Method for extracting carotenoid in corn gluten meal by using eutectic solvent and application of carotenoid

Abstract

The invention discloses a method for extracting carotenoid in corn gluten meal by using a deep eutectic solvent. The method comprises the following steps: step 1, preparing the deep eutectic solvent and pretreating the corn gluten meal; 2, mixing the pretreated maize yellow powder and a deep eutectic solvent according to a material-liquid ratio of 1: 5-1: 25, carrying out water bath, and cooling to room temperature; step 3, performing ultrasonic extraction on the mixture to obtain an extracted solid-liquid mixture; and step 4, carrying out centrifugal separation on the solid-liquid mixture, wherein supernate is a carotenoid solution extracted from the corn gluten meal. The invention further discloses application of the carotenoid extracted from the corn gluten meal by using the deep-eutectic solvent to preparation of food coloring or storage in the industry. The method has the characteristics of better extraction effect, higher extraction amount and energy and cost saving.

Description

Technical Field

[0001] This invention relates to the field of food technology, and more specifically, to a method for extracting carotenoids from corn yellow powder using a eutectic solvent and its application. Background Technology

[0002] Corn gluten meal, also known as corn gluten meal or corn protein meal, is a byproduct of industrial corn wet starch production or ethanol extraction. Corn gluten meal is mainly composed of protein, starch, lipids and a small amount of cellulose, and also contains a variety of inorganic salts and carotenoids. However, corn gluten meal has a high hardness and is difficult to dissolve in water, which greatly limits its application in food processing.

[0003] Currently, corn meal is mainly disposed of in two ways: one is as an additive in livestock feed, and the other is as a waste product from corn processing, which is then discharged as wastewater. Both methods not only waste resources but also cause environmental damage. Current research on corn meal primarily focuses on the extraction and utilization of zeaxanthin and the extraction of carotenoids from corn meal.

[0004] Carotenoids are a general term for natural pigments, and their colors vary depending on the number of conjugated double bonds. Carotenoids are an important source of vitamin A in the human body, and they also have antioxidant, immune-regulating, and anti-aging effects.

[0005] Carotenoids in corn starch are mostly fat-soluble pigments that are insoluble in water. In addition, considering solvent residues and food safety, organic solvents are often used as extraction agents. Therefore, in recent years, the main research directions for the extraction methods of carotenoids in corn starch in China have been organic solvent extraction, ultrasound-assisted extraction, and microwave-assisted extraction.

[0006] Response surface methodology (RSM) is a method that studies the influence of multiple factors on a corresponding variable by establishing a mathematical model. It involves continuous analysis of different factor variables, selecting appropriate experimental points to establish quadratic or multivariate equations, and analyzing the steepness of the response surface plot and the density of contour lines to determine the interaction between different variables. Finally, optimal conditions are selected. However, the results of a single RSM experiment cannot be accurately applied to other response variables. That is, the optimal extraction conditions for one raw material determined by a single RSM experiment cannot be applied to the optimal extraction conditions for other raw materials. Furthermore, due to the different variables, it cannot be effectively applied to the optimization of other component extractions. Therefore, finding the optimal process for extracting carotenoids from corn starch still requires process optimization.

[0007] Therefore, those skilled in the art are dedicated to developing a process for extracting carotenoids from corn starch to overcome the shortcomings of the prior art. Summary of the Invention

[0008] The purpose of this invention is to design and develop a method for extracting carotenoids from corn yellow powder using a eutectic solvent, optimizing extraction process parameters, and improving extraction efficiency.

[0009] This invention also designed and developed an application for extracting carotenoids from corn yellow powder using a eutectic solvent, thereby increasing production capacity.

[0010] The technical solution provided by this invention is as follows:

[0011] A method for extracting carotenoids from corn starch using a eutectic solvent includes the following steps:

[0012] Step 1: Prepare the eutectic solvent and pretreat the corn yellow powder;

[0013] Step 2: Mix the pretreated corn yellow powder with a eutectic solvent at a ratio of 1:5 to 1:25 and cool to room temperature in a water bath.

[0014] Step 3: Perform ultrasonic extraction on the mixture to obtain the extracted solid-liquid mixture;

[0015] The ultrasonic extraction was performed using an ultrasonic water bath at a temperature of 10-50℃, for a time of 6-18 minutes, with an extraction power of 20%-40%.

[0016] Step 4: Centrifuge the solid-liquid mixture to separate the solids and liquids. The supernatant is the carotenoid solution extracted from corn starch.

[0017] Preferably, the hydrogen bond acceptor of the eutectic solvent includes any one of octanoic acid, lauric acid, or DL-menthol;

[0018] The hydrogen bond donor of the eutectic solvent includes any one of decanoic acid, nonanoic acid, camphor, eucalyptus oil, or hexanoic acid.

