Medium-chain and long-chain fatty acid edible oil with reasonable fatty acid proportion and preparation method thereof

Abstract

The invention belongs to the technical field of edible oil and enzymes, and discloses medium-chain and long-chain fatty acid edible oil with a reasonable fatty acid proportion and a preparation method, the edible oil simultaneously meets the requirements that the mass percentage content of medium-chain and long-chain fatty acid triglyceride is 45%-65%, the proportion of saturated fatty acid to monounsaturated fatty acid to polyunsaturated fatty acid is (1-1.5): 2: 1, and the content of fatty acid is 1-1.5%. The polyunsaturated fatty acid is composed of n-6 polyunsaturated fatty acid and n-3 polyunsaturated fatty acid, and the ratio of the n-6 polyunsaturated fatty acid to the n-3 polyunsaturated fatty acid is (4-6): 1; the edible oil contains phytosterol ester with the final mass concentration of 0.5%-1.5%. The edible oil contains a certain amount of MLCT, the proportion of various fatty acid components is reasonable, and the proportion of n-6 polyunsaturated fatty acid to n-3 polyunsaturated fatty acid also meets the health requirements of human bodies.

Description

Technical Field

[0001] The invention belongs to the technical field of edible oils and enzymes, in particular to a medium- and long-chain fatty acid edible oil with a reasonable fatty acid ratio and a preparation method thereof. Background Art

[0002] Edible oils play an important role in people's daily lives. People can supplement essential fatty acids, energy substances, etc. by consuming edible oils. Therefore, the quality of edible oils is crucial to people's nutrition and health. Studies have shown that the composition of fatty acids in oils and fats and the ratio of various fatty acids have a significant impact on human health. When considering the healthy supplementation of oils and fats, we should not only pay attention to the composition and types of fatty acids contained in the oils and fats, but also take the ratio of various fatty acids into consideration. Studies have shown that the ratio of various fatty acids in oils and fats also plays a vital role. The ratio of n-6 polyunsaturated fatty acids (n-6 PUFA) to n-3 polyunsaturated fatty acids (n-3 PUFA) in the diet has a profound impact on people's health. The appropriate ratio of n-6 to n-3 will have a beneficial effect on people's health. These effects have been verified in improving diseases such as inflammation and asthma. The "Dietary Reference Intakes for Chinese Residents (2023 Edition)" describes the intake of various fatty acid components. For adults, the acceptable range for unsaturated fatty acid intake is 2.5% to 9% E (the percentage of total energy consumed by adults through fat or fatty acid function). The acceptable ranges for n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids are 2.5% to 9% E and 0.5% to 2% E, respectively. In 2012, the European Commission recommended a monounsaturated fatty acid intake of 10% to 20% E for everyone over one year old. Currently, my country does not have a specific acceptable range for monounsaturated fatty acid intake. The recommended intake principle is to control the total dietary fat energy ratio and the saturated fatty acid energy ratio, while ensuring an appropriate intake of n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids. The remaining dietary fat energy can be provided by MUFA. Combined with the above-mentioned recommendations on fatty acid intake and the research results of various literatures, it can be inferred that the ideal nutritional balance conditions are when the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids in edible oils is approximately 1:1 to 2:1, and the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is approximately 4 to 6:1.

[0003] With the continuous advancement of edible oil and fat research, more beneficial lipid components and structural lipids have gradually attracted attention. Medium- and long-chain triacylglycerols (MLCTs) are one of the most sought-after functional structural lipids. MLCTs are structural lipids containing medium-chain fatty acids (MCFA) and long-chain fatty acids (LCFA) on a glycerol backbone. MLCTs not only overcome the metabolic and immune deficiencies of LCTs, but also compensate for the digestive discomfort caused by excessive intake of medium-chain triacylglycerols (MCTs). Compared with physically mixed oils, MLCTs exhibit significant advantages in clinical nutritional support. Studies have found that MLCTs can reduce the metabolic burden on the liver, reduce inflammatory responses, and thus enhance nutritional status. MLCTs have been shown to address immunosuppression and have important clinical significance for enhancing cellular immunity. MLCTs also have significant effects on controlling weight and body fat and improving apolipoprotein metabolism. MLCT cooking oil was approved as a new resource food as early as 2012, and its functionality and safety have been verified in many aspects. Therefore, MLCT is a food with important applications in both medical and healthcare. Phytosterols are natural active ingredients found in various vegetable oils, nuts, and seeds, and have numerous physiological activities, including lowering cholesterol levels and preventing cardiovascular disease. Phytosterol esters are the esterified form of phytosterols. Compared to phytosterols, they have better oil solubility and bioavailability. Due to their excellent physical properties and physiological activities, phytosterol esters are currently used in foods such as edible oils and creams.

