Preparation method of linseed oil with long shelf life

Abstract

The invention discloses a preparation method of linseed oil with a long shelf life, and belongs to the field of edible oil preparation, and the method comprises the following steps: cleaning a linseed raw material with clear water, mixing with water, extruding, filtering, degumming, drying and squeezing by a filter press to obtain crude oil, adding an adsorbent into the crude oil, heating and stirring for deodorizing treatment, standing and precipitating, and separating to obtain essential oil, according to the invention, degumming and odor removal are carried out in sequence in the squeezing process, so that the flavor and active ingredients of the linseed oil are not influenced, the quality of the produced oil is improved, the preservation time is prolonged, no additive is introduced, the linseed oil is safe and harmless, and the shelf life can reach 18 months.

Description

Technical Field

[0001] The invention relates to a method for preparing linseed oil, in particular to a method for preparing linseed oil with a long shelf life, and belongs to the field of edible oil preparation. Background Art

[0002] Flaxseed, also known as sesame seed, is the seed of the annual or perennial herb flax of the Linaceae family and the genus Linum. The main components of flax seed are fat, protein, and dietary fiber. Other components include minerals, α-linolenic acid, lignans, flaxseed gum, vitamins, etc.

[0003] At present, there are three methods for extracting flaxseed oil: hot pressing, cold pressing, solvent extraction, etc. Among them, the hot pressing method is also called the cooked pressing method, which is to press the fried flax seeds. This method is mature, but the internal structure of the obtained flaxseed oil is destroyed by heating, making most of the active substances in it inactivated. Therefore, this method is gradually eliminated by the market. Although the solvent extraction method can avoid the loss of nutrients, the organic solvent and oil are not easy to separate, which affects the quality of flaxseed oil.

[0004] Although the cold pressing method can retain the active ingredients in linseed oil and will not introduce impurities, the unsaturated fatty acids such as α-linolenic acid contained in the directly squeezed linseed oil make it very easy to oxidize during the pressing, refining and storage process, causing it to deteriorate in about 3 months, making the linseed oil have a very obvious bitter taste, affecting the taste and flavor. The more commonly used method in the prior art is to add artificial antioxidants, but this problem has not been effectively solved. Summary of the invention

[0005] In view of this, the present invention provides a method for preparing linseed oil with a long shelf life, which effectively prolongs the shelf life of linseed oil by degumming and deodorizing in the pressing process of linseed oil without introducing other additives.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for preparing linseed oil with a long shelf life, comprising the following steps:

[0008] (1) washing the flax seed raw material with clean water, removing the unfilled flax seed raw material, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying and removing water to a water content of 6-10%, thereby obtaining degummed flax seed;

[0009] (2) pressing the degummed linseed to obtain crude oil;

[0010] (3) washing the crude oil with water, adding an adsorbent, heating and stirring to remove water and odor, and separating and obtaining the essential oil after standing and settling;

[0011] (4) Add allicin to the essential oil, sterilize and encapsulate after ultrasonic vibration to obtain linseed oil.

[0012] On the basis of the above technical solution, the present invention further defines the solution as follows:

[0013] Furthermore, the drying in step (1) is hot air drying.

[0014] Furthermore, in step (3), the adsorbent is silicon dioxide; preferably, the amount of the adsorbent added is 1%-5%.

[0015] Furthermore, the water washing operation in step (3) is to heat the crude oil to 80-85° C., add 10%-15% of the weight of the oil in water, and stir at the temperature for 10-20 minutes;

[0016] The heating and stirring pressure is 0.5-0.8KPa, the temperature is 75-85℃, and the time is 20-30min;

[0017] The settling time is 2-3 days.

[0018] Furthermore, in step (4), the allicin is an ethanol solution of allicin adjusted to pH 9-11 by alkali; preferably, the amount of allicin added is 1%-1.5% of the weight of the oil.

[0019] Furthermore, the ultrasonic oscillation in step (4) is 400KHz ultrasonic oscillation at 40-50°C for 8-10 minutes;

[0020] Sterilization is done by ultraviolet light.

[0021] The beneficial effects of the present invention are:

[0022] During the pressing process, degumming and deodorization are carried out in sequence, which keeps the flavor and active ingredients of the linseed oil intact, improves the oil quality and extends the shelf life. No additives are introduced, it is safe and harmless, and the shelf life can reach 18 months. DETAILED DESCRIPTION

[0023] The following will be combined with the technical solutions in the embodiments of the present invention to clearly and completely describe. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0026] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 6%, thereby obtaining degummed flax seeds;

[0027] (2) pressing the degummed linseed to obtain crude oil;

[0028] (3) heating the crude oil to 85° C., adding water (10% of the weight of the oil), keeping warm and stirring for 20 min, adding adsorbent silica in an amount of 1% of the weight of the crude oil, 0.8 KPa, heating and stirring at 80° C. for 30 min to remove water and odor, and separating and settling for 3 days to obtain the essential oil;

