Method for extracting tea oil by aqueous enzymatic method

Abstract

The invention provides a method for extracting tea oil by an aqueous enzymatic method, which comprises the following steps: taking fresh tea-oil tree fruits or dry tea-oil tree seeds as raw materials, adding water for treatment to obtain tea-oil tree seed slurry or tea-oil tree seed mixed liquid, heating for gelatinization, adjusting the pH value, adding biological enzyme for enzymolysis, performing centrifugal separation to obtain crude tea-oil tree seed oil, and dehydrating, winterizing and filtering to obtain the finished product tea-oil tree seed oil. According to the method, pullulanase capable of hydrolyzing amylopectin and naringinase capable of hydrolyzing glycoside substances are added, so that the constraint of the amylopectin and the glycoside substances on grease is reduced, the oil extraction rate of the grease is improved, after high-temperature gelatinization, acid is adopted for adjusting the pH value, the pH value of an enzymolysis system is made to range from 4.0 to 5.0, and proper enzymolysis conditions are formed. Compared with a method of firstly adjusting the pH and then gelatinizing, the method has the advantages that the acid value of the grease is not subjected to high-temperature gelatinizing and is rapidly increased, the grease quality is guaranteed, the process is mild in condition and simple to operate, nutritional active ingredients of the grease are greatly reserved, meanwhile, the acid value of the grease is effectively inhibited from increasing, and the grease quality is guaranteed to be stable.

Description

Technical Field

[0001] The invention relates to a method for extracting tea oil using a water-enzyme method, in particular to an extraction method integrating oil extraction using a water-enzyme method, oil dehydration and winterization and dewaxing. Technical Background

[0002] Tea oil and olive oil are known as the two major woody edible oils in the world, and have been known as "treasures among oils" since ancient times. The quality of tea oil is better than that of olive oil. Compared with olive oil, high-grade refined tea oil has higher nutritional and health quality. Tea oil can effectively improve cardiovascular and cerebrovascular diseases, reduce cholesterol and fasting blood sugar, inhibit the increase of triglycerides, and help patients with "three highs" improve their health.

[0003] Oil exists inside oilseed cells and usually combines with other macromolecules to form complexes such as lipopolysaccharides and lipoproteins. Only by destroying the cell structure and oil complex of oilseed tissues can the oil be taken out. On the basis of mechanical crushing, the oilseed is treated with enzymes that have a degrading effect on oilseed tissues and complexes such as lipopolysaccharides and lipoproteins to further destroy the cell structure, decompose lipoproteins and lipopolysaccharides, and increase the fluidity of oil in oilseed tissues, thereby increasing the oil yield. The water enzyme oil extraction process is based on the mechanical destruction of the cell structure of oil crops, so that the enzyme is hydrolyzed in the water phase, and the oil is separated from the solid particles. The oil and non-oil components are separated by using the difference in affinity of non-oil components to oil and water, and the different specific gravity of oil and water. In addition, oil tea seeds contain macromolecules such as protein and starch, which can wrap oil and are not conducive to oil separation. Among them, oil tea seed starch includes 20% to 30% straight chain starch and 70% to 80% branched chain starch. The use of enzyme treatment to decompose macromolecules into small molecules is conducive to the release of oil and separation of oil.

[0004] The aqueous enzymatic extraction of oil has attracted increasing attention from the scientific research and industrial circles due to its low energy consumption, low pollution and high oil quality. Patents CN101569329B, CN104928018B and CN101967423B use cellulase, α-amylase, protease and pectinase to extract tea oil by aqueous enzymatic method. However, cellulase, α-amylase, protease and pectinase cannot hydrolyze glycosides that can emulsify water and oil, and α-amylase cannot hydrolyze branched starch, so that the oil cannot be completely separated, resulting in a low oil aqueous enzymatic extraction rate.

[0005] Oils extracted by the aqueous enzymatic method contain a high level of water and impurities such as water-soluble sugars and proteins. If they are not removed in time, the quality of the oils will deteriorate. Summary of the invention

[0006] The present invention aims to solve the defects of the above-mentioned prior art and provides a method for extracting tea oil by water-enzyme method. The method uses water-enzyme method to extract oil from fresh tea fruit or dry tea seeds. On the basis of determining the process scheme of enzymatic extraction, a higher oil extraction rate is obtained by optimizing the process, and the oil extracted by water-enzyme method is dehydrated and winterized to obtain a finished edible tea oil with stable quality.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0008] Fresh camellia fruit or dried camellia seeds are used as raw materials, water is added to obtain camellia seed slurry or camellia kernel mixture, the mixture is heated for gelatinization, the pH value is adjusted, biological enzymes are added for enzymolysis, and the crude camellia seed oil is obtained by centrifugation. The finished camellia seed oil is then dehydrated, winterized and filtered.

