Preparation method for stable diacylglycerol oil and use

Abstract

A preparation method for a stable diacylglycerol oil, a stable diacylglycerol oil prepared thereby, and a use. The method comprises the following steps: carrying out moderate glycerolysis on a vegetable oil; and first carrying out molecular distillation purification on crude diacylglycerol obtained by means of glycerolysis and then carrying out a fractionation modification process. A diacylglycerol isomer composition is prepared by controlling the degree of glycerolysis and the fractionation process. Compared with other processes, the diacylglycerol oil is prepared by controlling the degree of the glycerolysis and the fractionation conditions, in particular the content of diacylglycerol and the proportion of 1,3 / 1,2 diacylglycerol, and when the diacylglycerol oil is used as a thermally processed cooking oil, the oxidation stability is significantly improved, thereby significantly reducing the formation of risk factors.

Description

Preparation method and application of stable diglyceride oil TECHNICAL FIELD

[0001] The present application belongs to the field of light industry food oil and fat, and particularly relates to a preparation method and application of stable diglyceride oil. BACKGROUND

[0002] Glycerol diester (DAG) has attracted widespread attention as a functional food ingredient. Its metabolic pathway is different from that of glycerol triester (TAG). DAG oil is believed to reduce body fat accumulation, reduce postprandial serum TAG levels, reduce obesity and cardiovascular diseases, etc. Currently, DAG is mainly used as an emulsifier, crystallization modifier, baking product regulator, etc. in the food industry. In high-temperature cooking, edible oil undergoes a series of physical and chemical changes in a short time due to its large specific surface area, resulting in changes in color, peroxide value, anisidine value, tocopherol and phytosterol, etc. At the same time, harmful substances such as 3-chloropropanol ester (3-MCPDE) and glycidyl ester (GE) are also produced. In different vegetable oil systems, various substances have certain differences in antioxidant effect on oil. In a high-temperature environment, the antioxidant capacity of edible oil during cooking is mainly determined by its fatty acid composition and antioxidant concentration. Naturally occurring antioxidants in edible oil, such as tocotrienol and tocopherol, can effectively inhibit the oil oxidation process to some extent. The oxidation of phytosterol is affected by many factors, including temperature, free radical initiator and oxygen, etc. The sterol oxides derived therefrom are proved to have toxic and side effects such as carcinogenicity and mutagenicity. Therefore, the oxidation stability of edible oil has an important influence on the storage and cooking process. At present, there are still many controversies about the influence of DAG on the oxidation stability of oil. Generally, it is believed that the thermal stability of TAG oil is much higher than that of DAG oil.

[0003] Currently, to enhance the oxidative stability of DAG oil, it is usually through adding antioxidants, or selecting raw material oil with high saturation, or through post-embedding, powder spraying and other ways to DAG oil to improve the stability during application. Currently, the academia generally believes that the formation of 3-MCPDE and GEs in the process of oil and fat thermal processing is related to TAG and part of glycerides, including DAG and MAG. Studies have shown that the concentration of 3-MCPDE is proportional to the heating temperature, but when the temperature is higher than 220℃, the generation rate of 3-MCPDE decreases. The heating time does not have the same trend on the formation of 3-MCPDE and GEs. It has been found in some studies that a large amount of 3-MCPDE is produced in the early stage of thermal processing, and with the extension of time, 3-MCPDE is in fluctuating change, and the degradation rate is higher than the generation rate, and the concentration of GEs decreases with the extension of thermal processing time. In other studies, the concentration of GEs is proportional to the thermal processing time. Therefore, 3-MCPDE and GEs tend to be unstable in the process of long-time heating, in addition to which the content of chlorides, antioxidants and the type of oil may be related to the formation of 3-MCPDE and GEs. SUMMARY

[0004] In view of the problems of poor oxidative stability of DAG oil during thermal processing, high growth rate of risk factors such as 3-MCPDE and GEs and other product quality changes, the purpose of the present application is to provide a preparation method for obtaining high-stability DAG oil through glycerolysis and fractionation process. The DAG oil obtained by the method has significantly improved oxidative stability (low growth rate of acid value AV and total oxidation value TOTOX) during thermal processing without adding antioxidants, and the growth rate of risk factors is greatly reduced.

