Selenium-enriched wheat bran selenium stabilizing method

Abstract

The invention belongs to the technical field of selenium stabilization, and particularly relates to a selenium stabilization method for selenium-rich wheat bran. The wheat bran selenium steady-state liquid provided by the invention consists of chitosan, pig plasma protein, oleic acid and a dispersion medium, and the mass ratio of the chitosan to the pig plasma protein to the oleic acid is (0.5-1.5): (1-3): (0.5-3). The selenium stabilizing method for the selenium-enriched wheat bran comprises the following steps: freezing the selenium-enriched wheat bran at-4 to-10 DEG C for 12-24 hours, performing freeze drying, and then crushing the obtained freeze-dried selenium-enriched wheat bran to 60-100 meshes to obtain freeze-dried selenium-enriched wheat bran powder; and uniformly mixing the freeze-dried selenium-enriched wheat bran powder with the wheat bran selenium steady-state liquid, freezing for 12-24 hours at the temperature of-4 DEG C to-10 DEG C, and freeze-drying to obtain the selenium-stabilized selenium-enriched wheat bran powder. According to the method, the selenium content of the selenium-rich wheat bran can be efficiently reserved.

Description

Technical Field

[0001] This invention belongs to the field of selenium stabilization technology, and specifically relates to a method for selenium stabilization of selenium-enriched wheat bran. Background Technology

[0002] Selenium (Se) is an essential trace element for living organisms. Selenoproteins and their derivatives can promote health by participating in physiological activities such as antioxidation, enhancing the immune system's emergency response, and antibacterial activity. Long-term selenium deficiency may lead to Keshan disease and Kashin-Beck disease.

[0003] Noodles are an important component of the diet, and wheat is an important carrier of selenium. However, the selenium content in ordinary wheat is too low to meet people's selenium intake needs. Selenium-enriched wheat bran contains 32% selenium, so adding selenium-enriched wheat bran to ordinary wheat products can supplement their selenium content to meet people's needs. However, the heat treatment during wheat product processing leads to a serious loss of selenium. Therefore, developing selenium stabilization technology can effectively improve the selenium retention rate in selenium-enriched noodles, thus providing an effective way to solve the problem of insufficient selenium intake. Summary of the Invention

[0004] To address the problem of effective selenium preservation in pasta products, this invention provides a selenium-enriched wheat bran selenium-stabilized liquid and a selenium stabilization method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a selenium-stabilized wheat bran solution, wherein the selenium-stabilized solution is composed of chitosan, porcine plasma protein, oleic acid, and a dispersion medium, wherein the mass ratio of chitosan, porcine plasma protein, and oleic acid is (0.5-1.5):(1-3):(0.5-3). Furthermore, the dispersion medium is water. The molecular weight of the chitosan is 5000-15000.

[0006] In a further preferred embodiment, the mass ratio of chitosan, porcine plasma protein, and oleic acid is 1.2:2.5:1.2.

[0007] Secondly, the present invention provides a method for preparing a selenium-stabilized wheat bran solution, comprising: Chitosan, porcine plasma protein, and oleic acid are added to the dispersion medium and mixed evenly to obtain the final product.

[0008] Thirdly, the present invention provides a method for selenium stabilization of selenium in selenium-enriched wheat bran, comprising: Selenium-enriched wheat bran is frozen at -4℃ to -10℃ for 12 to 24 hours, freeze-dried, and then the freeze-dried selenium-enriched wheat bran is pulverized to 60-100 mesh to obtain freeze-dried selenium-enriched wheat bran powder. Freeze-dried selenium-enriched wheat bran powder was mixed evenly with a selenium-stabilized liquid, frozen at -4℃ to -10℃ for 12 to 24 hours, and then freeze-dried to obtain selenium-stabilized selenium-enriched wheat bran powder. The concentration of the selenium-stabilized liquid was 2 to 5% wt, and the amount of selenium-stabilized liquid added was 1 to 5% of the mass of the freeze-dried selenium-enriched wheat bran powder.

[0009] In a further optimized scheme, the freezing temperature is -10℃. The pulverization mesh size is 100 mesh. The freezing time is 21.2 hours. The concentration of the selenium stabilized solution is 2%wt, and the amount of selenium stabilized solution added is 4.4% of the mass of the freeze-dried selenium-enriched wheat bran powder.

