An extraction method and application for improving the stability of pigments in orange peel.

Abstract

This invention belongs to the field of plant extraction, specifically relating to an extraction method and application for improving the stability of orange peel pigments, comprising the following steps: orange peel pigment extraction; plasma treatment. This invention improves the stability of orange peel pigments under different light, temperature, and acid-base conditions by subjecting them to short-term plasma treatment, ensuring that their color development performance is not affected, thus making them better suited for processing, preservation, and transportation in the food and pharmaceutical fields.

Description

Technical Field

[0001] This invention belongs to the field of plant extraction, specifically relating to an extraction method and application for improving the stability of pigments in orange peel. Background Technology

[0002] Synthetic colorings, when used as food additives, are harmful to human health. Natural colorings, such as orange peel pigment, are favored due to their excellent safety profile and certain antibacterial, anti-inflammatory, and antiviral properties. Orange peel pigment can be added to food or medicine.

[0003] Methods for extracting pigments from orange peel mainly include ethanol extraction, microwave extraction, ultrasonic extraction, and enzymatic extraction. However, using existing extraction methods often presents challenges in pigment stability. Orange peel pigments are easily affected by external factors such as light, temperature, and pH levels during food processing, storage, and transportation, resulting in fading, discoloration, or loss of color.

[0004] In the prior art, in order to improve the stability of orange peel pigment, microencapsulated orange peel pigment is prepared to achieve the purpose of improving stability. However, the preparation of microencapsulated orange peel pigment requires the additional construction of core material and wall material. The preparation process is complicated and introduces additional components, which limits the scope of application.

[0005] Therefore, it is necessary to provide an extraction method that improves the stability of orange peel pigments. This method involves performing a simple treatment on the orange peel pigments to improve their stability under different light, temperature, and acid-base conditions, while ensuring that the color development performance is not affected. Summary of the Invention

[0006] The purpose of this invention is to provide an extraction method and application that improves the stability of pigments in orange peel.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows: an extraction method for improving the stability of pigments in orange peel, comprising the following steps:

[0008] 1) Orange peel pigment extraction:

[0009] Wash and dry the citrus peels; pulverize them into citrus peel powder; extract the citrus peel powder with 90%~98% ethanol solution 1~2 times, placing it in a microwave with a power of 180~230W for 1~2 minutes during extraction; filter the extract to obtain a yellow liquid, concentrate it under reduced pressure at 50~58℃ to 11-14% of the original yellow liquid volume, and dry it to obtain citrus peel pigment powder.

[0010] 2) Plasma treatment:

[0011] Orange peel pigment powder was treated with cold plasma, with nitrogen or air as the carrier gas, power of 20-50W, treatment time of 5-30s, and nitrogen or air flow rate of 40-60mL / min to obtain orange peel pigment after cold plasma treatment.

[0012] The power and duration of plasma treatment are crucial to the stability of orange peel pigments. Using lower plasma treatment power and shorter treatment times helps to improve the light stability, thermal stability, and acid-base stability of orange peel pigments. Experiments have shown that using higher plasma treatment power or longer treatment times is detrimental to light stability, thermal stability, and acid-base stability.

[0013] In a preferred embodiment, in step 2), orange peel pigment with a thickness ≤0.5mm is evenly spread on a glass dish and subjected to cold plasma treatment.

[0014] Furthermore, in step 2), the carrier gas is nitrogen.

[0015] In a preferred embodiment, the processing time in step 2) is 10~20s.

[0016] Furthermore, in step 1), the mass-to-volume ratio of orange peel powder to 90%~98% ethanol solution is 1g:3~5mL each time during extraction.

[0017] This invention also discloses an extraction method for improving the stability of pigments in orange peel, comprising the following steps:

[0018] 1) Extraction of pigment from orange peel to obtain orange peel pigment powder;

[0019] 2) Plasma treatment:

[0020] Orange peel pigment powder was treated with cold plasma, with nitrogen or air as the carrier gas, power of 20-50W, treatment time of 5-30s, and nitrogen or air flow rate of 40-60mL / min to obtain orange peel pigment after cold plasma treatment.