[0019] Preferably, the molar mass ratio of the hydrogen bond donor to the hydrogen bond acceptor in the eutectic solvent satisfies:

[0020] Caprylic acid: Decanoic acid = 3:1;

[0021] Lauric acid:nonanoic acid = 1:3;

[0022] Lauric acid: Decanoic acid = 1:2;

[0023] DL-Menthol: Camphor = 1:1;

[0024] DL-menthol: eucalyptus oil = 1:1;

[0025] DL-Menthol: Hexanoic acid = 2:1.

[0026] Preferably, the preparation process of the eutectic solvent includes:

[0027] The hydrogen bond donor and hydrogen bond acceptor of the eutectic solvent were mixed in a molar mass ratio and then stirred in a turbine until the mixture was homogeneous and transparent.

[0028] The turbine stirring temperature is 65℃, and the turbine stirring speed is 450r / min.

[0029] Preferably, the pretreatment of the corn yellow powder includes:

[0030] The corn yellow powder is obtained by drying, crushing and sieving in sequence.

[0031] The drying temperature is 45°C, the drying time is 90 minutes, and the sieve aperture is 0.15 mm.

[0032] Preferably, in step two, the water bath temperature is 100°C and the water bath time is 0–60 min.

[0033] Preferably, the centrifugation speed in step four is 4000 r / min, and the centrifugation time is 10 min.

[0034] Preferably, the carotenoid content extracted from the corn yellow flour meets the following requirements:

[0035]

[0036] In the formula, W is the carotenoid content extracted from corn yellow powder, C is the carotenoid mass concentration of the sample solution, V is the sample volume, and M is the mass of corn yellow powder.

[0037] Preferably, the carotenoid concentration of the sample solution is obtained by detecting the supernatant using an enzyme-linked immunosorbent assay (ELISA) reader.

[0038] An application for extracting carotenoids from corn starch using a eutectic solvent, wherein the carotenoids extracted using the method described above are used in the industrial production of food colorings or for storage.

[0039] The beneficial effects of this invention are as follows:

[0040] (1) The present invention designs and develops a method for extracting carotenoids from corn yellow powder using a low eutectic solvent. The extraction process parameters are optimized by response surface methodology and single-factor experimental method to obtain the optimal parameter settings for extracting carotenoids from corn yellow powder. Compared with traditional organic solvent extraction methods, this method solves the defects of low extraction efficiency, environmentally harmful solvents, and difficulty in optimizing process conditions. The actual extraction results of carotenoids from corn yellow powder by the optimized extraction process parameters are close to the theoretical extraction amount and far exceed the normal extraction effect, which greatly improves the extraction efficiency of carotenoids. The conditions are mild and environmentally friendly, which is conducive to saving energy and costs and facilitates large-scale industrial application.

[0041] (2) An application of the present invention to extract carotenoids from corn yellow powder using a low eutectic solvent, thereby improving production capacity. Attached Figure Description

[0042] Figure 1 This is a full-wavelength scan of the corn yellow powder extract and β-carotene standard described in this invention.

[0043] Figure 2 This is a bar chart illustrating the extraction rates of carotenoids from different DES samples according to the present invention.

[0044] Figure 3 This is a bar graph illustrating the extraction rates of carotenoids after different DES heat treatments according to the present invention.

[0045] Figure 4 This is a schematic diagram illustrating the effect of heat treatment time on the amount of carotenoids extracted according to the present invention.

[0046] Figure 5 This is a schematic diagram illustrating the effect of ultrasonic temperature on the extraction yield of carotenoids as described in this invention.

[0047] Figure 6 This is a schematic diagram illustrating the effect of ultrasound time on the extraction amount of carotenoids described in this invention.

[0048] Figure 7 This is a schematic diagram illustrating the effect of ultrasonic power on the extraction amount of carotenoids described in this invention.

[0049] Figure 8 This is a schematic diagram illustrating the effect of the material-liquid ratio on the extraction amount of carotenoids described in this invention.

[0050] Figure 9 This is a contour diagram illustrating the interaction between ultrasonic power and extraction time as described in this invention.

[0051] Figure 10 This is a schematic diagram of a 3D response surface model of the interaction between ultrasonic power and extraction time as described in this invention.

[0052] Figure 11 This is a contour diagram illustrating the interaction between ultrasonic power and feed-liquid ratio as described in this invention.

[0053] Figure 12 This is a schematic diagram of a 3D response surface model of the interaction between ultrasonic power and feed-liquid ratio as described in this invention.

[0054] Figure 13 This is a contour diagram illustrating the interaction between extraction time and material-liquid ratio as described in this invention.

