Functional grease composition and preparation method thereof

Abstract

The invention relates to a grease composition and a preparation method thereof, and the preparation method comprises the following steps: mixing squeezed tea oil, lipase and partial glyceride lipase, adding isopropanol, stirring for reaction, and simply separating the reacted grease mixture to obtain the grease composition. Timing from the beginning of adding the isopropanol, and adding the isopropanol in a manner that a first part of isopropanol (4%-6% of the mass of the squeezed tea oil) is fed at a constant speed within 0-1 hour, a second part of isopropanol (13%-17% of the mass of the squeezed tea oil) is fed at a constant speed within 2-4 hours, and a third part of isopropanol (18%-22% of the mass of the squeezed tea oil) is fed at a constant speed within 4-6 hours; the reaction temperature is kept at 30-45 DEG C in 0-4 hours, the temperature is reduced to 15-28 DEG C in 4-5 hours, the temperature is kept for 6 hours, and the temperature is reduced to 12 DEG C or below after 6 hours, and the temperature is kept until the reaction is ended. The obtained grease composition is high in isopropyl ester content and good in oxidation stability.

Description

Technical Field

[0001] This invention belongs to the field of biotechnology, and relates to oils and fats, specifically to a functional oil and fat composition and its preparation method. Background Technology

[0002] Isopropyl fatty acid esters are a class of hydrophobic organic compounds formed by the catalytic esterification reaction of fatty acids and isopropanol. Their general formula is R-COO-CH(CH3)2, where the R group depends on the fatty acid composition of the raw oil. These compounds possess physical properties such as low pour point, relatively high boiling point, and excellent interfacial compatibility. Due to their excellent skin permeability and compatibility, isopropyl fatty acid esters have demonstrated significant application value in the cosmetics and pharmaceutical fields. These substances have low surface tension (22.5-25.5 mN / m, typical value) and a unique amphiphilic structure, allowing them to not only form a breathable liquid film in close contact with the skin but also act as lipid-soluble carriers to deliver active ingredients (such as vitamins and hormones) to the deeper layers of the skin, while significantly reducing the greasiness of the product. In makeup products such as lipsticks and foundation creams, they improve product texture by enhancing pigment dispersion, strengthening the stability of the cream structure, and increasing gloss; in skincare formulations, they improve the cream texture and adjust the product's gloss, making the cream whiter and smoother and enhancing its moisturizing function. As a novel nonionic surfactant, isopropyl fatty acid esters can be used in the pharmaceutical field as a matrix to construct molecular gel carriers to improve drug transdermal efficiency (e.g., isopropyl myristate gel loaded with triptolide exhibits better transdermal performance than traditional ointments). In the energy sector, their branched structure disrupts crystal regularity, effectively reducing the pour point of biodiesel. In daily chemical applications, they synergistically enhance system stability with components such as mineral oil and lanolin. Their combination of biodegradability and low allergenicity makes them a key material bridging green chemistry and high-end cosmetic development. With the increasing demand for precision delivery, their applications in the daily chemical and pharmaceutical fields continue to expand.

[0003] Refined camellia oil is not only a high-grade edible oil but also widely used in various high-end daily chemical products and pharmaceuticals. Camellia oil isopropyl ester is a functional oil derivative obtained through the esterification of camellia oil and isopropanol. Studies have found that camellia oil isopropyl ester combines the nourishing properties of natural camellia oil with the excellent performance of synthetic esters. Its core advantages lie in its light and non-greasy skin feel, excellent oxidative stability, strong penetration and carrying capacity for active ingredients, and green biodegradability. Current research focuses on its high-value applications, such as enzymatic green synthesis, its use as a functional carrier in high-end cosmetics, and its application as an environmentally friendly industrial lubricant.

[0004] The chemical reaction for synthesizing fatty acid isopropyl esters or tea oil is essentially an esterification reaction between fatty acids in oils and isopropanol, or an transesterification reaction between glycerides and isopropanol. Traditional preparation processes include concentrated sulfuric acid catalysis and alkaline catalysis. Concentrated sulfuric acid catalysis, as a typical homogeneous acid catalysis process, has advantages such as wide adaptability to raw materials and low cost. However, its strong corrosiveness leads to increased equipment requirements, side reactions result in decreased product purity, and the three wastes generated during neutralization and post-treatment severely restrict its green development. Alkaline catalysis exhibits excellent kinetic characteristics in transesterification reactions; however, its stringent requirements for the acid value of the raw materials, the impact of saponification side reactions on separation efficiency, and the similar equipment corrosion and wastewater treatment problems limit its application with low-quality raw materials.

