CN102504938B - Cold pressing and physical refining process of camellia oil - Google Patents

Abstract

The invention relates to the pressing and physical refining process of camellia seed oil. A kind of camellia oil cold pressing and physical refining process, it is characterized in that: comprise the following steps: (1) select ripe camellia seed, adopt microwave vacuum drying to water content 3-6%, send the dried camellia seed into shelling machine Shell; (2) cold pressing camellia oil from shelled camellia seeds, the temperature of the pressing chamber is 100-150°C, and the temperature of oil output is 80-120°C; (3) the pressed camellia oil is filtered through plate and frame (4) Winterize the camellia oil after plate and frame pressure filtration at -5°C to 5°C; (5) Molecular distillation removes free fatty acid and oil peroxidation in the camellia oil after winterization Product, moisture and other low-boiling substances; (6) the camellia oil after molecular distillation uses white clay, active carbon and alumina mixture as filter media to filter and remove impurities and pigments to obtain the finished product. Environmental protection, high oil yield, and high retention rate of micronutrient elements in refined oil.

Description

A kind of camellia oil cold pressing and physical refining process

technical field

The invention relates to a pressing and refining process of camellia seed oil, in particular to a low-temperature cold pressing process of camellia oil and a physical refining process of camellia oil.

Background technique

Camellia oil, also known as camellia oil, is obtained from the seeds of the Camellia oleifera Abel tree. It is one of the oldest traditional woody edible vegetable oils in my country. Its fatty acid composition is very similar to that of olive oil. Known as "Oriental Olive Oil". Camellia oil also contains various active substances such as tea polysaccharides, camellia saponins, flavonoids, tea polyphenols, vitamins and phytosterols. Regular consumption can reduce cholesterol, increase high-density lipoprotein, reduce low-density lipoprotein, lower blood fat, and prevent heart disease. For cerebrovascular diseases, improving immunity, anti-radiation, scavenging free radicals, preventing tumors and other effects, the International Food and Agriculture Organization has listed it as a healthy edible oil that is mainly promoted.

At present, the extraction process of camellia oil crude oil basically adopts oil extraction or steaming, frying and pressing, and the refining process of crude oil basically adopts hydration degumming-alkali refining and deacidification-water washing-filtration decolorization-high temperature steam deodorization-winterization degreasing-finished product Oil. The protein and phospholipid film on the outer layer of oil droplets can be destroyed by high-temperature steaming and frying to improve the oil yield, while the extraction process will cause solvent residues in the finished oil. The steaming processing temperature is generally 100°C-140°C, the frying processing temperature is generally 200°C-300°C, and the cavity temperature of the screw press is generally 200°C-250°C. The above processing process will generate carcinogen benzene. And (a) pyrene, simultaneous leaching and steaming processes will cause a large amount of free fatty acids in the oil, which will increase the acid value, resulting in a large amount of peroxides in the oil. Chemical refining requires the addition of lye to neutralize free fatty acids, high-temperature deodorization and other steps, which will reduce the content of vitamins, phytosterols and other nutrients in the refined oil to an extremely low level, which not only destroys the nutrition of camellia oil, but also reduces the discharge of alkali refining waste liquid. Will cause environmental pollution.

Existing camellia oil pressing, extraction and refining processes have problems such as solvent residues, carcinogens exceeding the standard, and massive loss of nutrients. But there are also some relatively good camellia oil extraction and refining processes at present. For example, the domestic patent whose authorization date is December 19, 2007 and whose patent number is ZL200610031452.1 discloses a new process of physical low-temperature cold pressing of camellia oleifera seed oil. The process adopts sun-drying, shell breaking, post-ripening after low-temperature storage, seed selection, cleaning, shelling and separation, embryo rolling, cold pressing, multiple filtration, adsorption and decolorization to obtain finished tea oil. The process is simple and easy, and can retain most of the oil. Nutrients, but the pre-treatment of this process only adopts low-temperature after-cooking, without frying or other methods, it cannot destroy the outer protein and phospholipid film of the oil, and the oil yield is low.

