Refining process capable of reducing loss of squalene in camellia oleosa seed oil

Abstract

The invention discloses a refining process capable of reducing loss of squalene in camellia oleifera seed oil. The refining process comprises the following steps: 1) degumming crude camellia oleifera seed oil; (2) deacidification; 3) deodorization: introducing water vapor into the deacidified oil subjected to deacidification treatment under the condition that the temperature is 110-120 DEG C, carrying out distillation deodorization for 30-45 minutes, then cooling, adding the nigre obtained by deacidification in the step 2), and carrying out adsorption treatment; 4) decoloring; and 5) winterizing to obtain the refined camellia oleosa seed oil. According to the method, the temperature of steam distillation deodorization can be reduced, the time of steam distillation deodorization is shortened, the energy consumption of steam distillation deodorization and the loss of squalene are reduced, and the quality of the refined camellia oleosa seed oil is improved; moreover, the removal rate of benzo (a) pyrene, di-n-butyl phthalate (DBP) and di (2-ethyl) hexyl phthalate (DEHP) can be effectively improved, and the safety of the camellia oleifera seed oil is improved.

Description

Technical Field

[0001] The invention relates to the technical field of camellia oil refining, in particular to a refining process capable of reducing the loss of squalene in camellia oil. Background Art

[0002] The nutritional components and fatty acids of camellia oil are very similar to those of olive oil. It is a high-quality, high-nutrient edible oil with certain health benefits. Raw camellia oil is produced through pressing or extraction processes. It contains a high content of free fatty acids, poor color, and many impurities, which results in low quality and certain safety risks. It needs to be refined and prepared into camellia oil before it can be eaten.

[0003] The refining of raw tea oil mainly includes the following steps: degumming, deacidification, decolorization, deodorization and winterization, among which the deodorization step is to remove the odorous substances in the raw tea oil. The conventional deodorization method is steam distillation, such as the preparation method of edible tea oil disclosed in patent application number CN201810864430.6, which includes the following steps: step one, pretreatment of raw materials; step two, crushing and breaking the shell; step three, separation of shell and kernel; step four, steaming and frying of oil materials; step five, one-time pressing; step six, leaching and oil production; step seven, precipitation and filtration; step eight, refining and processing: degumming the tea oil obtained in step seven; after the degumming treatment is completed, adding a sufficient amount of sodium hydroxide to the tea oil and potassium hydroxide for deacidification; after the deacidification is completed, activated white clay and activated carbon are added to the tea oil for decolorization, after the decolorization is completed, the decolorized oil is placed in a high-temperature low-pressure evaporator, and the decolorized oil is deodorized for 1 hour by steam distillation at a distillation temperature of 200-250°C; after the deodorization is completed, the tea oil is fractionated, the tea oil is cooled to precipitate crystals, and then the tea oil and the crystals are separated into crystals and liquids; after the fractionation is completed, edible tea oil is produced; step nine, packaging and storage.

[0004] When using this method for refining, it was found that when using high-temperature steam distillation for deodorization, not only is there a disadvantage of high energy consumption, but also the deodorized distillate also carries a lot of squalene, which causes a large loss of squalene in camellia oil; and Zhang Dongsheng et al. published "Research on the Effect of Refining Process on the Quality of Camellia Oil" and found that steam distillation at 260°C can significantly reduce the content of squalene by 40%, which may be because the temperature of steam distillation is high, and squalene will flow out with the deodorized distillate, increasing the loss of squalene in camellia oil. However, squalene is a natural antioxidant that can effectively remove free radicals in the body and increase the activity of superoxide dismutase in the body. The loss of squalene significantly reduces the antioxidant function of camellia oil.

[0005] In addition, when using high-temperature steam distillation for deodorization, it was found that benzo(a)pyrene, di-n-butyl phthalate (DBP), and di(2-ethyl)hexyl phthalate (DEHP) could not be effectively removed. Benzo(a)pyrene is one of the most carcinogenic polycyclic aromatic hydrocarbons known and is genotoxic; DBP and DEHP are commonly used plasticizers, which are widely present in the atmosphere, water bodies, and soil, and are also commonly detected in vegetable oils and vegetable oils. Camellia seeds can be deodorized or not before oil extraction. Studies have found that oil is commonly contaminated by plasticizers. Plasticizers are lipophilic substances. Plasticizers in seeds will migrate to crude oil during the oil production process, causing plasticizer contamination in the crude oil, and the crude oil will carry some plasticizers (such as DBP and DEHP).