[0009] The fresh tea fruit processing process is as follows: fresh tea seeds are obtained after the outer tea fruit shell is removed from the fresh tea fruit, the fresh tea seeds are crushed, soft water is added, and then finely ground by a stone mill to obtain tea seed slurry, and the tea seed slurry is pressed to obtain tea seed slurry.

[0010] Furthermore, the weight of the added soft water is 0 to 2 times the weight of the crushed fresh camellia seeds.

[0011] Furthermore, the pressing pressure is 0.6MPa to 0.8MPa.

[0012] The dry camellia seed processing process is as follows: after removing the seed shell from the dry camellia seeds, the camellia seed kernels are obtained; after ultrafine grinding, soft water is added to obtain the camellia seed kernel mixed liquid.

[0013] Furthermore, the acid value of the oil in the dry camellia seeds is less than or equal to 2.0 mgKOH / g.

[0014] Furthermore, the weight of the added soft water is 4 to 6 times the weight of the ultrafinely ground camellia seed kernels.

[0015] Furthermore, the particle size of the ultrafinely ground camellia oil seed kernels is 0.1 to 100 microns.

[0016] The heating gelatinization temperature is 80° C. to 90° C., and the gelatinization time is 30 minutes.

[0017] The pH adjustment range is 4.0-5.0, and the pH adjuster is food grade phosphoric acid or food grade citric acid.

[0018] The biological enzymes include pullulanase, naringinase, cellulase, alpha-amylase and acid protease.

[0019] The added amount of the biological enzymes is 0.1% to 1% pullulanase, 0.1% to 1% naringinase, 0.5% to 2% cellulase, 0.5% to 2% alpha-amylase and 0.1% to 0.5% acid protease in weight percentage of camellia seed slurry or camellia seed kernel mixed liquid.

[0020] The biological enzyme activity is pullulanase 2000U / g-8000U / g, naringinase 50000U / g-100000U / g, cellulase 10000U / g-50000U / g, α-amylase 50000U / g-200000U / g, and acid protease 400000U / g-500000U / g.

[0021] The enzymatic hydrolysis process is to add pullulanase, naringinase, cellulase and α-amylase to the tea seed slurry or the mixed solution of the tea seed kernel for enzymatic hydrolysis for 2 to 4 hours, and then add acid protease for enzymatic hydrolysis for 1 to 2 hours. The enzymatic hydrolysis temperature is 45°C to 55°C.

[0022] The dehydration conditions are as follows: dehydration temperature of 85°C, vacuum degree of 0.1MPa, and dehydration time of 30 to 40 minutes.

[0023] The winterization conditions are as follows: after the dehydrated oil is cooled to 45°C, it is cooled to 3°C at a cooling rate of 5°C / h to 8°C / h, and the stirring rate is set to 20rpm to 30rpm; the crystal growth temperature is maintained at 3°C ​​for 10h to 12h, and the stirring rate is set to 11rpm to 20rpm.

[0024] The beneficial effects of the present invention are:

[0025] (1) Compared with other related aqueous enzymatic processes, this method reduces the binding of amylopectin and glycosides to oil by adding pullulanase that can hydrolyze amylopectin and naringinase that can hydrolyze glycosides, thereby improving the oil extraction rate of oil.

[0026] (2) This method uses acid to adjust the pH after high-temperature gelatinization, so that the enzymatic hydrolysis system is between pH 4.0 and 5.0, forming suitable enzymatic hydrolysis conditions. Compared with adjusting the pH before gelatinization, the acid value of the oil is not rapidly increased by high-temperature gelatinization, and the quality of the oil is guaranteed.

[0027] (3) It integrates technologies such as aqueous enzymatic oil extraction, oil dehydration and winterization dewaxing. The process conditions are mild and the operation is simple. The nutritional active ingredients of the oil are greatly retained while ensuring the stability of the oil quality.

