Preparation method of high oxidation stability camellia seed oil

Abstract

The application discloses a kind of high oxidative stability camellia seed oil preparation method, belong to oil processing technical field.The following steps are included: selecting pollution-free, mildew-free, full-granular camellia seed, cleaning and removing impurities;Crushing, screening, obtaining the uniform particle size of camellia seed powder;Camellia seed powder is mixed with deionized water in proportion, and the solubilization heat treatment of camellia seed suspension;High-voltage electrostatic field treatment, active substance is in active state of release;Adjust the acid-base value of camellia seed suspension, stimulate oil body;Optimum temperature activation treatment of biological enzyme, constant-temperature enzymolysis extraction;Increase system temperature, enzyme, terminate reaction;Ice bath, centrifugal collection upper layer clean oil.The processing method of the high oxidative stability camellia seed oil is safe, environment-friendly, mild, simple equipment, convenient operation, low cost, good oil quality, provides technical support for non-thermal physical field flexible extraction of high-quality oil.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of oil processing, in particular to a preparation method of camellia seed oil with high oxidation stability. BACKGROUND

[0002] Camellia seed, the seed of a camellia tree, is a unique woody edible oil material in China. The camellia seed kernel contains 40-60% of oil, and the camellia seed oil is light yellow, clear and transparent, with a fragrance, and has a similar fatty acid composition and physical and chemical data to olive oil, and is known as “Oriental olive oil”. The camellia seed oil is highly recommended by the Food and Agriculture Organization of the United Nations as a high-quality healthy edible oil. The camellia seed oil has rich nutritional value, with more than 90% of unsaturated fatty acids, 80-83% of oleic acid and 7-13% of linoleic acid, and especially contains linolenic acid which is essential for human bodies. In addition, the camellia seed oil is rich in various natural active ingredients, such as vitamins A, B, D and E, squalene, tea polyphenols and phytosterols, and has the functions of antioxidation, anti-aging and improving human immunity, and has the special effects of preventing cardiovascular sclerosis, reducing blood pressure and blood fat and preventing and treating cancer. Therefore, the camellia seed oil is an oil with extremely high nutritional value and high edible value, but improper processing methods can easily lead to oil oxidation and loss of trace nutrients.

[0003] The current industrial processing technology includes a series of processes such as frying, pressing or leaching and refining processing. However, the traditional processing technology is backward and has low technical content, so that the comprehensive utilization rate of by-products is low and the oil processing requirements cannot be met. High temperature in high-temperature steaming or frying can cause protein denaturation, thermal degradation of unsaturated fatty acids in oil, reduction of tocopherols and other bioactive substances, and further reduction of oil quality. With the development of economy and science and technology, various heating methods such as microwave and infrared technology are applied to the field of oil processing, but there are still many problems. The microwave heating technology is greatly affected by the water content due to its selective heating characteristics. At the same time, the temperature of the material heated by microwave is unstable, which is not conducive to the stable progress of the Maillard reaction. In addition, reducing sugars such as glucose and sucrose in food are easily melted by microwave radiation, which can cause caramelization reaction and cause material loss. The low penetration of infrared radiation is one of the limitations of this method.

[0004] At present, the domestic mainly adopts the pressing method and solvent extraction method to prepare oil, but both of the two processing methods have defects: the oil yield of the pressing method is low, and the oil stability is poor; the investment of the solvent extraction method is large, the solvent usage is large, there are hidden troubles of residue, and it is easy to cause environmental pollution and other problems. Compared with the pressing method and the solvent extraction method, the aqueous enzymatic method can realize the synchronous extraction of oil and protein, which can obtain high-quality edible oil, and can also avoid the loss of nutrients caused by denaturation of protein in the processing process, so that the processing characteristics and nutritional function of oilseeds are well preserved. The subsequent refining process further destroys beneficial ingredients, damages natural antioxidants, reduces the nutritional value and flavor of oil, and may also generate trans fatty acids.

[0005] In the prior art, the patent CN 112029567 A discloses a low-temperature pressing process for improving the oil yield of oil tea seed oil, which uses magnetic field assisted enzymatic treatment of oil tea seed kernels to promote the dissolution of oil in oil tea seeds, but the process has the following shortcomings: the enzymatic hydrolysis time is long, the degree of hydrolysis is low, the enzyme activity is lost, and it is time-consuming; the steps are complicated, the residue after hydrolysis is dried again under vacuum, which consumes a lot of energy and is not environmentally friendly; the material needs to be crushed to a certain particle size during enzymatic hydrolysis to improve the oil yield, but such small particles are prone to jamming during the subsequent low-temperature pressing process, and the oil yield is poor.

[0006] Therefore, there is currently a lack of an energy-saving and environmentally friendly oil tea seed oil extraction method that is simple to prepare, improves oil yield and nutrient dissolution rate. SUMMARY

[0007] TECHNICAL PROBLEM

[0008] The current oil tea seed oil extraction method cannot meet the requirements of oil processing, the material loss is large, the preparation is complicated and time-consuming, and the oil stability is poor.

