Method for prolonging shelf life of walnut oil

Abstract

The invention discloses a method for prolonging the shelf life of walnut oil. The method comprises the following steps: step 1, refining: 1.1, dephosphorizing and deacidifying: a, adding alkali into the walnut oil in a rapid stirring manner; b, after the alkaline water is added, slowly stirring for 5 minutes, precipitating, and then adding Chinese honeylocust fruit; 1.2: two times of saline water: a, adding the saline water with the salt content of 2000g into the walnut oil added with the alkali and the Chinese honeylocust fruits for cleaning, adding the saline water while quickly stirring, and adding the saline water twice; b, fully stirring the salt water after the salt water is added, performing precipitation treatment, and discharging water; 1.3, clear water is added for three times, wherein clear water is added into the walnut oil in a rapid stirring mode for cleaning; step 2, dehydrating: dehydrating the walnut oil under vacuum negative pressure, and slowly stirring the walnut oil; 3, filtering: filtering the walnut oil dehydrated in the step 2 by using high-strength filter paper of a plate-and-frame filter. The invention belongs to the technical field of walnut oil processing, particularly relates to a method for prolonging the shelf life of walnut oil, and at least solves the problem that the shelf life of walnut oil processed from walnut raw materials is short.

Description

Technical Field

[0001] The present invention belongs to the technical field of walnut oil processing, and specifically refers to a method for extending the shelf life of walnut oil. Background Art

[0002] Walnuts are one of the "four major dried fruits in the world". Their protein content is about 15%, and 90% of the fatty acids they contain are unsaturated fatty acids (especially linoleic acid and linolenic acid), which are easily digested and absorbed by the human body, can effectively reduce cholesterol, prevent arteriosclerosis, and protect the cardiovascular and cerebrovascular system.

[0003] The oil content of walnuts is as high as 65% - 70%. At present, by using modern technology to extract its essence, it can be processed into walnut oil. Walnut oil is known as the "Oriental olive oil" and is as popular among consumers as olive oil. Due to the limitations of the preparation process, there are various unsaturated fatty acids in walnut oil, so its storage time is short. Usually, the shelf life of walnut oil is 6 - 12 months, which limits the circulation and sales of walnut oil. Therefore, how to overcome the deficiencies of the existing technology is an urgent problem to be solved in the current walnut oil technology field. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the existing technology, the present invention provides a method for extending the shelf life of walnut oil, aiming to at least solve the problem of the short shelf life of walnut oil processed from walnut raw materials.

[0005] The technical solution adopted by the present invention is as follows: A method for extending the shelf life of walnut oil provided by the present invention includes the following steps:

[0006] Step 1:

[0007] Refining:

[0008] 1.1: Phosphorus and acid removal:

[0009] a: Add alkali to the walnut oil in a rapid stirring manner, and control the oil temperature and alkali addition time during the alkali addition process; b: After the alkali water is added, perform slow stirring for 5 minutes, precipitate, and then discharge the soapstock.

[0010] 1.2: Brine washing twice:

[0011] a: Add brine with a salt content of 2000 g to the walnut oil after adding alkali and soapstock for cleaning, stir rapidly while adding the brine, add the brine in two portions, and control the oil temperature at 60° during the brine addition process;

[0012] b: After the brine is added, perform full stirring, conduct precipitation treatment, and then discharge the water.

[0013] 1.3: Fresh water washing three times:

[0014] Add water to the walnut oil in a way of rapid stirring. After adding the water, continue slow stirring for 5 minutes. After the stirring is completed, let it settle for ≥2 hours and then drain the water.

[0015] Step Two:

[0016] Dehydration:

[0017] Dehydrate the walnut oil under vacuum negative pressure. The negative pressure is 0.75 Mpa, heat the oil temperature to 75°, and slowly stir the walnut oil.

[0018] Step Three:

[0019] Filtration:

[0020] Filter the walnut oil dehydrated in Step Two with high-strength filter paper of a plate-and-frame filter press. When filtering, the pressure of the equipment is ≤0.4 Mpa.

[0021] Furthermore, the amount of alkali added in Step 1 is calculated according to the acid value of crude oil, the quality of refined oil, and the target value to be reduced.

[0022] Furthermore, in Step 1.1a, the oil temperature is 60° and the alkali addition time is 5 - 10 minutes.

[0023] Furthermore, in Step 1.1b, the precipitation time is ≥8 hours.

[0024] Furthermore, in Step 1.2, the time for adding brine is controlled at 5 - 10 minutes, the slow stirring time after adding brine is 5 minutes, and the precipitation time is ≥2 hours.

