Method for refining tea oil from tea seeds

Abstract

The invention discloses a method for refining tea oil from tea seeds, and belongs to the technical field of tea oil preparation. The method comprises the following steps: S1, material pretreatment: screening tea seeds, and drying the tea seeds to obtain pretreated tea seeds; s2, squeezing: performing cold squeezing on the tea seeds pretreated in the S1 to obtain oil, and obtaining a mixed oil sample; s3, refining: adding activated carbon and diatomite into the mixed oil sample obtained by squeezing in S2 to obtain a mixture; adding strong base into the mixture for first mixing, then adding phosphoric acid for second mixing, and finally performing low-temperature degreasing to obtain the tea oil. According to the invention, the adsorbent (biochar and diatomite), strong alkali, phosphoric acid and a low-temperature degreasing process are combined, and the steps of degumming, deacidification, decoloration, deodorization and degreasing can be completed in a short time, so that the process flow is greatly simplified, and the refining time is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of tea oil preparation, and more specifically relates to a method for refining tea oil by using tea seeds. Background Art

[0002] Tea seeds are the seeds of the oil-tea tree, which belongs to the Camellia genus of the Theaceae family. It is a unique woody plant oil resource in my country and is mainly distributed in the Yangtze River Basin and the middle subtropical areas to the south and some tropical and northern subtropical areas. Tea seeds are rich in oil, with an oil content of about 30-45%, and an unsaturated fatty acid content of more than 90%, of which oleic acid content is about 79%. It also contains protein, vitamin B2, niacin, tea polyphenols, camellia glycosides, squalene and other nutrients, with high nutritional value and health benefits.

[0003] With the improvement of people's living standards and the focus on healthy diet, the demand for high-quality edible oil is increasing. Tea oil, as a nutritious edible oil with multiple health functions, is favored by more and more consumers, and market demand has promoted the development of tea seed refining tea oil industry. In the early days, tea oil production mainly used traditional pressing methods, which had simple processes, but low production efficiency and unstable product quality. With the continuous advancement of science and technology, tea oil refining technology is also constantly developing and improving, and a variety of refining methods such as physical refining, chemical refining, enzymatic refining, and supercritical extraction have emerged. These methods have achieved remarkable results in improving the quality of tea oil, retaining nutrients, and reducing production costs.

[0004] However, there are many problems with the above methods: Problems with chemical refining: (1) Loss of nutrients: During the alkali refining and deacidification process, a strong base needs to be added to neutralize free fatty acids, which may cause some nutrients in tea oil, such as vitamin E, squalene, sterols, etc. to be destroyed or lost, thereby reducing the nutritional value of tea oil; (2) Production of harmful substances: During the chemical refining process, some harmful substances may be produced, such as trans fatty acids. In addition, if the quality of the chemical reagents used in the degumming and decolorization processes is not up to standard or is improperly handled, it may also cause problems such as heavy metal residues and excessive benzopyrene, posing a potential threat to human health; (3) Environmental pollution: Wastewater, waste residues and other wastes generated during the chemical refining process contain a large amount of chemical substances. If they are directly discharged without treatment, they will cause serious pollution to the environment, such as water pollution and soil pollution.

[0005] Problems with physical refining: (1) High process requirements: Physical refining has high requirements for equipment and process. For example, the control of parameters such as distillation temperature and vacuum degree needs to be very precise, otherwise it will affect the refining effect and product quality. In addition, the investment cost of equipment is relatively high, which may put some economic pressure on some small enterprises; (2) High energy consumption: In the physical refining process, such as distillation and deodorization, a large amount of energy is consumed, which not only increases production costs, but also puts high demands on energy supply. In addition, high energy consumption also means an increase in carbon emissions, which has a certain negative impact on the environment.

