.1 kg of dextran is stirred and dispersed in 4 to 5 kg of distilled water, then 0.05 to 0.07 kg of sodium periodate is added in a dark environment, stirred at room temperature in a dark environment for 4 to 5 hours, dialyzed with a dialysis bag with a molecular weight cutoff of 14,000, and freeze-dried to obtain the oxidized dextran.

[0077] In step (2), the process conditions for sufficient stirring are: stirring at 300-400 r / min for 30-40 minutes.

[0078] In step (2), the process conditions for cold plasma treatment are as follows: the gas source is a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20 - 25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40 - 45 mm, and the treatment time is 3 - 4 minutes.

[0079] In step (3), the process conditions for the first ultrasonic oscillation treatment are as follows: the ultrasonic frequency is 30 kHz, the power density is 100 - 120 W / L, the pulse working time is 10 s, the pulse intermittent time is 5 s, and the treatment time is 30 - 40 minutes.

[0080] In step (3), the fibrillated soy protein is prepared by the following method: first, 0.1 kg of soy protein isolate is uniformly dispersed in 2 - 2.5 kg of distilled water, the pH is adjusted to 12 using 1 - 2 mol / L sodium hydroxide solution, heated at 80 - 85 °C for 10 - 12 minutes, centrifuged to obtain the supernatant, added with 0.5 - 0.7 mol / L tartaric acid solution of the same volume as the supernatant, stirred at 65 - 75 °C for 40 - 50 minutes, centrifuged to obtain the precipitate, and freeze-dried to obtain it.

[0081] In step (3), the process conditions for the second ultrasonic oscillation treatment are as follows: the ultrasonic frequency is 30 kHz, the power density is 100 - 120 W / L, the pulse working time is 10 s, the pulse intermittent time is 5 s, and the treatment time is 10 - 15 minutes.

[0082] In step (3), the process conditions for standing are as follows: standing at 0 - 4 °C for 12 - 15 hours.

[0083] Example 5( Figure 1 in F)

[0084] A processing technology based on stepwise induction and regulation of the soy protein gel structure by salt ions is as follows:

[0085] (1) First, 1 kg of soy protein isolate is uniformly dispersed in 8 - 10 kg of distilled water to obtain a protein solution;

[0086] (2) Then, add 2 - 3% by mass of dextran oxide to the protein solution, stir well to obtain a mixed solution, and perform cold plasma treatment to obtain a pretreated protein solution;

[0087] (3) Then, add 5 mmol / L CaSO4 to the pretreated protein solution, stir at room temperature for 30 - 40 minutes, add 5 mmol / L MgCl2, stir at room temperature for 30 - 40 minutes, add 25 mmol / L CaSO4, perform the first ultrasonic oscillation treatment, and finally add fibrillated soy protein (the dosage is 0.8 - 1% of the mass of the pretreated protein solution), perform the second ultrasonic oscillation treatment, and stand to obtain a gel product.

[0088] Among them, in step (2), the oxidized dextran is prepared by the following method: 0.1 kg of dextran is stirred and dispersed in 4 - 5 kg of distilled water, then 0.05 - 0.07 kg of sodium periodate is added under light - shielding conditions, and stirred at room temperature for 4 - 5 hours under light - shielding. Dialyze with a dialysis bag with a cut - off molecular weight of 14,000, and freeze - dry to obtain it.

[0089] In step (2), the process conditions for sufficient stirring are: stirring at 300 - 400 r / min for 30 - 40 minutes.

[0090] In step (2), the process conditions for cold plasma treatment are: the gas source uses a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20 - 25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40 - 45 mm, and the treatment time is 3 - 4 minutes.

[0091] In step (3), the process conditions for the first ultrasonic oscillation treatment are: ultrasonic frequency 30 kHz, power density 100 - 120 W / L, pulse working time 10 s, pulse interval time 5 s, and treatment time 30 - 40 minutes.

[0092] In step (3), the fibrillar soy protein is prepared by the following method: first, 0.1 kg of soy protein isolate is uniformly dispersed in 2 - 2.5 kg of distilled water, adjust the pH = 12 with 1 - 2 mol / L sodium hydroxide solution, heat at 80 - 85 °C for 10 - 12 minutes, centrifuge to take the supernatant, add a 0.5 - 0.7 mol / L tartaric acid solution with the same volume as the supernatant, stir at 65 - 75 °C for 40 - 50 minutes, centrifuge to take the precipitate, and freeze - dry to obtain it.

[0093] In step (3), the process conditions for the second ultrasonic oscillation treatment are: ultrasonic frequency 30 kHz, power density 100 - 120 W / L, pulse working time 10 s, pulse interval time 5 s, and treatment time 10 - 15 minutes.

[0094] In step (3), the process conditions for standing are: standing at 0 - 4 °C for 12 - 15 hours.