[0006] However, the traditional refining process cannot effectively remove plasticizers, so a small amount of plasticizers remain in the refined camellia oil. Plasticizers can not only enter the human body through skin contact, respiratory tract and digestive system, and then form pseudo-hormones, affecting the body's hormone content, but also have toxic effects on multiple systems of the body. If you eat foods containing plasticizers for a long time, it will cause abnormalities in the reproductive development system. At the same time, it also has certain liver toxicity and teratogenic and carcinogenic effects, which will greatly affect the safety of camellia oil.

[0007] In summary, how to provide a refining method that can reduce the loss of squalene and improve the safety of camellia oil has become a technical problem that needs to be solved urgently. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a refining process that can reduce the loss of squalene in camellia oil. The refining process is simple and can not only effectively remove benzo(a)pyrene, DBP and DEHP, but also reduce the loss of squalene.

[0009] The technical solution adopted by the present invention to solve the technical problem is: a refining process capable of reducing the loss of squalene in camellia oil, comprising the following steps: 1) degumming of raw camellia oil; 2) deacidification; 3) deodorization: firstly, the deacidified oil after deacidification treatment is introduced into water vapor at a temperature of 110-120 DEG C for distillation and deodorization for 30-45 minutes, and then after cooling, the soap stock obtained by deacidification in step 2) is added for adsorption treatment; 4) decolorization; 5) winterization to obtain refined camellia oil.

[0010] Furthermore, the specific operation steps of step 1) are: heating the raw tea oil to 65° C., adding H3PO4 at a mass percentage of 0.4-0.8% to the raw tea oil, slowly stirring for 20 minutes, and centrifuging to obtain degummed oil.

[0011] Furthermore, the specific operation steps of step 2) are: heating the degummed oil to 75-85°C, adding KOH solution and stirring for 30 minutes, then adding soft water and mixing thoroughly for washing, centrifuging, standing and separating to obtain a water phase, an oil phase and soap stock; then placing the oil phase in a vacuum drying oven, under a vacuum condition of 0.1 MPa, at a temperature of 90-95°C, drying for 20 minutes, and taking out when the oil temperature drops below 50°C to obtain deacidified oil.

[0012] Furthermore, in the step 3), the amount of soapstock added is 3% to 5% of the mass of the deacidified oil, the adsorption time after adding the soapstock is 20-30 minutes, and the temperature during adsorption is 80°C.

[0013] Preferably, the temperature during the steam distillation is 120° C., the pressure is 0.1 MPa, the distillation time is 35 min, the amount of soapstock added is 4% of the mass of the deacidified oil, and the adsorption time after adding the soapstock is 25 min.

[0014] Furthermore, the specific operation steps of step 4) are: adding activated carbon to the deodorized oil obtained by deodorization treatment, the amount of activated carbon added is 0.5% to 1.0% of the mass of the deodorized oil, decolorizing reaction is carried out at 95° C. to 115° C. and vacuum degree less than 10 kPa for 30 minutes, and filtering to obtain the decolorized oil.

[0015] Furthermore, the specific operation steps of step 5) are: refrigerating the decolorized oil obtained by the decolorization treatment at a temperature below 10° C. for 8 hours, and then quickly filtering to obtain refined camellia seed oil.

[0016] Furthermore, the raw tea oil is prepared by using tea fruit as raw material, and pre-treating the tea fruit and then adopting a low-temperature pressing method.

[0017] Furthermore, the pretreatment steps of the tea fruit are as follows: drying the tea fruit at 30-35°C for 5-6 days, and then drying at 45-55°C for 48 hours to reduce the moisture content of the tea fruit to 6-8%; then screening the dried tea fruit, shelling it, and then drying and crushing the tea seeds obtained by shelling.