[0055] Figure 14 This is a schematic diagram of a 3D response surface model of the interaction between extraction time and material-liquid ratio as described in this invention. Detailed Implementation

[0056] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0057] This invention provides a method for extracting carotenoids from corn starch using a eutectic solvent, the materials used of which include:

[0058] The corn yellow powder experimental material was provided by the National Laboratory for Deep Processing of Maize at Jilin Agricultural University, and the β-carotene standard was purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0059] The main reagents used in this invention include:

[0060] Caprylic acid, capric acid, lauric acid, eucalyptus oil, DL-menthol, hexanoic acid, nonanoic acid, and camphor were all purchased from Shanghai Aladdin Chemical Reagent Co., Ltd., and all reagents were of analytical grade.

[0061] The instruments used in this invention include:

[0062] Analytical balance, constant temperature magnetic stirrer, ultrasonic crusher, enzyme-linked immunosorbent assay (ELISA) reader, electric heating blower dryer, and handheld high-speed crusher.

[0063] The method for extracting carotenoids from corn starch using a eutectic solvent, as described in this invention, specifically includes the following steps:

[0064] Step 1: Prepare the eutectic solvent and pretreat the corn yellow powder;

[0065] The preparation of the eutectic solvent includes:

[0066] The hydrogen bond donor and hydrogen bond acceptor of the eutectic solvent are mixed and then stirred in a turbine until the mixture is homogeneous and transparent.

[0067] The turbine stirring temperature is 60-80℃, and the turbine stirring speed is 450 r / min;

[0068] The pretreatment of the corn yellow powder includes:

[0069] The corn yellow powder is obtained by drying, crushing and sieving in sequence.

[0070] The drying temperature is 45°C, the drying time is 60-90 minutes, and the sieve aperture is 0.15 mm.

[0071] Step 2: Mix the pretreated corn yellow powder with a eutectic solvent at a ratio of 1:5 to 1:25 and cool to room temperature in a water bath.

[0072] The water bath temperature is 100℃ and the water bath time is 0 to 60 minutes.

[0073] Step 3: Perform ultrasonic extraction on the mixture to obtain the extracted solid-liquid mixture;

[0074] The ultrasonic extraction was performed using an ultrasonic water bath, with an extraction temperature of 10–50°C, an extraction time of 6–18 min, and an extraction power of 20%–40%.

[0075] Step 4: Centrifuge the solid-liquid mixture to separate the solids and liquids. The supernatant is the carotenoid solution extracted from corn starch.

[0076] The centrifugation speed is 4000 r / min, and the centrifugation time is 10 min.

[0077] In this embodiment, the eutectic solvent includes a hydrogen bond donor and a hydrogen bond acceptor. The hydrogen bond acceptor includes any one of caprylic acid, lauric acid, or DL-menthol, and the hydrogen bond donor includes any one of decanoic acid, nonanoic acid, camphor, eucalyptus oil, or hexanoic acid.

[0078] The molar ratios of hydrogen bond donors and acceptors in the eutectic solvent satisfy the following: octanoic acid: capric acid = 3:1; lauric acid: nonanoic acid = 1:3; lauric acid: capric acid = 1:2; DL-menthol: camphor = 1:1; DL-menthol: eucalyptus oil = 1:1; DL-menthol: hexanoic acid = 2:1.

[0079] In this embodiment, the selection of hydrogen bond donors and hydrogen bond acceptors for the eutectic solvent is as follows:

[0080] 1) Preparation of different eutectic solvents

[0081] Accurately weigh the hydrogen bond acceptors and hydrogen bond donors of different eutectic solvents into a beaker at molar mass ratios (octanoic acid:decanoic acid = 3:1, lauric acid:nonanoic acid = 1:3, lauric acid:decanoic acid = 1:2, DL-menthol:camphor = 1:1, DL-menthol:eucalyptus oil = 1:1, DL-menthol:hexanoic acid = 2:1), place them into a beaker, add a polytetrafluoroethylene stir bar, and place the beaker on a thermostatic magnetic stirrer set at 65°C. Stir until the mixture is clear, transparent, and homogeneous, and store it away from light.

[0082] Take 0.002g of β-carotene standard (a monomer of carotenoids) into a 100ml brown volumetric flask, dilute to the mark with the solvent prepared above (decanoic acid: octanoic acid = 1:3), invert the flask ten times, mix well, and obtain the mother liquor;

[0083] Accurately pipette 0.5 ml, 1.0 ml, 1.5 ml, 2.0 ml, and 2.5 ml of the mother liquor into 10 ml volumetric flasks, add eutectic solvent to the mark, invert dozens of times, and shake well to obtain standard samples of β-carotene at various concentrations.

[0084] The above-mentioned β-carotene standard sample was used, with a eutectic solvent (decanoic acid: octanoic acid = 1:3) as a blank control. The absorbance was measured at a direct measurement wavelength of 450 nm using a spectrophotometer. A β-carotene corrected standard curve was plotted with the mass concentration of the standard as the abscissa and the corresponding absorbance as the ordinate. The standard curve shows a good linear relationship between the mass concentration of β-carotene and the absorbance. The linear equation is as follows:

[0085] y = 0.0076x + 0.07;

[0086] R 2 =0.9976.