[0021] In the preferred embodiment, step 1) specifically involves: washing and drying the citrus peel; pulverizing it into citrus peel powder; extracting the citrus peel powder with 95%~98% ethanol solution 1~2 times, placing it in a microwave with a power of 180~230W for 1~2 minutes during extraction; filtering the extract to obtain a yellow liquid, concentrating it under reduced pressure at 50~58℃ to 11-14% of the original yellow liquid volume, and drying it to obtain citrus peel pigment powder.

[0022] Further, in step 2), orange peel pigment with a thickness ≤0.5mm is evenly spread on a glass dish and subjected to cold plasma treatment.

[0023] Another object of the present invention is to provide an orange peel pigment obtained by the aforementioned extraction method.

[0024] Another object of the present invention is to disclose the application of the aforementioned extraction method in improving the light stability, heat stability or acid-base stability of pigments in orange peel.

[0025] The advantages of this invention are:

[0026] By simultaneously using microwave treatment during extraction, the number of extraction cycles can be reduced, soaking time can be decreased, and extraction efficiency can be improved.

[0027] Plasma treatment using lower plasma power and shorter plasma treatment time helps to better improve the light stability, thermal stability and acid-base stability of orange peel pigments.

[0028] The thickness of the orange peel pigment is ≤0.5mm to ensure more uniform and thorough plasma treatment.

[0029] This invention improves the stability of orange peel pigment under different light, temperature, and acid-base conditions by subjecting it to short-time plasma treatment, ensuring that its color development performance is not affected. This makes it more suitable for processing, preservation, and transportation in the food and pharmaceutical fields. Detailed Implementation

[0030] The present invention will be described in detail below with reference to specific embodiments.

[0031] Example 1

[0032] 1) Orange peel pigment extraction:

[0033] Wash and dry the citrus peels; pulverize them into citrus peel powder; extract the citrus peel powder twice with 95% ethanol solution (15 min each time), with a mass-to-volume ratio of citrus peel powder to 95% ethanol solution of 1 g: 4 mL each time; place the mixture of citrus peel powder and 95% ethanol solution in a microwave oven at 200 W for 1 min each time; combine the extracts; filter the extract to obtain a yellow liquid; concentrate under reduced pressure at 55℃ to 12% of the original yellow liquid volume, and dry to obtain citrus peel pigment powder;

[0034] 2) Plasma treatment:

[0035] Orange peel pigment powder was treated with cold plasma (using a cold plasma device) with nitrogen as the carrier gas, a power of 30W, a treatment time of 20s, and a nitrogen or air flow rate of 50mL / min to obtain cold plasma-treated orange peel pigment. The orange peel pigment, with a thickness ≤0.5mm, was evenly spread on a glass dish before cold plasma treatment.

[0036] Example 2

[0037] 1) Orange peel pigment extraction:

[0038] Wash and dry the citrus peels; pulverize them into citrus peel powder; extract the citrus peel powder once with 95% ethanol solution (soaking for 20 min), the mass-to-volume ratio of citrus peel powder to 95% ethanol solution is 1 g: 5 mL; during extraction, place the mixture of citrus peel powder and 95% ethanol solution in a microwave with a power of 230 W for 2 min; filter the extract to obtain a yellow liquid; concentrate under reduced pressure at 50℃ to 14% of the original yellow liquid volume, and dry to obtain citrus peel pigment powder;

[0039] 2) Plasma treatment:

[0040] Orange peel pigment powder was treated with cold plasma (using a cold plasma device) with nitrogen as the carrier gas, a power of 50W, a treatment time of 15s, and a nitrogen or air flow rate of 60mL / min to obtain cold plasma-treated orange peel pigment. The orange peel pigment, with a thickness ≤0.5mm, was evenly spread on a glass dish before cold plasma treatment.

[0041] Example 3

[0042] 1) Orange peel pigment extraction:

[0043] Wash and dry the citrus peels; pulverize them into citrus peel powder; extract the citrus peel powder twice with 95% ethanol solution (15 min each time), with a mass-to-volume ratio of citrus peel powder to 95% ethanol solution of 1 g: 3 mL each time; place the mixture of citrus peel powder and 95% ethanol solution in a microwave oven at 180 W for 2 min each time; combine the extracts; filter the extract to obtain a yellow liquid; concentrate under reduced pressure at 55℃ to 11% of the original yellow liquid volume, and dry to obtain citrus peel pigment powder;

[0044] 2) Plasma treatment:

[0045] Orange peel pigment powder was treated with cold plasma (using a cold plasma device) with nitrogen as the carrier gas, a power of 20W, a treatment time of 30s, and a nitrogen or air flow rate of 40mL / min to obtain cold plasma-treated orange peel pigment. The orange peel pigment, with a thickness ≤0.5mm, was evenly spread on a glass dish before cold plasma treatment.