[0004] With increasing interest in healthy eating, research on functional edible oils is ongoing. Patent publication CN 106922853 discloses a balanced fatty acid blended oil. The blended oil has a saturated fatty acid (SFA) to monounsaturated fatty acid (MUFA) to polyunsaturated fatty acid (PUFA) ratio of approximately 0.8:1:1, and an n-6 to n-3 ratio of 5:1. However, the blended oil does not address the content of medium- and long-chain fatty acids. Patent publication CN 101331901 discloses a combined edible oil with a reasonable fatty acid ratio. The pure edible oil used in this study has a total monounsaturated fatty acid content of 33.3% to 50% by weight, a total polyunsaturated fatty acid content of 33.3% to 50% by weight, and a weight ratio of n-6 to n-3 polyunsaturated fatty acids of 4 to 6:1. Similarly, the patent does not address the content of medium- and long-chain fatty acids. Patent publication CN 117694408 discloses an edible vegetable blended oil with the ability to reduce hyperlipidemia. This study specifies an MLCT content of 8-16%, in addition to a GLA content of 6-8%, a DAG content of 8-20%, and an ALA content of 3.25-6.5%. While this patent primarily addresses the reduction of hyperlipidemia, it does not address the optimal ratio of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. Therefore, while various functional edible oil solutions have been proposed in the prior art, research on more comprehensive, nutritionally balanced edible oils remains lacking. With the continuous advancement of edible oil research, people's expectations for edible oils are becoming increasingly stringent. Simply possessing either nutritional balance or special functions is no longer sufficient. Edible oils that combine both nutritional and health benefits are urgently needed in the market.

[0005] At present, phytosterol esters in edible oils are mainly obtained by direct addition, which makes the cost of edible oils containing phytosterol esters high or the production process complicated. Patent publication CN111321191 discloses a method for preparing phytosterol esters by enzymatic method, in which immobilized lipase is added to catalyze the synthesis of phytosterol esters from fatty acids and phytosterols. The yield of phytosterol esters synthesized by this method is high, but fatty acids must be used alone as raw materials for synthesis; Patent publication CN103352067 proposes a method for preparing edible oils rich in phytosterol esters and diglycerides, but the yield of phytosterol esters in this method is low, and the method mainly focuses on the content of phytosterol fats and diglycerides, without paying attention to more comprehensive nutritional indicators such as the balance of fatty acid component ratios.

[0006] There are two main methods for preparing MLCT edible oil: chemical synthesis and enzymatic preparation. Due to the shortcomings of chemical synthesis such as low efficiency, easy pollution, and high by-product content, enzymatic preparation has become the main means of MLCT edible oil production. Patent publication CN119184165A discloses a method for preparing medium- and long-chain fatty acid glyceride edible oil. In this study, a functional lipase was prepared by mixing an activated sialic acid derivative with a lipase, and an ester exchange reaction was carried out in a supercritical carbon dioxide medium to prepare MLCT edible oil with a high yield. However, this method first requires the preparation of an activated sialic acid derivative and the reaction needs to be carried out under supercritical carbon dioxide medium conditions, and its universality is relatively low. Patent publication CN111763697A discloses a method for enzymatically preparing MLCT edible oil by modifying lipase with a monoglyceride surfactant. This method can improve the catalytic activity of the enzyme and the resulting MLCT has a high purity. However, this method also requires the modification of the lipase first and adds a step of removing monoglycerides and diglycerides. The method is relatively cumbersome. Therefore, it is necessary to develop a preparation method that is efficient, convenient, and ensures the yield of MLCT. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a medium- and long-chain fatty acid edible oil with a reasonable fatty acid ratio and a preparation method thereof.

[0008] The technical solution adopted by the present invention to solve its technical problem is:

[0009] The invention discloses an edible oil of medium- and long-chain fatty acids having a reasonable fatty acid ratio. The edible oil satisfies the following requirements: the mass percentage of medium- and long-chain fatty acid triglycerides is 45% to 65%, the ratio of saturated fatty acids, monounsaturated fatty acids to polyunsaturated fatty acids is 1 to 1.5:2:1, the polyunsaturated fatty acids are composed of n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids, and the ratio of n-6 polyunsaturated fatty acids to n-3 polyunsaturated fatty acids is 4 to 6:1; and the edible oil contains phytosterol esters at a final mass concentration of 0.5% to 1.5%.