[0005] Enzymatic preparation of fatty acid isopropyl esters is an important direction in green catalytic synthesis, utilizing lipases to catalyze esterification or transesterification reactions under mild conditions. The high selectivity of enzyme catalysis in this process avoids side reactions, ensuring high purity and light color of the product; the mild operating conditions reduce energy consumption while protecting heat-sensitive components; its environmental friendliness lies in completely eliminating the neutralization and washing steps of traditional processes, thus preventing saline / acidic wastewater at the source. While enzymatic preparation of fatty acid isopropyl esters has advantages such as being green, environmentally friendly, and highly selective, its industrialization still faces some technical bottlenecks. At the catalyst level, lipases inherently have low catalytic efficiency and are easily deactivated by the destruction of the essential aqueous layer when in contact with highly polar solvents or substrates; during the stirred reaction, bioactive components such as squalene and vitamins in natural oils are easily oxidized and degraded by the formation of peroxides, leading to the loss of natural active ingredients; at the reaction kinetics level, feedback inhibition of enzymes by byproducts makes it difficult for transesterification reactions to break the equilibrium state, severely limiting the conversion efficiency of raw materials and product yield. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a method for preparing an oil composition with high isopropyl ester content and good oxidative stability.

[0007] The technical solutions for achieving the above objectives include the following.

[0008] In a first aspect, the present invention provides a method for preparing an oil and fat composition, comprising the following steps:

[0009] (1) Mix tea oil, lipase and glyceryl lipase, then add isopropanol and stir to react to obtain the reacted oil mixture;

[0010] The reaction time begins from the addition of isopropanol, and the isopropanol is added in the following manner: the first portion of isopropanol is added at a constant flow rate over 0-1 hour; the second portion is added at a constant flow rate over 2-4 hours; and the third portion is added at a constant flow rate over 4-6 hours. The mass of the first portion of isopropanol is 4%-6% of the mass of the tea oil, the mass of the second portion is 13%-17% of the mass of the tea oil, and the mass of the third portion is 18%-22% of the mass of the tea oil.

[0011] The reaction time starts from the addition of isopropanol, and the temperature of the stirred reaction is: 30℃-45℃ for 0-4h, 15℃-28℃ for 4h-5h and kept at this temperature for 6h, and then 12℃ for 6h and kept at this temperature until the reaction is terminated.

[0012] (2) The oil mixture after the reaction is washed with alkaline water, isopropanol is recovered and washed with acid water in sequence to obtain the oil composition.

[0013] Secondly, the present invention provides an oil composition prepared by the preparation method described herein.

[0014] The present invention has the following beneficial effects:

[0015] The method for preparing the oil composition provided by the present invention uses lipase and glyceryl ester lipase to catalyze the reaction of the acyl donor in tea oil with isopropanol to prepare tea oil isopropyl ester. After simple separation, the reaction product can be used to obtain tea oil isopropyl ester with significantly higher oxidative stability than that obtained by chemical method.

[0016] The method for preparing the oil composition provided by this invention significantly improves the conversion rate and yield of isopropyl ester by using lipase and glyceryl ester lipase in combination, along with a specific addition method of isopropyl alcohol and a specific temperature control program. This results in an isopropyl ester content of over 90% in the obtained oil composition, high retention rates of active ingredients such as squalene, phytosterols, and vitamin E in the raw materials, and significantly higher oxidative stability than that of tea oil isopropyl ester prepared by chemical methods. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the oxidation stability test. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0019] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0020] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0021] Furthermore, as used herein, the term "or" is an inclusive "or" sign and is equivalent to the term "and / or" unless the context clearly specifies otherwise. The term "based on" is not exclusive and allows for basing on other factors not described unless the context clearly specifies otherwise. Additionally, throughout the specification, the meanings of "an," "a," and "the" include plural indicators. The meaning of "in" includes both "in" and "on."

