Extraction process of walnut oil

Abstract

This invention relates to the field of vegetable oil production technology and proposes a walnut oil extraction process, comprising the following steps: S1, soaking dried walnut kernel powder in a pretreatment agent solution to obtain pretreated walnut kernel powder; S2, extracting walnut oil from the pretreated walnut kernel powder using an organic solvent extraction method; the pretreatment agent in the pretreatment agent solution includes urea and / or mercaptoethanol. This technical solution solves the problem of low oil yield in organic solvent extraction of walnut oil in related technologies.

Description

Technical Field

[0001] This invention relates to the field of vegetable oil production technology, specifically to an extraction process for walnut oil. Background Technology

[0002] Walnuts, also known as walnuts or jujubes, belong to the Juglandaceae family and are considered one of the world's four major dried fruits, along with almonds, cashews, and hazelnuts. Walnut kernels are rich in walnut oil, with an oil content reaching up to 75%. The unsaturated fatty acids in walnut oil are a good source of structural fats for brain tissue cells and have excellent antioxidant and anti-aging effects.

[0003] Currently, there are several methods for extracting walnut oil, mainly including pressing, organic solvent extraction, water extraction, and supercritical carbon dioxide fluid extraction. Among these, organic solvent extraction has the advantages of simple operation and low cost, and is the most commonly used method in the oil processing industry. The organic solvents used in the extraction process mainly include petroleum ether, n-hexane, and acetone, but the oil yield is not high. Summary of the Invention

[0004] This invention proposes a walnut oil extraction process that solves the problem of low oil yield in organic solvent extraction methods used in related technologies.

[0005] The technical solution of the present invention is as follows: A walnut oil extraction process includes the following steps: S1. Soak the dried walnut kernel powder in a pretreatment agent solution to obtain pretreated walnut kernel powder; S2. Extract walnut oil from the pretreated walnut kernel powder using an organic solvent extraction method; The pretreatment agent in the pretreatment solution includes urea and / or mercaptoethanol.

[0006] In this invention, urea and / or mercaptoethanol are first prepared into a solution. Then, the walnut kernels are peeled, dried, and pulverized to obtain dried walnut kernel powder. The dried walnut kernel powder is then soaked in the solution of urea and / or mercaptoethanol to promote the release of walnut oil from the walnut kernels during the subsequent organic solvent extraction process, ensuring that the extracted walnut oil has a high oil yield.

[0007] As a further technical solution, the pretreatment agent includes urea and mercaptoethanol, wherein the mass of the urea is ≥ 4 times the mass of the mercaptoethanol.

[0008] In this invention, urea and mercaptoethanol are used as pretreatment agents, and the mass of urea is limited to ≥ 4 times the mass of mercaptoethanol, which further improves the oil yield of walnut oil.

[0009] As a further technical solution, the pretreatment agent includes urea and mercaptoethanol in a mass ratio of 4 to 7:1.

[0010] In this invention, urea and mercaptoethanol in a mass ratio of 4 to 7:1 are used as pretreatment agents, which further improves the oil yield of walnut oil.

[0011] As a further technical solution, the mass ratio of pretreatment agent to solvent in the pretreatment agent solution is 1~5:100.

[0012] In the pretreatment solution of this invention, the mass ratio of pretreatment agent to solvent is 1~5:100. When the amount of pretreatment agent is small, the pretreatment effect is not obvious; when the amount of pretreatment agent is large, it will lead to reagent waste and increase costs. Therefore, while ensuring cost and effectiveness, this invention uses a mixture of pretreatment agent and solvent at a mass ratio of 1~5:100 as the pretreatment solution.

[0013] As a further technical solution, soaking also includes filtration, washing, and drying.

[0014] In this invention, after soaking in the pretreatment agent solution, the solid material needs to be filtered and collected. Then, the solid material is washed to remove the residual pretreatment agent and finally dried to obtain pretreated walnut kernel powder.

[0015] As a further technical solution, the soaking process is accompanied by stirring, the stirring speed is 100~150 rpm, and the stirring time is 2~3 hours.

[0016] In this invention, the amount of dried walnut kernel powder and pretreatment agent solution used is such that the liquid level of the pretreatment agent solution can cover the dried walnut kernel powder. Preferably, the mass-volume ratio of dried walnut kernel powder to pretreatment agent solution is 1g:15~30mL.

[0017] In this invention, the organic solvent extraction method can be any conventional organic solvent extraction method in the art. Preferably, step S2 is as follows: the pretreated walnut kernel powder is mixed with an organic solvent, extracted, filtered, and the filtrate is evaporated and desolventized to obtain walnut oil.

[0018] As a further technical solution, the organic solvent includes one or more of petroleum ether, n-hexane, and acetone.

[0019] As a further technical solution, the mass-volume ratio of the pretreated walnut kernel powder to the organic solvent is 1g:7~9mL.

[0020] As a further technical solution, the extraction temperature is 50~60℃, and the extraction time is 1~2h.

[0021] The working principle and beneficial effects of this invention are as follows: In this invention, the dried walnut kernel powder is pretreated in a solution of urea and / or mercaptoethanol, which helps to promote the release of walnut oil during subsequent organic solvent extraction, thereby increasing the oil yield of the walnut kernels. The walnut oil extracted using the extraction process provided by this invention has an oil yield of over 65.41%, which is far higher than the oil yield of traditional extraction processes. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] In the following embodiments and comparative examples: Walnut kernels: Xinjiang Wensu 185 paper-shelled walnuts from Xiyu Meinong; Petroleum ether: boiling point 60~90℃.