[0028] (4) The aglycones obtained by decomposing glycosides can increase the content of nutritional active ingredients in oils and fats, which is conducive to the development of multifunctional oil and fat products.

[0029] (5) Naringinase, which hydrolyzes glycosides, can effectively inhibit the increase in oil acid value and improve oil quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 : The present invention is a schematic diagram of a tea oil extraction process using fresh tea fruit as the starting material.

[0031] Figure 2 : Schematic diagram of tea oil extraction process using tea seed as the starting material of the present invention. DETAILED DESCRIPTION

[0032] Example 1

[0033] Weigh 1000 kg of camellia seeds (olein acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafinely grind, the particle size of the camellia kernel powder is 50-100 μm, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, heat to 80°C for gelatinization for 30 minutes, cool to 40°C, adjust the pH to 5.0 with food-grade phosphoric acid, and then add 0.1% pullulanase, 0.1% naringinase, 0.5% cellulase, and 0.5% α-starch by weight of the camellia kernel mixed solution. Enzyme, the first enzymolysis reaction is 4 hours, after the first enzymolysis reaction, 0.1% acid protease by weight of the camellia kernel mixed solution is added for enzymolysis for 2 hours, after the enzymolysis is completed, centrifugal separation is performed to obtain the raw camellia oil, which is dehydrated at a temperature of 85°C, a vacuum degree of 0.1MPa, and a dehydration time of 40 minutes, cooled to 45°C, at a cooling rate of 8°C / h, cooled to 3°C, with a cooling stirring rate of 20rpm, maintained at a crystal growing temperature of 3°C for 12h, with a crystal growing stirring rate of 20rpm, and filtered to obtain the finished camellia seed oil.

[0034] Example 2

[0035] 5000 kg of camellia oleifera fruit (olein acid value 0.35 mgKOH / g) was weighed, the husks were removed to obtain fresh camellia oleifera seeds, which were crushed, soft water twice the weight of the crushed fresh camellia oleifera seeds was added, and the seeds were finely ground in a stone mill to obtain camellia oleifera seed slurry, which was squeezed at 0.6 MPa to obtain camellia oleifera seed slurry, stirred, heated to 90°C for gelatinization for 30 minutes, cooled to 50°C, adjusted to pH 5.0 with food-grade phosphoric acid, and then 0.1% pullulanase, 0.1% naringinase, 0.5% cellulase, 0. 5% α-amylase, the first enzymatic hydrolysis reaction is 4 hours, after the first enzymatic hydrolysis reaction, 0.1% acid protease by weight of the camellia kernel mixed liquid is added for enzymatic hydrolysis for 2 hours, after the enzymatic hydrolysis is completed, centrifuge to obtain the raw camellia oil, dehydrate at a temperature of 85°C, a vacuum degree of 0.1MPa, and a dehydration time of 40 minutes, cool to 45°C, at a cooling rate of 8°C / h, cool to 3°C, with a cooling stirring rate of 20rpm, maintain the crystallization temperature at 3°C ​​for 12h, with a crystallization stirring rate of 20rpm, filter to obtain the finished camellia seed oil.

[0036] Example 3

[0037] Weigh 1000 kg of camellia seeds (oleic acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafinely grind the camellia kernel powder to a particle size of 0.1 to 50 μm, add soft water 5 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, heat to 90° C. for gelatinization for 30 minutes, cool to 50° C., adjust the pH to 4.0 with food-grade citric acid, add 1% pullulanase, 1% naringinase, 2% cellulase, and 2% α-amylase by weight of the camellia kernel mixed solution, and then add the mixture to obtain a mixture of the camellia kernels. The enzymatic hydrolysis reaction is carried out for 2 hours. After the first enzymatic hydrolysis reaction, 0.5% acid protease by weight of the camellia kernel mixture is added for enzymatic hydrolysis for 1 hour. After the enzymatic hydrolysis is completed, the raw camellia oil is obtained by centrifugation, and dehydrated at a temperature of 85°C, a vacuum degree of 0.1 MPa, and a dehydration time of 30 minutes. The temperature is reduced to 45°C, and the temperature is reduced to 3°C at a cooling rate of 5°C / h. The cooling stirring rate is 30rpm, and the crystal growing temperature is maintained at 3°C ​​for 10 hours. The crystal growing stirring rate is 11rpm, and the finished camellia seed oil is obtained by filtration.