[0046] Comparative Example 1

[0047] Orange peel pigment extraction:

[0048] Wash and dry the citrus peels; pulverize them into citrus peel powder; extract the citrus peel powder twice with 95% ethanol solution (15 min each time), with a mass-to-volume ratio of citrus peel powder to 95% ethanol solution of 1 g: 4 mL each time; place the mixture of citrus peel powder and 95% ethanol solution in a microwave oven at 200 W for 1 min each time; combine the extracts; filter the extract to obtain a yellow liquid; concentrate under reduced pressure at 55℃ to 12% of the original yellow liquid volume, and dry to obtain citrus peel pigment powder.

[0049] Comparative Example 2

[0050] 1) Orange peel pigment extraction:

[0051] Wash and dry the citrus peels; pulverize them into citrus peel powder; extract the citrus peel powder twice with 95% ethanol solution (15 min each time), with a mass-to-volume ratio of citrus peel powder to 95% ethanol solution of 1 g: 4 mL each time; place the mixture of citrus peel powder and 95% ethanol solution in a microwave oven at 200 W for 1 min each time; combine the extracts; filter the extract to obtain a yellow liquid; concentrate under reduced pressure at 55℃ to 12% of the original yellow liquid volume, and dry to obtain citrus peel pigment powder;

[0052] 2) Plasma treatment:

[0053] Orange peel pigment powder was treated with cold plasma (using a cold plasma device) with nitrogen as the carrier gas, a power of 300W, a treatment time of 20s, and a nitrogen or air flow rate of 50mL / min to obtain cold plasma-treated orange peel pigment. The orange peel pigment, with a thickness ≤0.5mm, was evenly spread on a glass dish before cold plasma treatment.

[0054] Comparative Example 3

[0055] 1) Orange peel pigment extraction:

[0056] Wash and dry the citrus peels; pulverize them into citrus peel powder; extract the citrus peel powder twice with 95% ethanol solution (15 min each time), with a mass-to-volume ratio of citrus peel powder to 95% ethanol solution of 1 g: 4 mL each time; place the mixture of citrus peel powder and 95% ethanol solution in a microwave oven at 200 W for 1 min each time; combine the extracts; filter the extract to obtain a yellow liquid; concentrate under reduced pressure at 55℃ to 12% of the original yellow liquid volume, and dry to obtain citrus peel pigment powder;

[0057] 2) Plasma treatment:

[0058] Orange peel pigment powder was treated with cold plasma (using a cold plasma device) with nitrogen as the carrier gas, a power of 30W, a treatment time of 5 minutes, and a nitrogen or air flow rate of 50 mL / min to obtain cold plasma-treated orange peel pigment. The orange peel pigment, with a thickness ≤0.5 mm, was evenly spread on a glass dish before cold plasma treatment.

[0059] Application Example 1: Illumination Stability

[0060] For the orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3, 1 g / L orange peel pigment solutions were prepared respectively. Under the condition of light intensity of 40000 Lux, the absorbance value at 436 nm was measured every 3 days to compare and analyze the light stability of the orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3. The results are shown in Table 1 below.

[0061] Table 1. Absorbance values ​​of orange peel pigments in Examples 1-3 and Comparative Examples 1-3 after being prepared into solutions.

[0062]

[0063] First, plasma treatment itself can slightly increase the absorbance of orange peel pigment when it is prepared into a solution. When the orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3 are prepared into 1 g / L orange peel pigment solutions, there is no obvious difference in color between the examples and the comparative examples.

[0064] Comparative Example 1 only extracted orange peel pigment without any additional treatment. Over time, the absorbance of the prepared orange peel pigment solution decreased significantly, indicating that the orange peel pigment was destroyed.