[0087] 2) Preparation and extraction of corn yellow powder

[0088] Corn starch powder was dried in a 45℃ electric hot air dryer for 90 minutes, then crushed by a handheld high-speed crusher and passed through a No. 6 sieve with a 0.15mm aperture to obtain corn starch powder. 1g of corn starch powder was accurately weighed using an analytical balance and mixed with the above-mentioned different eutectic solvents. The mixture was then boiled in a water bath for 15 minutes and cooled to room temperature. Ultrasonic-assisted extraction was performed (extraction temperature 40℃, extraction time 15 minutes, extraction power 35%). The extracted mixture was centrifuged at 4000r / min for 10 minutes, and the supernatant was collected to obtain a corn starch pretreatment test sample containing carotenoids.

[0089] 3) Content of corn starch extract under different eutectic solvents

[0090] like Figure 1As shown, the mother liquor of the pretreated corn yellow powder containing carotenoids (decanoic acid: octanoic acid = 1:3) and the prepared β-carotene standard sample solution were scanned at full wavelength using an enzyme-linked immunosorbent assay (ELISA) reader with ultraviolet light of intensity 300–800 nm to quantitatively analyze the accuracy and precision of the carotenoids extracted from the corn yellow powder.

[0091] The absorbance of several pretreated corn starch samples containing carotenoids was measured at a wavelength of 450 nm. The measured absorbance was then substituted into the β-carotene standard curve to obtain the concentration of the carotenoid solution extracted from the corn starch. The content of carotenoids in the extracted corn starch was calculated based on the concentration of the obtained carotenoid solution using the following formula:

[0092]

[0093] In the formula, W is the carotenoid content extracted from corn yellow powder (ug / g), C is the carotenoid mass concentration of the sample solution (ug / ml), which is the concentration of carotenoid solution in the corn yellow powder pretreatment test sample containing carotenoids, V is the sample volume (ml), which is the volume of the corn yellow powder pretreatment test sample containing carotenoids after concentration and volume adjustment, and M is the mass of corn yellow powder (g), which is the mass of the weighed corn yellow powder.

[0094] A comparative chart was drawn to show the carotenoid content in the corn yellow flour, as follows: Figure 2 and Figure 3The figures show the carotenoid content in corn starch under different eutectic solvents before and after pretreatment (corn starch mixed with a eutectic solvent and then subjected to a boiling water bath). Specifically, A-decanoic acid:octanoic acid = 1:3, B-lauric acid:decanoic acid = 1:2, C-lauric acid:nonanoic acid = 1:3, D-DL-menthol:camphor = 1:1, E-DL-menthol:eucalyptus oil = 1:1, F-DL-menthol:hexanoic acid = 2:1, and G is the control group (no boiling water bath pretreatment) extracted with anhydrous ethanol. Before pretreatment: A = 23.14 ug / g, B = 13.84 ug / g, C = 28.65 ug / g, D = 26.68 ug / g, E = 13.51 ug / g, F = 27. 66ug / g, G=85.38ug / g; After pretreatment: A=754.80ug / g, B=446.43ug / g, C=710.69ug / g, D=53.10ug / g, E=35.96ug / g, F=239.41ug / g; This indicates that the eutectic solvent with a decanoic acid:octanoic acid ratio of 1:3 has the highest extraction content of carotenoids from corn yellow powder, higher than other extraction solvents. The eutectic solvent with a decanoic acid:octanoic acid ratio of 1:3 has the best extraction effect. Therefore, the eutectic solvent with a decanoic acid:octanoic acid ratio of 1:3 was selected as the optimal extraction solvent, and the corn yellow powder was pretreated by mixing it with the eutectic solvent in a boiling water bath for 15 minutes before extraction.

[0095] In this embodiment, the effects of each factor on corn yellow powder extract were determined through single-factor experiments:

[0096] 1) Effect of pretreatment time on carotenoids extracted from corn yellow powder

[0097] Corn starch powder was dried in a 45℃ electric hot air dryer for 90 minutes. After being crushed by a handheld high-speed crusher, it was passed through a No. 6 sieve with a 0.15mm aperture to obtain corn starch powder. 1g of corn starch powder was accurately weighed using an analytical balance and mixed with a eutectic solvent of decanoic acid:octanoic acid = 1:3 at a material-to-liquid ratio of 1:20. The mixture was then boiled in a water bath for 0, 15, 30, 45, and 60 minutes. After cooling to room temperature, ultrasonic water bath extraction was performed at 40℃ for 12 minutes at an extraction power of 30%. The extracted mixture was centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected. The absorbance of this supernatant was measured at a wavelength of 450nm. The extracted carotenoid content in the corn starch sample was calculated, and a comparison chart was plotted. The results are shown below. Figure 4 As shown, after the pretreatment time reaches 15 minutes, further increasing the pretreatment time does not significantly improve the experimental results. Considering energy and time costs, the optimal pretreatment time is 15 minutes.