[0025] Furthermore, in Step 1.3, when adding water, the oil temperature is controlled at 60°.

[0026] The beneficial effects achieved by the present invention with the above structure are as follows: A method for extending the shelf life of walnut oil of the present invention processes the walnut oil through refining, dehydration, and filtration. After adding alkali, put in sapindus to remove phosphorus and acid from the walnut oil. Subsequently, wash, precipitate, and drain the walnut oil with brine and water respectively. Finally, dehydrate and filter the walnut oil again, which maximally extends the shelf life of the walnut oil and improves the quality of the walnut oil. Description of the Drawings

[0027] Figure 1 It is a flowchart of a method for extending the shelf life of walnut oil of the present invention. Detailed Embodiments

[0028] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0029] Embodiment 1:

[0030] A method for extending the shelf life of walnut oil, comprising the following steps:

[0031] Step 1:

[0032] Refining:

[0033] 1.1: Phosphorus and acid removal:

[0034] a: Add alkali to the walnut oil in a way of rapid stirring, and control the oil temperature and alkali addition time during the alkali addition process; b: After the alkali water is added, perform slow stirring for 5 minutes, precipitate, and then remove the soapstock;

[0035] 1.2: Brine washing twice:

[0036] a: Add brine with a salt content of 2000 g to the walnut oil after adding alkali and soapstock for cleaning, and stir rapidly while adding the brine. The brine is added in two portions, and the oil temperature is controlled at 60° during the brine addition process;

[0037] b: After the brine is added, perform full stirring, conduct precipitation treatment, and then drain the water;

[0038] 1.3: Fresh water washing three times:

[0039] Add fresh water to the walnut oil in a way of rapid stirring. After the fresh water is added, continue slow stirring for 5 minutes. After the stirring is completed, precipitate for ≥ 2 hours and then drain the water;

[0040] Step 2:

[0041] Dehydration:

[0042] Dehydrate the walnut oil under vacuum negative pressure. The negative pressure is 0.75 Mpa, the oil temperature is heated to 75°, and slow stirring is performed on the walnut oil;

[0043] Step 3:

[0044] Filtration:

[0045] Filter the walnut oil dehydrated in Step 2 with high-strength filter paper of a plate and frame filter press. The pressure of the equipment during filtration is ≤ 0.4 Mpa.

[0046] The amount of alkali added in Step 1 is calculated according to the acid value of the crude oil, the quality of the refined oil, and the target value to be reduced.

[0047] The oil temperature in Step 1.1a is 60° and the alkali addition time is 5 minutes.

[0048] The precipitation time in Step 1.1b is ≥ 8 hours.

[0049] The time for adding brine in Step 1.2 is controlled at 5 minutes, the slow stirring time after the brine is added is 5 minutes, and the precipitation time is ≥ 2 hours.

[0050] In step 1.3, adding clear water is to control the oil temperature at 60°.

[0051] Example 2:

[0052] A method for extending the shelf life of walnut oil, comprising the following steps:

[0053] Step one:

[0054] Refining:

[0055] 1.1: Dephosphorization and deacidification:

[0056] a: Add alkali to the walnut oil in a way of rapid stirring, and control the oil temperature and alkali addition time during the alkali addition process; b: After the alkali water is added, perform slow stirring for 5 minutes, then precipitate and remove the soapstock.

[0057] 1.2: Wash with brine twice:

[0058] a: Add brine with a salt content of 2000 g to the walnut oil after adding alkali and soapstock for cleaning, stir rapidly while adding brine, add the brine in two portions, and control the oil temperature at 60° during the brine addition process;

[0059] b: After the brine is added, perform full stirring, and perform precipitation treatment and then drain the water.

[0060] 1.3: Wash with clear water three times:

[0061] Add clear water to the walnut oil in a way of rapid stirring. After the clear water is added, continue slow stirring for 5 minutes. After the stirring is completed, precipitate for ≥ 2 hours and then drain the water.

[0062] Step two:

[0063] Dehydration:

[0064] Dehydrate the walnut oil under vacuum negative pressure, with the negative pressure being 0.75 Mpa, heat the oil temperature to 75°, and perform slow stirring on the walnut oil.

[0065] Step three:

[0066] Filtration:

[0067] Filter the walnut oil dehydrated in step two with high-strength filter paper of a plate and frame filter press, and the pressure of the equipment during filtration is ≤ 0.4 Mpa.

[0068] The amount of alkali added in step 1 is calculated according to the acid value of crude oil, the quality of refined oil, and the target value to be reduced.

[0069] In step 1.1a, the oil temperature is 60° and the alkali addition time is 7.5 minutes.