[0009] TECHNICAL CONTENT

[0010] The purpose of the present application is to provide a method for preparing oil tea seed oil with high oxidative stability, which comprises the following steps:

[0011] (1) crushing and sieving: crushing and sieving the oil tea seeds to obtain oil tea seed powder;

[0012] (2) solubilization and heat treatment: mixing and incubating the oil tea seed powder in step (1) with water to obtain an oil tea seed suspension;

[0013] (3) high-voltage electrostatic field activation treatment: high-voltage electrostatic treatment of the oil tea seed suspension in step (2), the high-voltage electrostatic field treatment voltage is 30-80KV, the treatment time is 30-90min, and the high-voltage electrostatic treatment of the oil tea seed suspension is obtained;

[0014] (4) acid-base stimulation: adjusting the pH of the high-voltage electrostatic field treated oil-tea camellia seed suspension in (3), and standing to obtain a standing oil-tea camellia seed suspension;

[0015] (5) biological enzyme treatment: activating the biological enzyme, and then adding it into the standing oil-tea camellia seed suspension in step (4) for enzymolysis treatment to obtain a feed liquid;

[0016] (6) enzyme inactivation centrifugation: inactivating the enzyme in the feed liquid in step (5), and then cooling and centrifuging to collect the upper clear oil to obtain the oil-tea camellia seed oil with high oxidation stability.

[0017] In an embodiment of the present application, the sieving in step (1) is sieving through a 40-80 mesh sieve.

[0018] In an embodiment of the present application, the water in step (2) is water with a temperature of 60-90°C.

[0019] In an embodiment of the present application, the mass ratio of the oil-tea camellia seed powder to water in step (2) is 1:4-10.

[0020] In an embodiment of the present application, the incubation in step (2) is oscillation incubation in a constant temperature reactor for 10-20 min.

[0021] In an embodiment of the present application, the voltage of the high-voltage electrostatic field treatment in step (3) is preferably 30-80 KV, and the treatment time is 20-70 min.

[0022] In an embodiment of the present application, the voltage of the high-voltage electrostatic field treatment in step (3) is specifically selected to be 60 KV, and the treatment time is 50 min.

[0023] In an embodiment of the present application, the pH in step (4) is 7-10.

[0024] In an embodiment of the present application, the standing time in step (4) is 5-20 min.

[0025] In an embodiment of the present application, the enzyme in step (5) is one or more of cellulase, bromelain, pectinase, amylase, alkaline protease, and papain.

[0026] In an embodiment of the present application, the activation treatment of the biological enzyme in step (5) is treatment at 50-60°C for 1-2 min.

[0027] In an embodiment of the present application, the addition amount of the biological enzyme in step (5) is 1-5% of the mass of the oil-tea camellia seed protein.

[0028] In an embodiment of the present application, the enzymatic treatment in step (5) is carried out at a temperature of 40-60 DEG C for 0.5-3 hours.

[0029] Specifically, the enzyme in step (5) is papain and bromelain in a mass ratio of 1:1, and the total amount of papain and bromelain is 2% of the mass of the oil tea seed protein.

[0030] Specifically, the activation treatment of the biological enzyme in step (5) is carried out at 55-60 DEG C for 1 minute.

[0031] In an embodiment of the present application, the enzyme inactivation temperature in step (6) is 90-100 DEG C, and the enzyme inactivation time is 10-15 minutes.

[0032] In an embodiment of the present application, the centrifugation in step (6) is carried out at 5000-8000 rpm for 10-20 minutes.

[0033] The above method provided by the present application is applied in the field of oil processing technology.

[0034] The oil tea seed oil with high oxidation stability prepared by the above method is provided.

[0035] The oil tea seed oil with high oxidation stability provided by the present application is applied in the field of food.

[0036] Advantages

[0037] (1) The present application adopts solubilization heat treatment, high-voltage electrostatic field activation and biological enzyme treatment, which can effectively destroy the cell wall, lipoprotein, lipopolysaccharide and other complexes in the oil cells, facilitate the release of oil and various bioactive ingredients, improve the dissolution rate of antioxidant substances such as vitamin E and polyphenol, reduce the generation of harmful ingredients, and also reduce the amount of enzyme and enzyme hydrolysis time.

[0038] (2) The natural oil tea seed oil prepared by the present application can retain beneficial accompanying substances to a large extent, improve the oxidation stability of the oil tea seed oil, solve the problems of flavor decline and product deterioration caused by oil oxidation and rancidity, and prolong the shelf life of food.

[0039] (3) The preparation method adopted by the present application is safe, environmentally friendly, mild, simple in equipment, convenient in operation, low in cost, and good in oil quality, which provides technical support for non-thermal physical field flexible extraction of high-quality oil. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is the process flow chart of the preparation method for improving the oxidation stability of oil tea seed oil according to the present application.

[0041] Figure 2is the process diagram of the oil-tea camellia seed oil prepared by biological enzyme method under different conditions (1 is solubilization at room temperature, comparative example 3; 2 is solubilization at 60℃, example 1; 3 is solubilization at 90℃, comparative example 2).

[0042] Figure 3 is the oil-tea camellia seed oil prepared by biological enzyme method (upper diagram - example 1; lower diagram - comparative example 2).