[0010] The beneficial effects of this invention are as follows: 1. The selenium stabilization method of selenium-enriched wheat bran of the present invention can efficiently retain the selenium content of selenium-enriched wheat bran. The selenium-enriched wheat bran powder prepared by this method can be used as a selenium source to supplement wheat foods to increase their selenium content.

[0011] 2. The selenium in the selenium-enriched wheat bran powder prepared by the method of the present invention is in a protected state, and the loss of selenium when added to wheat products is small. The selenium retention rate in bread with added stabilized selenium-enriched wheat bran powder is 33.3% higher than that in bread with added unstabilized selenium-enriched wheat bran powder. Attached Figure Description

[0012] Figure 1 The effect of different grinding mesh sizes on the selenium content of selenium-enriched bran flour bread.

[0013] Figure 2 The effect of different freezing times on the selenium content in bread.

[0014] Figure 3 The effect of different ratios of chitosan, porcine plasma protein, and oleic acid on the selenium content of bread.

[0015] Figure 4 The effect of the amount of selenium stabilized liquid added on the selenium content of bread. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0017] Experimental materials used in the examples: Selenium-enriched wheat bran (selenium content 2.4 mg / kg), from Henan Huifeng Flour Co., Ltd. Chitosan (water-soluble, molecular weight 5000-15000), prepared in-house. Preparation method: Chitosan (degree of deacetylation 80%-90%) was prepared into a 10 g / L solution, pH adjusted to 4.5, and treated with ultrasound at 480 W and 35℃ for 300 min. The temperature was then raised to 45℃, and pepsin was added at a dosage of 0.20 g / g chitosan for 120 min. After enzyme inactivation, the mixture was cooled to room temperature, desalted, filtered through gel resin, and the fraction with a molecular weight of 5000-15000 was collected, concentrated, and freeze-dried. Porcine plasma protein, from Shenzhen Ruiqing Bioinformatics Technology Co., Ltd. Oleic acid, potassium ferricyanide, and disodium hydrogen phosphate, from Shanghai Maclean Biochemical Technology Co., Ltd. Yeast and sugar, from Dennis Department Store.

[0018] Some of the experimental instruments used in the examples: The temperature and humidity chamber is from Shanghai Xinmiao Medical Equipment Co., Ltd., model CH-250A. The multi-functional oven is from Guangzhou Bangjie Electronic Products Co., Ltd., model AG-12C. The dough mixer is from Guangdong Chubang Machinery Co., Ltd., model TA-12. The micronizer is from Shanghai Baize Instruments Co., Ltd., model XF-68S. The atomic fluorescence spectrometer is from Beijing LabTech Instruments Co., Ltd., model LabAF 1000. The double-beam UV-Vis spectrophotometer is from Shanghai Xipu Instruments Co., Ltd., model UV7600.

[0019] In this example, the experiment was repeated three times, and the results were averaged. Excel 2016 was used for data processing, Origin 2021 was used for plotting and correlation analysis, and SPSS 26 was used for regression analysis.

[0020] Example 1: Optimization of Selenium-Enriched Wheat Bran Stabilization Process 1. Effect of the mesh size of freeze-dried selenium-enriched bran on the selenium content of bread 1.1 Selenium-enriched wheat bran stabilization treatment Weigh out selenium-enriched wheat bran, freeze it at -10℃ for 24 hours, then freeze-dry the frozen selenium-enriched wheat bran using a freeze dryer, and then finely pulverize the resulting freeze-dried selenium-enriched wheat bran at a low temperature (maintaining the temperature between -20℃ and -10℃) to 60, 70, 80, 90, and 100 mesh to obtain freeze-dried selenium-enriched wheat bran powder for later use.

[0021] Take 2% by weight of a selenium-stabilized liquid from freeze-dried selenium-enriched wheat bran powder, mix it evenly with the freeze-dried selenium-enriched wheat bran powder, freeze at -10℃ for 24 hours, and then freeze-dry using a freeze dryer to obtain selenium-stabilized selenium-enriched wheat bran powder. The selenium-stabilized liquid is prepared by adding chitosan, porcine plasma protein, and oleic acid to water to prepare a liquid with a concentration of 2% wt; wherein, by mass ratio, chitosan:porcine plasma protein:oleic acid = 1:3:0.5.

