A kind of preparation method of low-ester tangerine peel

Abstract

The present invention relates to the technical field of food processing, and discloses a method for making low-ester tangerine peel, comprising the following steps: in an alkaline environment, semi-dried tangerine peel is subjected to vacuum soaking and swelling treatment, and the obtained wet tangerine peel is dried again to obtain a finished product. Under alkaline conditions, β-elimination reaction is prone to occur, thereby reducing the molecular weight of pectin in tangerine peel, and obtaining a small molecule pectin of 1-20,000 Daltons; under alkaline conditions, the esterification degree of pectin is also reduced, so that the esterification degree of pectin in tangerine peel is below 10%. Low-ester small molecule pectin can be directly absorbed into the blood, thereby playing the role of anti-cancer, lowering cholesterol, reducing arteriosclerosis and preventing heart disease, and at the same time, the ability to remove heavy metals from the human body is relatively stronger, and it is easy to eliminate heavy metal poisoning that causes many chronic diseases. At the same time, when the alkaline tangerine peel is brewed, the solubility of flavonoids such as hesperidin, its main functional component, in water will be greatly improved, thereby improving the absorption efficiency of the human body.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a method for preparing low-ester tangerine peel. Background Art

[0002] It is recorded in the Chinese Medicine Classics that tangerine peel is the dried mature peel of the citrus plant and its cultivated varieties of the Rutaceae family. Pick the ripe fruit, peel it, and dry it in the sun or at a low temperature.

[0003] According to traditional Chinese medicine, tangerine peel is bitter, pungent, and warm in nature, and belongs to the lung and spleen meridians. It has the functions of regulating qi and strengthening the spleen, drying dampness and resolving phlegm, and is mainly used to treat abdominal distension, vomiting and diarrhea, cough and sputum.

[0004] In addition to flavonoids (hesperidin, nobiletin, tangeretin, etc.) and citrus essential oils, tangerine peel also contains rich pectin. Pectin is a natural polysaccharide, accounting for about 15% by weight in tangerine peel, which is much higher than flavonoids (3%-4%) and essential oils (0.5%-1.2%).

[0005] Pectin is an important functional substance, especially the citrus low-ester pectin which has been studied in depth. Many studies have shown that if the molecular weight of citrus pectin is between 10,000 and 20,000 Daltons and the degree of esterification is below 10%, it can be directly absorbed into the blood, thereby playing a role in anti-cancer, lowering cholesterol, reducing arteriosclerosis, preventing heart disease, and eliminating heavy metal poisoning, which causes many chronic diseases. And there are also studies showing that small molecule citrus pectin can prevent and even reverse Alzheimer's disease.

[0006] However, tangerine peel produced by traditional methods usually does not process the molecular weight of pectin, which is not conducive to human absorption.

[0007] The main shortcomings are as follows:

[0008] 1. The content of macromolecular pectin in tangerine peel is large, which is not easy to dissolve when brewing or boiling, and is not conducive to human absorption;

[0009] 2. The pectin in tangerine peel is high-ester pectin, and its ability to remove heavy metals from the human body is relatively weak;

[0010] 3. The main functional substances in tangerine peel, such as hesperidin, have very low solubility in water and are absorbed by the human body inefficiently.

[0011] Based on this, it is necessary to design a method for preparing low-ester tangerine peel. Summary of the invention

[0012] In order to overcome the above technical problems, the present invention provides a method for preparing low-ester tangerine peel, so as to achieve the purpose of reasonably and safely utilizing the effective ingredients in tangerine peel.

[0013] To achieve the above object, the present invention provides the following technical solutions:

[0014] A method for preparing low-ester tangerine peel comprises the following steps:

[0015] In an alkaline environment, the semi-dried orange peel is subjected to a vacuum soaking treatment, and the obtained moist orange peel is dried again to obtain a finished product.

[0016] Preferably, the semi-dried orange peel is obtained by the following method:

[0017] The washed oranges are peeled and pulped to obtain fresh orange peels;

[0018] The fresh orange peel is then placed in a 60-65°C environment and baked for 3-4 hours to obtain semi-dried orange peel.