[0018] Furthermore, the operation steps of the low-temperature pressing are: steaming the crushed tea seeds at 60°C for 50 minutes, then pressing at a temperature of 40-45°C for 20 minutes, filtering, and obtaining raw tea oil.

[0019] Beneficial effects of the refining process of the present invention for reducing the loss of squalene in camellia oil:

[0020] (1) The refining process of camellia oil of the present invention is simple, convenient and highly safe. In the refining deodorization process, it only needs to carry out steam distillation deodorization at 110°C to 120°C for 30min to 45min, and then use soap stock for adsorption deodorization treatment at 80°C. Compared with the traditional steam distillation deodorization process, it can not only reduce the temperature during steam distillation deodorization, shorten the time of steam distillation deodorization, and greatly reduce the energy consumption of steam distillation deodorization, but also significantly reduce the loss of squalene during deodorization, thereby increasing the content of squalene in refined camellia oil and improving the quality of refined camellia oil;

[0021] (2) The present invention adopts a deodorization method combining steam distillation and soap stock, which can not only recycle the by-product soap stock obtained by deacidification, but also effectively improve the removal rate of benzo(a)pyrene, DBP and DEHP, thereby reducing the content of benzo(a)pyrene, DBP and DEHP in refined camellia oil, and improving the safety of camellia oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 — is a flow chart of a refining process for reducing the loss of squalene in camellia oil according to the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and examples, but these specific implementation schemes do not limit the protection scope of the present invention in any way.

[0024] The raw tea oil used in the following examples, comparative examples and experimental examples was prepared by the following method:

[0025] Preparation method of raw tea oil:

[0026] 1) Dry the oil tea fruit at 30-35°C for 5-6 days, and then dry it at 50°C for 48 hours to reduce the moisture content of the oil tea fruit to 6-8%; screen the oil tea fruit after drying through a 2cm×2cm sieve, and then screen out metal impurities and the like through a magnetic separator; then shell the fried fruit after screening, and then dry the oil tea seeds obtained by shelling at 55°C for 12 hours to control the moisture content to 8%; and then crush to 5-8mm;

[0027] 2) The tea seed powder obtained by crushing the tea seeds is steamed at 60° C. for 50 min, pressed at 40° C. to 45° C. for 20 min, and filtered with a plate and frame filter press to obtain raw tea oil.

[0028] Example 1

[0029] A refining process for reducing the loss of squalene in camellia oil, the process flow chart of which is as follows Figure 1 As shown, the following steps are included:

[0030] 1) Degumming of raw tea oil: Take raw tea oil, heat it to 65°C, add 0.6% by mass of H3PO4 with a concentration of 80% to the raw tea oil, slowly stir for 20 minutes, and centrifuge to obtain degummed oil;

[0031] 2) Deacidification: the degummed oil is heated to 80° C., a 10% KOH solution is added to the degummed oil according to 0.4% of the mass of the degummed oil, and the mixture is stirred for 30 minutes. When obvious soap particles appear, the stirring speed is slowed down; soft water is then added according to 8% of the mass of the degummed oil, and the mixture is fully mixed and washed, centrifuged, and allowed to stand for separation. The degummed oil is repeatedly washed with soft water until the water phase obtained by centrifugal and standing separation is neutral, thereby obtaining a water phase, an oil phase, and soap stock; the oil phase is then placed in a vacuum drying oven, dried for 20 minutes at a temperature of 90° C. under a vacuum condition of 0.1 MPa, and taken out when the oil temperature drops below 50° C. to obtain a deacidified oil; after testing, the content of squalene in the deacidified oil is 166.32 mg / kg, the content of benzo(a)pyrene is 5.45 μg / kg, the content of DBP is 3.15 mg / kg, and the content of DEHP is 9.27 mg / kg;

[0032] 3) Deodorization: firstly, the deacidified oil is introduced with steam at a temperature of 120°C, and deodorized by steam distillation at a pressure of 0.1MPa for 35min, and then the temperature is lowered to 80°C and soap stock is added, and adsorption treatment is carried out at this temperature for 25min, and centrifugal separation is performed to obtain deodorized oil; the amount of soap stock added is 4% of the mass of the deacidified oil;

[0033] 4) Decolorization: Add activated carbon to the deodorized oil according to 1% of the mass of the deodorized oil, carry out decolorization reaction at 105°C and vacuum degree 8kPa for 30 minutes, and filter to obtain the decolorized oil;

[0034] 5) Winterization: Refrigerate the bleached oil at a temperature below 10°C for 8 hours, and then quickly filter to obtain refined camellia seed oil.