[0006] Problems with other refining methods: (1) Long process flow: The traditional tea oil refining process generally includes multiple steps such as hydration degumming, alkali refining and deacidification, water washing, filtration and decolorization, high-temperature steam deodorization, winterization and degreasing. The entire process flow is complicated and the production cycle is long, resulting in low production efficiency and increased production costs and time costs; (2) Risk of solvent residue: In refining methods such as extraction, the organic solvents used may remain in the tea oil. If the solvent residue exceeds the standard, it will not only affect the quality and taste of the tea oil, but also cause harm to human health.

[0007] Therefore, it is of great significance to develop a method for refining tea oil from tea seeds which can retain the nutrients in tea seeds to the greatest extent, has a simple refining process, and is green and pollution-free. Summary of the invention

[0008] The purpose of the present invention is to provide a method for refining tea oil using tea seeds to solve the problems existing in the above-mentioned prior art and to achieve the refining of tea oil which retains the nutrients in tea seeds to a great extent, has a simple refining process and is green and pollution-free.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] One of the technical solutions of the present invention is to provide a method for refining tea oil using tea seeds, comprising the following steps:

[0011] S1: Material pretreatment: screening tea seeds and drying them to obtain pretreated tea seeds;

[0012] S2: pressing: cold pressing the tea seeds obtained by the pretreatment in S1 to extract oil and obtain a mixed oil sample;

[0013] S3: Refining: Add activated carbon and diatomaceous earth to the mixed oil sample squeezed in S2 to obtain a mixture; add a strong base to the mixture for a first mixing, then add phosphoric acid for a second mixing, and finally perform low-temperature degreasing to obtain the tea oil.

[0014] The present invention firstly extracts oil by cold pressing, and can retain the nutrients in tea seeds, such as vitamin E, squalene, sterols, etc., to the greatest extent, while also maintaining the natural flavor and color of tea oil. Then, by combining adsorbent (biochar and diatomaceous earth), strong alkali and phosphoric acid and low-temperature degreasing process, the steps of degumming, deacidification, decolorization, deodorization and degreasing can be completed in a relatively short time, which greatly simplifies the process flow and saves the time of refining; and, the deacidification effect can be significantly improved by combining adsorbent and strong alkali, and free fatty acids in oil are neutralized with alkali by alkali refining method to generate substances such as soap, which can be adsorbed by adsorbent and effectively removed by subsequent separation steps; the degumming effect can be significantly improved by combining adsorbent and phosphoric acid, and phosphoric acid can hydrate colloidal substances such as phospholipids in oil, form precipitation and be adsorbed by adsorbent, and effectively removed by subsequent separation steps.

[0015] Preferably, the water content of the pretreated tea seeds is 10-15%.

[0016] Preferably, the cold pressing temperature is 50-60° C., and the cold pressing pressure is 20-50 MPa.

[0017] The invention controls the cold pressing temperature and pressure to avoid excessive pressure and high temperature which may damage the nutrients in the tea seeds or cause excessive oxidation of the oil, thereby affecting the quality and nutrition of the tea oil.

[0018] Preferably, the volume ratio of the total mass of the activated carbon and diatomaceous earth to the mixed oil sample is 1 g:2-5 mL; the mass ratio of the activated carbon and diatomaceous earth is 1:2-3.

[0019] Preferably, the strong base includes sodium hydroxide and / or potassium hydroxide; the dosage ratio of the strong base to the mixture is 0.5-0.8 g:10-15 mL.

[0020] Preferably, the stirring rate of the first mixing is 100-150 r / min; and the time of the first mixing is 1-2 h.

[0021] Preferably, the usage ratio of the phosphoric acid and the mixture is 0.6-0.8 g:15-20 mL.

[0022] Preferably, the stirring rate of the second mixing is 120-180 r / min; and the time of the second mixing is 50-80 min.

[0023] Preferably, the temperature of the low-temperature degreasing is 5 to 10° C., the rotation speed of the low-temperature degreasing is 30 to 60 r / min, and the time of the low-temperature degreasing is 2 to 3 hours.