[0019] Preferably, the alkaline environment is:

[0020] An aqueous solution with a pH value ranging from 9.5 to 10.5, wherein the aqueous solution is prepared with edible alkali; and a vacuum pot for containing the aqueous solution and semi-dried orange peel.

[0021] Preferably, the vacuum soaking treatment comprises the following steps:

[0022] Before soaking, adjust the temperature of the aqueous solution to 15-20°C;

[0023] During the soaking process, the semi-dried orange peel and the aqueous solution are added into the vacuum pot in proportion, and then the first vacuum soaking treatment is carried out under the set conditions, and then the peel is taken out and drained, and then the peel is swelled for the first time under the natural environment, and then the second vacuum soaking treatment is carried out, and then the peel is taken out and drained, and then the peel is swelled for the second time under the natural environment to obtain the moist orange peel.

[0024] Preferably, 1 part of the semi-dried orange peel and 8-10 parts of the aqueous solution are mixed according to the mass ratio.

[0025] Preferably, the conditions of the first vacuum immersion treatment are:

[0026] The vacuum degree is 0.06-0.08Mpa, and the soaking time is 5-10min.

[0027] Preferably, the first swelling time is 1.5-2h.

[0028] Preferably, the conditions for the second vacuum immersion treatment are:

[0029] The vacuum degree is 0.06-0.08Mpa, and the soaking time is 3-5min;

[0030] After the first vacuum soaking treatment is completed, the aqueous solution is re-added according to the proportion and then used for the second vacuum soaking treatment.

[0031] Preferably, the second swelling time is 1-1.5 hours.

[0032] Preferably, the drying of the wet orange peel is carried out under the following conditions:

[0033] Bake the wet orange peel at 45-50°C for 1.5-2.5h and then cool;

[0034] Preferably, the moisture content of the finished product is less than 13%.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. When produced under alkaline conditions, β-elimination reaction is likely to occur, which reduces the molecular weight of pectin and forms a small molecule pectin of 10,000-20,000 Daltons. At the same time, the degree of esterification of pectin is reduced, forming a low-ester pectin with an esterification degree of less than 10%. The solubility of small molecule low-ester pectin in water is relatively greatly improved, which improves the absorption efficiency of the human body and can be directly absorbed into the blood, thereby playing a role in anti-cancer, lowering cholesterol, reducing arteriosclerosis and preventing heart disease. The ability to remove heavy metals from the human body is relatively stronger, and it is easy to eliminate heavy metal poisoning that causes many chronic diseases.

[0037] 2. Under alkaline conditions, the prepared tangerine peel is slightly alkaline, and its functional substances such as hesperidin and other flavonoids are easily soluble in water, which is more conducive to improving the human body's absorption efficiency.

[0038] 3. Under alkaline conditions, the Maillard reaction is prone to occur during the drying process of aged products. The sensory performance of the product is rich in aroma and slightly alkaline. Compared with traditional tangerine peel, it has better aroma and taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a process flow chart of a method for producing low-ester tangerine peel in one embodiment of the present invention. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but should not be understood that the present invention is limited to the following embodiments.

[0041] Embodiment 1:

[0042] A method for preparing low-ester tangerine peel comprises the following steps:

[0043] Step S100, peeling and pulping the washed tangerine fruits to obtain fresh tangerine peels, and then baking the fresh tangerine peels at 60° C. for 4 hours to obtain semi-dried tangerine peels for standby use;

[0044] Step S200, preparing an aqueous solution with a pH value of 10, wherein the aqueous solution is prepared with potassium carbonate and is set aside;

