Quinoa seedling general flavone extract and extraction method thereof

Abstract

The invention provides a quinoa seedling general flavone extract and an extraction method thereof, and belongs to the technical field of flavone extraction. The method for extracting the total flavonoids of the quinoa seedlings comprises the following steps: 1) drying the quinoa seedlings to constant weight, and crushing to obtain quinoa seedling powder; 2) weighing the quinoa seedling powder, adding an ethanol solution, and performing ultrasonic-assisted extraction to obtain an extracting solution; and 3) centrifuging the extracting solution, and taking supernatant to obtain the quinoa seedling total flavone extract. The optimal extraction condition is determined by testing the ethanol volume fraction, the material-liquid ratio, the extraction temperature, the ultrasonic power and the extraction time of the extracting solution, and the extraction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of flavonoid extraction, and in particular to a quinoa seedling total flavonoid extract and an extraction method thereof. Background Art

[0002] Quinoa (Chenopodium quinoa) is a dicotyledonous plant of the Chenopodium genus of the Chenopodiaceae family. It originated in the Andes Mountains of South America. It has a wide ecological adaptability and can grow in different types of soil and climatic conditions. It is also highly resistant to stress. Quinoa has a comprehensive nutritional composition, rich in protein, minerals, vitamins, fatty acids, etc. It is rich in secondary metabolites and has antioxidant and lipid-lowering effects, which can reduce the risk of cardiovascular disease. The main active substance in quinoa is flavonoids, which are significantly higher than other grains (rice, wheat, barley and rye, etc.), and has obvious advantages as a "functional food".

[0003] Quinoa is rich in active ingredients and has antioxidant and anti-inflammatory functions. Flavonoids are the main active ingredients in quinoa, and the level of flavonoids can be used as the main basis for evaluating the quality of quinoa seedlings. Therefore, an accurate and efficient total flavonoid extraction method is needed to clarify the total flavonoid content in quinoa seedlings at different stages. Summary of the invention

[0004] The purpose of the invention is to provide a method for extracting total flavonoids from quinoa seedlings, optimize the extraction conditions and improve the extraction efficiency.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for extracting total flavonoids from quinoa seedlings, comprising the following steps:

[0007] 1) taking quinoa seedlings, drying them to constant weight, and grinding them to obtain quinoa seedling powder;

[0008] 2) weighing the quinoa seedling powder, adding ethanol solution, and performing ultrasonic-assisted extraction to obtain an extract;

[0009] 3) After the extract is centrifuged, the supernatant is collected to obtain the quinoa seedling total flavonoids extract.

[0010] Preferably, in step 1), the quinoa seedlings are the above-ground parts of fresh quinoa growing to 30 to 35 cm; the drying temperature is 80 to 90° C.; and the crushing particle size is 60 to 70 meshes.

[0011] Preferably, the volume fraction of the ethanol solution in step 2) is 60-80%; the solid-liquid ratio of the quinoa seedling powder to the ethanol solution is 1 g: 20-40 mL.

[0012] Preferably, the power of the ultrasound in step 2) is 300W to 500W; and the time of the ultrasound is 10 to 30 minutes.

[0013] Preferably, the extraction temperature in step 2) is 20-60°C.

[0014] Preferably, the centrifugal speed in step 3) is 8000-10000 r / min; and the centrifugal time is 10-15 min.

[0015] The present invention also provides a quinoa seedling total flavonoids extract prepared by the extraction method.

[0016] The invention determines the optimal conditions by testing the ethanol volume fraction of the extract, the solid-liquid ratio, the extraction temperature, the ultrasonic power and the extraction time, and provides a method for extracting total flavonoids from quinoa seedlings, which is beneficial to the determination and development and utilization of the total flavonoids content in quinoa seedlings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the standard curve diagram of rutin in Example 1.

[0018] Figure 2 This is a graph showing the effect of different ethanol volume fractions on the yield of total flavonoids from quinoa seedlings in Example 2.

[0019] Figure 3 This is a graph showing the effect of different material-liquid ratios on the yield of total flavonoids from quinoa seedlings in Example 2.

[0020] Figure 4 This is a graph showing the effect of different temperatures on the yield of total flavonoids from quinoa seedlings in Example 2.

[0021] Figure 5 This is a graph showing the effect of different ultrasonic powers on the yield of total flavonoids from quinoa seedlings in Example 2.

[0022] Figure 6 This is a graph showing the effect of different ultrasonic extraction times on the yield of total flavonoids from quinoa seedlings in Example 2.