[0038] Example 4

[0039] Weigh 5000 kg of camellia oleifera fruit (olein acid value 0.35 mgKOH / g), remove the husk to obtain fresh camellia oleifera seeds, crush, directly grind in a stone mill to obtain camellia oleifera seed slurry, squeeze at 0.8 MPa to obtain camellia oleifera seed slurry, stir, heat to 90°C for gelatinization for 30 minutes, cool to 50°C, adjust pH to 4.0 with food-grade citric acid, add 1% pullulanase, 1% naringinase, 2% cellulase, 2% α-amylase by weight of the camellia oleifera seed mixture, and then add 1% tantalum phosphate, ... The enzymatic hydrolysis reaction is carried out for 2 hours. After the first enzymatic hydrolysis reaction, 0.5% acid protease by weight of the camellia kernel mixture is added for enzymatic hydrolysis for 1 hour. After the enzymatic hydrolysis is completed, the crude camellia oil is obtained by centrifugation, and dehydrated at a temperature of 85°C, a vacuum degree of 0.1 MPa, and a dehydration time of 30 minutes. The temperature is reduced to 45°C, and the temperature is reduced to 3°C at a cooling rate of 5°C / h. The cooling stirring rate is 30rpm, and the crystal growing temperature is maintained at 3°C ​​for 10 hours. The crystal growing stirring rate is 11rpm, and the finished camellia seed oil is obtained by filtration.

[0040] Example 5

[0041] Weigh 1000 kg of camellia seeds (oleic acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafinely grind, the particle size of the camellia kernel powder is 0.1-50 microns, add soft water 5 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, heat to 90°C for gelatinization for 40 minutes, cool to 55°C, adjust the pH to 4.5 with food-grade citric acid, add 0.5% pullulanase, 0.5% naringinase, 1% cellulase, and 1% α-amylase by weight of the camellia kernel mixed solution, The first enzymatic hydrolysis reaction is 3 hours. After the first enzymatic hydrolysis reaction, 0.3% acid protease by weight of the camellia kernel mixed liquid is added for enzymatic hydrolysis for 1.5 hours. After the enzymatic hydrolysis is completed, the raw camellia oil is obtained by centrifugation, and dehydrated at a temperature of 85°C, a vacuum degree of 0.1 MPa, and a dehydration time of 35 minutes. The temperature is reduced to 45°C, at a cooling rate of 7°C / h, and then reduced to 3°C, with a cooling stirring rate of 25rpm. The crystallization temperature is maintained at 3°C ​​for 11 hours, with a crystallization stirring rate of 16rpm, and the finished camellia seed oil is obtained by filtration.

[0042] Comparative Example 1

[0043] Weigh 1000 kg of camellia seeds (olein acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafine grind, the particle size of the camellia kernel powder is 50-100 microns, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, adjust the pH to 5.0 with food-grade phosphoric acid, heat to 80°C for gelatinization for 30 minutes, and then centrifuge to obtain the finished camellia seed oil.

[0044] Comparative Example 2

[0045] 1000 kg of camellia seeds (oil acid value 0.8 mgKOH / g) are weighed, seed shells are removed to obtain camellia kernels, which are ultrafinely ground to obtain a particle size of 50-100 μm of camellia kernel powder, and soft water 4 times the weight of the camellia kernel powder is added to obtain a camellia kernel mixed solution, which is stirred, heated to 80° C. for gelatinization for 30 minutes, cooled to 40° C., 0.1% pullulanase, 0.1% naringinase, 0.5% cellulase and 0.5% alpha-amylase are added to the camellia kernel mixed solution according to the weight of the camellia kernel mixed solution after adjusting the pH to 5.0 with food-grade phosphoric acid, and the first enzymolysis reaction is performed for 4 hours, and then 0.1% acid protease by weight of the camellia kernel mixed solution is added after the first enzymolysis reaction for enzymolysis for 2 hours, and the finished camellia seed oil is obtained by centrifugation after the enzymolysis is completed.

[0046] Comparative Example 3

[0047] Weigh 1000 kg of camellia seeds (olein acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafine grind, the particle size of the camellia kernel powder is 50-100 microns, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, adjust the pH to 5.0 with food-grade phosphoric acid, heat to 80°C for gelatinization for 30 minutes, then centrifuge to obtain raw camellia oil, dehydrate at a temperature of 85°C, a vacuum degree of 0.1 MPa, and a dehydration time of 40 minutes, cool to 45°C, at a cooling rate of 8°C / h, cool to 3°C, with a cooling stirring rate of 20rpm, maintain the crystallization temperature at 3°C ​​for 12h, with a crystallization stirring rate of 20rpm, filter to obtain finished camellia seed oil.