[0022] Some embodiments of the present invention relate to a method for preparing an oil and fat composition, comprising the following steps:

[0023] (1) Mix tea oil, lipase and glyceryl lipase, then add isopropanol and stir to react to obtain the reacted oil mixture;

[0024] The reaction time begins from the addition of isopropanol, and the isopropanol is added in the following manner: the first portion of isopropanol is added at a constant flow rate over 0-1 hour; the second portion is added at a constant flow rate over 2-4 hours; and the third portion is added at a constant flow rate over 4-6 hours. The mass of the first portion of isopropanol is 4%-6% of the mass of the tea oil, the mass of the second portion is 13%-17% of the mass of the tea oil, and the mass of the third portion is 18%-22% of the mass of the tea oil.

[0025] The reaction time starts from the addition of isopropanol, and the temperature of the stirred reaction is: 30℃-45℃ for 0-4h, 15℃-28℃ for 4h-5h and kept at this temperature for 6h, and then 12℃ for 6h and kept at this temperature until the reaction is terminated.

[0026] (2) The oil mixture after the reaction is washed with alkaline water, isopropanol is recovered and washed with acid water in sequence to obtain the oil composition.

[0027] In some embodiments, the lipase is one or more combinations of Eversa Transform 2.0, Lipozyme TL100L, and Lipozyme CALB, preferably Eversa Transform 2.0.

[0028] In some embodiments, the metaglycerol lipase is Lipase G50.

[0029] In some embodiments, the amount of lipase added is 0.4%-2.0% of the mass of the tea oil, preferably 0.5%-1.0%.

[0030] In some embodiments, the amount of the glyceryl lipase added is 0.08%-0.4% of the mass of the tea oil, preferably 0.1%-0.2%.

[0031] In some embodiments, the mass of the first portion of isopropanol is 4.5%-5.5% of the mass of the tea oil, the mass of the second portion of isopropanol is 14.5%-15.5% of the mass of the tea oil, and the mass of the third portion of isopropanol is 19.5%-20.5% of the mass of the tea oil.

[0032] In some embodiments, the first portion of isopropanol has a mass of 5% of the mass of the tea oil, the second portion of isopropanol has a mass of 15% of the mass of the tea oil, and the third portion of isopropanol has a mass of 20% of the mass of the tea oil.

[0033] In some embodiments, when the reaction time begins from the addition of isopropanol, the temperature of the stirred reaction is: 35°C-40°C for 0-4h, cooled to 20°C-25°C for 4h-5h and kept at that temperature for 6h, and then cooled to below 10°C (preferably 0°C-10°C, more preferably 5°C-10°C) and kept at that temperature until the reaction is terminated.

[0034] In some embodiments, the reaction timing begins from the addition of isopropanol, and the reaction ends 8-30 hours after the start of the reaction timing, preferably 10-24 hours, and more preferably 12-14 hours.

[0035] In some embodiments, the alkaline washing includes washing with a saturated aqueous solution of Na2CO3.

[0036] In some embodiments, the alkaline washing includes: adding a saturated aqueous solution of Na2CO3 to the reacted oil mixture and stirring at 35°C-45°C for 10-35 minutes.

[0037] In some embodiments, the ratio of the saturated aqueous solution of Na2CO3 to the tea oil is 0.05ml-0.1ml:1g.

[0038] In some embodiments, the acid washing includes washing with an aqueous solution of citric acid.

[0039] In some embodiments, the acid washing includes adding an aqueous citric acid solution to the oil mixture in which isopropanol has been recovered, and stirring at 35°C-45°C for 10-35 minutes.

[0040] In some embodiments, the ratio of the citric acid aqueous solution to the tea oil is 0.05ml-0.1ml:1g.

[0041] In some embodiments, the citric acid aqueous solution has a mass concentration of 1%-2%.

[0042] Some embodiments of the present invention also relate to oil compositions prepared by the preparation method described in the present invention. These oil compositions have high isopropyl ester content, high retention rate of active ingredients, low free fatty acid content, and good oxidative stability.

[0043] In some embodiments, the oil composition contains more than 90% tea oil isopropyl ester by mass, preferably more than 92%.

[0044] The present invention will be further described in detail below with reference to specific embodiments.

[0045] The raw materials used in the following examples are described below:

[0046] Pressed tea oil: meets the requirements of GB11765 (2018).

[0047] Lipase Eversa Transform 2.0, lipase Lipozyme TL 100L, and lipase Lipozyme CALB were all purchased from Novozymes (China) Biotechnology Co., Ltd.; lipase G50 was purchased from Amano Enzyme Products Co., Ltd., Japan.