[0022] 1.2 Bread Making Mix 170g wheat flour, 30g selenium-stabilized selenium-enriched wheat bran powder, 4g yeast, 12g white sugar, and 3g salt. Add 130ml cold water (adjust the amount according to water absorption). Mix on speed 2 with a dough mixer for 2 minutes. Cover the dough with plastic wrap and let it rest in a proofing box (30℃, 80% humidity) for 20 minutes. Remove the dough and add 6g butter. Mix on a dough mixer for 13 minutes (until the dough can form a thin membrane). Shape the dough and let it rest in the proofing box for 20 minutes. Remove the dough and roll it out to release air. Roll it up and let it rest in the proofing box for 30 minutes. Repeat the above steps for another 20 minutes. Remove the dough, shape it, place it in a mold, and let it rise for 60 minutes (adjust according to the dough's resilience). Bake at 180℃ for 20 minutes.

[0023] 1.3 Determination of selenium content in bread Establishing a standard working curve: (1) Selenium standard application solution: Take 1.0 mL of 100 μg / mL selenium standard stock solution and make up to 100 mL. The concentration of this application solution is 1 μg / mL.

[0024] (2) Take 0.00 ml, 0.10 ml, 0.20 ml, 0.30 ml, 0.40 ml and 0.50 ml of standard working solution respectively into 15 ml centrifuge tubes and dilute to 10 ml with deionized water. Then add 2 ml of hydrochloric acid and 1.0 ml of potassium ferricyanide solution respectively and mix well.

[0025] (3) Plot the standard working curve. The selenium content was determined by atomic fluorescence spectrometry (GB 5009.93—2010). The main operating parameters of the instrument were: negative high voltage 280 V, lamp current 50 mA, carrier gas flow rate 300 ml / min, shielding gas flow rate 600 mL / min, and atomizer temperature 200℃.

[0026] Determination: Accurately weigh 1 g (accurate to 0.001 g) of the sample to be tested into a digestion flask, add 10 ml of mixed acid (HNO3 and HClO4 volume ratio of 4:1) and a few glass beads, and digest overnight in a cold environment. The next day, heat on a hot plate and add nitric acid as needed. When the solution becomes clear and colorless with white fumes, add 5.0 ml of 6 mol / L hydrochloric acid and continue heating until the solution becomes clear and colorless with white fumes. Transfer the digestion solution to a 50 ml volumetric flask and dilute to volume. Determine the selenium content. Perform a blank test simultaneously.

[0027] Depend on Figure 1 As shown, the selenium content in the flour produced by adding selenium-enriched wheat bran powder ground to 60, 70, and 80 meshes differed significantly (p < 0.05), while the selenium content in the flour produced by adding selenium-enriched wheat bran powder ground to 80, 90, and 100 meshes was not significantly different. This indicates that the particle size of the selenium-enriched wheat bran powder has a significant impact on the retention of selenium during its thermal processing.

[0028] Taking all factors into consideration, we chose to grind the material to 80 mesh for further optimization experiments.

[0029] 2. The effect of freezing time on the selenium content of bread 2.1 Selenium-enriched wheat bran stabilization treatment Weigh out selenium-enriched wheat bran and freeze it at -10℃ for 12, 15, 18, 21 and 24 hours respectively. Then freeze-dry the frozen selenium-enriched wheat bran using a freeze dryer. Finally, pulverize the freeze-dried selenium-enriched wheat bran at low temperature to 80 mesh. Other conditions are the same as in 1.1 to prepare selenium-stabilized selenium-enriched wheat bran powder.

[0030] 2.2 Bread Making Make bread according to the procedure in 1.2.

[0031] 2.3 Determination of selenium content in bread The selenium content in bread was determined according to the procedure in 1.3.

[0032] Depend on Figure 2 As shown, the selenium content of the selenium-enriched wheat bran flour prepared with different freezing times varied significantly (p < 0.05), with the flour prepared after freezing for 21 hours having the highest selenium content. This indicates that the freezing time has a significant impact on the retention of selenium during the thermal processing of selenium-enriched wheat bran flour.

[0033] Taking all factors into consideration, freezing for 21 hours was chosen for subsequent optimization experiments.

[0034] 3. Effect of the ratio of chitosan, porcine blood protein, and oleic acid on the selenium content of bread 3.1 Selenium-enriched wheat bran stabilization treatment Weigh out selenium-enriched wheat bran, freeze it at -10℃ for 21 hours, freeze-dry the frozen selenium-enriched wheat bran using a freeze dryer, and then pulverize the resulting freeze-dried selenium-enriched wheat bran at low temperature to 80 mesh to obtain freeze-dried selenium-enriched wheat bran powder for later use.