[0048] Comparative Example 4

[0049] Weigh 1000 kg of camellia seeds (olein acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafine grind, the particle size of the camellia kernel powder is 50-100 μm, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, adjust the pH to 5.0 with food-grade phosphoric acid, stir, heat to 80°C for gelatinization for 30 minutes, cool to 40°C, add 0.1% pullulanase, 0.1% naringinase, 0.5% cellulase, and 0.5% α-starch by weight of the camellia kernel mixed solution Enzyme, the first enzymolysis reaction is 4 hours, after the first enzymolysis reaction, 0.1% acid protease by weight of the camellia kernel mixed solution is added for enzymolysis for 2 hours, after the enzymolysis is completed, centrifugal separation is performed to obtain the raw camellia oil, which is dehydrated at a temperature of 85°C, a vacuum degree of 0.1MPa, and a dehydration time of 40 minutes, cooled to 45°C, at a cooling rate of 8°C / h, cooled to 3°C, with a cooling stirring rate of 20rpm, maintained at a crystal growing temperature of 3°C for 12h, with a crystal growing stirring rate of 20rpm, and filtered to obtain the finished camellia seed oil.

[0050] Comparative Example 5

[0051] Weigh 1000 kg of camellia seeds (oil acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafine grind, the particle size of the camellia kernel powder is 50-100 microns, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, heat to 80°C for gelatinization for 30 minutes, cool to 40°C, adjust pH to 5.0 with food-grade phosphoric acid, add 0.5% cellulase and 0.5% α-amylase by weight of the camellia kernel mixed solution, and perform the first enzymatic hydrolysis reaction. The mixture was heated to 40 ℃ and then heated to 30 ℃ for 4 hours. After the first enzymatic hydrolysis reaction, 0.1% acid protease by weight of the camellia kernel mixture was added for enzymatic hydrolysis for 2 hours. After the enzymatic hydrolysis was completed, the crude camellia oil was obtained by centrifugation. The crude camellia oil was dehydrated at 85 ℃, 0.1 MPa in vacuum and 40 minutes in dehydration time. The temperature was lowered to 45 ℃ at a cooling rate of 8 ℃ / h, lowered to 3 ℃ at a cooling stirring rate of 20 rpm, and the crystallization temperature was maintained at 3 ℃ for 12 hours at a crystallization stirring rate of 20 rpm. The finished camellia oil was obtained by filtration.

[0052] Comparative Example 6

[0053] Weigh 1000 kg of camellia seeds (oleic acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafinely grind the camellia kernel powder to a particle size of 50 to 100 μm, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, heat to 80° C. for gelatinization for 30 minutes, cool to 40° C., adjust the pH to 5.0 with food-grade phosphoric acid, add 0.1% pullulanase, 0.5% cellulase, and 0.5% α-amylase by weight of the camellia kernel mixed solution, and then add the mixture to obtain a mixture of the camellia kernels. The enzymatic hydrolysis reaction is carried out for 4 hours. After the first enzymatic hydrolysis reaction, 0.1% acid protease by weight of the camellia kernel mixture is added for enzymatic hydrolysis for 2 hours. After the enzymatic hydrolysis is completed, the raw camellia oil is obtained by centrifugation, and dehydrated at a temperature of 85°C, a vacuum degree of 0.1 MPa, and a dehydration time of 40 minutes. The temperature is reduced to 45°C, at a cooling rate of 8°C / h, and then reduced to 3°C, with a cooling stirring rate of 20rpm. The crystal growing temperature is maintained at 3°C ​​for 12 hours, with a crystal growing stirring rate of 20rpm, and the finished camellia seed oil is obtained by filtration.