[0098] 2) Effect of ultrasonic temperature on carotenoids extracted from corn yellow powder

[0099] Corn starch powder was dried in a 45℃ electric hot air dryer for 90 minutes. After being crushed by a handheld high-speed crusher, it was passed through a No. 6 sieve with a 0.15mm aperture to obtain corn starch powder. 1g of corn starch powder was accurately weighed using an analytical balance and mixed with a eutectic solvent of decanoic acid:octanoic acid = 1:3 at a material-to-liquid ratio of 1:20. The mixture was then boiled in a water bath for 15 minutes, cooled to room temperature, and subjected to ultrasonic-assisted extraction for 12 minutes at 30% extraction power. Extraction temperatures were 10, 20, 30, 40, and 50℃. The extracted mixture was centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected. The absorbance of this supernatant was measured at a wavelength of 450nm. The extracted carotenoid content in the corn starch sample was calculated, and a comparison chart was plotted. The results are shown below. Figure 5 As shown, when the ultrasonic temperature reaches 40℃, the eutectic solvent extracts 780.58 ug / g of carotenoids from corn starch, which is higher than the carotenoid content extracted at other temperatures. The optimal ultrasonic temperature is 40℃.

[0100] 3) Effect of ultrasound time on carotenoids extracted from corn yellow powder

[0101] Corn starch powder was dried in a 45℃ electric hot air dryer for 90 minutes. After being crushed by a handheld high-speed crusher, it was passed through a No. 6 sieve with a 0.15mm aperture to obtain corn starch powder. 1g of corn starch powder was accurately weighed using an analytical balance and mixed with a eutectic solvent of decanoic acid:octanoic acid = 1:3 at a material-to-liquid ratio of 1:20. The mixture was then boiled in a water bath for 15 minutes, cooled to room temperature, and subjected to ultrasonic-assisted extraction at 40℃ for 6, 9, 12, 15, and 18 minutes at an extraction power of 30%. The extracted mixture was centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected. The absorbance of this supernatant was measured at a wavelength of 450nm. The extracted carotenoid content in the corn starch sample was calculated, and a comparison chart was plotted. The results are shown below. Figure 6 As shown, when the ultrasonic time reached 12 min, the eutectic solvent extracted 876.10 ug / g of carotenoids from corn starch, which was higher than the carotenoid content extracted at other times. Therefore, the optimal ultrasonic time was selected as 12 min.

[0102] 4) Effect of ultrasonic power on carotenoids extracted from corn yellow powder

[0103] Corn starch powder was dried in a 45℃ electric hot air dryer for 90 minutes. After being crushed by a handheld high-speed crusher, it was passed through a No. 6 sieve with a 0.15mm aperture to obtain corn starch powder. 1g of corn starch powder was accurately weighed using an analytical balance and mixed with a eutectic solvent of decanoic acid:octanoic acid = 1:3 at a material-to-liquid ratio of 1:20. The mixture was then boiled in a water bath for 15 minutes, cooled to room temperature, and subjected to ultrasonic-assisted extraction at 40℃ for 12 minutes. Extraction powers of 20%, 25%, 30%, 35%, and 40% were used. The extracted mixture was centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected. The absorbance of this supernatant was measured at a wavelength of 450nm. The extracted carotenoid content in the corn starch sample was calculated, and a comparison chart was plotted. The results are shown below. Figure 7 As shown, the maximum power of the ultrasonic disruptor is 40%. When the ultrasonic power reaches 30%, the extraction amount of carotenoids from corn yellow powder by the eutectic solvent reaches 834.12 ug / g. However, it is slightly lower at 35% power than at 30% power, and there is a significant decrease at 40% power. Therefore, based on the principle of saving energy, the optimal power of 30% is selected.

[0104] 5) Effect of the material-to-liquid ratio on the extraction of carotenoids from corn starch

[0105] Corn starch powder was dried in a 45℃ electric hot air dryer for 90 minutes. After being crushed by a handheld high-speed crusher, it was passed through a No. 6 sieve with a 0.15mm aperture to obtain corn starch powder. 1g of corn starch powder was accurately weighed using an analytical balance and mixed with a eutectic solvent of decanoic acid:octanoic acid = 1:3 at material-to-liquid ratios of 1:5, 1:10, 1:15, 1:20, and 1:25, respectively. The mixture was then boiled in a water bath for 15 minutes, cooled to room temperature, and subjected to ultrasonic-assisted extraction at 40℃ for 12 minutes at an extraction power of 30%. The extracted mixture was centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected. The absorbance of this supernatant was measured at a wavelength of 450nm. The extracted carotenoid content in the corn starch sample was calculated, and a comparison chart was plotted. The results are shown below. Figure 8 As shown, when the material-liquid ratio reaches 1:20, the eutectic solvent extracts 873.50 ug / g of carotenoids from corn starch, which is higher than that of 1:5 and 1:10 material-liquid ratios, and slightly higher than that of 1:15 and 1:25 material-liquid ratios. Therefore, the optimal material-liquid ratio is selected as 1:20.