[0035] Take 2% by weight of selenium-stabilized liquid from freeze-dried selenium-enriched wheat bran powder, mix it evenly with the freeze-dried selenium-enriched wheat bran powder, freeze at -10℃ for 24 hours, and then freeze-dry using a freeze dryer to obtain selenium-stabilized selenium-enriched wheat bran powder. The selenium-stabilized liquid is prepared by adding chitosan, porcine plasma protein, and oleic acid to water to prepare a liquid with a concentration of 2% wt; wherein, by mass ratio, the ratios of chitosan:porcine plasma protein:oleic acid are (0.3:1:0.3), (0.6:1.5:0.6), (0.9:2.0:0.9), (1.2:2.5:1.2), and (1.5:3.0:1.5).

[0036] 3.2 Bread Making Make bread according to the procedure in 1.2.

[0037] 3.3 Determination of selenium content in bread The selenium content in bread was determined according to the procedure in 1.3.

[0038] Depend on Figure 3 As shown, the selenium content of the wheat bran flour prepared with different chitosan:pork plasma protein:oleic acid ratios varied significantly (p < 0.05), with the highest selenium content observed in the chitosan:pork plasma protein:oleic acid ratio of 1.2:2.5:1.2. This indicates that the ratio of chitosan, protein, and oleic acid in the preparation of selenium-enriched wheat bran flour significantly affects the retention of selenium during thermal processing.

[0039] Taking all factors into consideration, a ratio of chitosan:pork plasma protein:oleic acid of 1.2:2.5:1.2 was selected for subsequent optimization experiments.

[0040] 4. Effect of the amount of selenium-stabilized liquid added on the selenium content of bread 4.1 Selenium-enriched wheat bran stabilization treatment: Weigh out selenium-enriched wheat bran and freeze it at -10℃ for 21 hours. Then freeze-dry the frozen selenium-enriched wheat bran using a freeze dryer. Finally, pulverize the freeze-dried selenium-enriched wheat bran at low temperature to 80 mesh to obtain freeze-dried selenium-enriched wheat bran powder for later use.

[0041] Selenium-stabilized liquids at concentrations of 1%, 2%, 3%, 4%, and 5% by weight of freeze-dried selenium-enriched wheat bran powder were taken respectively, mixed evenly with the freeze-dried selenium-enriched wheat bran powder, and then freeze-dried at -10℃ for 24 hours to obtain selenium-stabilized selenium-enriched wheat bran powder. The selenium-stabilized liquid was prepared by adding chitosan, porcine plasma protein, and oleic acid to water to prepare a liquid with a concentration of 2% wt; wherein, by mass ratio, chitosan:porcine plasma protein:oleic acid was 1.2:2.5:1.2.

[0042] 4.2 Bread Making Make bread according to the procedure in 1.2.

[0043] 4.3 Determination of selenium content in bread The selenium content in bread was determined according to the procedure in 1.3.

[0044] Depend on Figure 4 As shown, the selenium content in the flour of selenium-enriched wheat bran flour prepared with different amounts of selenium stabilized solution varied significantly (p < 0.05), with the flour prepared with 4% selenium stabilized solution having the highest selenium content. This indicates that the amount of selenium stabilized solution added has a significant impact on the retention of selenium during the thermal processing of selenium-enriched wheat bran flour.

[0045] Taking all factors into consideration, we selected to add 4% selenium to the stabilized solution for subsequent optimization experiments.

[0046] 5. Response surface factor level table To further optimize the method of selenium stabilization in selenium-enriched wheat bran, 29 sets of experiments were designed based on the previous single-factor experiments (Box-Behnken central composite experimental design principle).

[0047] Table 1. Response Surface Factor Level Table The experimental design and results are shown in Table 2.

[0048] Table 2. Results of Response Surface Design 5.1 Regression Model and Analysis of Variance Using Design-Expert 13 software, the response surface methodology was analyzed, with selenium content as the response value. Model fitting was performed on four influencing factors, resulting in a multiple quadratic regression equation model: Y=3.83+0.1942A-0.2992B+0.01C-0.025D+0.19AB+0.015AC-0.2225AD-0.075BC+0.0525BD+0.175CD-0.4229A 2 -0.5104B 2-0.1092C 2 -0.3892D 2 (1); Analysis of variance was performed on the data, as shown in Table 3.