[0043] Figure 4 is the gallic acid standard curve.

[0044] Figure 5 is the α-tocopherol standard curve.

[0045] Figure 6 is the β-tocopherol standard curve.

[0046] Figure 7 is the γ-tocopherol standard curve.

[0047] Figure 8 is the δ-tocopherol standard curve. DETAILED DESCRIPTION

[0048] The application will be further described in conjunction with examples, but the application is not limited to the scope of the examples. Modifications or substitutions made to the application without departing from the spirit and essence of the application shall fall within the protection scope of the application.

[0049] Raw material sources

[0050] Oil-tea camellia seeds were provided by Liujiaxiang Food Co., Ltd. in Juzhou; 2.4L, enzyme activity ≥2.4U / g; cellulase, enzyme activity 400U / mg; α-amylase, enzyme activity 100U / mg; bromelain, enzyme activity ≥1200GDU / g; pectinase, enzyme activity 500U / mg; alkaline protease, enzyme activity 200U / mg; papain, enzyme activity 800U / mg.

[0051] Test process

[0052] Peroxide value determination method:

[0053] Reference is made to the national standard GB / T 5009.227-2016 “Determination of Peroxide Value in Food”.

[0054] Oxidation induction time determination method:

[0055] About 3.0g of oil-tea camellia seed oil was weighed into a sample tube, and the Rancimat oil oxidation stability instrument was used to determine the oxidation induction time. The parameters were set as follows: temperature 120℃, air flow rate 20L / h, and the result was expressed by oxidation induction time (h).

[0056] Polyphenol content determination method:

[0057] The polar polyphenols in oil tea seed oil were adsorbed and concentrated by using Diol diol-based solid phase extraction cartridges activated by methanol and n-hexane, and then quantified by the external standard method using gallic acid as the standard sample, and the final calculation result was expressed in gallic acid (GAE) equivalent. The preparation of GAE standard curve was carried out according to the second method in GB / T 8313-2018, and the standard curve was drawn in Figure 4 , and the linear regression equation was y = 0.5865x + 0.0215, R2 = 0.9994.

[0058] Tocopherol content determination method:

[0059] (1) Preparation of standard solution

[0060] Accurately take a certain amount of α-tocopherol, β-tocopherol, γ-tocopherol and δ-tocopherol, and prepare a certain mass concentration, and then dilute to the calibration line with n-hexane;

[0061] (2) Preparation of series standard solution

[0062] Take the α-tocopherol, β-tocopherol, γ-tocopherol and δ-tocopherol standard solutions with mass concentrations of 5, 10, 20, 40 and 80 μg / mL respectively into 10 mL volumetric flasks, and dilute to the calibration line with n-hexane; The standard curve is drawn in Figure 5 , 6 , 7, 8;

[0063] (3) Preparation of sample solution

[0064] Accurately weigh 1.0 g of sample into a 10 mL volumetric flask, add 5 mL of n-hexane, and dissolve under ultrasonic condition, then dilute to the calibration line with n-hexane, take 1.5 mL of sample solution into a 2 mL centrifugal tube, centrifuge at 10000 r / min for 10 min, and prepare for use;

[0065] (4) Chromatographic analysis

[0066] Chromatographic column: Lichrospher SI silica gel column (25 cm x 4.6 mm, 5 μm); mobile phase: n-hexane-isopropyl alcohol (98.5:1.5, V:V); volume flow rate is 1 mL / min; injection volume: 20 μL; detection wavelength: 295 nm; column temperature: 30℃.

[0067] Example 1

[0068] The present example provides a method for preparing oil tea seed oil with high oxidation stability, comprising the following steps:

[0069] (1) Raw material screening and impurity removal: The oil tea seeds are screened and impurities are removed, and the oil tea seeds without pollution, mildew, and full particles are selected and cleaned;

[0070] (2) Crushing and sieving: The oil tea seeds cleaned in step (1) are crushed and sieved through a 40-mesh sieve to obtain oil tea seed powder with uniform particle size;

[0071] (3) Solubilization and heat treatment: The oil tea seed powder sieved in step (2) is mixed with deionized water preheated to 60°C at a mass ratio of 1:5, and is incubated in a constant-temperature reactor for 15 min to prepare an oil tea seed suspension;

[0072] (4) High-voltage electrostatic field activation treatment: The oil tea seed suspension in step (3) is placed in a high-voltage electrostatic field processor with a voltage of 50KV for 30 min to obtain an oil tea seed suspension treated by high-voltage electrostatic field;

[0073] (5) Acid-base stimulation: 2 mol / L sodium hydroxide solution is added to the oil tea seed suspension treated by high-voltage electrostatic field in step (4) to adjust the pH of the system to 8.0, and then the system is allowed to stand for 10 min to stimulate the oil bodies in the oil tea seeds;

[0074] (6) Biological enzyme treatment: 1.5% (based on the content of oil tea seed protein) cellulase 2.4L is activated at 60°C for 1 min, and then is added to the oil tea seed suspension treated by alkali in step (5) and is incubated at constant temperature for 1.5 h for enzymatic hydrolysis treatment. Then, the pH of the system is adjusted to 5.0 by using 2 mol / L hydrochloric acid solution, and the system is allowed to stand for 5 min to stimulate the oil bodies in the oil tea seeds again. Cellulase 2.4L activated at 60°C for 1 min is added to the system for enzymatic hydrolysis treatment, and the system is incubated at constant temperature for 1.0 h;

[0075] (7) Enzyme inactivation: The reaction system in step (6) is placed in a 95°C water bath for 10 min for enzyme inactivation to terminate the reaction;

[0076] (8) Centrifugation: The reaction system in step (7) is cooled to room temperature in an ice bath, and then is centrifuged at a low temperature of 5000 rpm for 15 min to collect the upper clear oil.