[0010] The method for preparing the above-mentioned medium-chain and long-chain fatty acid edible oil with a reasonable fatty acid ratio comprises the following steps:

[0011] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0012] Step 2: Mix the raw materials, add the raw oil, medium-chain triglycerides and phytosterols, dehydrate under vacuum at 95° C., and then stir and mix for 10 minutes to obtain a pre-reaction oil mixture;

[0013] Step 3: Esterification reaction: The three mixed immobilized lipases are placed in a fixed container with a built-in sieve plate to form a lipase fixed bed. The pre-reaction oil and fat mixture is circulated through the lipase fixed bed for transesterification reaction at a temperature of 60±20°C. The reaction is terminated after 8 to 12 hours, and the catalyst and oil are separated;

[0014] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to a refining process to obtain a finished edible oil with a reasonable proportion of medium and long chain fatty acids.

[0015] Furthermore, the raw material oil is one or a mixture of two or more of soybean oil, corn oil, high oleic sunflower oil, sunflower oil, rapeseed oil, coconut oil, palm oil, palm kernel oil, linseed oil, walnut oil, perilla seed oil, olive oil, wheat germ oil, grape seed oil, rice bran oil, safflower seed oil, pumpkin seed oil, milk thistle oil, maple oil, evening primrose oil, and borage oil.

[0016] Furthermore, the immobilized lipase is one of the lipases derived from Candida antarctica, Fusarium oxysporum, Thermomyces lanuginosus, Rhizomucor miehe, Fusarium culmorum, Fusarium hetreosporum, Aspergillus niger var. tubingensis, Fusarium oxysporum, and Penicillium camembertii.

[0017] Furthermore, the refining process includes water washing, decolorization and deodorization.

[0018] Furthermore, the phytosterol is one or a mixture of two or more of β-sitosterol, stigmasterol, campesterol, and brassicasterol.

[0019] Furthermore, in step 2, the mass ratio of raw material oil to medium chain triglycerides is 3 to 14:1, and the amount of phytosterol added is 1.5% of the total mass of the raw material oil and medium chain triglycerides.

[0020] Furthermore, the immobilized lipase is commercially available Lipase G50, Lipozyme TL IM and Novozyme435.

[0021] Furthermore, the mass ratio of Lipase G50, Lipozyme TL IM and Novozyme 435 is 1:3:6.

[0022] The advantages and positive effects achieved by the present invention are:

[0023] 1. To address the problems existing in existing edible oil products and production technologies, the present invention provides a medium-chain fatty acid edible oil. This edible oil contains a certain amount of MLCT, and the various fatty acid components are in a reasonable ratio, with the ratio of n-6 polyunsaturated fatty acids to n-3 polyunsaturated fatty acids also meeting human health requirements.

[0024] 2. The edible oil of the present invention is different from the existing MLCT edible oil. The existing MLCT edible oil does not provide a reasonable ratio of various fatty acids. However, the MLCT edible oil of the present invention has a reasonable ratio of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids, and the ratio of n-6:n-3 in the polyunsaturated fatty acids meets the health needs of the human body.

[0025] 3. The edible oil provided by the present invention is different from the existing blended oil with a reasonable fatty acid ratio. The blended oil is obtained by mixing different vegetable oils in a certain ratio. The triglyceride molecules in the obtained mixed oil are still long-chain fatty acid triglycerides or medium-chain fatty acid triglycerides with a higher content in the raw material oil, and have no more obvious promoting effect on digestion and absorption; the MLCT edible oil provided by the present invention is obtained by mixing different vegetable oils as raw material oils in a reasonable ratio, and undergoing a lipase-catalyzed ester exchange reaction. The fatty acids in the triglyceride molecules in the raw material oil are rearranged to obtain an edible oil rich in both medium-chain and long-chain triglyceride molecules. The medium- and long-chain fatty acid edible oil can have a higher absorption efficiency, can provide energy to the human body for a long time, and has better health value.

[0026] 4. The method for preparing MLCT edible oil of the present invention is different from the existing method for preparing MLCT edible oil. Due to the different substrate preferences of different lipases, the use of three mixed lipases is not only conducive to the efficient synthesis of MLCT, but also can ensure the sufficient reaction of monoglyceride and diglyceride to synthesize triglyceride. This method proposes a method for using three immobilized lipases in combination for transesterification. This method is simple to operate and has simple steps. The resulting product has a high MLCT content and low residual monoglyceride and diglyceride. It can solve the problems of the existing technology such as complicated steps, harsh conditions, and low triglyceride purity.