[0048] The oxidative stability testing in the following examples follows the method described in the reference "Study on Enzymatic Preparation of Medium- and Long-Chain Fatty Acid Triglycerides Rich in α-Linolenic Acid [D]. South China University of Technology". Figure 1 As shown, the oil and fat composition (3.0 g) was weighed and placed in a glass reaction vessel. The oxidation stabilization apparatus (Rancimat 892, Metrohm, Switzerland) was used under the following conditions: 100°C, constant airflow of 10 L / h. The oxidation induction periods (IP) of the oil sample were recorded.

[0049] Example 1

[0050] (1) Mix 200g of pressed tea oil with 2g of Eversa Transform 2.0 lipase and 0.4g of Lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0051] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0052] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase and keep it at 40℃ and stir and wash it with water for 30 min; after washing, the oil phase is centrifuged at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0053] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 92.4%, and the oxidation induction time was 4.51 h when the oxidation stability test was conducted.

[0054] Example 2

[0055] (1) Mix 200g of pressed tea oil with 2g of Eversa Transform 2.0 lipase and 0.2g of Lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0056] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 24h to terminate the reaction.

[0057] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0058] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 92.7%, and the oxidation induction time was 4.15 h when the oxidation stability test was conducted.

[0059] Example 3

[0060] (1) Mix 200g of pressed tea oil with 2g of Eversa Transform 2.0 lipase and 0.4g of Lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0061] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 24h to terminate the reaction.

[0062] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0063] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 93.1%, and the oxidation induction time was 4.55 h when the oxidation stability test was conducted.

[0064] Example 4

[0065] (1) Mix 200g of pressed tea oil with 1g of Eversa Transform 2.0 lipase and 0.2g of lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0066] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0067] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0068] (1) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 94.4%, and the oxidation induction time was 4.21 h when the oxidation stability test was conducted.

[0069] Example 5

[0070] (1) Mix 200g of pressed tea oil with 4g of Eversa Transform 2.0 lipase and 0.8g of Lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0071] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0072] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0073] (1) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 94.2%, and the oxidation induction time was 4.19 h when the oxidation stability test was conducted.

[0074] Example 6

[0075] (1) Mix 200g of pressed tea oil with 2g of lipase Lipozyme TL 100L and 0.4g of glyceryl lipase Lipase G50, and then place them in an alcoholysis reaction apparatus and keep them warm at 40°C while stirring.

[0076] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0077] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0078] (1) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 91.4%, and the oxidation induction time was 4.27 h when the oxidation stability test was conducted.

[0079] Example 7

[0080] (1) Mix 200g of pressed tea oil with 2g of lipase Lipozyme CALB and 0.4g of glyceryl lipase Lipase G50, and then place them in an alcoholysis reaction apparatus and keep them warm at 40°C while stirring.

[0081] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0082] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0083] (1) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 90.25%, and the oxidation induction time was 4.48 h when the oxidation stability test was conducted.

[0084] Comparative Example 1

[0085] Following the method described in the reference "Study on Enzymatic Synthesis of Camellia Oil Isopropyl Ester [D]. South China University of Technology, 2011," camellia oil isopropyl ester was synthesized from camellia oil and isopropanol via alcoholysis in a solvent-free system using immobilized lipase Novozym 435. The molar ratio of substrate isopropanol to camellia oil was 5:1, the amount of Novozym 435 added was 2% of the substrate mass, and the reaction temperature was 55 °C. After reacting for 24 h under the above conditions, the mixture of camellia oil and isopropanol after the enzymatic reaction was placed in a 500 mL round-bottom flask. The round-bottom flask was then placed in a rotary evaporator set to temperature (60 °C, vacuum 0.1 MPa), and a water circulation pump was turned on simultaneously for distillation to remove isopropanol and obtain camellia oil isopropyl ester prepared by lipase Novozym 435 catalysis. Liquid chromatography analysis showed that the camellia oil isopropyl ester content was 90.4%, and oxidation stability testing showed that the oxidation induction time was 3.23 h.