[0095] Example 6( Figure 1 in G)

[0096] A processing technology based on step - by - step induction and regulation of the soybean protein gel structure by salt ions, the specific steps are as follows:

[0097] (1) First, 1 kg of soy protein isolate is uniformly dispersed in 8 - 10 kg of distilled water to obtain a protein solution;

[0098] (2) Then, add oxidized dextran with a mass of 2 - 3% of the protein solution thereto, stir well to obtain a mixed solution, and subject it to cold plasma treatment to obtain a pretreated protein solution;

[0099] (3) Next, add 5 mmol / L CaCl2 to the pretreated protein solution, stir at room temperature for 30 - 40 minutes, add 5 mmol / L MgCl2, stir at room temperature for 30 - 40 minutes, add 25 mmol / L CaSO4, perform the first ultrasonic oscillation treatment, and finally add fibrillar soy protein (with a dosage of 0.8 - 1% of the mass of the pretreated protein solution), perform the second ultrasonic oscillation treatment, and let it stand to obtain a gel product.

[0100] Among them, in step (2), the oxidized dextran is prepared by the following method: Disperse 0.1 kg of dextran in 4 - 5 kg of distilled water by stirring, then add 0.05 - 0.07 kg of sodium periodate under light - shielding conditions, stir at room temperature for 4 - 5 hours under light - shielding, dialyze with a dialysis bag with a cut - off molecular weight of 14000, and freeze - dry to obtain it.

[0101] In step (2), the process conditions for thorough stirring are: Stir at 300 - 400 r / min for 30 - 40 minutes.

[0102] In step (2), the process conditions for cold plasma treatment are: The gas source uses a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20 - 25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40 - 45 mm, and the treatment time is 3 - 4 minutes.

[0103] In step (3), the process conditions for the first ultrasonic oscillation treatment are: The ultrasonic frequency is 30 kHz, the power density is 100 - 120 W / L, the pulse working time is 10 s, the pulse interval time is 5 s, and the treatment time is 30 - 40 minutes.

[0104] In step (3), the fibrillar soy protein is prepared by the following method: First, uniformly disperse 0.1 kg of soy protein isolate in 2 - 2.5 kg of distilled water, adjust the pH = 12 with 1 - 2 mol / L sodium hydroxide solution, heat at 80 - 85 °C for 10 - 12 minutes, centrifuge to take the supernatant, add a 0.5 - 0.7 mol / L tartaric acid solution with the same volume as the supernatant, stir and treat at 65 - 75 °C for 40 - 50 minutes, centrifuge to take the precipitate, and freeze - dry to obtain it.

[0105] In step (3), the process conditions for the second ultrasonic oscillation treatment are: The ultrasonic frequency is 30 kHz, the power density is 100 - 120 W / L, the pulse working time is 10 s, the pulse interval time is 5 s, and the treatment time is 10 - 15 minutes.

[0106] In step (3), the static process conditions are: static at 0 - 4°C for 12 - 15 hours.

[0107] Figure 1 It is the gel structure diagram of the gel products obtained in the comparative example and Examples 1 - 6 of the present invention. Among them, in the comparative example, heat denaturation and calcium sulfate gelation are used. In Examples 1 and 2, the salt is added in one step, and in Examples 3 - 6, the salt is added step by step. The binding rates and binding strengths between different salt ions and proteins are different (MgCl2 > CaCl2 > MgSO4 > CaSO4). The aggregation rate and aggregation degree of proteins can be regulated by controlling the type of salt ions and the concentration of salt ions, thereby controlling the formation of protein aggregates. Finally, under the action of the coagulant (CaSO4), a gel network with different microstructures is formed. The slow protein - salt ion binding rate enables the protein molecules to aggregate slowly and orderly, and finally the gel structure is uniform and dense; if the binding rate is too fast, the protein molecules aggregate randomly and disorderly, resulting in a rough and porous gel structure. Therefore, by using the salt ion step - by - step induction technology and controlling the induction times, the type and concentration of salt ions, the gel structure of proteins can be effectively regulated, and then it can be applied in different demand scenarios.

[0108] Randomly select 10 volunteers to evaluate the taste and flavor of the gel products obtained in the comparative example and Examples 1 - 6. The evaluation criteria are as follows:

[0109] Taste: Excellent 5 points, Good 4 points, Fair 3 points, Poor 2 points, Very poor 1 point;

[0110] Flavor: Excellent 5 points, Good 4 points, Fair 3 points, Poor 2 points, Very poor 1 point;

[0111] Take the average score for each product, and the evaluation results are shown in Table 1.

