Treatment method for synchronously removing fishy smell and improving taste and chromaticity of soybean protein

Abstract

The invention discloses a treatment method for synchronously deodorizing soybean protein and improving taste and chromaticity. The treatment method comprises the following steps: step 1, treating a combination agent: adding citric acid and phytic acid into deionized water to obtain the treatment combination agent; step 2, deodorization treatment: putting soybean raw materials into the treatment combination agent obtained in the step 1 for treatment; step 3, cleaning: washing the treated soybean raw materials, and removing the residual composite agent; and 4, soybean protein extraction: extracting soybean protein by using an alkali-solution and acid-isolation method. The method has the advantages of high efficiency, low energy consumption, low cost, convenience in operation and the like. According to the invention, an alkali-solution and acid-isolation method is combined with the treatment combination agent, so that the soybean protein treatment efficiency is improved, and the beneficial effects of removing fishy smell and improving taste and chromaticity are achieved.

Description

Technical Field

[0001] The invention belongs to a processing method for simultaneously removing the fishy smell and improving the taste and chromaticity of soybean protein, and can be used in the food pre-processing industry. Background Art

[0002] Soy protein is a nutritious plant protein widely used in the food industry. However, during the extraction and processing of soy protein, a unique fishy smell often occurs. This fishy smell mainly comes from fat oxidation products, volatile sulfides and some amino acid degradation products in soybeans, and the color is poor. Therefore, it not only affects the sensory quality of soy protein, but also limits its application range in food. Therefore, how to effectively remove the fishy smell of soy protein, improve its color, and enhance its sensory quality and market competitiveness has become a key issue of concern to researchers.

[0003] At present, there are three main methods for removing fishy smell and improving taste and color of soy protein: physical method, chemical method and biological method. Physical method includes heating, ultrasonic treatment, membrane separation, etc., which remove fishy smell components by changing physical conditions; chemical method mainly uses chemical reagents such as acid, alkali, oxidant to destroy or transform fishy smell substances and improve color; biological method uses biotechnology means such as enzymolysis and fermentation to degrade fishy smell components and improve color. These methods have their own advantages and disadvantages, but often have incomplete fishy removal effect, large nutritional loss, complex process and high cost, and it is difficult to achieve simultaneous fishy removal and color improvement. Therefore, it is of great practical significance and broad application prospects to develop an efficient, economical, simple method that can achieve simultaneous fishy removal and improve taste and color.

[0004] With the development of science and technology, new processing technologies continue to emerge. For example, Chinese patent document CN104920622A discloses a method for removing the fishy smell of soybeans, which uses vacuum degassing, flash deodorization and enzyme inactivation to remove the fishy smell of soybeans. Although the fishy smell and bitter taste of soybeans are eliminated, the cost of the deodorization process is high, which is not conducive to large-scale deodorization. Chinese patent document CN108935915A discloses a method for removing the fishy smell of soybeans, which uses low-temperature defatted soybean meal and water to mix and steam blanching to remove the fishy smell. Although the obtained soybean protein powder has no fishy smell, there are many process steps, and the steam blanching deodorization step consumes too much energy. Chinese patent document CN114766583A discloses a method for removing the fishy smell of soybeans, which uses oxygen enzymolysis to degrade macromolecular proteins, and uses food-grade acid precipitation to obtain soybean protein and then performs high-voltage pulse electric field treatment. Although soybean protein with fishy smell removed is obtained, the subsequent high-frequency electromagnetic field treatment and atmospheric pressure cold plasma treatment have a high purchase cost of the instrument. Chinese patent document CN1043430A discloses a method for removing the fishy smell of soybeans, using instantaneous (1 to 300 seconds) high temperature (100°C to 220°C) and variable pressure (1013.25PA to 101.325PA), and rapidly reducing pressure to achieve the purpose of removing the fishy smell, but using high temperature, variable pressure, this method has the disadvantage of high energy consumption. Although these technologies can achieve the removal of fishy smell of soybean protein, due to its complex operation, high energy consumption and high cost, it cannot meet the production requirements of green, efficient and low cost. Therefore, this area is in urgent need of proposing a method for synchronously removing the fishy smell of soybean protein and improving colorimetry that is green, environmentally friendly and efficient.