[0077] The properties of the oil tea seed oil prepared in this example are as follows: the peroxide value is ≤0.20 mmol / kg, the oxidation induction time is 9.87 h, the polyphenol content is 23.78 μg / g, the α-tocopherol content is 317.02 μg / mL, and the VE content is 359.57 μg / mL.

[0078] Example 2

[0079] Referring to Example 1, the enzymolysis time of cellulase in the step (6) biological enzyme treatment is shortened to 0.5 h, and the rest of the steps, conditions and Example 1 are the same, and camellia seed oil is prepared; the rest is unchanged, and the corresponding product is obtained.

[0080] The properties of the obtained product are measured, and the attributes of the camellia seed oil after shortening the biological enzyme enzymolysis time: the peroxide value is ≤0.20 mmol / kg, the oxidation induction time is 9.85 h, the polyphenol content is 23.77 μg / g, the α-tocopherol content is 316.98 μg / mL, and the VE content is 359.54 μg / mL. Compared with Example 1, the parameters after shortening the enzymolysis time are not much different from Example 1, which shows that the biological enzyme enzymolysis time can be reduced under the treatment of solubilization heat treatment and high-voltage electrostatic field activation.

[0081] Example 3

[0082] The present example provides a method for preparing camellia seed oil with high oxidation stability, comprising the following steps:

[0083] (1) Raw material selection and impurity removal: select and remove impurities from camellia seeds, select camellia seeds without pollution, mildew and full particles, and clean and remove impurities;

[0084] (2) Crushing and sieving: crush and sieve the camellia seeds cleaned in step (1) through a 40-mesh sieve to obtain camellia seed powder with uniform particle size;

[0085] (3) Solubilization heat treatment: mix the camellia seed powder sieved in step (2) with deionized water preheated to 90°C at a mass ratio of 1:6, and incubate in a constant temperature reactor for 10 min to prepare a camellia seed suspension;

[0086] (4) High-voltage electrostatic field activation treatment: place the camellia seed suspension in step (3) in a high-voltage electrostatic field processor with a voltage of 40KV for 30 min, so that the active substances are in an active state ready to be released by the electrostatic field;

[0087] (5) Acid and alkali stimulation: add 2 mol / L sodium hydroxide solution to the camellia seed suspension after high-voltage electrostatic treatment in step (4) to adjust the pH of the system to 7.5, and then stand for 10 min to stimulate the oil bodies in the camellia seeds;

[0088] (6) Biological enzyme treatment: 1.5% (the content of camellia seed protein is the base) of 2.4L was activated at 55°C for 1 minute, then added to the oil tea seed suspension treated with alkali solution in step (5), and incubated for 2.0h for enzymatic hydrolysis treatment. Then the pH of the system was adjusted to 6.0 with 1 mol / L citric acid solution, and the oil bodies in the oil tea seed were stimulated by standing for 5 min. Then 2.4L and α-amylase activated at 55°C for 1 minute (mass ratio 3:1) were added to the system for enzymatic hydrolysis treatment, and incubated for 0.5h at constant temperature. 2.4L and α-amylase mass ratio 3:1) were added to the system for enzymatic hydrolysis treatment, and incubated for 0.5h at constant temperature.

[0089] (7) Enzyme inactivation: the reaction system in step (6) was placed in a 95°C water bath for 10 min for enzyme inactivation to terminate the reaction.

[0090] (8) Centrifugation: the reaction system in step (7) was cooled to room temperature in an ice bath, and then centrifuged at 6000 rpm for 10 min at low temperature to collect the upper clear oil.

[0091] The properties of the oil tea seed oil prepared in this example are as follows: peroxide value ≤0.24 mmol / kg, oxidation induction time 9.36h, polyphenol content 20.25μg / g, α-tocopherol content 311.63μg / mL, and VE content 356.93μg / mL.