[0054] Comparative Example 7

[0055] Weigh 1000 kg of camellia seeds (oleic acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafinely grind the camellia kernel powder to a particle size of 50 to 100 μm, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, heat to 80° C. for gelatinization for 30 minutes, cool to 40° C., adjust the pH to 5.0 with food-grade phosphoric acid, then add 0.1% naringinase, 0.5% cellulase, and 0.5% α-amylase by weight of the camellia kernel mixed solution, and then add the mixture to obtain a mixture of the camellia kernels. The enzymatic hydrolysis reaction is carried out for 4 hours. After the first enzymatic hydrolysis reaction, 0.1% acid protease by weight of the camellia kernel mixture is added for enzymatic hydrolysis for 2 hours. After the enzymatic hydrolysis is completed, the raw camellia oil is obtained by centrifugation, and dehydrated at a temperature of 85°C, a vacuum degree of 0.1 MPa, and a dehydration time of 40 minutes. The temperature is reduced to 45°C, at a cooling rate of 8°C / h, and then reduced to 3°C, with a cooling stirring rate of 20rpm. The crystal growing temperature is maintained at 3°C ​​for 12 hours, with a crystal growing stirring rate of 20rpm, and the finished camellia seed oil is obtained by filtration.

[0056] Comparative Example 8

[0057] Weigh 1000 kg of camellia seeds (olein acid value 0.8 mgKOH / g), remove the seed shell to obtain camellia kernels, ultrafinely grind, the particle size of the camellia kernel powder is 50-100 microns, add soft water 4 times the weight of the camellia kernel powder to obtain a camellia kernel mixed solution, stir, heat to 80°C for gelatinization for 30 minutes, cool to 40°C, adjust the pH to 5.0 with food-grade phosphoric acid, add 0.1% naringinase, 0.5% cellulase, 0.5% α-amylase, and 0.1% acid protease by weight of the camellia kernel mixed solution for enzymolysis for 4 hours, centrifuge to obtain raw camellia oil after the enzymolysis is completed, dehydrate at a temperature of 85°C, a vacuum degree of 0.1 MPa, and a dehydration time of 40 minutes, cool to 45°C, cool to 3°C at a cooling rate of 8°C / h, cool to 20rpm, maintain a crystal growing temperature of 3°C for 12h, and a crystal growing stirring rate of 20rpm, and filter to obtain finished camellia seed oil.

[0058] Comparative Example 9

[0059] Weigh 5000 kg of camellia fruit (oil acid value 0.35 mgKOH / g), remove the husk to obtain fresh camellia seeds, crush them, add soft water twice the weight of the crushed fresh camellia seeds, and then grind them on a stone mill to obtain camellia seed slurry, press them at 0.6 MPa to obtain camellia seed slurry, stir, heat to 90°C to gelatinize for 30 minutes, and then centrifuge to obtain finished camellia seed oil.

[0060] The analysis indicators of the finished camellia oil prepared in Examples 1-5 and Comparative Examples 1-8 were compared, and the experimental results are shown in Table 1.

[0061] Table 1 Comparison results of analysis indexes of finished tea seed oil

[0062]

[0063] As shown in Table 1, Examples 1-5 can effectively extract camellia oil from camellia fruit and camellia seeds, and the oil acid value meets the quality requirements of first-grade camellia oil in GB / T11765-2018 Camellia Oil, and the oil extraction rate is high. It is clear and transparent when stored at 20°C for 8 months, and the quality is stable, indicating that the camellia oil obtained by this extraction method is of good quality and stable quality. In addition, increasing the amount of enzyme added can effectively inhibit the increase in oil acid value.

[0064] It can be seen from Example 1 and Comparative Examples 1, 2 and 3 that after adding biological enzymes, enzymatic hydrolysis of macromolecular substances and emulsifying glycoside substances is beneficial to the release of oil, thereby improving the oil extraction rate. In addition, adding dehydration and winterization steps is beneficial to the stability of oil storage.

[0065] It can be seen from Example 1 and Comparative Example 4 that adjusting the pH before gelatinization can slightly increase the oil extraction rate, but it leads to an increase in the acid value of the oil.

[0066] From Example 1 and Comparative Examples 5, 6 and 7, it can be seen that the addition of pullulanase or naringinase can improve the oil extraction rate, and the addition of naringinase can effectively inhibit the increase in oil acid value, which may be related to the fact that the naringinase catalysis process requires H + Participate in related matters and snatch the H in the system + , thereby reducing H + Effect on oil hydrolysis.

[0067] It can be seen from Example 1 and Comparative Example 8 that pullulanase, naringinase, cellulase, α-amylase and acid protease are added together. Since pullulanase, naringinase, cellulase and α-amylase are all proteins, they are hydrolyzed by acid protease at the same time during the enzymatic hydrolysis of the substrate, resulting in a decrease in the oil extraction rate and an increase in the acid value of the oil.