[0035] Example 2

[0036] The difference between this embodiment and embodiment 1 is that: step 3) deodorization: first, steam is introduced into the deacidified oil at a temperature of 115° C., and steam distillation is performed for deodorization at a pressure of 0.1 MPa for 30 minutes, and then the temperature is lowered to 80° C. and soap stock is added, and adsorption treatment is performed at this temperature for 20 minutes, and centrifugal separation is performed to obtain deodorized oil; the amount of soap stock added is 3% of the mass of the deacidified oil.

[0037] Example 3

[0038] The difference between this embodiment and embodiment 1 is that: step 3) deodorization: first, steam is introduced into the deacidified oil at a temperature of 110° C., and steam distillation is performed for deodorization at a pressure of 0.1 MPa for 45 minutes, and then the temperature is lowered to 80° C. and soap stock is added, and adsorption treatment is performed at this temperature for 30 minutes, and centrifugal separation is performed to obtain deodorized oil; the amount of soap stock added is 5% of the mass of the deacidified oil.

[0039] The present invention measures the quality indexes of the refined camellia oil prepared in Examples 1-3 according to the standard for squeezing first-grade camellia oil in GB / T 11765-2018 Camellia Oil, and the results are shown in the following table:

[0040] Table 1 Quality indexes of refined camellia oil prepared in Examples 1-3

[0041] Acid value (mg / g) Peroxide value (g / 100g) Moisture and volatile matter content (%) Insoluble impurities content (%) Example 1 0.36 0.107 0.07 0.04 Example 2 0.41 0.115 0.08 0.02 Example 3 0.37 0.113 0.09 0.03

[0042] It can be seen from Table 1 that various quality indicators of the refined camellia oil prepared by the refining process of the present invention can be controlled within the requirement range of the first-grade camellia oil pressed in "GB / T 11765-2018 Camellia Oil", and meet the standard of the first-grade camellia oil pressed in "GB / T 11765-2018 Camellia Oil".

[0043] Comparative Example 1

[0044] The difference between this comparative example and Example 1 is that step 3) adopts the traditional steam distillation method for deodorization, the steps are: steam is introduced into the deacidified oil at a temperature of 220° C., and steam distillation is performed for deodorization at a pressure of 0.1 MPa for 60 minutes to obtain deodorized oil.

[0045] Comparative Example 2

[0046] The difference between this comparative example and Example 1 is that, in step 3) deodorization: steam is introduced into the deacidified oil at a temperature of 120° C., and deodorization is performed by steam distillation at a pressure of 0.1 MPa for 60 min.

[0047] Comparative Example 3

[0048] The difference between this comparative example and Example 1 is that, step 3) deodorization: firstly, the deacidified oil is heated to 80°C and then soap stock is added, and adsorption treatment is carried out at this temperature for 60 minutes to obtain deodorized oil; the amount of soap stock added is 4% of the mass of the deacidified oil;

[0049] Comparative Example 4

[0050] The difference between the comparative example and the embodiment 1 is that, step 3) deodorization: firstly, the deacidified oil is heated to 80°C and then soap stock is added, and adsorption treatment is carried out at this temperature for 25 minutes, the amount of soap stock added is 4% of the mass of the deacidified oil, and centrifugal separation is performed to obtain an oil phase; then, water vapor is introduced into the oil phase at a temperature of 115°C, and water vapor distillation is carried out for deodorization at a pressure of 0.1 MPa for 35 minutes to obtain a deodorized oil.