[0005] Alkali extraction and acid precipitation is a commonly used method for extracting soy protein in industrial enterprises. Its principle is that under alkaline conditions, the protein structure changes, the secondary bonds (hydrogen bonds) of protein molecules are destroyed, and some polar groups dissociate, which promotes the separation of the conjugate and protein. The pH value of the supernatant after centrifugation is adjusted so that the pH reaches the isoelectric point of the protein, which increases the solubility of the protein and allows the protein to precipitate. This method is easy to operate for protein extraction and does not produce harmful substances. The protein extraction rate and purity of the alkali-soluble acid precipitation method are high, easy to operate, and low in cost. It has less pollution to the environment and is low in cost. It is a conventional method for extracting soy protein in the industrial sector. Summary of the invention

[0006] The purpose of the present invention is to provide a method for simultaneously removing the odor and improving the taste and color of soybean protein, wherein the soybean raw materials such as soybean meal are treated with a combination of phytic acid and citric acid, and then the treated soybean raw materials such as soybean meal are extracted by an alkali dissolution and acid precipitation method to obtain the soybean protein with the odor removed and the improved taste and color, and the extraction rate of the obtained soybean protein is not affected. The method has the advantages of high efficiency, low energy consumption, low cost, convenient operation, new green, no three wastes discharge, and solvent recyclability.

[0007] In order to achieve the above object, the present invention provides a method for simultaneously removing the fishy smell and improving the taste and color of soybean protein, comprising the following steps:

[0008] Step 1: treating a composition: adding citric acid and phytic acid to deionized water to obtain a treating composition;

[0009] Step 2: deodorization treatment: placing the soybean raw material into the treatment composition obtained in step 1 for treatment;

[0010] Step 3: Cleaning: Wash the processed soybean raw material to remove the residual composition agent;

[0011] Step 4: Soy protein extraction: Soy protein is extracted using the alkali dissolution and acid precipitation method.

[0012] Preferably, in step 1, the addition ratio of deionized water, citric acid and phytic acid is 500 mg citric acid and 5 mL phytic acid per 1 L deionized water. The treatment composition at this ratio is clearer, more transparent and has a lower viscosity, and is more suitable for treating soybean raw materials, especially soybean meal.

[0013] Any of the above items is preferably that the amount of citric acid added to the treatment combination is 250mg~450mg, more preferably 250mg, 300mg, 350mg, 400mg, 450mg; any of the above items is preferably that the amount of phytic acid added is 1mL~4mL, more preferably 1mL, 2mL, 3mL, 4mL; preferably, the amount of deionized water added is adjusted according to the ratio of adding 500mg citric acid and 5mL phytic acid to every 1L of deionized water; preferably, deionized water, citric acid and phytic acid are mixed at room temperature; preferably, the concentration of phytic acid is 100%.

[0014] Any of the above items is preferably that in step 2, the soybean raw material and the treatment composition must be fully mixed, and the treatment time is 1 to 5 hours; further, the time required for treating the soybean meal is preferably 1 hour, 2 hours, 3 hours, 4 hours, 5 hours and ranges therebetween, and the soybean meal must be completely immersed in the treatment composition during the treatment process; further preferably, it is 3 hours.

[0015] Because soybeans produce a variety of volatile substances during their growth process, they will produce an unpleasant smell commonly known as beany smell. The beany smell is composed of substances such as alcohols and aldehydes. More importantly, the fat in the beans is oxidized during the processing or storage process, producing the fishy smell.

[0016] Any of the above is preferably that in step 2, the soybean raw material is soybean meal. The deodorization treatment requires that the soybean meal is completely immersed in the treatment agent so that the soybean meal is in close contact with the treatment composition.

[0017] Any of the above items is preferably that in step 3, the treated soybean raw material is washed with deionized water for 3 times, and the soybean raw material is completely immersed in the washing process and thoroughly washed; the mass ratio of the deionized water used for washing to the treated soybean raw material is 1:1. The water used is deionized water, and the purpose of such washing is to rinse away most of the residual treatment composition agent to ensure that the extraction of soybean protein is not affected in the subsequent extraction.

[0018] Any one of the above is preferably that in step 4, the steps of extracting soybean protein by alkali dissolution and acid precipitation are as follows:

[0019] Step a: preparing NaOH solution and HCL solution; the purpose is to adjust the pH to extract soybean protein;

[0020] Step b: Soaking the soybean raw material in a NaOH solution for 1-5 hours, the temperature during the alkali soaking is 45° C.-65° C., and the ratio of the soybean raw material to the NaOH solution is 1:10 w / v to 1:30 w / v;

[0021] Step c: centrifuging the soaked solution and taking the supernatant;

[0022] Step d: collecting the supernatant and adjusting the pH value of the supernatant to 3.5;

[0023] Step e: Centrifuge again to obtain soybean protein precipitate.

[0024] Any one of the above is preferably that in step a, the NaOH solution is 0.5 mol / L to 3.0 mol / L.

[0025] Any of the above is preferably that in step a, the NaOH solution is 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L and ranges therebetween.

[0026] Any of the above is preferably that in step a, the HCL solution is 0.5 mol / L to 3.0 mol / L.