[0068] It can be seen from Example 2 and Comparative Example 9 that without the participation of biological enzymes, the camellia seed slurry is in a highly emulsified state, and it is difficult to separate the oil by heating and gelatinization. Obviously, the biological enzymes participate in the substances that cause the camellia seed slurry system to be highly emulsified, thereby releasing the oil.

[0069] It can be seen from the above embodiments, comparative examples and experimental examples that the present invention combines aqueous enzymatic oil extraction, dehydration and winterization processes and operates at low temperature, which not only avoids the loss of active ingredients in camellia oil, but also can inhibit the increase in oil acid value and improve the storage stability of camellia oil.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for extracting tea oil by aqueous enzymatic method, characterized in that: The steps include: Fresh camellia fruit or dried camellia seeds are used as raw materials, water is added to obtain camellia seed slurry or camellia kernel mixture, heated for gelatinization, pH is adjusted, biological enzymes are added for enzymolysis, centrifuged to obtain crude camellia seed oil, and then dehydrated, winterized and filtered to obtain finished camellia seed oil. The fresh tea fruit processing process is as follows: fresh tea seeds are obtained after the outer layer of the tea fruit shell is removed from the fresh tea fruit; the fresh tea seeds are crushed, soft water is added, and then finely ground by a stone mill to obtain tea seed slurry; the tea seed slurry is squeezed to obtain tea seed slurry; The processing technology of dry oil-tea camellia seeds is as follows: after removing the seed shells from the dry oil-tea camellia seeds, the oil-tea camellia seed kernels are obtained; after ultrafine grinding, soft water is added to obtain the oil-tea camellia seed kernel mixed liquid.

2. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: In the fresh tea fruit processing process, the weight of soft water added is 0 to 2 times the weight of crushed fresh tea seeds, and the pressing pressure is 0.6 MPa to 0.8 MPa.

3. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: The acid value of the oil in the dry camellia seeds is less than or equal to 2.0 mgKOH / g.

4. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: In the dry camellia seed processing process, the weight of the added soft water is 4 to 6 times the weight of the ultrafinely ground camellia seed kernels, and the particle size of the ultrafinely ground camellia seed kernels is 0.1 to 100 microns.

5. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: The heating gelatinization temperature is 80° C. to 90° C., and the gelatinization time is 30 minutes.

6. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: The pH adjustment range is 4.0-5.0, and the pH adjuster is food grade phosphoric acid or food grade citric acid.

7. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: The biological enzyme includes one or more of pullulanase, naringinase, cellulase, alpha-amylase and acid protease.

8. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: The enzymatic hydrolysis process comprises the following steps: adding pullulanase, naringinase, cellulase and alpha-amylase to the oil-tea camellia seed slurry or the oil-tea camellia kernel mixed liquid for enzymatic hydrolysis for 2 to 4 hours, and then adding acidic protease for enzymatic hydrolysis for 1 to 2 hours. The enzymatic hydrolysis temperature is 45° C. to 55° C. The added amount of the biological enzymes is 0.1% to 1% of pullulanase, 0.1% to 1% of naringinase, 0.5% to 2% of cellulase, 0.5% to 2% of alpha-amylase and 0.1% to 0.5% of acidic protease in the weight percentage of the oil-tea camellia seed slurry or the oil-tea camellia kernel mixed liquid.

9. The aqueous enzymatic tea oil extraction method according to claim 8, characterized in that: The biological enzyme activity is pullulanase 2000U / g-8000U / g, naringinase 50000U / g-100000U / g, cellulase 10000U / g-50000U / g, α-amylase 50000U / g-200000U / g, and acid protease 400000U / g-500000U / g.

10. The aqueous enzymatic tea oil extraction method according to claim 1, characterized in that: The dehydration conditions are as follows: a dehydration temperature of 85°C, a vacuum degree of 0.1MPa, and a dehydration time of 30 minutes to 40 minutes. The winterization conditions are as follows: after the dehydrated oil is cooled to 45°C, the temperature is reduced to 3°C at a cooling rate of 5°C / h to 8°C / h, and the stirring rate is set to 20rpm to 30rpm; the crystal growth temperature is maintained at 3°C ​​for 10h to 12h, and the stirring rate is set to 11rpm to 20rpm.

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