[0086] Comparative Example 2

[0087] The method described in the reference "Xu Yongqiang, et al. Study on the synthesis of soybean oil isopropyl ester [J]. Applied Chemical Industry, 2012, 41(06): 988-991" was used to prepare an oil composition containing tea oil isopropyl ester: 200g of tea oil was weighed by the weight reduction method, preheated to 80 ℃, and 450g of isopropanol and 4g of potassium hydroxide catalyst were weighed to prepare a solution. The solution and tea oil were mixed and stirred for 1h. Then, 10ml of concentrated hydrochloric acid solution was poured in while stirring to terminate the reaction. The mixture was poured into a separatory funnel and allowed to stand for separation. The upper crude product was washed with water until pH = 7 and then subjected to vacuum distillation to obtain alkali-catalyzed tea oil isopropyl ester. Liquid phase analysis showed that the tea oil isopropyl ester content was 52.6%, and the oxidation induction time was 2.72h, which was found to be oxidatively induced.

[0088] Comparative Example 3

[0089] (1) Mix 200g of pressed tea oil with 2.4g of lipase Eversa Transform 2.0 and place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0090] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0091] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0092] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil reached 77.2%, and the oxidation induction time was 4.04 h when the oxidation stability test was conducted.

[0093] Comparative Example 4

[0094] (1) Mix 200g of pressed tea oil with 2.4g of lipase G50 and place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0095] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0096] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0097] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil reached 2.3%, and the oxidation induction time was 4.84 h when the oxidation stability test was conducted.

[0098] Comparative Example 5

[0099] (1) Mix 200g of pressed tea oil with 2g of Eversa Transform 2.0 lipase and 0.4g of Lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0100] (2) Add isopropanol to the mixture in step (1) and stir to react. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. The reaction is carried out in a constant temperature mode of 40℃ and the temperature is maintained until the reaction is terminated after 24h.

[0101] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0102] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil reached 80.4%, and the oxidation induction time was 4.17 h when the oxidation stability test was conducted.

[0103] Comparative Example 6

[0104] (1) Mix 200g of pressed tea oil with 2g of Eversa Transform 2.0 lipase and 0.4g of Lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0105] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. The reaction is carried out in a constant temperature mode of 10℃ and the temperature is maintained until the reaction is terminated after 24h.

[0106] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0107] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil reached 74.8%, and the oxidation induction time was 4.41 h when the oxidation stability test was conducted.

[0108] Comparative Example 7

[0109] (1) Mix 200g of pressed tea oil with 2g of Eversa Transform 2.0 lipase and 0.4g of Lipase G50, and then place it in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0110] (2) Add isopropanol to the mixture in step (1) and stir to react. Start the reaction time from the beginning of adding isopropanol. Add 80g of isopropanol at a time. Use programmable temperature control mode during the reaction. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h. After 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0111] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0112] (4) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 33.8%, and the oxidation induction time was 4.33 h when the oxidation stability test was conducted.

[0113] Comparative Example 8

[0114] (1) Mix 200g of pressed tea oil with 0.5g of Eversa Transform 2.0 lipase and 0.1g of Lipase G50, and then place the mixture in an alcoholysis reaction apparatus and keep it warm at 40°C while stirring.

[0115] (2) Add isopropanol to the mixture in step (1) and stir the reaction. Start the reaction time from the beginning of adding isopropanol. The method of adding isopropanol is as follows: add 10g of isopropanol at a constant rate within 0-1h, add 30g of isopropanol at a constant rate within 2h-4h, and add 40g of isopropanol at a constant rate within 4h-6h. During the reaction, use the program temperature control mode. Maintain the reaction temperature at 35℃-40℃ for 0-4h, cool down to 20-25℃ for 4h-5h and keep it at that temperature for 6h, and after 6h, lower the reaction temperature to 10℃ and keep it at that temperature for 12h to terminate the reaction.

[0116] (3) Add 14 ml of saturated Na2CO3 aqueous solution to the oil mixture after the reaction, keep it at 40℃ and stir for 30 min, and centrifuge at 3000 rpm to recover the upper oil phase; distill the upper oil phase under reduced pressure to recover isopropanol, add 14 ml of citric acid aqueous solution (mass concentration 1%) to the remaining oil phase, keep it at 40℃ and stir and wash with water for 30 min; after washing, centrifuge the oil phase at 3000 rpm to obtain the oil phase, which is the oil composition containing tea oil isopropyl ester.

[0117] (1) Liquid phase analysis showed that the content of isopropyl ester in tea oil was 77.2%, and the oxidation induction time was 4.36 h when the oxidation stability test was conducted.