[0027] Any of the above is preferably that in step a, the HCL solution is 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L and ranges therebetween.

[0028] Any of the above is preferably that in step b, the ratio of soybean meal to NaOH solution is 1:10 (w / v), 1:15 (w / v), 1:20 (w / v) 1:25 (w / v), 1:30 (w / v) and ranges therebetween; soaking is 1-5 hours, preferably 1, 2, 3, 4, 5 hours and ranges therebetween.

[0029] Any of the above is preferably that in step b, the temperature during alkali leaching is 45°C-65°C, preferably 45, 50, 55, 60, 65°C and the range therebetween. Too high a temperature will cause denaturation of the soy protein, affecting the extraction rate and extraction purity. Too low a temperature will cause a change in the extraction rate.

[0030] Any of the above items is preferably that in step b, the ratio of the soybean raw material to the 0.5 mol / L NaOH solution is 1:10 w / v, the treatment time is 3 h, and the liquid surface of the alkaline solution must completely immerse the soybean raw material.

[0031] Preferably, in any of the above items, in step c, the soaked solution is centrifuged to obtain a supernatant.

[0032] Preferably, in any of the above, in step c, the centrifugation parameter is 8000 rpm for 10 min. The supernatant after centrifugation must be clear and transparent to ensure that other impurities are not mixed in during extraction.

[0033] Any of the above is preferably that in step d, the solution for adjusting pH is a 0.5 mol / L HCL solution. In step d,

[0034] The pH value of the supernatant was adjusted to 3.5 with hydrochloric acid in order to make the pH of the soy protein reach its isoelectric point so that the soy protein precipitates from the solution.

[0035] Preferably, in any of the above items, in step e, the centrifugation parameter is centrifugation at 8000 rpm for 10 min.

[0036] The technical solution of the present invention has the following advantages:

[0037] 1. The present invention provides a method for simultaneously removing the odor and improving the taste and color of soybean protein, and relates to the field of deep processing of food. The method comprises: using phytic acid and citric acid as a treatment combination agent to treat soybean raw materials, especially soybean meal, to obtain the treated soybean raw materials, wherein the treatment combination agent is composed of phytic acid and citric acid. These two reagents are low in price, easy to obtain, and the steps are simple to operate.

[0038] 2. The extraction method is an alkali dissolution and acid precipitation method; this method has the advantages of high efficiency, low energy consumption, low cost, and convenient operation. The present invention combines the alkali dissolution and acid precipitation method with the treatment combination agent to improve the soy protein treatment efficiency and achieve the beneficial effects of removing fishy smell and improving taste and color. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a process flow chart for simultaneously removing the fishy smell and improving the taste and color of soybean protein.

[0040] Figure 2This is a color comparison diagram of the alkaline solution before and after deodorization treatment in preferred embodiment 1 of the present invention.

[0041] Figure 3 This is a comparison chart of the color of the soy protein after extraction without deodorization treatment and the color of the soy protein after deodorization treatment in the preferred embodiment 1 of the present invention.

[0042] Figure 4 This is a graph showing the odor analysis of untreated and treated soy protein by the electronic nose 10 sensor in preferred embodiment 1 of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below through the accompanying drawings and specific embodiments.

[0044] like Figure 1 As shown, the present invention Figure 1 Flow chart of the processing process for simultaneously removing the fishy smell and improving the taste and color of soy protein.

[0045] Example 1

[0046] (1) Add 500 mg of citric acid and 5 mL of phytic acid to 1 L of deionized water to prepare a treatment agent. The preparation can be performed at room temperature.

[0047] (2) Deodorization: Place the soybean meal in the treatment agent and treat for 3 hours.

[0048] (3) Cleaning: The deodorized soybean meal was washed three times with deionized water to remove the residual treatment agent.

[0049] (4) Extraction: Soybean protein was extracted using the alkali dissolution and acid precipitation method.

[0050] The treatment agent preferably comprises 500 mg citric acid and 5 mL phytic acid. The treatment agent at this ratio is clearer, more transparent and has a lower viscosity, and is more suitable for treating soybean meal.

[0051] Further, the steps of extracting soybean protein by alkali dissolution and acid precipitation are as follows:

[0052] (1) Prepare 0.5 mol / L NaOH solution and 0.5 mol / L HCl solution to adjust the pH to extract the soybean protein.

[0053] (2) The ratio of soybean meal to NaOH solution is 1:10 (w / v), and the soaking time is 3 hours. The temperature during the alkali soaking is 55°C. Too high a temperature will cause the soybean protein to denature, affecting the extraction rate and extraction purity. Too low a temperature will affect the extraction rate.