Another example is that the public date is July 14, 2010, and the domestic patent with the publication number CN101775332A discloses a method for extracting tea seed oil from microwave pretreated water. The method uses shelled tea seed kernels as raw materials and adds tea The seed oil is used as an oil-inducing agent, and after being pulverized, it is subjected to microwave irradiation, hot water slurry mixing, constant temperature stirring, centrifugal separation and vacuum drying to obtain the finished tea seed oil. This patented method imitates the processing technology of olive oil, and eliminates the pressing and extraction process and chemical refining process, avoiding the residue of chemical substances and the loss of nutrients, but this method does not consider the two woody oils of camellia seed and olive fruit The difference between the picking and processing process is that olive oil is pulp oil, and generally it must be controlled within 8 hours from picking to processing. At this time, the free fatty acid and peroxidation products in the oil are extremely low, so this process can be considered. Camellia oleifera grows mostly in low mountain and hilly areas. It usually takes dozens of days to complete from picking, transportation, drying, shelling to crushing, and the free fatty acids and fatty acid peroxidation products produced during this process cannot be removed. , it is difficult to guarantee the quality of the finished product.

Another example is that the publication date is December 10, 2008, and the publication number is CN101317611A in the domestic patent, which discloses a continuous deacidification process of high acid value grease by multi-stage molecular distillation. After filtering, washing with saturated NaCl, removing water by thin film evaporation, most of the fatty acids are removed by molecular distillation for 2 to 5 times. This method avoids the problems of high alkali consumption and large loss of nutrients in the alkali refining method. This method is suitable for high acid It is more suitable for the treatment of low-quality oils such as valuable waste oil and improperly stored spoiled oils, but it is not suitable for freshly processed high-grade woody oils such as camellia oil.

To sum up, there is no cold pressing process and physical refining method of camellia oil with low pressing temperature, high oil yield, low energy consumption, few steps, high nutritional value, low acid value and peroxide value.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned deficiencies in the existing camellia oil pressing technology and refining process, and provide a low-temperature pressing process that does not require high-temperature steaming and frying pretreatment, and has fewer steps, simple operation, low energy consumption, and high product quality. The advanced physical refining process avoids the damage to the oil quality during the chemical refining process and the cold pressing and physical refining process of camellia oil that pollutes the environment.

The technical scheme adopted by the present invention to solve the above-mentioned problems is: a kind of camellia oil cold pressing and physical refining process, it is characterized in that: this method comprises the following steps:

(1) Select mature camellia seeds, use microwave vacuum drying to water content of 3-6% (mass content), and send the dried camellia seeds to the shelling machine for shelling, with a shelling rate of more than 99%; dry the camellia seeds with microwave vacuum , the camellia seeds can be dried at a relatively low temperature to prevent the high temperature from destroying the nutrients beneficial to the human body in the camellia seeds, and dried to a moisture content of 3-6%, so that the moisture content of the camellia seeds will not be too high to affect the camellia oil Quality, and the cold pressing process will not be difficult due to too little moisture content.

(2) Cold press the camellia seeds after shelling to extract camellia oil, control the temperature of the pressing chamber at 100°C to 150°C, and the temperature of the oil output at 80°C to 120°C; control the temperature of the pressing chamber at 100°C to 150°C, so that the camellia seeds can Cold rolling at a lower temperature not only protects the nutrients that are easily oxidized in camellia seeds, but also prevents the cold pressing temperature from being too low to make the cold pressing process difficult; If the temperature is too high, the quality of the camellia seed oil that is cold-pressed is ensured, and the temperature is not too low, which affects the fluidity of the oil and reduces the efficiency of cold-pressing, so as to ensure the quality of the pressed oil.

(3) The pressed camellia oil crude oil removes solid impurities by a plate and frame filter press; removing impurities by a plate and frame filter press can handle a large amount of camellia oil, and can also remove most of the solid impurities in the camellia oil crude oil, preventing the The presence of solid impurities causes the camellia oil to deteriorate easily, thereby improving the stability of the camellia oil and prolonging the shelf life of the camellia oil.

(4) Winterize the camellia oil obtained after pressure filtration at -5°C to 5°C to remove waxes, esters and other high-melting point substances; both remove part of the high-molecular impurities in the camellia oil and increase the freezing point of the camellia oil , is beneficial to the storage of camellia oil, and also improves the fluidity and clarity of camellia oil.