[0045] Step S300, before soaking, the temperature of the aqueous solution in the hollow pot is adjusted to 15°C; during soaking, according to the mass ratio, 1 part of semi-dried orange peel and 10 parts of aqueous solution are put into the vacuum pot, and the conditions of the first vacuum soaking treatment are adjusted as follows: the vacuum degree is 0.06Mpa, the soaking time is 8min, then the peel is taken out and drained, and the first natural swelling is 1.8h at room temperature, and then the peel is put into the vacuum pot again, and the conditions of the second vacuum soaking treatment are adjusted as follows: the vacuum degree is 0.08Mpa, the soaking time is 3min, then the peel is taken out and drained, and the second natural swelling is 1h at room temperature, so as to obtain moist orange peel;

[0046] After the first vacuum soaking treatment, the aqueous solution is added again according to the ratio and then used for the second vacuum soaking treatment;

[0047] Step S400, baking the wet orange peel at 45° C. for 1.5 hours and then cooling to obtain a finished product;

[0048] Among them, the moisture content of the finished product is less than 13%.

[0049] Embodiment 2:

[0050] A method for preparing low-ester tangerine peel comprises the following steps:

[0051] Step S100, peeling and pulping the washed tangerine fruits to obtain fresh tangerine peels, and then baking the fresh tangerine peels at 65° C. for 3 hours to obtain semi-dried tangerine peels for standby use;

[0052] Step S200, preparing an aqueous solution with a pH value of 10.5, wherein the aqueous solution is prepared with sodium hydroxide and is set aside;

[0053] Step S300, before soaking, the temperature of the aqueous solution in the hollow pot is adjusted to 15°C; during soaking, according to the mass ratio, 1 part of semi-dried orange peel and 8 parts of aqueous solution are put into the vacuum pot, and the conditions of the first vacuum soaking treatment are adjusted as follows: the vacuum degree is 0.08Mpa, the soaking time is 5min, then the peel is taken out and drained, and the first natural swelling is 1.5h at room temperature, and then the peel is put into the vacuum pot again, and the conditions of the second vacuum soaking treatment are adjusted as follows: the vacuum degree is 0.06Mpa, the soaking time is 5min, then the peel is taken out and drained, and the second natural swelling is 1.2h at room temperature, so as to obtain moist orange peel;

[0054] After the first vacuum soaking treatment, the aqueous solution is added again according to the ratio and then used for the second vacuum soaking treatment;

[0055] Step S400, baking the wet orange peel at 50° C. for 2 hours and then cooling to obtain a finished product;

[0056] Among them, the moisture content of the finished product is less than 13%.

[0057] Embodiment three:

[0058] A method for preparing low-ester tangerine peel comprises the following steps:

[0059] Step S100, peeling and pulping the washed Wenzhou mandarin oranges to obtain fresh orange peels, and then baking the fresh orange peels at 62° C. for 3.5 hours to obtain semi-dried orange peels for standby use;

[0060] Step S200, preparing an aqueous solution with a pH value of 9.5, wherein the aqueous solution is prepared with sodium carbonate and is set aside;

[0061] Step S300, before soaking, the temperature of the aqueous solution in the hollow pot is adjusted to 18°C; during soaking, according to the mass ratio, 1 part of semi-dried orange peel and 9 parts of aqueous solution are put into the vacuum pot, and the conditions of the first vacuum soaking treatment are adjusted as follows: the vacuum degree is 0.07Mpa, the soaking time is 10min, then the peel is taken out and drained, and the first natural swelling is carried out at room temperature for 2h, and then the peel is put into the vacuum pot again, and the conditions of the second vacuum soaking treatment are adjusted as follows: the vacuum degree is 0.07Mpa, the soaking time is 4min, then the peel is taken out and drained, and the second natural swelling is carried out at room temperature for 1.5h, so as to obtain moist orange peel;

[0062] After the first vacuum soaking treatment, the aqueous solution is added again according to the ratio and then used for the second vacuum soaking treatment;

[0063] Step S400, baking the wet orange peel at 48° C. for 2.5 hours and then cooling to obtain a finished product;

[0064] Among them, the moisture content of the finished product is less than 13%.