[0051] The present invention measures the loss rate of squalene, the removal rate of benzo(a)pyrene, the removal rate of DBP and the removal rate of DEHP after deodorization in the refining processes of Examples 1-3 and Comparative Examples 1-4. The loss rate of squalene / %=(the content of squalene in deacidified oil-the content of squalene in deodorized oil) / the content of squalene in deacidified oil, the removal rate of benzo(a)pyrene / %=(the content of benzo(a)pyrene in deacidified oil-the content of benzo(a)pyrene in deodorized oil) / the content of benzo(a)pyrene in deacidified oil, the removal rate of DBP / %=(the content of DBP in deacidified oil-the content of DBP in deodorized oil) / the content of DBP in deacidified oil, and the removal rate of DEHP / %=(the content of DEHP in deacidified oil-the content of DEHP in deodorized oil) / the content of DEHP in deacidified oil.

[0052] The detection method of benzo(a)pyrene refers to GB 5009.27-2016; the detection method of plasticizers (DBP, DEHP) refers to the second method of GB5009.271-2016; the detection method of squalene refers to LS / T 6120-2017; the results are shown in the following table:

[0053] Table 2 Loss rate of squalene and removal rate of benzo(a)pyrene, DBP and DEHP after deodorization in the refining process of Examples 1-3 and Comparative Examples 1-4

[0054]

[0055] The present invention also measured the contents of squalene, benzo(a)pyrene, DBP and DEHP in the refined camellia oil obtained by the refining process of Examples 1-3 and Comparative Examples 1-4, and the results are shown in Table 3:

[0056] Table 3 Contents of benzo(a)pyrene, DBP, DEHP and squalene in the refined camellia oil obtained by refining in Examples 1-3 and Comparative Examples 1-4

[0057] Benzo(a)pyrene(μg / kg) DBP (mg / kg) DEHP(mg / kg) Squalene (mg / kg) Example 1 1.14 0.038 0.137 112.6 Example 2 1.24 0.052 0.146 110.1 Example 3 1.29 0.06 0.154 109.4 Comparative Example 1 1.64 0.457 1.73 54.64 Comparative Example 2 1.94 0.465 1.792 91.48 Comparative Example 3 2.09 0.326 1.129 100.5 Comparative Example 4 1.58 0.303 1.016 101.3

[0058] It can be seen from Table 3 that the benzo(a)pyrene in the refined camellia oil prepared by the refining process of Examples 1-3 meets the requirements of GB2762-2022, and DBP and DEHP are lower than the maximum residual amounts of 0.3 mg / kg and 1.5 mg / kg, respectively.

[0059] It can be seen from Tables 2 and 3 that the comparison between Example 1 and Comparative Example 1 shows that the steam distillation + soap stock adsorption deodorization in the refining process of the present invention is compared with conventional steam distillation. Not only is the deodorization temperature low, the distillation time is short, only 35 minutes is required, and the energy consumption required for deodorization is greatly reduced, but also the soap stock, a refining by-product of camellia oil, is fully utilized, and the loss of squalene can be effectively reduced. The content of squalene in refined camellia oil can also be significantly improved (p < 0.05), and the removal rate of benzo(a)pyrene, DBP, and DEHP is effectively reduced. The content of benzo(a)pyrene, DBP, and DEHP in refined camellia oil is made to meet the requirements of GB2762-2022 by the refining process of Examples 1-3, and the contents of DBP and DEHP do not exceed the maximum residual amount.

[0060] Comparison between Example 1 and Comparative Example 2 shows that when the deodorization treatment is carried out at the same distillation temperature as Example 1 for the same time, although the loss of squalene can be reduced to a certain extent compared with the temperature distillation of Comparative Example 1, the method of performing steam distillation deodorization treatment at this temperature alone cannot effectively remove benzo(a)pyrene, DBP and DEHP in the oil, so that the removal rates of benzo(a)pyrene, DBP and DEHP after deodorization treatment are significantly lower than those in Example 1 (p < 0.05), and the contents of benzo(a)pyrene, DBP and DEHP in the refined camellia oil are significantly higher than those in Example 1.