[0106] In another embodiment, response surface methodology was used to optimize the carotenoid extraction process:

[0107] Based on the Box-Behnken method, ultrasonic power X1, ultrasonic time X2, and material-to-liquid ratio X3 were selected to conduct a three-factor, three-level experiment. The specific values ​​are shown in Table 1.

[0108] Table 1 Response Surface Design Scheme

[0109]

[0110] A total of 17 groups were used to extract carotenoids from corn yellow powder under the following process conditions. The absorbance of the obtained corn yellow powder test samples was detected at a wavelength of 450 nm, and the content of carotenoids extracted from the pretreated corn yellow powder test samples was calculated. The results are shown in Table 2.

[0111] The process conditions at this time are as follows: corn yellow powder is dried in a 45℃ electric hot air dryer for 90 minutes, crushed by a hand-held high-speed crusher, and then passed through a No. 6 sieve with a 0.15mm aperture to obtain corn yellow powder. 1g of corn yellow powder is accurately weighed by an analytical balance and mixed with a eutectic solvent of decanoic acid: octanoic acid = 1:3. The mixture is then boiled in a water bath for 15 minutes, cooled to room temperature, and then extracted with ultrasonic water bath assistance: the extraction temperature is 40℃, the extraction power is 25-35%, the extraction time is 9-15 minutes, and the extraction material-to-liquid ratio is 1:15-1:25 g / ml. After extraction, the mixture is centrifuged at 4000r / min for 10 minutes and the supernatant is collected.

[0112] Table 2 Results of Response Surface Experiment

[0113]

[0114]

[0115] Using Designexpert 13.0 software, a multiple regression was performed on the experimental results in Table 2, and the resulting quadratic multinomial regression equation is as follows:

[0116] Y=-3799.83861+215.90151X1+221.36058X2-2.82679X3

[0117] -0.720433X1X2+0.911043X1X3+1.07413X2X3;

[0118] -3.57243(X1) 2 -8.84662(X2) 2 -1.05404(X3) 2

[0119] Further, a regression model was obtained;

[0120] The variance of the response surface of the regression model was analyzed, and the results are shown in Table 3:

[0121] Table 3. Significance of experimental results, regression model, and analysis of variance results.

[0122]

[0123]

[0124] Table 3 shows that the F-value of this model is 47.98, and the P-value is <0.0001, indicating that the model has a certain degree of significance. The P-value of the lack-of-fit term is 0.207, which is not significant, indicating that the model has a good fit. The correlation coefficient R predicted by the regression equation is... 2 =0.8267, adjusted correlation coefficient R 2 =0.9635, indicating that the model fits the experimental data well. The results show that X1 has a highly significant effect on the extraction content, while X2 and X3 have significant effects on the extraction content; the quadratic term X1... 2 X2 2 The effect on the extract content is extremely significant, with a quadratic term X3. 2 The effect on the extraction content was significant; therefore, in the three-factor experiment, the results affecting the extraction content of carotenoids in corn yellow powder were: X1>X2>X3, that is, ultrasonic power>ultrasonic time>liquid-to-material ratio;

[0125] The above model data is used to form a response surface plot to analyze the interaction of various factors, such as Figure 8 As shown:

[0126] The steeper the response surface, the greater its impact on the target; the denser and more elliptical the contour lines, the greater their impact on the target; therefore, in the response surface... Figure 9 , Figure 10 In the response surface, the steepness of the surface X2 > X1, meaning that the interaction between ultrasonic power and extraction time has a greater impact on the extracted carotenoid content than ultrasonic power; Figure 11 , Figure 12 In the mean square, the steepness of the surface X3 > X1, meaning that under the interaction of ultrasonic power and extraction time, the effect of the material-liquid ratio on the extracted carotenoid content is greater than that of ultrasonic power; in the response surface methodology... Figure 13 , Figure 14 In the study, the steepness of the surface X3 > X2, meaning that under the interaction of ultrasonic time and material-liquid ratio, the material-liquid ratio has a greater influence on the extracted carotenoid content than the ultrasonic time. The optimal extraction process parameters designed by Designexpert 13.0 software are: ultrasonic power 35%, ultrasonic time 15 min, material-liquid ratio 1:20, and the final predicted extraction value is 814.002 ug / g.

[0127] Example 1

[0128] Step 1: Dry the corn yellow powder in a 45℃ blower dryer for 90 minutes, then pulverize it and pass it through a No. 6 sieve with a 0.15mm aperture to obtain corn yellow powder.