[0027] 5. The preparation method of MLCT edible oil of the present invention is different from the existing preparation method of phytosterol ester edible oil. The prior art does not have a technology for synthesizing phytosterol esters while synthesizing MLCT edible oil. Generally, free fatty acids and phytosterols are used as raw materials to separately synthesize phytosterol esters, and then they are added to edible oil. The present invention uses a mixed lipase as a catalyst to synthesize phytosterol esters through ester exchange with the original free fatty acids and glycerides in the raw material oil. No additional fatty acids need to be added, which simplifies the preparation method of edible oil containing phytosterol esters. The use of the mixed lipase can ensure the synthesis efficiency of phytosterol esters, and finally obtains an edible oil rich in both phytosterol esters and MLCT. The process flow is simple and no additional phytosterol ester synthesis step is required.

[0028] 6. The method for preparing MLCT edible oil in the present invention can make up for the shortcomings of the existing technology. The edible oil obtained by the existing edible oil preparation method does not have the three characteristics of a reasonable formula, rich in MLCT, and rich in plant sterol esters. The MLCT edible oil obtained by this method can meet the above characteristics and provide a functional edible oil with the triple effects of nutritional balance, metabolism promotion and cardiovascular health.

[0029] 7. The present invention selects natural plant oils as raw materials, mixes them in a certain proportion, and then conducts a composite enzymatic transesterification to obtain medium-chain fatty acid edible oils. The medium-chain fatty acid triglyceride content in the oil can reach 50% to 65%, and the phytosterol ester content can reach 0.5% to 1.5%. Among all fatty acids, the ratio of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids is approximately 1 to 1.5:2:1. Among all polyunsaturated fatty acids, the ratio of n-6 polyunsaturated fatty acids to n-3 polyunsaturated fatty acids is approximately 4 to 6:1. The medium-chain fatty acid edible oil provided by the present invention can meet consumers' needs for both nutritional balance and health benefits of oils and has important application value. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the following examples. The following examples are descriptive rather than restrictive, and the scope of protection of the present invention cannot be limited by the following examples.

[0031] The various experimental operations involved in the specific embodiments are all routine techniques in the field. For parts not specifically annotated in this document, ordinary technicians in this field can refer to various commonly used reference books, scientific literature or related instructions, manuals, etc. before the filing date of this invention to implement them.

[0032] The invention discloses an edible oil of medium- and long-chain fatty acids having a reasonable fatty acid ratio. The edible oil satisfies the following requirements: the mass percentage of medium- and long-chain fatty acid triglycerides is 45% to 65%, the ratio of saturated fatty acids, monounsaturated fatty acids to polyunsaturated fatty acids is 1 to 1.5:2:1, the polyunsaturated fatty acids are composed of n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids, and the ratio of n-6 polyunsaturated fatty acids to n-3 polyunsaturated fatty acids is 4 to 6:1; and the edible oil contains phytosterol esters at a final mass concentration of 0.5% to 1.5%.

[0033] The method for preparing the above-mentioned medium-chain and long-chain fatty acid edible oil with a reasonable fatty acid ratio comprises the following steps:

[0034] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0035] Step 2: Mix the raw materials, add the raw oil, medium-chain triglycerides and phytosterols, dehydrate under vacuum at 95° C., and then stir and mix for 10 minutes to obtain a pre-reaction oil mixture;

[0036] Step 3: Esterification reaction: The three mixed immobilized lipases are placed in a fixed container with a built-in sieve plate to form a lipase fixed bed. The pre-reaction oil and fat mixture is circulated through the lipase fixed bed for transesterification reaction at a temperature of 60±20°C. The reaction is terminated after 8 to 12 hours, and the catalyst and oil are separated;

[0037] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to a refining process to obtain a finished edible oil with a reasonable proportion of medium and long chain fatty acids.

[0038] Preferably, the raw material oil is one or a mixture of two or more of soybean oil, corn oil, high oleic sunflower oil, sunflower oil, rapeseed oil, coconut oil, palm oil, palm kernel oil, linseed oil, walnut oil, perilla seed oil, olive oil, wheat germ oil, grape seed oil, rice bran oil, safflower seed oil, pumpkin seed oil, milk thistle oil, maple oil, evening primrose oil, and borage oil.