[0049] Table 3. Simulation analysis of variance for regression equations with selenium content as the response value. * in Table 3 represents significant ( p <0.05), ** indicates highly significant ( p <0.01).

[0050] Table 3 shows that the F-value of the model is 11.31, and the p-value of the equation is <0.05, indicating that the corresponding factors have a significant impact on the response value. The lack-fit term represents the change in data in the model. The lack-fit term 0.7499 > 0.05 in this equation indicates that the lack of fit is not significant, which shows that the equation fits well.

[0051] D, AC, BC, BD, CD, C 2 The p-value > 0.05 indicates that the interaction effects of the factors are not significant. The p-values ​​of the AB and AD interaction terms are less than 0.05, indicating that the interaction between freezing time and the amount of (chitosan: porcine plasma protein: oleic acid) and steady-state solution is strong. The quadratic term A... 2 B 2 D 2 The p-value is <0.05, indicating a significant impact. Based on the p-value, the impact of each factor is ranked as follows: B>A>D>C.

[0052] Analysis using Design-Export 13 software revealed the optimal conditions for preparing stabilized selenium-enriched wheat bran: freezing time 21.2 hours, chitosan:pork plasma protein:oleic acid ratio 1.2:2.5:1.2, selenium stabilized solution addition 4.4%, and bran mesh size 100 mesh. The experiment was repeated three times under these conditions, and the average value was calculated. The selenium content of bread prepared under the optimal conditions was 0.55 mg / kg (see Table 4). The selenium content of the stabilized selenium-enriched wheat bran bread was 77.42% higher than that of the unstabilized selenium-enriched wheat bran bread. The selenium retention rate of bread with 30% unstabilized selenium-enriched wheat bran was 43.1%, while the selenium retention rate of bread with 30% stabilized selenium-enriched wheat bran was 76.4%.

[0053] Table 4. Optimal conditions for preparing bread selenium content by adding stabilized selenium-enriched wheat bran Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A selenium-stabilized liquid from wheat bran, characterized in that, The selenium-stabilized liquid is composed of chitosan, porcine plasma protein, oleic acid and a dispersion medium, wherein the mass ratio of chitosan, porcine plasma protein and oleic acid is (0.5-1.5):(1-3):(0.5-3).

2. The wheat bran selenium-stabilized liquid according to claim 1, characterized in that, The dispersion medium is water.

3. The wheat bran selenium-stabilized liquid according to claim 1, characterized in that, The molecular weight of the chitosan is 5000-15000.

4. The wheat bran selenium-stabilized liquid according to claim 1, characterized in that, The mass ratio of chitosan, porcine plasma protein, and oleic acid is 1.2:2.5:1.

2.

5. The method for preparing the wheat bran selenium-stabilized liquid according to any one of claims 1-4, characterized in that, include: Chitosan, porcine plasma protein, and oleic acid are added to the dispersion medium and mixed evenly to obtain the final product.

6. A method for stabilizing selenium in selenium-enriched wheat bran, characterized in that, include: Selenium-enriched wheat bran is frozen at -4℃ to -10℃ for 12 to 24 hours, freeze-dried, and then the freeze-dried selenium-enriched wheat bran is pulverized to 60-100 mesh to obtain freeze-dried selenium-enriched wheat bran powder. Freeze-dried selenium-enriched wheat bran powder is mixed evenly with the wheat bran selenium-stabilized liquid according to any one of claims 1-4, frozen at -4℃ to -10℃ for 12 to 24 hours, and freeze-dried to obtain selenium-stabilized selenium-enriched wheat bran powder.

7. The method for selenium stabilization of selenium in selenium-enriched wheat bran according to claim 6, characterized in that, The concentration of the selenium-stabilized liquid is 2-5%wt, and the amount of selenium-stabilized liquid added is 1-5% of the mass of freeze-dried selenium-enriched wheat bran powder.

8. The method for selenium stabilization of selenium in selenium-enriched wheat bran according to claim 6, characterized in that, The freezing temperature is -10℃, and the pulverization mesh size is 100 mesh.

9. The method for selenium stabilization of selenium in selenium-enriched wheat bran according to claim 6, characterized in that, The freezing time is 21.2 hours.

10. The method for selenium stabilization of selenium in selenium-enriched wheat bran according to claim 6, characterized in that, The concentration of the selenium-stabilized liquid is 2%wt, and the amount of selenium-stabilized liquid added is 4.4% of the mass of freeze-dried selenium-enriched wheat bran powder.

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