[0023] Figure 7 A is a response surface test result diagram for different ethanol volume fractions in Example 2; B is a response surface test result diagram for different solid-liquid ratios in Example 2; C is a response surface test result diagram for different ultrasonic extraction times in Example 2. DETAILED DESCRIPTION

[0024] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0025] Example 1

[0026] 1. Materials

[0027] Quinoa seeds were sown at 7 g / row, with a row width of 150 cm and a row spacing of 33 cm, and covered with net film and watered after sowing. Quinoa seeds were purchased from Inner Mongolia Yiji Biotechnology Co., Ltd.

[0028] 2. Methods

[0029] When the quinoa seedlings grow to about 30 cm, samples are taken from the aerial part of the quinoa seedlings, which are dried at 80°C to constant weight, crushed through a 60-mesh sieve to obtain quinoa seedling powder, and sealed and stored in a -20°C refrigerator for later use.

[0030] Accurately weigh 0.500 g of quinoa seedling powder, add 17 ml of 60% ethanol solution by volume, and perform ultrasonic extraction for 24 min at 20° C. and an ultrasonic power of 300 W to obtain an extract.

[0031] The extract was centrifuged at 8000 r / min for 10 min to obtain the total flavonoids extract of quinoa seedlings.

[0032] Accurately weigh the rutin standard and dissolve it in 70% ethanol solution to 100 mL to prepare a 1 mg / mL stock solution. Dilute the stock solution to 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mg / mL standard solutions.

[0033] Pipette 1mL of standard solution into a 10mL centrifuge tube, add 0.4mL of 5% sodium nitrite solution, shake well and let stand for 6min, then add 0.4mL of 10% aluminum nitrate solution, shake well and let stand for 6min, finally add 4mL of 10% sodium hydroxide solution, mix well, let stand at room temperature for 15min, and measure the absorbance at 510nm. Draw a standard curve with rutin mass concentration as the horizontal axis (X) and absorbance as the vertical axis (Y) (see Figure 1 ). The correlation coefficient of rutin solution concentration of 0.10mg / mL to 0.70mg / mL is R 2 =0.9981, the linear relationship is good within the range, and the regression equation is y=0.8917x+0.0111, where: y is absorbance; x is the concentration of rutin solution.

[0034] The total flavonoids extract of quinoa seedlings was taken to measure the absorbance, and the total flavonoids yield of quinoa seedlings was calculated according to the standard curve.

[0035] Example 2

[0036] (1) Effect of different ethanol volume fractions on the yield of total flavonoids from quinoa seedlings

[0037] According to the method of Example 1, the solid-liquid ratio was set to 1g:30ml, the extraction temperature was 20°C, the extraction time was 30min, and the ultrasonic power was 500W. The effect of the volume fraction of ethanol in the extract (50, 60, 70, 80, 90%) on the yield of total flavonoids was investigated.

[0038] Effect of ethanol volume fraction on the yield of total flavonoids from quinoa seedlings Figure 2 As shown in the figure, when the volume fraction of ethanol in the extraction solution was 50% to 70%, the total flavonoid yield showed an increasing trend, and there was no significant difference between 70% and 80%, and the total flavonoid yield was 22.28 mg / g. When the volume of ethanol reached 90%, the total flavonoid yield decreased, so 60-80% was selected for the response surface optimization experiment.

[0039] (2) Effect of different solid-liquid ratios on the yield of total flavonoids from quinoa seedlings

[0040] According to the method of Example 1, the extraction temperature was set to 20°C, the extraction time was set to 30 min, the ultrasonic power was set to 500 W, and the ethanol volume fraction was set to 70% according to the result of item (1). The effect of the solid-liquid ratio (1g:20ml, 1g:30ml, 1g:40ml, 1g:50ml, 1g:60mL) on the total flavonoid yield was investigated.

[0041] Effect of solid-liquid ratio (g:mL) on the yield of total flavonoids from quinoa seedlings Figure 3 As shown in the figure, with the increase of the solid-liquid ratio, the total flavonoids yield increased to a maximum value and then gradually stabilized, reaching 22.42 mg / g. Therefore, the solid-liquid ratio was selected to be 1:20-1:40 for the response surface experiment.

[0042] (3) Effect of different temperatures on the yield of total flavonoids from quinoa seedlings

[0043] According to the method of Example 1, the ethanol volume fraction was set to 70%, the extraction time was 30 min, the ultrasonic power was 500 W, and the solid-liquid ratio was set to 1 g:30 ml according to the result of item (2). The effect of extraction temperature (20, 30, 40, 50, 60 ° C) on the total flavonoid yield was investigated.