[0092] Example 4

[0093] The present example provides a method for preparing oil tea seed oil with high oxidation stability, comprising the following steps:

[0094] (1) Raw material selection and impurity removal: the oil tea seeds were selected and impurities were removed, and the oil tea seeds without pollution, mildew, and full particles were selected and cleaned;

[0095] (2) Crushing and sieving: the oil tea seeds cleaned in step (1) were crushed and sieved through a 60 mesh sieve to obtain oil tea seed powder with uniform particle size;

[0096] (3) Solubilization and heat treatment: the oil tea seed powder sieved in step (2) was mixed with deionized water preheated to 60°C at a mass ratio of 1:8, and incubated in a constant temperature reactor for 15 min to prepare an oil tea seed suspension;

[0097] (4) High-voltage electrostatic field activation treatment: the oil tea seed suspension in step (3) was placed in a high-voltage electrostatic field processor with a voltage of 70KV for 45 min, so that the active substances were in an active state ready to be released by the electrostatic field;

[0098] (5) Acid and alkali stimulation: 1 mol / L sodium hydroxide solution was added to the oil tea seed suspension treated by high-voltage electrostatic field in step (4) to adjust the pH of the system to 7.0, and then the oil bodies in the oil tea seed were stimulated by standing for 10 min.

[0099] (6) biological enzyme treatment: 1.2% (oil tea seed protein content as the base) of bromelain was activated at 50°C for 1 minute, then added to the oil tea seed suspension after alkali treatment in step (5), and incubated for 2.0h for enzymatic hydrolysis treatment, then adjusted the pH of the system to 4.0 with 2 mol / L hydrochloric acid solution, and stood for 5 min, and then stimulated the oil body in the oil tea seed, and added pectinase (bromelain and pectinase mass ratio 3:1) activated at 50°C for 1 minute to the system for enzymatic hydrolysis treatment, and incubated for 0.5h at constant temperature;

[0100] (7) enzyme inactivation: the reaction system after step (6) was placed in a 95°C water bath for enzyme inactivation for 10 min to terminate the reaction;

[0101] (8) centrifugation: the reaction system in step (7) was cooled to room temperature in an ice bath, and then centrifuged at 6000 rpm for 10 min at low temperature to collect the upper clear oil.

[0102] The properties of the oil tea seed oil prepared in this example are as follows: peroxide value ≤0.16 mmol / kg, oxidation induction time is 10.72h, polyphenol content is 29.49μg / g, α-tocopherol content is 372.37μg / mL, and VE content is 384.21μg / mL.

[0103] Example 5

[0104] Referring to Example 4, the use ratio of pectinase in step (6) biological enzyme treatment was reduced to 4:1, and the other steps, conditions and Example 4 were the same, and the oil tea seed oil was prepared; other unchanged, the corresponding product was obtained.

[0105] The properties of the obtained product were determined, and the properties of the oil tea seed oil with reduced biological enzyme hydrolysis use amount were as follows: peroxide value ≤0.16 mmol / kg, oxidation induction time was 10.71h, polyphenol content was 29.47μg / g, α-tocopherol content was 372.35μg / mL, and VE content was 384.19μg / mL. Compared with Example 4, the parameters after reducing the use amount of biological enzyme were not much different from Example 4, which indicated that the use amount of biological enzyme could be reduced under the treatment of solubilization and heat treatment and high-voltage electrostatic field activation.

[0106] Example 6

[0107] The present example provides a preparation method of oil tea seed oil with high oxidation stability, comprising the following steps:

[0108] (1) raw material selection and impurity removal: the oil tea seeds were selected and impurities were removed, and the oil tea seeds without pollution, mildew and full particles were selected and cleaned;

[0109] (2) crushing and sieving: the oil tea seed after the preliminary cleaning in step (1) is crushed and sieved through a 40-mesh sieve to obtain oil tea seed powder with uniform particle size;

[0110] (3) solubilization and heat treatment: the oil tea seed powder after crushing and sieving in step (2) is mixed with deionized water preheated to 70℃ at a mass ratio of 1:7, and is incubated in a constant-temperature reactor for 10 min to prepare an oil tea seed suspension;

[0111] (4) high-voltage electrostatic field activation treatment: the oil tea seed suspension in step (3) is placed in a high-voltage electrostatic field processor with a voltage of 55KV for 60 min, so that the active substances are in an active state ready to be released by the electrostatic field;

[0112] (5) acid-base stimulation: 2 mol / L sodium hydroxide solution is added to the oil tea seed suspension after high-voltage electrostatic treatment in step (4) to adjust the pH of the system to 10.0, and then the system is allowed to stand for 10 min to stimulate the oil bodies in the oil tea seed;

[0113] (6) biological enzyme treatment: 1.5% (based on the content of oil tea seed protein) of alkaline protease is activated at 55℃ for 1 min, and then is added to the oil tea seed suspension after alkali treatment in step (5), and is incubated at constant temperature for 2.0 h for enzymatic hydrolysis treatment. Then, the pH of the system is adjusted to 5.5 with 2 mol / L hydrochloric acid solution, and the system is allowed to stand for 5 min to stimulate the oil bodies in the oil tea seed again. Cellulase and pectinase (mass ratio of alkaline protease, cellulase and pectinase is 3:2:1) activated at 55℃ for 1 min are added to the system for enzymatic hydrolysis treatment, and the system is incubated at constant temperature for 0.5 h;

[0114] (7) enzyme inactivation: the enzyme in the system after enzymatic hydrolysis in step (6) is inactivated in a 95℃ water bath for 10 min to terminate the reaction;

[0115] (8) centrifugation: the reaction system in step (7) is cooled to room temperature in an ice bath, and then is centrifuged at a low temperature of 5000 rpm for 15 min to collect the upper clear oil.