[0024] Example 1 S1. Peel the walnut kernels, dry them in a constant temperature drying oven at 115℃ for 1 day, grind them into powder to obtain dried walnut kernel powder. S2. According to the mass-to-volume ratio of dried walnut kernel powder to pretreatment agent solution of 1g:15mL, the dried walnut kernel powder is soaked in a 5wt% pretreatment agent aqueous solution for 2h, while stirring at 100rpm during soaking, filtered, washed with water, and dried to obtain pretreated walnut kernel powder; the pretreatment agent is urea. S3. According to the mass-volume ratio of pretreated walnut kernel powder to petroleum ether of 1g:9mL, the pretreated walnut kernel powder and petroleum ether are mixed, extracted at 55℃ for 2h, filtered, and the filtrate is evaporated to remove petroleum ether to obtain walnut oil.

[0025] Example 2 S1. Peel the walnut kernels, dry them in a constant temperature drying oven at 115℃ for 1 day, grind them into powder to obtain dried walnut kernel powder. S2. According to the mass-to-volume ratio of dried walnut kernel powder to pretreatment agent solution of 1g:30mL, the dried walnut kernel powder is soaked in a 1wt% pretreatment agent aqueous solution for 3h, while stirring at 150rpm during soaking, filtered, washed with water, and dried to obtain pretreated walnut kernel powder; the pretreatment agent is urea. S3. According to the mass-volume ratio of pretreated walnut kernel powder to petroleum ether of 1g:7mL, the pretreated walnut kernel powder and petroleum ether are mixed, extracted at 50℃ for 1.5h, filtered, and the filtrate is evaporated to remove petroleum ether to obtain walnut oil.

[0026] Example 3 The only difference from Example 1 is that the pretreatment agent is mercaptoethanol.

[0027] Example 4 The only difference from Example 1 is that the pretreatment agent consists of urea and mercaptoethanol in a mass ratio of 1:1.

[0028] Example 5 The only difference from Example 1 is that the pretreatment agent consists of urea and mercaptoethanol in a mass ratio of 4:1.

[0029] Example 6 The only difference from Example 1 is that the pretreatment agent consists of urea and mercaptoethanol in a mass ratio of 7:1.

[0030] Example 7 The only difference from Example 1 is that the pretreatment agent consists of urea and mercaptoethanol in a mass ratio of 9:1.

[0031] Comparative Example 1 S1. Peel the walnut kernels, dry them in a constant temperature drying oven at 115℃ for 1 day, grind them into powder to obtain dried walnut kernel powder. S2. According to the mass-volume ratio of dried walnut kernel powder to petroleum ether of 1g:9mL, the dried walnut kernel powder and petroleum ether are mixed, extracted at 55℃ for 2h, filtered, and the filtrate is evaporated to remove petroleum ether to obtain walnut oil.

[0032] Calculate the oil yield using the following formula: Oil yield (%) = mass of walnut oil ÷ mass of walnut kernels × 100%; The final result is the average of the results of 5 repeated experiments, and is recorded in Table 1.

[0033] Table 1. Oil yield of walnut oil

[0034] As can be seen from Table 1, compared with Comparative Example 1, the walnut oil extraction process provided in Examples 1-7 of the present invention yields walnut oil with a content of over 65.41%, indicating that pretreatment of the dried walnut kernel powder with urea and / or mercaptoethanol solution improves the oil yield of the walnut kernels.

[0035] Testing showed that the walnut oil extracted by this invention meets the standard requirements in GB / T 22327-2019.

[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A walnut oil extraction process, characterized in that, Includes the following steps: S1. Soak the dried walnut kernel powder in a pretreatment agent solution to obtain pretreated walnut kernel powder; S2. Extract walnut oil from the pretreated walnut kernel powder using an organic solvent extraction method; The pretreatment agent in the pretreatment solution includes urea and / or mercaptoethanol.

2. The walnut oil extraction process according to claim 1, characterized in that, The pretreatment agent comprises urea and mercaptoethanol, wherein the mass of the urea is ≥ 4 times the mass of the mercaptoethanol.

3. The walnut oil extraction process according to claim 2, characterized in that, The pretreatment agent comprises urea and mercaptoethanol in a mass ratio of 4 to 7:

1.

4. The walnut oil extraction process according to any one of claims 1 to 3, characterized in that, The mass ratio of pretreatment agent to solvent in the pretreatment agent solution is 1~5:

100.

5. The walnut oil extraction process according to claim 1, characterized in that, Soaking also includes filtration, washing, and drying.

6. The walnut oil extraction process according to claim 1, characterized in that, The soaking process is accompanied by stirring at a speed of 100-150 rpm for 2-3 hours.

7. The walnut oil extraction process according to claim 1, characterized in that, Step S2 specifically involves mixing the pretreated walnut kernel powder with an organic solvent, extracting the mixture, filtering it, evaporating the filtrate to remove the solvent, and obtaining walnut oil.

8. The walnut oil extraction process according to claim 7, characterized in that, The organic solvent includes one or more of petroleum ether, n-hexane, and acetone.

9. The walnut oil extraction process according to claim 7, characterized in that, The mass-to-volume ratio of the pretreated walnut kernel powder to the organic solvent is 1g:7~9mL.

10. The walnut oil extraction process according to claim 7, characterized in that, The extraction temperature is 50~60℃, and the extraction time is 1~2h.

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