[0061] Comparison between Example 1 and Comparative Example 3 shows that when the deodorization treatment is carried out at the same soapstock deodorization temperature and deodorization time as in Example 1, although it can greatly reduce the loss rate of squalene and improve the removal rates of DBP and DEHP, the reason is that when the soapstock adsorption treatment is only carried out at 80°C, squalene cannot be volatilized at this temperature, so that the loss rate of squalene decreases, and DBP and DEHP can be partially removed by soapstock adsorption, but the removal is not sufficient; the corresponding removal effect of benzo(a)pyrene is poor, so that the content of squalene in the finally prepared camellia oil is lower than that in Example 1, and the contents of benzo(a)pyrene, DBP and DEHP are higher than those in Example 1.

[0062] Comparative analysis of Comparative Examples 2 and 3 with Example 1 shows that only when steam distillation is combined with soapstock adsorption treatment can the removal rates of benzo(a)pyrene, DBP and DEHP be improved while reducing the loss of squalene.

[0063] The comparison between Example 1 and Comparative Example 4 shows that the process of first using soap stock for adsorption and then performing steam distillation has an impact on the loss rate of squalene and the removal rates of benzo(a)pyrene, DBP and DEHP compared with first performing steam distillation and then performing soap stock adsorption. It shows that first taking steam distillation and then adding soap stock for adsorption can reduce the loss of squalene in refined camellia oil, and the safety and quality indicators meet the national standards.

[0064] Experimental Example 1 Effect of Steam Distillation Temperature on the Loss Rate of Squalene and the Removal Rates of Benzo(a)pyrene, DBP and DEHP

[0065] The raw tea oil was refined with reference to the refining process of Example 1, and the effects of different distillation temperatures (100°C, 110°C, 120°C, 130°C, 140°C, 160°C, 180°C, 200°C) in step 3) on the loss rate of squalene and the removal rates of benzo(a)pyrene, DBP and DEHP were studied.

[0066] Table 4 Effect of distillation temperature on the loss rate of squalene and the removal rate of benzo(a)pyrene, DBP and DEHP

[0067] Distillation temperature (℃) 100 110 120 130 140 160 180 200 Squalene loss rate / % 28.25 29.33 31.66 35.67 40.74 46.68 53.98 60.17 Benzo(a)pyrene removal rate / % 60.33 72.65 77.25 77.36 78.24 78.26 9.14 79.55 DBP clearance rate / % 75.33 92.12 98.67 98.85 99.12 99.40 99.45 99.60 DEHP removal rate / % 79.23 92.17 98.47 98.66 99.10 99.23 99.28 99.34

[0068] As can be seen from Table 4, with the increase of distillation temperature, the loss rate of squalene shows a trend of gradual increase, and the removal rates of benzo(a)pyrene, DBP, and DEHP show a trend of gradual increase. The results show that although the removal rates of benzo(a)pyrene, DBP, and DEHP increase with the increase of temperature, the loss rate of squalene also shows a trend of increase, and when the temperature is above 120°C, the loss rate of squalene reaches about 35% or more, while when the temperature is below 110°C, the removal rate of benzo(a)pyrene is less than 70%, and the removal rates of DBP and DEHP are both less than 90%. In order to reduce the content of benzo(a)pyrene, DBP, and DEHP in refined camellia oil while increasing the content of squalene, the preferred distillation temperature is 110°C to 120°C, and 120°C is selected as the best distillation temperature.

[0069] Experimental Example 2 Effect of Steam Distillation Time on the Loss Rate of Squalene and the Removal Rates of Benzo(a)pyrene, DBP and DEHP

[0070] The raw tea oil was refined with reference to the refining process of Example 1, and the effects of different distillation times (25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min) in step 3) on the loss rate of squalene and the removal rates of benzo(a)pyrene, DBP and DEHP were studied.