[0116] The properties of the oil tea seed oil prepared in this example are as follows: peroxide value ≤0.18 mmol / kg, oxidation induction time is 10.35 h, polyphenol content is 26.37 μg / g, α-tocopherol content is 339.35 μg / mL, and VE content is 387.06 μg / mL.

[0117] Example 7

[0118] The present example provides a method for preparing oil tea seed oil with high oxidation stability, comprising the following steps:

[0119] (1) Raw material screening and impurity removal: The oil tea seeds are screened and impurities are removed, and the oil tea seeds without pollution, mildew, and full particles are selected and cleaned;

[0120] (2) Crushing and sieving: The oil tea seeds cleaned in step (1) are crushed and sieved through a 60-mesh sieve to obtain oil tea seed powder with uniform particle size;

[0121] (3) Solubilization and heat treatment: The oil tea seed powder sieved in step (2) is mixed with deionized water preheated to 65°C at a mass ratio of 1:5, and is incubated in a constant temperature reactor for 15 min to prepare an oil tea seed suspension;

[0122] (4) High-voltage electrostatic field activation treatment: The oil tea seed suspension in step (3) is placed in a high-voltage electrostatic field processor with a voltage of 40KV for 60 min, so that the active substances are in an active state ready to be released by the electrostatic field;

[0123] (5) Acid-base stimulation: 1 mol / L sodium hydroxide solution is added to the oil tea seed suspension after high-voltage electrostatic treatment in step (4) to adjust the pH of the system to 7.0, and then it is left to stand for 10 min to stimulate the oil bodies in the oil tea seeds;

[0124] (6) Biological enzyme treatment: 2.0% (oil tea seed protein content as the base) papain and bromelain with a mass ratio of 1:1 are activated at 60°C for 1 min, and then they are added to the oil tea seed suspension after alkali treatment in step (5) and incubated at a constant temperature for 2.0 h for enzymatic hydrolysis;

[0125] (7) Enzyme inactivation: The enzyme solution after enzymatic hydrolysis in step (6) is placed in a 95°C water bath for 10 min to inactivate the enzyme and terminate the reaction;

[0126] (8) Centrifugation: The reaction system in step (7) is cooled to room temperature in an ice bath, and then it is centrifuged at 6000 rpm for 10 min at low temperature to collect the upper clear oil.

[0127] The properties of the oil tea seed oil prepared in this example are as follows: peroxide value ≤0.19 mmol / kg, oxidation induction time is 10.21 h, polyphenol content is 25.16 μg / g, α-tocopherol content is 337.41 μg / mL, and VE content is 361.18 μg / mL.

[0128] Example 8

[0129] This example is prepared according to Example 7, only the voltage in step (4) is adjusted to 50KV, and other operations and parameters remain unchanged.

[0130] The properties of the camellia seed oil prepared in the example are as follows: peroxide value ≤ 0.17 mmol / kg, oxidation induction time is 10.43 h, polyphenol content is 27.33 μg / g, α-tocopherol content is 356.71 μg / mL, and VE content is 379.24 μg / mL.

[0131] Example 9

[0132] The example is prepared by referring to example 7, only the voltage in step (4) is adjusted to 60KV, and other operations and parameters are unchanged.

[0133] The properties of the camellia seed oil prepared in the example are as follows: peroxide value ≤ 0.16 mmol / kg, oxidation induction time is 10.98 h, polyphenol content is 29.87 μg / g, α-tocopherol content is 375.41 μg / mL, and VE content is 392.36 μg / mL.

[0134] Example 10

[0135] The example is prepared by referring to example 7, only the voltage in step (4) is adjusted to 70KV, and other operations and parameters are unchanged.

[0136] The properties of the camellia seed oil prepared in the example are as follows: peroxide value ≤ 0.18 mmol / kg, oxidation induction time is 10.34 h, polyphenol content is 27.15 μg / g, α-tocopherol content is 350.48 μg / mL, and VE content is 372.17 μg / mL.

[0137] Example 11

[0138] The example is prepared by referring to example 7, only the voltage in step (4) is adjusted to 80KV, and other operations and parameters are unchanged.

[0139] The properties of the camellia seed oil prepared in the example are as follows: peroxide value ≤ 0.20 mmol / kg, oxidation induction time is 10.02 h, polyphenol content is 24.43 μg / g, α-tocopherol content is 325.29 μg / mL, and VE content is 363.51 μg / mL.