[0129] Step 2: Using an analytical apparatus, accurately weigh 14.4g of octanoic acid and 5.6g of decanoic acid, place them in a beaker, add a PTFE magnetic stir bar, and stir on a constant temperature magnetic stirrer at 65℃ and 450r / min until the beaker contains a homogeneous and transparent liquid.

[0130] Step 3: Accurately weigh 1g of corn yellow powder obtained in Step 1 using an analytical balance, pipette 15ml of the eutectic solvent obtained in Step 2 for 15min, and cool to room temperature in a boiling water bath for 15min to obtain a solid-liquid mixture.

[0131] Step 4: Use an ultrasonic disruptor to extract carotenoids from the solid-liquid mixture obtained in Step 3. The ultrasonic temperature is controlled at 30℃ using a water bath, the ultrasonic power is 35%, and the ultrasonic time is 15 minutes to obtain the extracted solid-liquid mixture.

[0132] Step 5: Centrifuge the extracted solid-liquid mixture obtained in Step 4 at a speed of 4000 r / min for 10 min. After measuring the volume of all supernatants, use an ELISA reader to measure the absorbance at 450 nm in a 200 μL 96-well plate. The entire process should be carried out in the dark.

[0133] Based on the equation corresponding to the standard curve of β-carotene, the concentration of carotenoid extract was obtained, and the extraction content was calculated. The extracted amount of carotenoids in corn yellow powder was found to be 865.44 ug / g.

[0134] Example 2

[0135] Step 1: Dry the corn yellow powder in a 45℃ blower dryer for 90 minutes, then pulverize it and pass it through a No. 6 sieve with a 0.15mm aperture to obtain corn yellow powder.

[0136] Step 2: Using an analytical apparatus, accurately weigh 14.4g of octanoic acid and 5.6g of decanoic acid, place them in a beaker, add a PTFE magnetic stir bar, and stir on a constant temperature magnetic stirrer at 65°C and 450r / min for 25 minutes until a uniform and transparent liquid appears in the beaker.

[0137] Step 3: Accurately weigh 1g of corn yellow powder obtained in Step 1 using an analytical balance, pipette 15ml of the eutectic solvent obtained in Step 2 for 15min, and cool to room temperature in a boiling water bath for 15min to obtain a solid-liquid mixture.

[0138] Step 4: Use an ultrasonic disruptor to extract carotenoids from the solid-liquid mixture obtained in Step 3. The ultrasonic temperature is controlled at 30℃ using a water bath, the ultrasonic power is 35%, and the ultrasonic time is 15 minutes to obtain the extracted solid-liquid mixture.

[0139] Step 5: Centrifuge the extracted solid-liquid mixture obtained in Step 4 at a speed of 4000 r / min for 10 min. After measuring the volume of all supernatants, use an ELISA reader to measure the absorbance at 450 nm in a 200 μL 96-well plate. The entire process should be carried out in the dark.

[0140] Based on the equation corresponding to the standard curve of β-carotene, the concentration of carotenoid extract was obtained, and the extraction content was calculated. The extracted amount of carotenoids in corn yellow powder was found to be 860.49 ug / g.

[0141] Example 3

[0142] Step 1: Dry the corn yellow powder in a 45℃ blower dryer for 90 minutes, then pulverize it and pass it through a No. 6 sieve with a 0.15mm aperture to obtain corn yellow powder.

[0143] Step 2: Using an analytical apparatus, accurately weigh 14.4g of octanoic acid and 5.6g of decanoic acid, place them in a beaker, add a PTFE magnetic stir bar, and stir on a constant temperature magnetic stirrer at 65°C and 450r / min for 25 minutes until a uniform and transparent liquid appears in the beaker.

[0144] Step 3: Accurately weigh 1g of corn yellow powder obtained in Step 1 using an analytical balance, pipette 15ml of the eutectic solvent obtained in Step 2 for 15min, and cool to room temperature in a boiling water bath for 15min to obtain a solid-liquid mixture.

[0145] Step 4: Use an ultrasonic disruptor to extract carotenoids from the solid-liquid mixture obtained in Step 3. The ultrasonic temperature is controlled at 30℃ using a water bath, the ultrasonic power is 35%, and the ultrasonic time is 15 minutes to obtain the extracted solid-liquid mixture.

[0146] Step 5: Centrifuge the extracted solid-liquid mixture obtained in Step 4 at a speed of 4000 r / min for 10 min. After measuring the volume of all supernatants, use an ELISA reader to measure the absorbance at 450 nm in a 200 μL 96-well plate. The entire process should be carried out in the dark.

[0147] Based on the equation corresponding to the standard curve of β-carotene, the concentration of carotenoid extract was obtained, and the extraction content was calculated. The extracted amount of carotenoids in corn yellow powder was found to be 864.61 ug / g.