[0029] (4) Adding an ethanol solution of allicin adjusted to pH 10 by sodium hydroxide to the essential oil in an amount of 1% of the weight of the oil, ultrasonically vibrating at 400 kHz for 10 min at 45° C., and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0030] Example 2

[0031] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0032] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 10%, thereby obtaining degummed flax seeds;

[0033] (2) pressing the degummed linseed to obtain crude oil;

[0034] (3) heating the crude oil to 80° C., adding water (10% of the weight of the oil), keeping warm and stirring for 10 min, adding adsorbent silica in an amount of 5% of the weight of the crude oil, 0.5 KPa, heating and stirring at 75° C. for 20 min to remove water and odor, and separating and settling for 2 days to obtain the essential oil;

[0035] (4) Adding an ethanol solution of allicin adjusted to pH 9 by sodium hydroxide to the essential oil in an amount of 1% of the weight of the oil, ultrasonically vibrating at 400 kHz for 8 min at 40° C., and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0036] Example 3

[0037] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0038] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 8%, thereby obtaining degummed flax seeds;

[0039] (2) pressing the degummed linseed to obtain crude oil;

[0040] (3) heating the crude oil to 85° C., adding 5% water by weight of the oil, and stirring at this temperature for 20 min. Then adding adsorbent silica in an amount of 3% of the weight of the crude oil, 0.8 KPa, heating and stirring at 85° C. for 205 min to remove water and odor, and separating and settling for 3 days to obtain the essential oil;

[0041] (4) Adding an ethanol solution of allicin adjusted to pH 11 by sodium hydroxide to the essential oil in an amount of 1.5% of the weight of the oil, ultrasonically vibrating at 400 kHz for 10 min at 50° C., and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0042] Example 4

[0043] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0044] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 8%, thereby obtaining degummed flax seeds;

[0045] (2) pressing the degummed linseed to obtain crude oil;

[0046] (3) heating the crude oil to 83° C., adding water (12% of the weight of the oil), keeping warm and stirring for 18 min, adding adsorbent silica in an amount of 3% of the weight of the crude oil, 0.7 KPa, heating and stirring at 79° C. for 27 min to remove water and odor, and letting it stand for 2.5 days to separate and obtain the essential oil;

[0047] (4) Adding an ethanol solution of allicin adjusted to pH 10 with alkali to the essential oil in an amount of 1% of the weight of the oil, ultrasonically vibrating at 400 kHz at 45° C. for 9 minutes, and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0048] Example 5

[0049] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0050] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 9%, thereby obtaining degummed flax seeds;

[0051] (2) pressing the degummed linseed to obtain crude oil;

[0052] (3) heating the crude oil to 81° C., adding water (15% of the weight of the oil), keeping warm and stirring for 18 min, adding adsorbent silica in an amount of 4% of the weight of the crude oil, 0.7 KPa, heating and stirring at 82° C. for 28 min to remove water and odor, and letting it stand for 2.6 days to separate and obtain the essential oil;

[0053] (4) Adding an ethanol solution of allicin adjusted to pH 9 with alkali to the essential oil in an amount of 1.2% of the weight of the oil, subjecting the oil to ultrasonic vibration at 400 kHz for 8 min at 42° C., and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0054] Example 6

[0055] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0056] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 6%, thereby obtaining degummed flax seeds;

[0057] (2) pressing the degummed linseed to obtain crude oil;

[0058] (3) heating the crude oil to 84° C., adding water (13% of the weight of the oil), keeping warm and stirring for 14 min, adding adsorbent silica in an amount of 4% of the weight of the crude oil, 0.7 KPa, heating and stirring at 83° C. for 22 min to remove water and odor, and letting it stand for 2.1 days to separate and obtain the essential oil;

[0059] (4) Adding an ethanol solution of allicin adjusted to pH 11 with alkali to the essential oil in an amount of 1.2% of the weight of the oil, ultrasonically vibrating at 400 kHz at 42° C. for 9 min, and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0060] Example 7

[0061] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0062] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 7%, thereby obtaining degummed flax seeds;

[0063] (2) pressing the degummed linseed to obtain crude oil;

[0064] (3) heating the crude oil to 84° C., adding water (14% of the weight of the oil), keeping warm and stirring for 17 min, adding adsorbent silica in an amount of 2% of the weight of the crude oil, 0.8 KPa, heating and stirring at 82° C. for 27 min to remove water and odor, and letting it stand for 2.2 days to separate and obtain the essential oil;

[0065] (4) Adding an ethanol solution of allicin adjusted to pH 11 with alkali to the essential oil in an amount of 1.1% of the weight of the oil, ultrasonically vibrating at 400 kHz at 41° C. for 8 min, and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0066] Example 8

[0067] The method for preparing linseed oil with a long shelf life comprises the following steps:

[0068] (1) washing the flax seed raw material with clean water for three times, removing the unfilled flax seeds during the washing process, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying with hot air from a blower to remove water to a water content of 9%, thereby obtaining degummed flax seeds;