[0140] Example 12

[0141] The example provides a preparation method of camellia seed oil with high oxidation stability, comprising the following steps:

[0142] (1) raw material selection and impurity removal: the camellia seeds are selected and impurities are removed, and the camellia seeds without pollution, mildew and full particles are selected and cleaned;

[0143] (2) crushing and sieving: the oil-tea camellia seed powder after the preliminary cleaning in step (1) is crushed and sieved through a 60-mesh sieve to obtain oil-tea camellia seed powder with uniform particle size;

[0144] (3) solubilization and heat treatment: the oil-tea camellia seed powder after the crushing and sieving in step (2) is mixed with deionized water preheated to 65℃ at a mass ratio of 1:5, and is incubated in a constant-temperature reactor for 15 min to prepare an oil-tea camellia seed suspension;

[0145] (4) high-voltage electrostatic field activation treatment: the oil-tea camellia seed suspension in step (3) is placed in a high-voltage electrostatic field processor with a voltage of 60 KV for 30 min, so that the active substances are in an active state ready to be released by the electrostatic field;

[0146] (5) acid-base stimulation: 1 mol / L sodium hydroxide solution is added to the oil-tea camellia seed suspension after the high-voltage electrostatic treatment in step (4) to adjust the pH of the system to 7.0, and then the system is allowed to stand for 10 min to stimulate the oil bodies in the oil-tea camellia seeds;

[0147] (6) biological enzyme treatment: 2.0% (the oil-tea camellia seed protein content is the base) of papain and bromelain with a mass ratio of 1:1 are activated at 60℃ for 1 min, and then are added to the oil-tea camellia seed suspension after the alkali treatment in step (5) for incubation at a constant temperature for 2.0 h for enzymatic hydrolysis treatment;

[0148] (7) enzyme inactivation: the enzyme hydrolysis completed in step (6) is placed in a 95℃ water bath for enzyme inactivation for 10 min to terminate the reaction;

[0149] (8) centrifugation: the reaction system in step (7) is cooled to room temperature by ice bath, and then is centrifuged at a low temperature of 6000 rpm for 10 min to collect the upper clear oil.

[0150] The properties of the oil-tea camellia seed oil prepared in this example are as follows: the peroxide value is ≤0.18 mmol / kg, the oxidation induction time is 10.26 h, the polyphenol content is 26.94 μg / g, the α-tocopherol content is 348.87 μg / mL, and the VE content is 370.28 μg / mL.

[0151] Example 13

[0152] This example is prepared according to Example 12, except that the time in the processor in step (4) is adjusted to 40 min, and other operations and parameters remain unchanged.

[0153] The properties of the oil-tea camellia seed oil prepared in this example are as follows: the peroxide value is ≤0.16 mmol / kg, the oxidation induction time is 10.96 h, the polyphenol content is 29.34 μg / g, the α-tocopherol content is 372.83 μg / mL, and the VE content is 391.24 μg / mL.

[0154] Example 14

[0155] This example was prepared according to Example 12, only the time in the processor in step (4) was adjusted to 50 min, and other operations and parameters were unchanged.

[0156] The properties of the oil-tea camellia seed oil prepared in this example were as follows: peroxide value ≤ 0.14 mmol / kg, oxidation induction time was 11.24 h, polyphenol content was 34.75 μg / g, α-tocopherol content was 387.46 μg / mL, and VE content was 406.93 μg / mL.

[0157] Example 15

[0158] This example was prepared according to Example 12, only the time in the processor in step (4) was adjusted to 70 min, and other operations and parameters were unchanged.

[0159] The properties of the oil-tea camellia seed oil prepared in this example were as follows: peroxide value ≤ 0.17 mmol / kg, oxidation induction time was 10.79 h, polyphenol content was 28.59 μg / g, α-tocopherol content was 368.75 μg / mL, and VE content was 388.64 μg / mL.

[0160] Comparative Example 1

[0161] According to Example 1, when step (4) was deleted, i.e., no high-voltage electrostatic field activation treatment was performed, and other steps, conditions and Example 1 were the same, oil-tea camellia seed oil was prepared; other unchanged, the corresponding product was obtained.

[0162] The properties of the obtained product were determined, and the properties of the oil-tea camellia seed oil without high-voltage electrostatic field activation treatment were as follows: peroxide value ≤ 0.38 mmol / kg, oxidation induction time was 7.69 h, polyphenol content was 18.86 μg / g, α-tocopherol content was 298.97 μg / mL, and VE content was 329.26 μg / mL. Compared with Example 1, the oxidation induction time was reduced by 22.09%, the polyphenol content was reduced by 20.69%, and the VE content was reduced by 8.43%.

[0163] Comparative Example 2

[0164] According to Example 1, in step (3) of solubilization and heat treatment, the deionized water was preheated to 90°C, and other steps, conditions and Example 1 were the same, oil-tea camellia seed oil was prepared; other unchanged, the corresponding product was obtained.

[0165] The properties of the obtained product were determined, and the properties of the oil-tea camellia seed oil subjected to solubilization heat treatment at 90°C were as follows: peroxide value ≤0.22 mmol / kg, oxidation induction time 9.63 h, polyphenol content 22.04 μg / g, α-tocopherol content 314.82 μg / mL, and VE content 358.43 μg / mL. Compared with Example 1, the oxidation induction time was reduced by 2.43%, the polyphenol content was reduced by 12.15%, and the VE content was reduced by 6.29%.

[0166] Comparative Example 3

[0167] Referring to Example 1, in the solubilization heat treatment in step (3), no preheating was performed, and deionized water at room temperature was used. The other steps, conditions, and Example 1 were the same, and oil-tea camellia seed oil was prepared. Other than that, the corresponding product was obtained.