[0112] Table 1. Taste and flavor evaluation

[0113] Taste Flavor Comparative Example 3 3.5 Example 1 4.8 5 Example 2 4.8 5 Example 3 5 5 Example 4 5 5 Example 5 5 5 Example 6 5 5

[0114] Respectively conduct TPA texture analysis on the gel products obtained in the comparative example and Examples 1 - 6 to detect elasticity. The specific method is as follows:

[0115] Take a cylindrical gel product (diameter 2.5 cm, height 1.5 cm), use a P / 36R cylindrical flat probe, with a compression force of 5 g, a compression amount of 30%, a pre - compression speed of 5 mm / s, a compression speed of 1 mm / s, and a post - compression speed of 5 mm / s. Measure 3 times and take the average value. The results are shown in Table 2.

[0116] The elasticity test results are shown in Table 2.

[0117] Table 2. Elasticity test results of gel products

[0118] Elasticity Comparative Example 0.621 Example 1 0.932 Example 2 0.935 Example 3 0.943 Example 4 0.947 Example 5 0.952 Example 6 0.959

[0119] As can be seen from Table 1 and Table 2, compared with the comparative examples, the gel products obtained in Examples 1 to 6 have significantly better taste and flavor, indicating that reducing the heat treatment can avoid the impact on the taste and flavor of the products.

[0120] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A processing technology for regulating the gel structure of soybean protein by stepwise induction of salt ions, characterized in that, The specific steps are as follows: (1) First, evenly disperse soy protein isolate in distilled water to obtain a protein solution; (2) Then, add dextran oxide to the protein solution, stir well to obtain a mixed solution, and perform cold plasma treatment to obtain a pretreated protein solution; (3) Next, add salt and a coagulant to the pretreated protein solution in sequence, perform the first ultrasonic oscillation treatment, finally add fibrillar soy protein, perform the second ultrasonic oscillation treatment, and let it stand to obtain a gel product; In step (1), the mass ratio of soy protein isolate to distilled water is 1:8 - 10; In step (2), the dosage of dextran oxide is 2 - 3% of the mass of the protein solution; By weight, the dextran oxide is prepared by the following method: Stir and disperse 1 part of dextran in 40 - 50 parts of distilled water, then add 0.5 - 0.7 part of sodium periodate under light-shielded conditions, stir at room temperature in the dark for 4 - 5 hours, dialyze with a dialysis bag with a cut-off molecular weight of 14000, and freeze-dry to obtain; In step (2), the process conditions of cold plasma treatment are: The gas source uses a mixed gas composed of argon and oxygen in a volume ratio of 98:2, the gas flow rate for exciting the plasma is 20 - 25 L / min, the distance between the plasma flame and the liquid surface of the mixed solution is 40 - 45 mm, and the treatment time is 3 - 4 minutes.

2. The processing technology according to claim 1, characterized in that, In step (2), the process conditions for sufficient stirring are: Stir at 300 - 400 r / min for 30 - 40 minutes.

3. The processing technology according to claim 1, characterized in that, In step (3), the salt is selected from any one of CaSO4, MgSO4, CaCl2, and MgCl2, the concentration of this salt in the system is 1 - 5 mmol / L, and stir at room temperature for 30 - 40 minutes after adding.

4. The processing technology according to claim 1, wherein, In step (3), the salt is selected from any two of CaSO4, MgSO4, CaCl2, and MgCl2, added step by step, the concentration of this salt in the system is 1 - 5 mmol / L, and stir at room temperature for 30 - 40 minutes after each addition.

5. The processing technology according to claim 1, characterized in that, In step (3), the coagulant is CaSO4, and after adding, the total concentration of all salt ions in the system is 35 mmol / L.

6. The processing technology according to claim 1, wherein, In step (3), the process conditions for the first ultrasonic oscillation treatment are: The ultrasonic frequency is 30 kHz, the power density is 100 - 120 W / L, the pulse working time is 10 s, the pulse interval time is 5 s, and the treatment time is 30 - 40 minutes; The dosage of fibrillar soy protein is 0.8 - 1% of the mass of the pretreated protein solution; By weight, the fibrillar soy protein is prepared by the following method: First, evenly disperse 1 part of soy protein isolate in 20 - 25 parts of distilled water, adjust the pH = 12 with 1 - 2 mol / L sodium hydroxide solution, heat at 80 - 85 °C for 10 - 12 minutes, centrifuge to take the supernatant, add a 0.5 - 0.7 mol / L tartaric acid solution with the same volume as the supernatant, stir at 65 - 75 °C for 40 - 50 minutes, centrifuge to take the precipitate, and freeze-dry to obtain; The process conditions for the second ultrasonic oscillation treatment are: The ultrasonic frequency is 30 kHz, the power density is 100 - 120 W / L, the pulse working time is 10 s, the pulse interval time is 5 s, and the treatment time is 10 - 15 minutes; The process conditions for standing still are: standing still at 0 - 4°C for 12 - 15 hours.

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