[0071] Table 5 Effect of distillation time on the loss rate of squalene and the removal rate of benzo(a)pyrene, DBP and DEHP

[0072] Distillation time (min) 25 30 35 40 45 50 55 60 Squalene loss rate / % 29.65 30.89 31.66 32.41 33.65 36.74 40.26 48.88 Benzo(a)pyrene removal rate / % 55.28 72.11 77.25 79.25 80.33 82.45 83.16 84.07 DBP clearance rate / % 78.65 90.33 98.67 98.87 99.14 99.35 99.41 99.67 DEHP removal rate / % 80.25 90.14 98.47 98.63 99.23 99.40 99.57 99.63

[0073] As shown in Table 5, the extension of distillation time will increase the loss rate of squalene, the removal rate of benzo(a)pyrene, DBP and DEHP. When the distillation time is above 45 minutes, the loss rate of squalene reaches more than 35%, resulting in a large loss of squalene in camellia oil. Although the control of benzo(a)pyrene, DBP and DEHP is relatively good when the distillation time is above 45 minutes, the loss of squalene will also increase. Therefore, while ensuring that benzo(a)pyrene, DBP and DEHP can be effectively removed, the loss of squalene is reduced. The preferred distillation time is 30 minutes to 45 minutes, and the optimal distillation time is 35 minutes.

[0074] Experimental Example 3 Effect of the amount of soap stock added on the loss rate of squalene and the removal rate of benzo(a)pyrene, DBP and DEHP

[0075] The raw tea oil was refined with reference to the refining process of Example 1, and the effects of different soap stock addition amounts (1%, 2%, 3%, 4%, 5%, 6%, 7%) in step 3) on the loss rate of squalene and the removal rates of benzo(a)pyrene, DBP and DEHP were studied.

[0076] Table 6 Effect of soap stock addition on squalene loss rate and benzo(a)pyrene, DBP and DEHP removal rates

[0077] Addition amount / % 1 2 3 4 5 6 7 Squalene loss rate / % 20.14 23.65 28.17 31.66 34.16 51.27 58.88 Benzo(a)pyrene removal rate / % 55.27 59.74 75.18 77.25 77.27 78.14 76.65 DBP clearance rate / % 76.27 80.88 92.96 98.67 98.87 96.27 95.14 DEHP removal rate / % 82.67 86.74 95.14 98.47 98.74 95.14 94.28

[0078] As can be seen from Table 6, with the increase of the amount of soap stock added, the loss rate of squalene also gradually increased, indicating that soap stock also has a strong adsorption effect on squalene, while the removal rates of benzo(a)pyrene, DBP and DEHP showed a trend of first increasing and then decreasing. When the addition amount was 3%, the removal rate of benzo(a)pyrene reached 70%, and the removal rates of DBP and DEHP reached 90%; when the addition amount was 4-6%, there was no significant change in the removal rates of DBP and DEHP, but when it was above 6%, the removal rates of benzo(a)pyrene, DBP and DEHP decreased. The reason is that when excessive soap stock is adsorbed, benzo(a)pyrene, DBP and DEHP will also dissolve in camellia oil, that is, the adsorption amount is less than the dissolution amount, resulting in a decrease in the removal rate. Considering the loss of squalene and the removal rates of benzo(a)pyrene, DBP and DEHP, the optimal amount of soap stock added is 3% to 5%, and the best is 4%.

[0079] Experimental Example 4 Effect of Soapstock Adsorption Time on the Loss Rate of Squalene and the Removal Rates of Benzo(a)pyrene, DBP and DEHP

[0080] The raw tea oil was refined with reference to the refining process of Example 1, and the effects of different adsorption times (10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min) of soapstock in step 3) on the loss rate of squalene and the removal rates of benzo(a)pyrene, DBP and DEHP were studied.

[0081] Table 7 Effect of soapstock adsorption time on the loss rate of squalene and the removal rate of benzo(a)pyrene, DBP and DEHP

[0082] Adsorption time / min 10 15 20 25 30 35 40 Squalene loss rate / % 20.17 25.33 29.17 31.66 34.22 44.27 58.12 Benzo(a)pyrene removal rate / % 56.12 62.33 70.85 77.25 80.33 75.18 73.30 DBP clearance rate / % 79.41 83.22 90.72 98.67 98.13 96.36 94.68 DEHP removal rate / % 75.28 82.33 90.17 98.47 98.14 97.40 95.67