(5) The camellia oil after winterization removes free fatty acids, oil peroxidation products, moisture and other low-boiling substances in the oil through molecular distillation; thereby removing harmful substances and unstable factors in camellia oil, which is beneficial to improve Storage resistance and oil quality of camellia oil.

(6) The camellia oil after molecular distillation is filtered with white clay, activated carbon and alumina mixture as a filter medium to remove impurities and pigments to obtain the finished product. The mixture of clay, activated carbon and alumina can remove impurities and harmful substances that cannot be removed by filtration, making camellia oil safer; the mixture of clay, activated carbon and alumina can also adsorb and remove pigments and other substances, making the appearance of camellia oil more beautiful.

As a preference, the drying of the camellia seeds in the step (1) adopts a microwave vacuum drying process, the absolute pressure during drying is 7KPa～20KPa, and the moisture content is 2～5%. Under the vacuum of 7KPa～20KPa, a better drying effect can be obtained, but the requirements for the vacuum pump are not high, and the vacuum pump does not need to consume a lot of power during operation.

Preferably, the temperature of the press chamber in the step (2) is controlled at 120°C to 140°C and the oil outlet temperature is controlled at 90°C to 100°C. The cold pressing process can achieve the best process effect, especially in this temperature range, the indicators such as color, phospholipid content, peroxide value and vitamin E content are better than other temperature ranges.

As preferably, the molecular distillation in the step (5) is to adopt a molecular distillation, the absolute pressure is 1 to 90pa, the evaporation temperature is 135°C to 195°C, and the condensation temperature is -5°C to 25°C; the acid value of camellia oil The content of malondialdehyde, peroxide value and oxidized toxic product decreased from 4-6 mg/g, 8-10 mmol/kg and 3-6 mg/kg before molecular distillation to 0.05-0.15 mg/g, 1-2 mmol/kg and Below 1μg/kg, moisture content is below 1mg/kg. . Molecular distillation can quickly and effectively reduce the toxic and harmful substances in camellia oil, lower the acid value and improve the quality of camellia oil. Using one-time molecular distillation can reduce energy loss and improve economic benefits compared with multiple molecular distillation.

As a preference, in the filtration process in the step (6), the filter medium is formed by mixing clay, activated carbon and alumina in a mass ratio of (60-95):(3-15):(1-15). Among them, white clay is a commonly used filter medium in edible oil refining. It mainly absorbs non-polar and low-polar substances, and can effectively remove pigments, phospholipids, saponins and other flocculent impurities in oil. Activated carbon has developed pore structure, uniform particles, and specific surface area. It mainly adsorbs polar substances, and can effectively remove pigments in oil, free organic pollutants, benzo(a)pyrene, pesticide residues, etc. Activated alumina is a molecular adsorbent with a large specific surface area , can effectively remove fluorine, chlorine pollutants and heavy metal pollutants such as arsenic and lead in oil. The clay, activated carbon and alumina are mixed according to the mass ratio (60-95):(3-15):(1-15), so that there is a synergistic effect between the clay, activated carbon and alumina, which can improve the adsorption effect.

Compared with the prior art, the present invention has the following advantages and effects:

(1) By controlling the pressure of microwave vacuum drying, 7KPa ~ 20KPa, the drying temperature is controlled at 40°C ~ 60°C, so that the protein and phospholipid film wrapped in the outer layer of oil droplets in the seed kernel are destroyed by microwave oscillation, and the dissolution of oil droplets is promoted. , improve the oil yield of pressing, in a lower vacuum state, the drying temperature can be controlled at a relatively low temperature, reduce the increase in free fatty acid content and oil peroxidation products caused by high temperature and oxygen, and reduce the difficulty of subsequent refining processes.

The material is dried to a moisture content of 3-6%. On the one hand, during the pressing process, the temperature will not be too high due to excessive pressure; Pressed oils are too high in phospholipids.

(2) By controlling the lower pressing temperature, the increase of acid value and peroxide value caused by high-temperature pressing can be avoided, and the production of benzo(a)pyrene can be prevented.