[0039] Preferably, the immobilized lipase is one of the lipases derived from Candida antarctica, Fusarium oxysporum, Thermomyces lanuginosus, Rhizomucor miehe, Fusarium culmorum, Fusarium hetreosporum, Aspergillus niger var. tubingensis, Fusarium oxysporum, and Penicillium camembertii.

[0040] Preferably, the refining process includes water washing, decolorization and deodorization.

[0041] Preferably, the phytosterol is one or a mixture of two or more of β-sitosterol, stigmasterol, campesterol, and brassicasterol.

[0042] Preferably, in step 2, the mass ratio of raw material oil to medium chain triglycerides is 3 to 14:1, and the amount of phytosterol added is 1.5% of the total mass of the raw material oil and medium chain triglycerides.

[0043] Preferably, the immobilized lipase is commercially available Lipase G50, Lipozyme TL IM and Novozyme 435.

[0044] Preferably, the mass ratio of Lipase G50, Lipozyme TL IM and Novozyme 435 is 1:3:6.

[0045] Specifically, the relevant preparation and detection are as follows:

[0046] Example 1

[0047] A method for preparing medium- and long-chain fatty acid edible oil with a reasonable fatty acid ratio comprises the following steps:

[0048] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0049] Step 2, mixing the raw materials. In the mixed raw materials, the mass ratios of the raw materials are 50% rapeseed oil, 13% high oleic sunflower oil, 17% sunflower oil and 20% medium chain triglycerides, respectively. The fatty acid content of the raw material oils used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. The mixture is vacuum dehydrated at 95° C. and then stirred for about 10 minutes to obtain a pre-reaction oil mixture;

[0050] Step 3: Esterification reaction: three lipases, namely Lipase G50, Lipozyme TL IM and Novozyme 435, are mixed in a mass ratio of 1:3:6 and added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the lipase fixed bed for transesterification reaction. The reaction temperature is 70±10°C. The reaction is terminated after 8 hours, and the catalyst is separated from the oil.

[0051] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 61.1%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 1:1.9:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 5.3:1; the content of glycidyl ester is approximately 0.1 mg / kg, and the content of 3-MCPD ester is approximately 0.2 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0052] Example 2

[0053] A method for preparing medium- and long-chain fatty acid edible oil with a reasonable fatty acid ratio comprises the following steps:

[0054] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0055] Step 2, mixing the raw materials. In the mixed raw materials, the mass proportions of each raw material are 5% linseed oil, 27% corn oil, 45% high oleic sunflower oil and 23% medium chain triglycerides, respectively. The fatty acid content of the raw material oil used is shown in Table 1. The fatty acid content of the raw material oil used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. Vacuum dehydration is carried out at 95° C., and then stirring and mixing for about 10 minutes to obtain a pre-reaction oil mixture;

[0056] Step 3: Esterification reaction: three lipases, namely Lipase G50, Lipozyme TL IM and Novozyme 435, are mixed in a mass ratio of 1:3:6 and added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the lipase fixed bed for transesterification reaction. The reaction temperature is 70±10°C. The reaction is terminated after 8 hours, and the catalyst is separated from the oil.

[0057] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 60%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 1.3:2.1:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 5.8:1; the content of glycidyl ester is approximately 0.2 mg / kg, and the content of 3-MCPD ester is approximately 0.3 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0058] Example 3

[0059] A method for preparing medium- and long-chain fatty acid edible oil with a reasonable fatty acid ratio comprises the following steps:

[0060] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0061] Step 2: Mixing the raw materials. In the mixed raw materials, the mass proportions of the raw materials are 28% soybean oil, 45% high oleic sunflower oil, 13% palm kernel oil, 2% linseed oil, and 12% medium-chain triglycerides, respectively. The fatty acid content of the raw material oils used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. The mixture is vacuum dehydrated at 95° C. and then stirred for about 10 minutes to obtain a pre-reaction oil mixture.

[0062] Step 3: Esterification reaction: three lipases, namely Lipase G50, Lipozyme TL IM and Novozyme 435, are mixed in a mass ratio of 1:3:6 and added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the lipase fixed bed for transesterification reaction. The reaction temperature is 70±10°C. The reaction is terminated after 8 hours, and the catalyst is separated from the oil.