[0024] Preferably, the low-temperature degreasing further comprises a filtering step.

[0025] The present invention discloses the following technical effects:

[0026] 1. The refining process of the present invention is simple, which solves the problems of complicated refining process and long production cycle in the existing tea oil preparation process, resulting in low production efficiency, increased production cost and time cost, and is suitable for promotion and application, laying a foundation for simplifying the tea oil refining process;

[0027] 2. The present invention combines adsorbents (biochar and diatomaceous earth), strong alkali and phosphoric acid and low-temperature degreasing process, and can complete the steps of degumming, deacidification, decolorization, deodorization and degreasing in a short time, which greatly simplifies the process flow and saves refining time;

[0028] 3. After the final separation treatment, the adsorbent (biochar and diatomaceous earth), strong alkali and phosphoric acid can be completely removed, avoiding the influence of the adsorbent and organic reagents on the nutritional components of tea oil and improving the nutritional value of tea oil. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0031] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0032] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0033] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0034] Unless otherwise specified, the raw materials used in the following examples and comparative examples are all commercially available products.

[0035] Example 1

[0036] This embodiment provides a method for refining tea oil using tea seeds, and the specific steps are as follows:

[0037] S1: Material pretreatment: screening tea seeds, washing the tea seeds, removing the shriveled tea seeds, and then placing them in a drying oven for drying to obtain pretreated tea seeds with a moisture content of 12%;

[0038] S2: pressing: the tea seeds obtained by the pretreatment in S1 were cold pressed at 50°C and 30MPa to extract oil, and a mixed oil sample was obtained;

[0039] S3: Refining: Add activated carbon and diatomaceous earth to the mixed oil sample squeezed in S2 (wherein, the total mass ratio of activated carbon and diatomaceous earth to the volume ratio of the mixed oil sample is 1g:5mL, and the mass ratio of activated carbon and diatomaceous earth is 1:2) to obtain a mixture; add potassium hydroxide to the mixture (the ratio of potassium hydroxide to the mixture is 0.5g:10mL) and mix at a speed of 120r / min for 2h, and then add phosphoric acid (the ratio of phosphoric acid to the mixture is 0.6g:20mL) and mix at a speed of 120r / min for 50min, finally carry out low-temperature degreasing at 5°C and 40r / min for 2.5h, place the product in a separation kettle and separate it at 2500r / min for 15min to obtain the tea oil.

[0040] Example 2

[0041] This embodiment provides a method for refining tea oil using tea seeds, and the specific steps are as follows:

[0042] S1: Material pretreatment: screening tea seeds, washing the tea seeds, removing the shriveled tea seeds, and then placing them in a drying oven for drying to obtain pretreated tea seeds with a moisture content of 15%;

[0043] S2: Pressing: The tea seeds pretreated in S1 were cold pressed at 55°C and 40MPa to extract oil, and a mixed oil sample was obtained;

[0044] S3: Refining: Add activated carbon and diatomaceous earth to the mixed oil sample squeezed in S2 (wherein, the total mass ratio of activated carbon and diatomaceous earth to the volume ratio of the mixed oil sample is 1g:4mL, and the mass ratio of activated carbon and diatomaceous earth is 1:2.5) to obtain a mixture; add potassium hydroxide to the mixture (the dosage ratio of potassium hydroxide to the mixture is 0.5g:15mL) and mix at a speed of 100r / min for 1h, and then add phosphoric acid (the dosage ratio of phosphoric acid to the mixture is 0.7g:15mL) and mix at a speed of 160r / min for 50min, finally carry out low-temperature degreasing at 8°C and 30r / min for 2h, place the product in a separation kettle and separate it at 2500r / min for 15min to obtain the tea oil.