(3) Through a one-step molecular distillation method, the acid value of camellia oil is reduced from 4 to 6 mg/g to 0.05 to 0.15 mg/g, and the peroxide value is reduced from 8 to 10 mg/kg to 1 to 2 mg/kg. The toxic product malondialdehyde is reduced from 3 to 6ppm to less than 1ppb, and the water content is reduced to less than 1ppm.

(4) Filter through clay, activated carbon and alumina as a filter medium to remove darker pigments and further remove impurities such as colloid and benzo(a)pyrene that may remain in the above process, making the whole process safer and more reliable .

(5) The cold pressing and physical refining process of camellia oil in the present invention adopts physical drying, pressing and refining processes. The whole process is green and environmentally friendly, with high oil yield and high retention rate of micronutrient elements in the finished oil. The finished oil obtained by this process The indicators are higher than the national first-class pressed oil standard.

The cold pressing and physical refining process of the camellia oil in the present invention is also suitable for nut woody oil crops such as Chinese torreya, walnut, hickory nut, thin-shelled hickory nut, pine nut, hazelnut, Yunnan nut, and sorbifolium.

Description of drawings

Fig. 1 is the flowchart of cold pressing and physical refining process of camellia oil among the present invention.

Detailed ways

The present invention will be described in further detail below through examples, and the following examples are explanations of the present invention and the present invention is not limited to the following examples.

Embodiment 1: Camellia oil cold pressing and physical refining process as shown in Figure 1 comprise:

(1) Select the raw material of mature camellia seed, which is dried in a microwave vacuum at a frequency of 2450MHz to a moisture content of 3%, and the pressure is controlled at 12KPa, so that the drying temperature will be controlled at 50°C to avoid excessive temperature and air Oxygen causes the oil in the camellia seed kernel to oxidize and decompose. Since camellia oleifera shells contain benzo(a)pyrene, the shelling rate of raw materials after drying should be above 99%, so as not to mix too much shells and produce benzo(a)pyrene during the pressing process. The microwave vacuum drying in the present invention is usually between the mass content of 3-6%, for example, it can be 4%, 4.5% or 5%. The microwave vacuum drying pressure in the present invention is usually 7KPa～20KPa, for example, it can be 10 KPa, 12KPa, 14KPa, 16KPa or 18KPa.

(2) Cold pressing the shelled camellia seeds, the pressing chamber temperature is 140°C, and the oil outlet temperature is 100°C, excessive pressure and temperature exceeding 150°C should be avoided to produce crude oil with high acid value and peroxide value; the present invention The temperature of the press chamber is usually 100-150°C, for example, it can be 100°C, 110°C, 120°C, 130°C or 140°C, and the oil outlet temperature is usually 80-120°C, for example, it can be 90°C, 95°C, 100°C, 105°C or 110°C.

(3) The pressed camellia oil is filtered through plate and frame to remove solid impurities.

(4) The camellia oil obtained by filtering the plate frame is winterized at 2°C to remove high-melting point waxes, esters, etc. The winterization temperature in the present invention is usually -5 to 5°C, for example, it can be -4°C, -3°C °C, -2°C, -1°C, 0°C, 1°C, 2°C, 3°C or 4°C. Winterization is one of the methods of crystallization and separation. It is a process of cooling oil to crystallize waxes and esters with higher melting points. In this example, cooling camellia oil to crystallize waxes and esters with higher melting points. the process of.

(5) Camellia oil after winterization undergoes molecular distillation only once. The conditions of molecular distillation are: absolute pressure 70pa, evaporation temperature 175°C, condensation temperature 5°C to remove free fatty acids, oil peroxidation products and water in the oil. The acid value of the obtained oil is reduced from 4 to 6 to 0.05 to 0.15, the peroxide value is reduced from 8 to 10 to 1 to 2, and the oxidized toxic product malondialdehyde is reduced from 3 to 6 mg/kg to less than 1 μg/kg. The portion content is less than 1mg/kg. Molecular distillation is a distillation method operated under high vacuum. At this time, the mean free path of vapor molecules is greater than the distance between the evaporation surface and the condensation surface, so that the difference in evaporation rate of each component in the feed liquid can be used to optimize the liquid mixture. to separate. A molecular distillation refers to a molecular distillation process. The molecular distillation pressure in the present invention is usually 1～90Pa, for example can be 5Pa, 10Pa, 15Pa, 20Pa, 25Pa, 30Pa, 35Pa, 40Pa, 45Pa, 50Pa, 55Pa, 60Pa or 65Pa; The evaporation temperature of molecular distillation is usually 135 ~195°C, for example, it can be 140°C, 150°C, 160°C, 170°C, 180°C or 190°C; the condensation temperature is usually -5~25°C, for example, it can be 0°C, 5°C, 10°C, 15°C or 20°C.