[0148] The optimal extraction process parameters designed using Designexpert 13.0 software are: ultrasonic power 35%, ultrasonic time 15 min, and material-liquid ratio 1:20. Based on these parameters, three repeated verification tests were conducted using the operation of Example 1. The predicted value was 814.002 ug / g, and the extraction example met the predicted value.

[0149] This invention presents a method for extracting carotenoids from corn starch using a eutectic solvent. The extraction process parameters were optimized using response surface methodology and single-factor experiments to obtain the optimal parameter settings for extracting carotenoids from corn starch. Compared to traditional organic solvent extraction methods, this method overcomes the shortcomings of low extraction efficiency, environmentally harmful solvents, and difficulty in optimizing process conditions. The optimized extraction process parameters yielded actual extraction results for carotenoids from corn starch that closely approached the theoretical extraction yield, significantly exceeding the normal extraction effect. This greatly improves the extraction efficiency of carotenoids, provides mild and environmentally friendly conditions, and helps save energy and costs, facilitating large-scale industrial application.

[0150] This invention also provides an application for extracting carotenoids from corn starch using a eutectic solvent. The carotenoids extracted using the method of extracting carotenoids from corn starch using a eutectic solvent are used in industry for the production of food colorings or for storage. Because the extraction of carotenoids from corn starch is more efficient, the production capacity of carotenoids in industrial applications is thus higher.

[0151] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for extracting carotenoids from corn starch using a eutectic solvent, characterized in that, Includes the following steps: Step 1: Prepare the eutectic solvent and pretreat the corn yellow powder; Step 2: Mix the pretreated corn yellow powder with a eutectic solvent at a ratio of 1:5 to 1:25 and cool to room temperature in a water bath. Step 3: Perform ultrasonic extraction on the mixture to obtain the extracted solid-liquid mixture; The ultrasonic extraction was performed using an ultrasonic water bath at a temperature of 10-50℃, for a time of 6-18 minutes, with an extraction power of 20%-40%. Step 4: Centrifuge the solid-liquid mixture to separate the solids and liquids. The supernatant is the carotenoid solution extracted from corn starch.

2. The method for extracting carotenoids from corn starch using a eutectic solvent as described in claim 1, characterized in that, The hydrogen bond acceptor of the eutectic solvent includes any one of caprylic acid, lauric acid, or DL-menthol; The hydrogen bond donor of the eutectic solvent includes any one of decanoic acid, nonanoic acid, camphor, eucalyptus oil, or hexanoic acid.

3. The method for extracting carotenoids from corn starch using a eutectic solvent as described in claim 2, characterized in that, The molar mass ratio of hydrogen bond donors to hydrogen bond acceptors in the eutectic solvent satisfies: Caprylic acid: Decanoic acid = 3:1; Lauric acid:nonanoic acid = 1:3; Lauric acid: Decanoic acid = 1:2; DL-Menthol: Camphor = 1:1; DL-menthol: eucalyptus oil = 1:1; DL-Menthol: Hexanoic acid = 2:

1.

4. The method for extracting carotenoids from corn starch using a eutectic solvent as described in claim 3, characterized in that, The preparation process of the eutectic solvent includes: The hydrogen bond donor and hydrogen bond acceptor of the eutectic solvent were mixed in a molar mass ratio and then stirred in a turbine until the mixture was homogeneous and transparent. The turbine stirring temperature is 65℃, and the turbine stirring speed is 450r / min.

5. The method for extracting carotenoids from corn starch using a eutectic solvent as described in claim 4, characterized in that, The pretreatment of the corn yellow powder includes: The corn yellow powder is obtained by drying, crushing and sieving in sequence. The drying temperature is 45°C, the drying time is 90 minutes, and the sieve aperture is 0.15 mm.

6. The method for extracting carotenoids from corn starch using a eutectic solvent as described in claim 5, characterized in that, In step two, the water bath temperature is 100℃ and the water bath time is 0 to 60 minutes.

7. The method for extracting carotenoids from corn starch using a eutectic solvent as described in claim 6, characterized in that, In step four, the centrifugation speed is 4000 r / min, and the centrifugation time is 10 min.

8. The method for extracting carotenoids from corn starch using a eutectic solvent as described in claim 7, characterized in that, The carotenoid content extracted from the corn yellow powder meets the following requirements: In the formula, W is the carotenoid content extracted from corn yellow powder, C is the carotenoid mass concentration of the sample solution, V is the sample volume, and M is the mass of corn yellow powder.

9. The method for extracting carotenoids from corn yellow powder using a eutectic solvent as described in claim 8, characterized in that, The carotenoid concentration of the sample solution was obtained by detecting the supernatant using an enzyme-linked immunosorbent assay (ELISA) reader.

10. An application for extracting carotenoids from corn starch using a eutectic solvent, wherein the carotenoids extracted using the method for extracting carotenoids from corn starch using a eutectic solvent as described in any one of claims 1-9 are characterized in that, The carotenoids are used in industry for the production of food colorings or for storage.

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