[0070] In step 1.1b, the precipitation time is ≥ 8 hours.

[0071] The time for adding brine in Step 1.2 is controlled at 7.5 min, the slow stirring time after the brine is added is 5 min, and the precipitation time is ≥2 h.

[0072] In Step 1.3, when adding clear water, the oil temperature is controlled at 60°.

[0073] Example 3:

[0074] A method for extending the shelf life of walnut oil, comprising the following steps:

[0075] Step 1:

[0076] Refining:

[0077] 1.1: Phosphorus and acid removal:

[0078] a: Add alkali to walnut oil in a way of rapid stirring, and control the oil temperature and alkali addition time during the alkali addition process; b: After the alkali water is added, perform slow stirring for 5 min, precipitate, and then remove the soapstock.

[0079] 1.2: Brine twice:

[0080] a: Add brine with a salt content of 2000 g to the walnut oil after adding alkali and soapstock for cleaning, stir rapidly while adding brine, add the brine in two portions, and control the oil temperature at 60° during the brine addition process;

[0081] b: After the brine is added, perform full stirring on it, conduct precipitation treatment, and then drain the water.

[0082] 1.3: Clear water three times:

[0083] Add clear water to the walnut oil in a way of rapid stirring. After the clear water is added, continue slow stirring for 5 min. After the stirring is completed, precipitate for ≥2 h and then drain the water.

[0084] Step 2:

[0085] Dehydration:

[0086] Dehydrate the walnut oil under vacuum negative pressure, with the negative pressure being 0.75 Mpa, heat the oil temperature to 75°, and perform slow stirring on the walnut oil.

[0087] Step 3:

[0088] Filtration:

[0089] Filter the walnut oil dehydrated in Step 2 with high-strength filter paper of a plate and frame filter press, and the pressure of the equipment during filtration is ≤0.4 Mpa.

[0090] The amount of alkali added in Step 1 is calculated according to the acid value of crude oil, the quality of refined oil, and the target value to be reduced.

[0091] In Step 1.1a, the oil temperature is 60° and the alkali addition time is 10 min.

[0092] The precipitation time in step 1.1b is ≥ 8h.

[0093] In step 1.2, the time for adding brine is controlled at 10 min, the slow stirring time after the brine is added is 5 min, and the precipitation time is ≥ 2h.

[0094] In step 1.3, when adding clear water, the oil temperature is controlled at 60°.

[0095] The above embodiments only represent one implementation mode of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A method for extending the shelf life of walnut oil, characterized in that: The following steps are involved: Step 1: Refining: 1.1: Dephosphorization and deacidification: a: Add alkali to walnut oil by rapid stirring, and control the oil temperature and alkali adding time during the alkali adding process; b: After adding the alkaline water, stir slowly for 5 minutes to settle and then add the soapberry; 1.2: Salt water 2 times: a: Add 2000g of salt water to the walnut oil after adding alkali and saponin to wash, stir quickly while adding the salt water, add the salt water twice, and control the oil temperature at 60° during the process of adding the salt water; b: After adding the salt water, stir it thoroughly, and drain it after precipitation; 1.3: Rinse with clean water 3 times: Add clean water to the walnut oil while stirring quickly. After adding the clean water, continue to stir slowly for 5 minutes. After the stirring is completed, let it settle for ≥ 2 hours before draining the water. Step 2: Dehydration: Dehydrate the walnut oil under vacuum negative pressure, the negative pressure is 0.75Mpa, the oil temperature is heated to 75°, and the walnut oil is slowly stirred; Step 3: filter: The walnut oil dehydrated in step 2 is filtered using high-strength filter paper of a plate and frame filter, and the pressure of the equipment during filtration is ≤0.4Mpa.

2. The method for extending the shelf life of walnut oil according to claim 1, wherein: The amount of alkali added in step 1 is calculated based on the acid value of crude oil, the quality of refined oil and the target value to be reduced.

3. The method for extending the shelf life of walnut oil according to claim 1, wherein: In step 1.1a, the oil temperature is 60° and the alkali addition time is 5-10 min.

4. The method for extending the shelf life of walnut oil according to claim 1, wherein: The precipitation time in step 1.1b is ≥8h.

5. The method for extending the shelf life of walnut oil according to claim 1, characterized in that: The time for adding salt water in step 1.2 is controlled to be 5-10 minutes, the slow stirring time after the salt water is added is 5 minutes, and the precipitation time is ≥2 hours.

6. The method for extending the shelf life of walnut oil according to claim 1, characterized in that: In step 1.3, the oil temperature is controlled at 60° when adding clean water.

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