Determination of acid value, GBT 15689-2008 Determination of acidity of vegetable oils and oils; Determination of peroxide value, GB/T 5538-2005 Determination of peroxide value of animal and vegetable oils; Determination of moisture content, GB/T 5528-2008 Vegetable oils and fats Determination of moisture and volatile content; Determination of malondialdehyde, GB_T 5009.181-2003 Determination of malondialdehyde in lard.

(6) For the heavy component camellia oil obtained by molecular distillation, the filter medium ratio is clay, activated carbon and alumina mass ratio 80: 3: 2, to remove darker pigments, and further remove some remaining colloids and benzene And (a) trace impurities such as pyrene to obtain the finished product. The mass ratio of clay, activated carbon and alumina in the filter medium of the present invention is usually (60-95):(3-15):(1-15), for example, any set of data in Table 1 can be used.

The mass ratio of clay, activated carbon and alumina in the filter medium of table 1

white clay activated carbon Aluminum oxide 60 3 1 60 3 5 60 3 10 60 3 15 60 8 1 60 8 5 60 8 10 60 8 15 60 12 1 60 12 5 60 12 10 60 12 15 60 15 1 60 15 5 60 15 10 60 15 15 70 3 1 70 3 5 70 3 10 70 3 15 70 8 1 70 8 5 70 8 10 70 8 15 70 12 1 70 12 5 70 12 10 70 12 15 70 15 1 70 15 5 70 15 10 70 15 15 80 3 1 80 3 5 80 3 10 80 3 15 80 8 1 80 8 5 80 8 10 80 8 15 80 12 1 80 12 5 80 12 10 80 12 15 80 15 1 80 15 5 80 15 10 80 15 15 95 3 1 95 3 5 95 3 10 95 3 15 95 8 1 95 8 5 95 8 10 95 8 15 95 12 1 95 12 5 95 12 10 95 12 15 95 15 1 95 15 5 95 15 10 95 15 15

Example 2:

Camellia oil cold pressing and physical refining process includes:

(1) Select 100 kg of mature camellia seeds, put them into a microwave vacuum drying oven, and dry them to a moisture content of 5% under microwaves with a frequency of 2450 MHz and a pressure of 20 KPa. Send the dried shelled camellia seeds to the sheller for shelling, the shelling rate is 99%;

(2) Send the husked camellia seeds to a cold press for pressing, control the temperature of the press chamber at 130°C, and control the oil outlet temperature below 100°C;

(3) the camellia oil squeezed out is filtered through plate and frame to remove solid impurities;

(4) The camellia oil obtained by filtering the plate frame was winterized at 3° C. for 24 hours to remove high melting point waxes, esters, etc.;

(5) Put the winterized camellia oil into the feed cup of molecular distillation, degas it under the vacuum of 200pa for 15min, and then degas it under the pressure of 70Pa, the evaporation temperature of 180°C, the condensation temperature of 15°C, and the speed of scraper Molecular distillation is carried out under the condition of 120 rpm, and the obtained heavy camellia oil has an acid value of less than 0.15, a peroxide value of less than 2, a toxic product of oxidation, malondialdehyde, of less than 1ppb, and a water content of less than 1ppm.

(6) Collect molecularly distilled heavy fractions, and use a ratio of 90:3:7 for clay, activated carbon and aluminum oxide mixed filter media to filter, remove darker pigments, and further remove some colloids and benzo(a) that may exist ) pyrene and other impurities to get the finished product.