[0063] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 59.7%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 1.3:2.1:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 5.1:1; the content of glycidyl ester is approximately 0.2 mg / kg, and the content of 3-MCPD ester is approximately 0.3 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0064] Example 4

[0065] A method for preparing medium- and long-chain fatty acid edible oil with a reasonable fatty acid ratio comprises the following steps:

[0066] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0067] Step 2, mixing the raw materials. In the mixed raw materials, the mass ratios of the raw materials are 7% palm stearin, 50% rapeseed oil, 20% palm oil, 13% corn oil and 10% medium chain triglycerides, respectively. The fatty acid content of the raw material oils used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. The mixture is vacuum dehydrated at 95° C. and then stirred for about 10 minutes to obtain a fat mixture before the reaction;

[0068] Step 3: Esterification reaction: three lipases, namely Lipase G50, Lipozyme TL IM and Novozyme 435, are mixed in a mass ratio of 1:3:6 and added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the lipase fixed bed for transesterification reaction. The reaction temperature is 70±10°C. The reaction is terminated after 8 hours, and the catalyst is separated from the oil.

[0069] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 60.8%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 1.1:1.8:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 4.1:1; the content of glycidyl ester is about 0.1 mg / kg, and the content of 3-MCPD ester is about 0.3 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0070] Example 5

[0071] A method for preparing medium- and long-chain fatty acid edible oil with a reasonable fatty acid ratio comprises the following steps:

[0072] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0073] Step 2: Mixing the raw materials. In the mixed raw materials, the mass proportions of the raw materials are 15% soybean oil, 10% coconut oil, 47% high oleic sunflower oil, 16% corn oil, 5% linseed oil and 7% medium chain triglycerides, respectively. The fatty acid content of the raw material oils used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. The mixture is vacuum dehydrated at 95° C. and then stirred for about 10 minutes to obtain a pre-reaction oil mixture.

[0074] Step 3: Esterification reaction: three lipases, namely Lipase G50, Lipozyme TL IM and Novozyme 435, are mixed in a mass ratio of 1:3:6 and added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the lipase fixed bed for transesterification reaction. The reaction temperature is 70±10°C. The reaction is terminated after 8 hours, and the catalyst is separated from the oil.

[0075] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 58.9%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 0.9:1.9:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 4.8:1; the content of glycidyl ester is approximately 0.1 mg / kg, and the content of 3-MCPD ester is approximately 0.2 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0076] Comparative Example 1

[0077] A method for preparing edible oil comprises the following steps (Comparative Example 1, only the linseed oil in Example 3 is replaced with algae oil, and other conditions remain unchanged):

[0078] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0079] Step 2: Mixing the raw materials. In the mixed raw materials, the mass proportions of each raw material are 28% soybean oil, 45% high oleic sunflower oil, 13% palm kernel oil, 2% algae oil and 12% medium chain triglycerides, respectively. The fatty acid content of the raw material oils used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. The mixture is vacuum dehydrated at 95° C. and then stirred for about 10 minutes to obtain a pre-reaction oil mixture.

[0080] Step 3: Esterification reaction: three lipases, namely Lipase G50, Lipozyme TL IM and Novozyme 435, are mixed in a mass ratio of 1:3:6 and added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the lipase fixed bed for transesterification reaction. The reaction temperature is 70±10°C. The reaction is terminated after 8 hours, and the catalyst is separated from the oil.

[0081] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 32.1%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 1.3:2.1:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 4.5:1; the content of glycidyl ester is approximately 0.2 mg / kg, and the content of 3-MCPD ester is approximately 0.2 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0082] Comparative Example 2

[0083] A method for preparing edible oil comprises the following steps (without adding phytosterols, and the rest is the same as in Example 1):

[0084] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0085] Step 2: Mixing the raw materials. In the mixed raw materials, the mass ratios of the raw materials are 50% rapeseed oil, 13% high oleic sunflower oil, 17% sunflower oil, and 20% medium chain triglycerides, respectively. The fatty acid content of the raw oils used is shown in Table 1. The mixture is vacuum dehydrated at 95° C. and then stirred and mixed for about 10 minutes to obtain a pre-reaction oil mixture.

[0086] Step 3: Esterification reaction: three lipases, namely Lipase G50, Lipozyme TL IM, and Novozyme 435, were selected and mixed in a mass ratio of 1:3:6 and then added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added was 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture was circulated through the lipase fixed bed for transesterification reaction. The reaction temperature was 70±10°C. The reaction was terminated after 8 hours, and the catalyst was separated from the oil.