[0045] Example 3

[0046] This embodiment provides a method for refining tea oil using tea seeds, and the specific steps are as follows:

[0047] S1: Material pretreatment: screening tea seeds, washing the tea seeds, removing the shriveled tea seeds, and then placing them in a drying oven for drying to obtain pretreated tea seeds with a moisture content of 10%;

[0048] S2: Pressing: The tea seeds obtained by the pretreatment in S1 were cold pressed at 58°C and 40MPa to extract oil, and a mixed oil sample was obtained;

[0049] S3: Refining: Add activated carbon and diatomaceous earth to the mixed oil sample squeezed in S2 (wherein, the total mass ratio of activated carbon and diatomaceous earth to the volume ratio of the mixed oil sample is 1g:4mL, and the mass ratio of activated carbon and diatomaceous earth is 1:2.5) to obtain a mixture; add potassium hydroxide to the mixture (the ratio of potassium hydroxide to the mixture is 0.5g:15mL) and mix at a speed of 150r / min for 1h, and then add phosphoric acid (the ratio of phosphoric acid to the mixture is 0.7g:15mL) and mix at a speed of 160r / min for 50min, finally carry out low-temperature degreasing at 8°C and 60r / min for 3h, place the product in a separation kettle and separate it at 2500r / min for 15min to obtain the tea oil.

[0050] Comparative Example 1

[0051] The difference from Example 1 is that the addition of activated carbon is omitted, and the rest is the same as Example 1.

[0052] Comparative Example 2

[0053] The difference from Example 1 is that the addition of diatomaceous earth is omitted, and the rest is the same as Example 1.

[0054] Comparative Example 3

[0055] The difference from Example 1 is that the addition of activated carbon and diatomaceous earth is omitted, and the rest is the same as Example 1.

[0056] Test example

[0057] The indicators of the tea oil obtained in the above examples and comparative examples were tested, and the results are shown in Table 1

[0058]

[0059] As can be seen from Table 1, the tea oil refining method of the present invention can ensure that the nutrients in the tea seeds are not lost, greatly retain the nutrient content in the tea oil, and improve its nutritional value.

[0060] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0061] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for refining tea oil using tea seeds, characterized in that: The steps include: S1: Material pretreatment: screening tea seeds and drying them to obtain pretreated tea seeds; S2: pressing: cold pressing the tea seeds obtained by the pretreatment in S1 to extract oil and obtain a mixed oil sample; S3: Refining: Add activated carbon and diatomaceous earth to the mixed oil sample squeezed in S2 to obtain a mixture; add a strong base to the mixture for a first mixing, then add phosphoric acid for a second mixing, and finally perform low-temperature degreasing to obtain the tea oil.

2. The method according to claim 1, characterized in that: The water content of the pretreated tea seeds is 10-15%.

3. The method according to claim 1, characterized in that The temperature of the cold pressing is 50-60° C., and the pressure of the cold pressing is 20-50 MPa.

4. The method according to claim 1, characterized in that: The volume ratio of the total mass of the activated carbon and diatomaceous earth to the mixed oil sample is 1 g:2-5 mL; the mass ratio of the activated carbon and diatomaceous earth is 1:2-3.

5. The method according to claim 1, characterized in that The strong base includes sodium hydroxide and / or potassium hydroxide; the usage ratio of the strong base to the mixture is 0.5-0.8 g:10-15 mL.

6. The method according to claim 1, characterized in that The stirring rate of the first mixing is 100-150 r / min; the time of the first mixing is 1-2 h.

7. The method according to claim 1, characterized in that The usage ratio of the phosphoric acid and the mixture is 0.6-0.8 g:15-20 mL.

8. The method according to claim 1, characterized in that The stirring rate of the second mixing is 120-180 r / min; the time of the second mixing is 50-80 min.

9. The method according to claim 1, characterized in that: The temperature of the low-temperature degreasing is 5 to 10° C., the rotation speed of the low-temperature degreasing is 30 to 60 r / min, and the time of the low-temperature degreasing is 2 to 3 hours.

10. The method according to claim 1, characterized in that The low-temperature degreasing further includes a filtering step.

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