[0044] Effect of extraction temperature on the yield of total flavonoids from quinoa seedlings Figure 4 As shown in the figure, under the same extraction conditions, different extraction temperatures had no significant effect on the yield of total flavonoids, so the extraction temperature was selected at 20°C and no response surface experiment was performed.

[0045] (4) Effect of different ultrasonic powers on the yield of total flavonoids from quinoa seedlings

[0046] According to the method of Example 1, the ethanol volume fraction was set to 70%, the solid-liquid ratio was 1 g:30 ml, the extraction temperature was 20°C, and the extraction time was 30 min. According to the result of item (3), the extraction temperature was set to 20°C, and the effect of ultrasonic power (300, 350, 400, 450, 500 W) on the total flavonoid yield was investigated.

[0047] Effect of extraction power on the yield of total flavonoids from quinoa seedlings Figure 5 As shown in the figure, under the same extraction conditions, different ultrasonic powers had no significant effect on the yield of total flavonoids, so the ultrasonic power was selected as 300 W and no response surface experiment was performed.

[0048] (5) Effect of different ultrasonic extraction times on the yield of total flavonoids from quinoa seedlings

[0049] According to the method of Example 1, the ethanol volume fraction was set to 70%, the solid-liquid ratio was 1 g:30 ml, the extraction temperature was 20°C, and the ultrasonic power was set to 300 W according to the result of item (4). The effect of ultrasonic extraction time (10, 20, 30, 40, 50 min) on the total flavonoid yield was investigated.

[0050] Effect of superextraction time on the yield of total flavonoids from quinoa seedlings Figure 6 As shown in the figure, the total flavonoids yield at 20 minutes of ultrasound was significantly higher than that at 10 minutes. After 20 minutes, the total flavonoids no longer increased significantly with the increase of time, so 10 to 30 minutes was selected for the response surface experiment.

[0051] (6) Response surface experiment

[0052] According to the above single factor test results, the Box-Behnken central composite test design principle in Design-Expert 13 software was used to conduct a response surface test with ethanol concentration (A), solid-liquid ratio (B), and extraction time (C) as the response value and three factors and three levels. See Table 1 below.

[0053] Table 1. Box-Benhnken design factor levels and coding values

[0054]

[0055] The response surface extraction condition experiment was designed according to Design-Expert13 software. The results are shown in Figure 7. The order of the influence of various factors on the total flavonoids yield is ethanol volume fraction > solid-liquid ratio > extraction time. The optimal extraction conditions obtained by response surface analysis are ethanol volume fraction of 60%, solid-liquid ratio of 1:34.20, extraction time of 24.45min, and total flavonoids yield of 21.53mg / g. According to the actual operation, the ethanol volume fraction is set to 60%, the solid-liquid ratio is 1:34, and the extraction time is 24min. The total flavonoids yield determined under this condition is 22.07mg / g, which is in line with the predicted value.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for extracting total flavonoids from quinoa seedlings, characterized in that: The following steps are involved: 1) taking quinoa seedlings, drying them to constant weight, and grinding them to obtain quinoa seedling powder; 2) weighing the quinoa seedling powder, adding ethanol solution, and performing ultrasonic-assisted extraction to obtain an extract; 3) After the extract is centrifuged, the supernatant is collected to obtain the quinoa seedling total flavonoids extract.

2. The extraction method according to claim 1, characterized in that In the step 1), the quinoa seedlings are the above-ground parts of fresh quinoa grown to 30 to 35 cm; the drying temperature is 80 to 90° C.; and the crushing particle size is 60 to 70 meshes.

3. The extraction method according to claim 1, characterized in that The volume fraction of the ethanol solution in the step 2) is 60-80%; the solid-liquid ratio of the quinoa seedling powder to the ethanol solution is 1 g: 20-40 mL.

4. The extraction method according to claim 1, characterized in that The power of the ultrasound in step 2) is 300W to 500W; the time of the ultrasound is 10 to 30 minutes.

5. The extraction method according to claim 1, characterized in that The extraction temperature in step 2) is 20-60°C.

6. The extraction method according to claim 1, characterized in that The centrifugal speed in step 3) is 8000-10000 r / min; the centrifugal time is 10-15 min.

7. A total flavonoids extract of quinoa seedlings prepared by the extraction method according to any one of claims 1 to 6.

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