[0065] Comparative Examples 2 and 3 employed higher plasma processing power or longer plasma processing time. As time progressed, the absorbance of the prepared orange peel pigment solution also decreased, demonstrating that the use of lower plasma processing power and shorter plasma processing time in this invention is more beneficial for light stability.

[0066] In Examples 1-3, after the extraction of pigment from orange peel, plasma treatment was performed using a lower plasma power and a shorter plasma treatment time. As time progressed, the absorbance of the prepared orange peel pigment solution remained basically unchanged and did not show a significant decrease.

[0067] Application Example 2: Thermal Stability

[0068] For the orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3, 1 g / L orange peel pigment solutions were prepared respectively. After 1 hour at temperatures of 30℃, 60℃, and 90℃, the absorbance at 436 nm was measured. The thermal stability of the orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3 was compared and analyzed. The results are shown in Table 2 below.

[0069] Table 2. Thermal stability of orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3

[0070]

[0071] Comparative Example 1, which only extracted orange peel pigment without any additional treatment, showed a decrease in absorbance of the prepared orange peel pigment solution during high-temperature treatment (especially at 90°C).

[0072] Comparative Examples 2 and 3 employed higher plasma processing power or longer plasma processing time. During high-temperature processing, the absorbance of the prepared orange peel pigment solution also decreased, which corroborates that the use of lower plasma processing power and shorter plasma processing time in this invention is more beneficial to thermal stability.

[0073] In Examples 1-3, after the extraction of pigment from orange peel, plasma treatment was performed using a lower plasma power and a shorter plasma treatment time. During high-temperature treatment, the absorbance of the prepared orange peel pigment solution also decreased, but the decrease was less than that of Comparative Examples 1-3.

[0074] Application Example 3: Acid-Base Stability

[0075] For the orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3, 1 g / L orange peel pigment solutions were prepared respectively. After 1 hour, the absorbance at 436 nm was measured under pH conditions of 1 and 11, respectively. The acid-base stability of the orange peel pigments obtained in Examples 1-3 and Comparative Examples 1-3 was compared and analyzed. The results are shown in Table 3 below:

[0076]

[0077] It is evident that the acid-base stability of Examples 1-3 is superior to that of Comparative Example 1. Among them, the absorbance of Comparative Example 1 increases (the color becomes darker) under strongly alkaline conditions and decreases significantly under strongly acidic conditions, while the stability of Examples 1-3 is superior to that of Comparative Example 1 under both strongly acidic and strongly alkaline conditions.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way. All technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. An extraction method for improving stability of orange peel pigments, characterized by, The method comprises the following steps: 1) orange peel pigment extraction, to obtain orange peel pigment powder; 2) plasma treatment: The orange peel pigment powder is treated by cold plasma, the carrier gas is nitrogen or air, the power is 20-50 W, the treatment time is 5-30 s, the nitrogen or air flow rate is 40-60 mL / min, to obtain the orange peel pigment after cold plasma treatment.

2. The method for improving the stability of orange peel pigments according to claim 1, characterized in that, Step 1) is specifically: washing the citrus peel, drying; crushing into orange peel powder; the orange peel powder is immersed with 90%-98% ethanol solution for 1-2 times, and the immersion is carried out in a microwave with a power of 180-230 W for 1-2 min; filtering the immersion liquid to obtain a yellow liquid, concentrating the yellow liquid at 50-58°C under reduced pressure to 11-14% of the original volume, and drying to obtain the orange peel pigment powder.

3. The method for improving the stability of orange peel pigments according to claim 1, characterized in that, In step 2), the orange peel pigment with a thickness of ≤0.5 mm is evenly spread on a glass dish, and cold plasma treatment is carried out.

4. The method for improving the stability of orange peel pigments according to claim 1, characterized in that, In step 2), the carrier gas is nitrogen.

5. The method for improving the stability of orange peel pigments according to claim 1, characterized in that, In step 2), the treatment time is 10-20 s.

6. The method for improving the stability of orange peel pigments according to claim 2, characterized in that, In step 1), the mass-volume ratio of the orange peel powder to 95%-98% ethanol solution is 1 g:3-5 mL during each immersion.

7. The orange peel pigment prepared by the extraction method of any one of claims 1-6.

8. The use of the extraction method of any one of claims 1-6 in improving the light stability, thermal stability or acid-base stability of the orange peel pigment.

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