Example 3:

Camellia oil cold pressing and physical refining process can also be used to produce Torreya oil, the steps are as follows:

(1) Select 500 kg of ripe torreya seeds without arils, put them into a microwave vacuum drying oven, and dry them to a moisture content of 3% with microwaves at a frequency of 2450 MHz and a vacuum of 10 KPa. The dried raw materials are sent to the shelling machine for shelling, and the shelling rate is 99%;

(2) Send the shelled Chinese torreya seed kernel to the cold press for pressing, the temperature of the pressing chamber is controlled at 120°C, and the oil outlet temperature is controlled below 80°C;

(3) the torreya torreya oil that squeezes out, removes solid impurity by plate and frame press filtration;

(4) The torreya oil obtained by filtering the plate frame was winterized at 1° C. for 18 hours to remove high melting point waxes, esters, etc.;

(5) Put the winterized torreya oil into the feeding cup of molecular distillation, degas it under 200pa vacuum degree for 15min, then use 5Pa vacuum degree, evaporating temperature of 150℃, condensation temperature of 5℃, scraper speed Under the condition of 120 revolutions/min, the feed is separated, and the separated heavy torreya oil has an acid value of less than 0.2, a peroxide value of less than 2, a toxic product of oxidation, malondialdehyde, of less than 1ppb, and a water content of less than 1ppm.

(6) To collect the molecularly distilled heavy fraction in step (5), use clay, activated carbon and alumina with a mass ratio of 85:13:2 to mix and filter as a filter medium to remove darker pigments and further remove possible existing Impurities such as some colloids and benzo(a)pyrene can be obtained as finished products.

Research on the influence of drying mode and temperature on the quality of pressed oil in the present invention:

The higher the drying temperature, the darker the color of the pressed oil, the higher the phospholipid content, the higher the peroxide value, and the lower the vitamin content. Therefore, controlling the drying temperature of raw materials is the primary condition for controlling the quality of pressed oil.

(1) Materials: Camellia oleifera seeds, collected from Yuyuan Township, Wuyi County, Zhejiang Province, Luo Weibo colorimeter, moisture analyzer, liquid chromatography, press machine, oven, microwave vacuum dryer, spectrophotometer.

(2) Experimental method: 140kg camellia seeds were taken, divided into 7 groups, and baked in microwave dryer (12kpa and 18kpa pressure), drying and oven respectively (50°C, 80°C, 110°C, 140°C, 170°C), Dry to a moisture content of 3%. Hulling, low-temperature pressing, pressing chamber temperature 140°C, measuring various indexes.

For the determination method of peroxide value, refer to GB/T 5538-2005 Determination of peroxide value of animal and vegetable oils and fats.

For the color determination method, refer to GB/T 22460-2008 Determination of the color of Lovibond in animal and vegetable oils.

For the determination method of vitamin E content, refer to GB/T 5009.82-2003 Determination of vitamin A and vitamin E in food.

磷脂含量测定方法，参照GB/T 5537-2008粮油检验磷脂含量的测定。

For the determination method of phospholipid content, refer to GB/T 5537-2008 Determination of phospholipid content in grain and oil inspection.

(3) Results

It can be seen from Table 2 that the oil yield of microwave vacuum drying is similar to that of high temperature drying, but the indicators such as color, phospholipid content, peroxide value and vitamin E content are all better than high temperature drying. The color, phospholipid content, peroxide value and vitamin E content of low-temperature drying are similar to those of microwave vacuum drying, but the oil yield is lower and the drying time is longer (under 12Kpa pressure, microwave vacuum drying for 0.5 hours It can reach a moisture content of 3%, while ordinary drying at 50°C takes 6.8 hours).

The oil in the plant seed kernel is a small oil drop in the form of triglyceride, which is wrapped with a layer of phospholipid. The inner side of the phospholipid is an lipophilic group, and the outer side is a hydrophilic group, which connects olein and calcium-binding olein protein. High-temperature treatment of seeds (drying and steaming) can denature protein, reduce oil and surface tension, destroy the combination of protein, phospholipid and triglyceride, and make oil crop seed oil easier to squeeze out during pressing, which is why ordinary Before pressing, it must be steamed and fried at high temperature, but at the same time, the high temperature will destroy the quality of the pressed oil, increase the acid value, peroxide value and phospholipid content, and reduce its nutrition. Microwave is a kind of electromagnetic wave with strong penetrating ability. Through the change of electromagnetic frequency, it makes the molecules in the dried material move and rub against each other to generate heat and take away the water, so that the seeds are evenly dried from the inside to the outside. In a vacuum state, the evaporation temperature of water can be reduced, thereby reducing the temperature of microwave drying. In this way, microwaves can not only strongly destroy the combination of oil, phospholipid and protein, but also prevent the temperature from being too high. On the basis of ensuring the oil yield On the other hand, the quality is guaranteed.