[0118] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing an oil and fat composition, characterized in that, Includes the following steps: (1) Mix tea oil, lipase and glyceryl lipase, then add isopropanol and stir to react to obtain the reacted oil mixture; The reaction time begins from the addition of isopropanol, and the isopropanol is added in the following manner: the first portion of isopropanol is added at a constant flow rate over 0-1 hour; the second portion is added at a constant flow rate over 2-4 hours; and the third portion is added at a constant flow rate over 4-6 hours. The mass of the first portion of isopropanol is 4%-6% of the mass of the tea oil, the mass of the second portion is 13%-17% of the mass of the tea oil, and the mass of the third portion is 18%-22% of the mass of the tea oil. The reaction time starts from the addition of isopropanol, and the temperature of the stirred reaction is as follows: 0-4h, maintain 30℃-45℃; 4h-5h, cool down to 15℃-28℃ and keep warm for 6h; after 6h, cool down to below 12℃ and keep warm until the reaction is terminated. (2) The oil mixture after the reaction is washed with alkaline water, isopropanol is recovered and washed with acid water in sequence to obtain the oil composition.

2. The method for preparing the oil and fat composition according to claim 1, characterized in that, The lipase is one or more combinations of EversaTransform 2.0, Lipozyme TL 100L, and Lipozyme CALB; And / or, the glycerol lipase is Lipase G50.

3. The method for preparing the oil and fat composition according to claim 1, characterized in that, The amount of lipase added is 0.4%-2.0% of the mass of the tea oil, preferably 0.5%-1.0%. And / or, the amount of the added glyceryl lipase is 0.08%-0.4% of the mass of the tea oil, preferably 0.1%-0.2%.

4. The method for preparing the oil and fat composition according to any one of claims 1-3, characterized in that, The first portion of isopropanol comprises 4.5%-5.5% of the mass of the tea oil, the second portion of isopropanol comprises 14.5%-15.5% of the mass of the tea oil, and the third portion of isopropanol comprises 19.5%-20.5% of the mass of the tea oil. Preferably, the mass of the first portion of isopropanol is 5% of the mass of the tea oil, the mass of the second portion of isopropanol is 15% of the mass of the tea oil, and the mass of the third portion of isopropanol is 20% of the mass of the tea oil.

5. The method for preparing the oil and fat composition according to any one of claims 1-3, characterized in that, The reaction time is started from the addition of isopropanol, and the stirring reaction temperature is as follows: 0-4h, maintain 35℃-40℃; 4h-5h, cool down to 20℃-25℃ and keep at this temperature for 6h; after 6h, cool down to below 10℃ and keep at this temperature until the reaction is terminated. Preferably, the temperature is lowered to 0℃-10℃ after 6 hours and maintained at that temperature until the reaction is terminated; Preferably, the temperature is lowered to 5℃-10℃ after 6 hours and kept at that temperature until the reaction is terminated.

6. The method for preparing the oil and fat composition according to any one of claims 1-3, characterized in that, The reaction time starts from the addition of isopropanol and ends 8-30 hours after the start of the reaction time, preferably 10-24 hours, and more preferably 12-14 hours.

7. The method for preparing the oil and fat composition according to any one of claims 1-3, characterized in that, The alkaline washing includes washing with a saturated aqueous solution of Na2CO3. Preferably, the alkaline washing includes: adding a saturated aqueous solution of Na2CO3 to the reacted oil mixture and stirring at 35℃-45℃ for 10min-35min; Preferably, the ratio of the saturated aqueous solution of Na2CO3 to the tea oil is 0.05ml-0.1ml:1g.

8. The method for preparing the oil and fat composition according to any one of claims 1-3, characterized in that, The acid washing includes washing with an aqueous citric acid solution; Preferably, the acid washing includes: adding an aqueous citric acid solution to the oil mixture in which isopropanol has been recovered, and stirring at 35°C-45°C for 10-35 minutes. Preferably, the ratio of the citric acid aqueous solution to the tea oil is 0.05ml-0.1ml:1g; Preferably, the mass concentration of the citric acid aqueous solution is 1%-2%.

9. An oil and fat composition prepared by the preparation method according to any one of claims 1-8.

10. The oil and fat composition according to claim 9, characterized in that, The mass content of tea oil isopropyl ester is greater than 90%, preferably greater than 92%.

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