[0083] As shown in Table 7, with the increase of soapstock adsorption time, the loss rate of squalene also gradually increased, indicating that the adsorption time of soapstock has a more obvious effect on the loss of squalene, while the removal rates of benzo(a)pyrene, DBP and DEHP showed a trend of first increasing and then decreasing. When the adsorption time was 20 minutes, the removal rate of benzo(a)pyrene reached 70%, and the removal rates of DBP and DEHP reached 90%; when the adsorption time was greater than 30 minutes, the removal rates of benzo(a)pyrene, DBP and DEHP began to decrease. The reason may be that the adsorption time was too long, and the benzo(a)pyrene, DBP and DEHP in the soapstock would be redissolved in the camellia oil, resulting in a decrease in the removal rate. Considering the loss of squalene and the removal rates of benzo(a)pyrene, DBP and DEHP, the adsorption time of 20 minutes to 30 minutes was selected, and the optimal time was 25 minutes.

[0084] It should be noted that the raw tea oil used in the above embodiments is not limited to the raw tea oil prepared by the low-temperature pressing method in the present invention, and other raw tea oils directly purchased can also be used.

[0085] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A refining process for reducing the loss of squalene in camellia oil, characterized in that: The following steps are involved: 1) degumming of raw tea oil; 2) deacidification; 3) deodorization: firstly, the deacidified oil after deacidification treatment is subjected to steam distillation and deodorization for 30-45 minutes at a temperature of 110-120° C., and then after cooling, the soap stock obtained by deacidification in step 2) is added for adsorption treatment; 4) decolorization; 5) Winterization to obtain refined camellia oil.

2. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 1, characterized in that: The specific operation steps of step 1) are: heating the raw tea oil to 65° C., adding H 3 PO 4 at a mass percentage of 0.4 to 0.8% to the raw tea oil, slowly stirring for 20 minutes, and centrifuging to obtain degummed oil.

3. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 1, characterized in that: The specific operation steps of step 2) are: heating the degummed oil to 75-85° C., adding KOH solution and stirring for 30 minutes, then adding soft water and mixing thoroughly for washing, centrifuging, standing and separating to obtain a water phase, an oil phase and soap stock; then placing the oil phase in a vacuum drying oven, under a vacuum condition of 0.1 MPa, at a temperature of 90-95° C., drying for 20 minutes, and taking out when the oil temperature drops below 50° C. to obtain deacidified oil.

4. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 1, characterized in that: In the step 3), the amount of soap stock added is 3% to 5% of the mass of the deacidified oil, the adsorption time after adding the soap stock is 20-30 minutes, and the temperature during adsorption is 80°C.

5. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 4, characterized in that: The temperature during the steam distillation is 120° C., the pressure is 0.1 MPa, the distillation time is 35 min, the amount of soap stock added is 4% of the mass of the deacidified oil, and the adsorption time after adding the soap stock is 25 min.

6. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 1, characterized in that: The specific operation steps of step 4) are: adding activated carbon to the deodorized oil obtained by deodorization treatment, wherein the amount of activated carbon added is 0.5% to 1.0% of the mass of the deodorized oil, performing a decolorization reaction at 95° C. to 115° C. and a vacuum degree of less than 10 kPa for 30 minutes, and filtering to obtain the decolorized oil.

7. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 1, characterized in that: The specific operation steps of step 5) are: refrigerating the decolorized oil obtained by the decolorization treatment at a temperature below 10° C. for 8 hours, and then quickly filtering to obtain refined camellia seed oil.

8. A refining process for reducing the loss of squalene in camellia oil as claimed in any one of claims 1 to 7, characterized in that: The raw tea oil is prepared by using tea fruit as raw material and pre-treating the tea fruit and then adopting a low-temperature pressing method.

9. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 8, characterized in that: The pretreatment steps of the tea fruit are as follows: drying the tea fruit at 30-35°C for 5-6 days, and then drying at 45-55°C for 48 hours to reduce the moisture content of the tea fruit to 6-8%; then screening the dried tea fruit, shelling it, and then drying and crushing the tea seeds obtained by shelling.

10. A refining process for reducing the loss of squalene in camellia oil as claimed in claim 9, characterized in that: The operation steps of the low-temperature pressing are: steaming the crushed tea seeds at 60°C for 50 minutes, pressing at 40-45°C for 20 minutes, filtering, and obtaining raw tea oil.

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