[0054] (3) Centrifuge the solution after alkali soaking to obtain the supernatant. The centrifugation parameters are 8000 rpm for 10 minutes. The supernatant after centrifugation must be clear and transparent to ensure that other impurities will not be mixed in during extraction.

[0055] (4) Collect the supernatant and adjust the pH value of the supernatant to 3.5 with hydrochloric acid. The purpose is to make the pH reach the isoelectric point of soybean protein so that the protein can precipitate.

[0056] (5) Centrifuge again to obtain soybean protein precipitate. The centrifugation parameters are 8000 rpm for 10 min.

[0057] In Example 1, preferably, the ratio of soybean raw material to 0.5 mol / L NaOH solution is 1:10 w / v, the processing time is 3 h; the temperature is 55° C.; preferably, the liquid surface of the NaOH solution must completely immerse the soybean meal; preferably, the solution for adjusting the pH requires the use of 0.5 mol / L HCl solution; and the preferred centrifugation parameters are centrifugation at 8000 rpm for 10 min.

[0058] The results are as follows Figure 2 , 3 , 4, Table 1 shows the sensitive substances of PEN3 electronic nose sensor:

[0059] Figure 2 The figure shows the color comparison of the alkaline solution before and after deodorization in the preferred embodiment 1 of the present invention.

[0060] Figure 3 This is a comparison chart of the color of soy protein after extraction without deodorization and the color of soy protein after deodorization.

[0061] Figure 4 The graph shows the odor analysis of untreated and treated soy protein by the electronic nose 10 sensor.

[0062] Table 1: Sensitive substances of PEN3 electronic nose sensor

[0063] serial number sensor Sensitive substances S1 W1C Aromatic compounds S2 W5S Nitrogen oxides S3 W3C Ammonia, aromatic molecule S4 W6C Hydride S5 W5C Olefins, aromatics, polar molecules S6 W1S Alkanes S7 W1W Sulfur compounds S8 W2S Alcohols, some aromatic compounds S9 W2W Aromatic compounds, sulfur-containing organic matter S10 W3S Alkanes and aliphatics

[0064] The above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for simultaneously removing the fishy smell of soybean protein and improving the taste and color. It is characterized in that The following steps are involved: Step 1: treating a composition: adding citric acid and phytic acid to deionized water to obtain a treating composition; Step 2: deodorization treatment: placing the soybean raw material into the treatment composition obtained in step 1 for treatment; Step 3: Cleaning: Wash the processed soybean raw material to remove the residual composition agent; Step 4: Soy protein extraction: Soy protein is extracted using the alkali dissolution and acid precipitation method.

2. The method according to claim 1, It is characterized in that In step 1, the addition ratio of deionized water, citric acid and phytic acid is 500 mg of citric acid and 5 mL of phytic acid per 1 L of deionized water.

3. The method according to claim 1, It is characterized in that In step 2, the soybean raw material and the treatment composition must be fully mixed, and the treatment time is 1 to 5 hours.

4. The method according to claim 3, It is characterized in that In step 2, the soybean raw material is soybean meal.

5. The method according to claim 1, It is characterized in that In step 3, the treated soybean raw material is washed with deionized water for 3 times, and the soybean raw material is completely immersed in the washing process and thoroughly cleaned; the mass ratio of the deionized water used for washing to the treated soybean raw material is 1:

1.

6. The method according to claim 1, It is characterized in that In step 4, the steps of extracting soybean protein by alkali dissolution and acid precipitation are as follows: Step a: prepare NaOH solution and HCL solution; Step b: Soaking the soybean raw material in a NaOH solution for 1-5 hours, the temperature during the alkali soaking is 45° C.-65° C., and the ratio of the soybean raw material to the NaOH solution is 1:10 w / v to 1:30 w / v; Step c: centrifuging the soaked solution and taking the supernatant; Step d: collecting the supernatant and adjusting the pH value of the supernatant to 3.5; Step e: Centrifuge again to obtain soybean protein precipitate.

7. The method according to claim 6, It is characterized in that In step a, the NaOH solution is 0.5 mol / L to 3.0 mol / L; the HCL solution is 0.5 mol / L to 3.0 mol / L.

8. The method according to claim 6, It is characterized in that In step b, the ratio of the soybean raw material to the 0.5 mol / L NaOH solution is 1:10 w / v, the treatment time is 3 h, and the liquid surface of the alkaline solution must completely immerse the soybean raw material.

9. The method according to claim 6, It is characterized in that In step d, the solution for adjusting pH is a 0.5 mol / L HCL solution.

10. The method according to claim 6, It is characterized in that In step e, the centrifugation parameter is 8000 rpm for 10 min.

Images