In the present invention, the pressing temperature is studied on the influence of benzo(a)pyrene content:

(1) Materials and instruments: Camellia oleifera seeds, collected from Yuyuan Township, Wuyi County, Zhejiang Province, gas chromatography, press, infrared thermometer.

(2) Experimental method: Take 140kg camellia seeds, divide them into 7 groups, dry them in an oven at 80°C until the moisture content is 5%, and press them in a press. Adjust the speed of the presses to control the temperature of the press chamber at 100°C, 130°C, Press at 150°C, 170°C, 190°C, 210°C, and 250°C to measure the oil yield and benzo(a)pyrene content.

For the determination method of benzo(a)pyrene content, refer to GBT 22509-2008 Determination of benzo(a)pyrene in animal and vegetable fats and oils by reversed-phase high performance liquid chromatography.

磷脂含量测定方法，参照GB/T 5537-2008粮油检验磷脂含量的测定。

For the determination method of phospholipid content, refer to GB/T 5537-2008 Determination of phospholipid content in grain and oil inspection.

It can be seen from Table 3 that with the increase of pressing temperature, the oil yield increases. When the pressing temperature reaches 250°C, the oil yield can reach 98%, but the oil quality also decreases. When the pressing temperature reaches 250°C, the phospholipid content is 32 times that of 100°C. Benzo(a)pyrene will not be produced in the pressing temperature range of 100°C-150°C, but will start to be produced when it reaches 170°C, so the pressing temperature should not exceed 150°C.

The above content described in this specification is only an illustration of the structure of the present invention. Those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims. All should belong to the protection scope of the present invention. the

Claims (4)

1. a kind of camellia oil cold pressing and physical refining process is characterized in that: comprise the following steps: (1) Select mature camellia seeds, adopt microwave vacuum drying to water content 3-6%, send the dried camellia seeds into the shelling machine for shelling, the shelling rate is more than 99%, and the microwave vacuum drying process condition is absolute pressure 7kPa～20kPa; (2) cold pressing the camellia seeds after shelling to extract camellia oil, the temperature of the pressing chamber is 100-150°C, and the temperature of the oil output is 80-120°C; (3) the camellia oil squeezed out removes solid impurities by a plate and frame filter press; (4) Winterize the camellia oil after press filtration at -5°C to 5°C to remove wax, ester and other high melting point substances; (5) The camellia oil after winterization removes free fatty acids, oil peroxidation products, moisture and other low boiling point substances in the camellia oil through molecular distillation; (6) The camellia oil after molecular distillation is filtered with clay, activated carbon and alumina mixture as a filter medium to remove impurities and pigments to obtain the finished product. 2. The camellia oil cold pressing and physical refining process according to claim 1, characterized in that: in the step (2), the temperature of the pressing chamber is controlled at 120-140° C., and the oil outlet temperature is controlled at 90-100° C. 3. The cold pressing and physical refining process of camellia oil according to claim 1 or 2, characterized in that: molecular distillation in the step (5) adopts primary molecular distillation, the condition is an absolute pressure of 1 to 90 Pa, and an evaporation temperature of 135 ~195°C, the condensation temperature is -5~25°C; the acid value, peroxide value and malondialdehyde content of the oxidized toxic product of camellia oil have changed from 4-6mg/g, 8-10mmol/kg and 3-6mg before molecular distillation /kg decreased to below 0.05～0.15mg/g, 1～2mmol/kg and 1μg/kg respectively, and the water content was lower than 1mg/kg. 4. The camellia oil cold pressing and physical refining process according to claim 1 or 2, characterized in that: the filter medium in the step (6) adopts a filter medium with a mass ratio of 60～95:3～15:1～15 A mixture of clay, activated carbon and alumina.

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