[0069] (2) pressing the degummed linseed to obtain crude oil;

[0070] (3) heating the crude oil to 83° C., adding water (14% of the weight of the oil), keeping warm and stirring for 14 min, adding adsorbent silica in an amount of 4% of the weight of the crude oil, 0.7 KPa, heating and stirring at 72° C. for 28 min to remove water and odor, and letting it stand for 2.8 days to separate and obtain the essential oil;

[0071] (4) Adding an ethanol solution of allicin adjusted to pH 9 with alkali to the essential oil in an amount of 1.1% of the weight of the oil, ultrasonically vibrating at 400 kHz at 42° C. for 9 minutes, and then sterilizing and packaging with ultraviolet light to obtain linseed oil.

[0072] Example 9

[0073] The linseed oil obtained by the traditional cold pressing method was used as a comparative example, that is, the linseed raw material was washed, inferior raw materials and impurities were removed, and then dried to a moisture content of 6%, and then pressed. After pressing, the linseed was allowed to stand for stratification, and the supernatant was obtained. The linseed used in the comparative example belonged to the same batch as that in Examples 1-3.

[0074] The performance of the oil products in Examples 1-3 and Comparative Example 1 was tested, and the items and methods were carried out in accordance with the relevant provisions of "GB / T8235-2019". The results are shown in Table 1 below.

[0075] Table 1 Linseed oil test results

[0076] project Example 1 Example 2 Example 3 Comparative Example 1 Refractive index 1.4817 1.4828 1.4805 1.4832 Relative density 0.9293 0.9307 0.9309 0.9322 Saponification value 192 190 193 186 Palmitic acid 6.2 6.5 6.3 6.8 Stearic acid 4.2 4.3 4.5 4.3 Oleic acid 15.2 15.5 15.3 15.6 Linoleic acid 16.7 16.2 16.4 16.9 α-linolenic acid 62.2 63.0 62.8 60.1 Acid value 0.1 0.3 0.2 0.5

[0077] From the above results, it can be seen that the acid value of linseed oil squeezed by the method of the present invention is significantly lower than that of the conventional method, the quality of the oil is improved, and the active ingredients in the oil are basically not affected.

[0078] The shelf life of the oil products in Examples 1-3 and Comparative Example 1 was simulated tested. The test method was as follows: filling equal volumes of the oil products into sealed bottles, sealing and storing them in a dry, light-proof place, opening the bottle caps three times a day for 1 minute in the morning, noon and evening, and shaking the bottles appropriately to simulate the use process. Whether the oil products had obvious odors was used as the deterioration standard. The results showed that the time for the oil products in Examples 1-3 and Comparative Example 1 to produce obvious odors was 10 months, 18 months, 17 months and 18 months, respectively. This shows that the method of the present invention can significantly improve the shelf life of the oil products.

Claims

1. A method for preparing linseed oil with a long shelf life, characterized in that: Here are the steps: (1) washing the flax seed raw material with clean water, removing the unfilled flax seed raw material, mixing the washed raw material with water, squeezing and filtering with a filter press to remove glue, and drying and removing water to a water content of 6-10%, thereby obtaining degummed flax seed; (2) pressing the degummed linseed to obtain crude oil; (3) washing the crude oil with water, adding an adsorbent, heating and stirring to remove water and odor, and separating and obtaining the essential oil after standing and settling; (4) Add allicin to the essential oil, sterilize and encapsulate after ultrasonic vibration to obtain linseed oil.

2. The method for preparing linseed oil with a long shelf life according to claim 1, characterized in that: The drying in step (1) is hot air drying.

3. The method for preparing linseed oil with a long shelf life according to claim 1, characterized in that: In step (3), the adsorbent is silicon dioxide.

4. The method for preparing linseed oil with a long shelf life according to claim 1 or 3, characterized in that: The amount of adsorbent added is 1%-5%.

5. The method for preparing linseed oil with a long shelf life according to claim 1, characterized in that: The water washing operation in step (3) is to heat the crude oil to 80-85° C., add 10%-15% of water by weight of the oil, and stir at the temperature for 10-20 minutes; The heating and stirring pressure is 0.5-0.8KPa, the temperature is 75-85℃, and the time is 20-30min; The settling time is 2-3 days.

6. The method for preparing linseed oil with a long shelf life according to claim 1, characterized in that: In step (4), the allicin is an ethanol solution of allicin adjusted to pH 9-11 by alkali.

7. The method for preparing linseed oil with a long shelf life according to claim 1 or 6, characterized in that: The amount of allicin added is 1%-1.5% of the oil weight.

8. The method for preparing linseed oil with a long shelf life according to claim 1, characterized in that: In step (4), the ultrasonic oscillation is 400KHz ultrasonic oscillation at 40-50°C for 8-10 minutes; and the sterilization is ultraviolet sterilization.