[0065] Among them, using the traditional drying process, the tangerine peel made from tangerine peel as the raw material was used as the control group, and the preparation was performed multiple times (no less than 50 times) according to the methods of Example 1, Example 2 and Example 3, and the average value of the finished product detection was taken for comparison, and the following table was obtained:

[0066]

[0067] It can be seen from the above table that, compared with the control group, the tangerine peel prepared according to the methods of Example 1, Example 2 and Example 3 has lower molecular weight and degree of esterification of pectin, so it is easy to dissolve during brewing or decocting, and is beneficial to human absorption. In addition, low-ester pectin has a relatively stronger ability to remove heavy metals from the human body, which can be beneficial to eliminate a series of chronic diseases caused by heavy metal poisoning.

[0068] The esterification degree of the tangerine peel prepared according to the methods of Example 1, Example 2 and Example 3 is all below 10%. The tangerine peel prepared according to the methods of Example 1 and Example 3 has a pectin relative molecular weight between 10,000 and 20,000 Daltons, so it can be directly absorbed into the blood, thereby playing a better role in anti-cancer, lowering cholesterol, reducing arteriosclerosis and preventing heart disease.

[0069] The tangerine peel prepared according to the method of embodiment one, embodiment two and embodiment three has a relatively high total flavonoid content in a 1:10 times brewing liquid, which is at least 10 times the content of traditional tangerine peel brewed in the same way. Therefore, the solubility of the main functional substances of tangerine peel in water is greatly improved relatively, so that the human body absorption rate is higher.

[0070] In addition, the brewing method of the tangerine peel prepared according to the method of Example 1, Example 2 and Example 3 is as follows: 10 g of the finished tangerine peel is brewed with 100 g of water at a temperature above 95° C. and the mixture can be drunk after being kept warm for 20 minutes.

[0071] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various specific technical features in any suitable manner. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing low-ester tangerine peel, characterized in that: The following steps are involved: Under an alkaline environment, the semi-dried orange peel is subjected to a vacuum soaking treatment, and the obtained wet orange peel is dried again to obtain a finished product; The semi-dried orange peel is obtained by: peeling and pulping the washed oranges to obtain fresh orange peels; and then baking the fresh orange peels at 60-65° C. for 3-4 hours to obtain semi-dried orange peels; The vacuum soaking treatment comprises the following steps: before soaking, adjusting the temperature of the aqueous solution to 15-20° C.; during soaking, adding the semi-dried orange peel and the aqueous solution into a vacuum pot in proportion, then performing a first vacuum soaking treatment under set conditions, then taking out and draining, and performing a first swelling in a natural environment, then performing a second vacuum soaking treatment, then taking out and draining, and performing a second swelling in a natural environment to obtain moist orange peel; The drying of the wet orange peel is carried out under the following conditions: the wet orange peel is placed at 45-50° C. for 1.5-2.5 hours and then cooled; The moisture content of the finished product is less than 13%; The degree of esterification of the finished product is below 10%; The conditions of the first vacuum immersion treatment are: vacuum degree of 0.06-0.08Mpa, immersion time of 5-10min; The conditions for the second vacuum soaking treatment are: vacuum degree of 0.06-0.08Mpa, soaking time of 3-5min; after the first vacuum soaking treatment, the aqueous solution is added again according to the ratio and then used for the second vacuum soaking treatment.

2. A method for preparing low-ester dried orange peel according to claim 1, characterized in that: The alkaline environment is: An aqueous solution with a pH value ranging from 9.5 to 10.5, wherein the aqueous solution is prepared with edible alkali; and a vacuum pot for containing the aqueous solution and semi-dried orange peel.

3. A method for preparing low-ester dried orange peel according to claim 1, characterized in that: Take 1 part of the semi-dried orange peel and 8-10 parts of the aqueous solution, and mix them according to the mass ratio.

4. A method for preparing low-ester dried orange peel according to claim 1, characterized in that: The time of the first imbibition is 1.5-2h.

5. A method for preparing low-ester dried orange peel according to claim 1, characterized in that: The second swelling time is 1-1.5h.

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