[0087] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 25.6%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 0.9:1.3:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 4.2:1; the content of glycidyl ester is approximately 0.1 mg / kg, and the content of 3-MCPD ester is approximately 0.2 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0088] Comparative Example 3

[0089] A method for preparing edible oil comprises the following steps (without adding lipase Novozyme 435, and the rest is the same as in Example 1):

[0090] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0091] Step 2, mixing the raw materials. In the mixed raw materials, the mass ratios of the raw materials are 50% rapeseed oil, 13% high oleic sunflower oil, 17% sunflower oil and 20% medium chain triglycerides, respectively. The fatty acid content of the raw material oils used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. The mixture is vacuum dehydrated at 95° C. and then stirred for about 10 minutes to obtain a pre-reaction oil mixture;

[0092] Step 3: Esterification reaction: Lipase G50 and Lipozyme TL IM are selected and mixed in a mass ratio of 1:9 and then added to a fixed container with a built-in sieve plate to form a lipase fixed bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the lipase fixed bed for transesterification reaction. The reaction temperature is 70±10°C. The reaction is terminated after 8 hours, and the catalyst and oil are separated;

[0093] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 27.9%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 1:1.9:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 4.6:1; the content of glycidyl ester is approximately 0.1 mg / kg, and the content of 3-MCPD ester is approximately 0.2 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0094] Comparative Example 4

[0095] A method for preparing edible oil comprises the following steps (without adding Lipase G50, and the rest is the same as in Example 1):

[0096] Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating;

[0097] Step 2, mixing the raw materials. In the mixed raw materials, the mass ratios of the raw materials are 50% rapeseed oil, 13% high oleic sunflower oil, 17% sunflower oil and 20% medium chain triglycerides, respectively. The fatty acid content of the raw material oils used is shown in Table 1. After mixing, 1.5% of the total mass of the mixed raw materials is added with β-sitosterol, and the mixture is mixed again. The mixture is vacuum dehydrated at 95° C. and then stirred for about 10 minutes to obtain a pre-reaction oil mixture;

[0098] Step 3: Esterification reaction: Lipozyme TL IM and Novozyme 435 are mixed in a mass ratio of 4:6 and then added to a fixed container with a built-in sieve plate to form a fixed lipase bed. The amount of lipase added is 0.1-0.2% by weight of the total feedstock oil. The pre-reaction oil mixture is circulated through the fixed lipase bed for transesterification reaction at a reaction temperature of 70±10°C. The reaction is terminated after 8 hours, and the catalyst is separated from the oil.

[0099] Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to refining processes such as degumming, neutralization, decolorization, and deodorization to obtain a finished medium-chain fatty acid edible oil; the finished product is tested, and the content of medium-chain fatty acid triglycerides in the finished product is 30.6%, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is 1:1.9:1, of which the ratio of n-6 polyunsaturated fatty acids: n-3 polyunsaturated fatty acids is 5.6:1; the content of glycidyl ester is approximately 0.1 mg / kg, and the content of 3-MCPD ester is approximately 0.2 mg / kg. The fatty acid components and contents in the finished product are shown in Table 2.

[0100] Table 1 Fatty acid composition and content of raw materials used in the examples and comparative examples of the present invention

[0101]

[0102]

[0103]

[0104] Table 2 Fatty acid composition and content of the products obtained in the examples of the present invention

[0105]

[0106] Note: “-” in the table means that the content of the tested substance is trace or not detected.

[0107] According to the results obtained in embodiments 1-5, it can be seen that the preparation method of the medium-long chain fatty acid triglyceride edible oil disclosed in the present application can obtain an edible oil rich in medium-long chain fatty acid triglycerides by complex enzyme transesterification reaction with plant oil and medium chain triglyceride as raw materials in a certain proportion, and by adjusting the types and adding proportions of the raw material oil, the content of MLCT in the obtained edible oil can be controlled between 45% and 65%, and the complex enzyme method reduces the generation of monoglyceride and diglyceride in the product, ensuring the content of MLCT in the medium-long chain fatty acid edible oil; by controlling the adding proportion of different raw material oils, the proportions of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids in the obtained product can be controlled around 1:1.5-2:1 which is beneficial to the human body, and the ratio of n-6 polyunsaturated fatty acids to n-3 polyunsaturated fatty acids in the polyunsaturated fatty acids can be controlled at 4-6:1 at the same time, which meets the human nutritional and health standards; in addition, by adding phytosterols in the raw materials, the purpose of simultaneously producing phytosterol esters in the transesterification process is achieved, so that the obtained edible oil contains 0.5%-1.5% of phytosterol esters, which reduces the proportion and loss of free fatty acids in the product, and is more beneficial to human health. In the prior art, there is no edible oil that can meet the above several points at the same time, so the medium-long chain fatty acid edible oil provided by the present application has certain innovation, which can meet various nutritional needs and standards beneficial to human health at the same time, and has great commercial value.