[0168] The properties of the obtained product were determined, and the properties of the oil-tea camellia seed oil subjected to solubilization heat treatment at room temperature were as follows: peroxide value ≤0.18 mmol / kg, oxidation induction time 9.48 h, polyphenol content 20.89 μg / g, α-tocopherol content 308.26 μg / mL, and VE content 336.95 μg / mL. Compared with Example 1, the oxidation induction time was reduced by 3.95%, the polyphenol content was reduced by 12.15%, and the VE content was reduced by 6.29%. Compared with the effects of solubilization heat treatment at 60°C and 90°C, as shown in Table 1, the effect of solubilization heat treatment at room temperature was the worst. Figure 2 .

[0169] Comparative Example 4

[0170] Referring to Example 1, the biological enzyme method was changed to the water substitution method, that is, no biological enzyme was added in step (6). The other steps, conditions, and Example 1 were the same, and oil-tea camellia seed oil was prepared. Other than that, the corresponding product was obtained.

[0171] The properties of the obtained product were determined, and the properties of the oil-tea camellia seed oil not subjected to biological enzyme extraction were as follows: peroxide value ≤0.29 mmol / kg, oxidation induction time 8.93 h, polyphenol content 20.48 μg / g, α-tocopherol content 309.53 μg / mL, and VE content 346.75 μg / mL. Compared with Example 1, the oxidation induction time was reduced by 9.52%, the polyphenol content was reduced by 13.88%, and the VE content was reduced by 3.57%.

[0172] Comparative Example 5

[0173] Referring to Example 1, in the solubilization heat treatment in step (3), no preheating was performed, and deionized water at room temperature was used. Step (4) was deleted, that is, no high-voltage electrostatic field activation treatment was performed. The biological enzyme method was changed to the water substitution method, that is, no biological enzyme was added in step (6). The other steps, conditions, and Example 1 were the same, and oil-tea camellia seed oil was prepared. Other than that, the corresponding product was obtained.

[0174] The properties of the obtained product were determined, and the oil-tea camellia seed oil extracted by water displacement method without high-voltage electrostatic field activation treatment had the following properties: peroxide value ≤0.46 mmol / kg, oxidation induction time 6.64 h, polyphenol content 14.37 μg / g, α-tocopherol content 276.53 μg / mL, and VE content 302.44 μg / mL. Compared with Example 1, the oxidation induction time was reduced by 32.73%, the polyphenol content was reduced by 39.57%, and the VE content was reduced by 15.89%.

[0175] According to the data of peroxide value, oxidation induction time, polyphenol, α-tocopherol and VE in Examples 1-15 and Comparative Examples 1-5, it can be seen that the solubilization heat treatment, high-voltage electrostatic field activation and biological enzyme treatment process used in the present application can reduce the use amount of biological enzyme and enzyme hydrolysis time, further reduce the production cost, improve the oxidation induction time of the oil-tea camellia seed oil, prolong the shelf life of food, and be beneficial to the dissolution and retention of vitamin E, polyphenol and other bioactive components, further improve the nutritional value of the oil-tea camellia seed oil.

[0176] Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be defined by the claims.

Claims

1. A method for preparing oil-tea camellia seed oil with high oxidative stability, characterized in that, The method comprises the following steps: (1) crushing and sieving: crushing and sieving the oil tea seed to obtain oil tea seed powder; (2) solubilization and heat treatment: mixing and incubating the oil tea seed powder in step (1) with water to obtain an oil tea seed suspension; the water is water with a temperature of 60-90 DEG C; the mass ratio of the oil tea seed powder to the water is 1:4-10; the incubation is oscillatory incubation in a constant-temperature reactor for 10-20 min; (3) high-voltage electrostatic field activation treatment: subjecting the oil tea seed suspension in step (2) to high-voltage electrostatic treatment, the high-voltage electrostatic field treatment voltage being 60 KV, and the treatment time being 50 min, to obtain a high-voltage electrostatic treatment oil tea seed suspension; (4) acid-alkali stimulation: adjusting the pH of the high-voltage electrostatic treatment oil tea seed suspension in step (3), and standing to obtain a standing oil tea seed suspension; (5) biological enzyme treatment: activating a biological enzyme, and then adding the biological enzyme to the standing oil tea seed suspension in step (4) for enzymolysis treatment to obtain a feed liquid; the biological enzyme is bromelain and papain; (6) enzyme inactivation and centrifugation: inactivating the feed liquid in step (5), then cooling, and centrifugally collecting the upper clear oil to obtain oil tea seed oil with high oxidation stability.

2. The method of claim 1, wherein, In step (4), the pH is 7-10; and the standing time in step (4) is 5-20 min.

3. The method of claim 1, wherein, In step (5), the activation treatment of the biological enzyme is treatment at 50-60 DEG C for 1-2 min.

4. The method of claim 1, wherein, In step (5), the addition amount of the biological enzyme is 1-5% of the mass of the oil tea seed protein; and the enzymolysis treatment temperature in step (5) is 40-60 DEG C, and the time is 0.5-3 h.

5. Oil tea seed oil with high oxidation stability prepared by the method in any one of claims 1-4.

6. Application of the oil tea seed oil with high oxidation stability in claim 5 in the field of food.

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