[0108] At the same time, it can be seen from comparative example 1, comparative example 2 and comparative example 3 that the sub-phytosterol, i.e. beta-sitosterol, and the lipase Novozyme 435 in the method of the present application have a synergistic effect, which can synergistically improve the related properties of the prepared medium-long chain fatty acid edible oil. It can be seen from comparative example 1, comparative example 3 and comparative example 4 that the lipase Novozyme 435 and Lipase G50 in the method of the present application have a synergistic effect, which can synergistically improve the related properties of the prepared medium-long chain fatty acid edible oil.

[0109] Although the embodiments of the present application are disclosed for illustrative purposes, those skilled in the art can understand that various alternatives, changes and modifications are possible without departing from the spirit and scope of the present application and the appended claims, therefore, the scope of the present application is not limited to the disclosed content of the embodiments.

Claims

1. A medium-chain fatty acid edible oil with a reasonable fatty acid ratio, characterized in that: The edible oil simultaneously meets the requirements that the mass percentage of medium- and long-chain fatty acid triglycerides is 45% to 65%, the ratio of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids is 1 to 1.5:2:1, the polyunsaturated fatty acids are composed of n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids, and the ratio of n-6 polyunsaturated fatty acids to n-3 polyunsaturated fatty acids is 4 to 6:1; and the edible oil contains a final mass concentration of 0.5% to 1.5% of plant sterol esters.

2. the preparation method of the medium and long chain fatty acid edible oil with reasonable fatty acid ratio as claimed in claim 1 is characterized in that: The steps include: Step 1: Preliminary preparation: vacuumizing the reaction tank, heating and dehydrating; Step 2: Mix the raw materials, add the raw oil, medium-chain triglycerides and phytosterols, dehydrate under vacuum at 95° C., and then stir and mix for 10 minutes to obtain a pre-reaction oil mixture; Step 3: Esterification reaction: The three mixed immobilized lipases are placed in a fixed container with a built-in sieve plate to form a lipase fixed bed. The pre-reaction oil and fat mixture is circulated through the lipase fixed bed for transesterification reaction at a temperature of 60±20°C. The reaction is terminated after 8 to 12 hours, and the catalyst and oil are separated; Step 4: Refining and processing: The oil obtained by the esterification reaction is subjected to a refining process to obtain a finished edible oil with a reasonable proportion of medium and long chain fatty acids.

3. The preparation method according to claim 2, wherein: The raw material oil is one or a mixture of two or more of soybean oil, corn oil, high oleic sunflower oil, sunflower oil, rapeseed oil, coconut oil, palm oil, palm kernel oil, linseed oil, walnut oil, perilla seed oil, olive oil, wheat germ oil, grape seed oil, rice bran oil, safflower seed oil, pumpkin seed oil, milk thistle oil, maple oil, evening primrose oil, and borage oil.

4. The preparation method according to claim 2, wherein: The immobilized lipase is one of the lipases derived from Candida antarctica, Fusarium oxysporum, Thermomyces lanuginosus, Rhizomucor miehe, Fusarium culmorum, Fusarium hetreosporum, Aspergillus nigervar. tubingensis, Fusarium oxysporum, and Penicillium camembertii.

5. The preparation method according to claim 4, characterized in that: The refining process includes water washing, decolorization and deodorization.

6. The preparation method according to claim 2, wherein: The phytosterol is one or a mixture of two or more of β-sitosterol, stigmasterol, campesterol and brassicasterol.

7. The preparation method according to claim 7, characterized in that: In step 2, the mass ratio of raw material oil to medium chain triglyceride is 3 to 14:1, and the amount of phytosterol added is 1.5% of the total mass of the raw material oil and medium chain triglyceride.

8. The preparation method according to any one of claims 2 to 7, characterized in that: The immobilized lipases are commercially available Lipase G50, Lipozyme TL IM and Novozyme 435.

9. The preparation method according to claim 8, characterized in that: The mass ratio of Lipase G50, Lipozyme TL IM and Novozyme 435 is 1:3:6.

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