[0005] Another purpose of the present application is to provide a high-stability DAG oil prepared by the above method.

[0006] Another purpose of the present application is to provide the application of the high-stability DAG oil prepared by the above method.

[0007] The purpose of the present application is achieved by the following technical scheme: A preparation method of stable DAG oil, comprising the following steps: (1) glycerolysis of plant oil, then collecting oil sample, and purifying by molecular distillation to obtain raw material DAG oil; (2) dry fractionation of the raw material DAG oil, collecting the fractionation liquid oil (low melting point component) to obtain the stable DAG oil.

[0008] The plant oil in step (1) is plant oil with a sliding melting point of ≥4℃, preferably peanut oil.

[0009] The enzymatic catalyzed glycerolysis in step (1) is catalyzed by lipase, preferably one of Lipozyme CALB, Lipozyme TL IM or Lipozyme RM IM; the mass ratio of vegetable oil to glycerol in glycerolysis is 2:1-1:1; the enzyme addition amount is 1-5% of the mass of substrate (vegetable oil+glycerol); the glycerolysis reaction temperature is 60-80℃ (preferably 60-75℃); the reaction time is 30-90min; and the vacuum degree is ≤2000pa.

[0010] Preferably, the enzymatic catalyzed glycerolysis in step (1) is catalyzed by lipase, the mass ratio of vegetable oil to glycerol is 2:1, the enzyme addition amount is 2% of the mass of substrate, the glycerolysis reaction temperature is 70℃, and the reaction time is 40min.

[0011] The molecular distillation in step (1) is used to obtain raw glyceride oil in light phase, wherein the glyceride content is 80-100%.

[0012] The molecular distillation in step (1) is operated according to the following parameters: distillation temperature is 180-190℃, vacuum degree is 0.5-1.0Pa, scraper rotation speed is 150-200rpm, condenser temperature is 30-50℃, and feed flow rate is ≤0.5mL / min.

[0013] The specific steps of the fractionation in step (2) are as follows: the raw glyceride oil is melted, then stirred and immersed at 5-10℃ for more than 90min until solid substances are precipitated, the stirring speed is less than 200rpm; after the stirring and immersion, suction filtration is performed to separate the solid part from the liquid part; the fractionated oil (low melting point component) is collected, the mass ratio of 1,3 glyceride to 1,2 glyceride in the glyceride product is controlled to be 6:4-8:2, and the stable glyceride oil is obtained.

[0014] The glyceride oil prepared by the method has the following properties: total oxidation value <120, peroxide value <13.0mmol / kg, acid value ≤0.9mg / g, 3MCPDE content <210ug / kg, GEs content <200ug / kg, 3MCPDE content growth rate ≤34%, and GEs content growth rate ≤81.4%, preferably ≤25.8%.

[0015] In order to obtain a more stable diglyceride oil, the present application uses peanut oil as raw material, adopts enzymatic glycerolysis process, controls the acyl migration degree of glycerolysis process, obtains diglyceride crude product, and further obtains diglyceride oil with suitable isomer proportion through molecular distillation purification and fractionation. Compared with traditional diglyceride oil obtained through glycerolysis, the diglyceride oil with suitable isomer proportion has significantly improved oxidative stability in the process of thermal processing and cooking, and the production rate of risk factors is obviously reduced.

[0016] A stable diglyceride oil prepared by the above method.

[0017] Application of the above stable diglyceride oil as thermal processing cooking oil.

[0018] Compared with the prior art, the present application has the following advantages and beneficial effects: the present application first realizes the preparation of diglyceride isomer composition by controlling the glycerolysis degree and fractionation process. Compared with other processes, the present application controls the glycerolysis degree, fractionation conditions, especially the diglyceride content and the 1,3 / 1,2 diglyceride ratio of the diglyceride oil, so that the oxidative stability of the diglyceride oil as thermal processing cooking oil is significantly improved, and the production of risk factors is significantly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the total oxidation value after thermal treatment and the growth rate of total oxidation value before and after thermal treatment of the embodiment and the comparative example of the present application. DETAILED DESCRIPTION

[0020] The present application will be further described in detail below in combination with examples and drawings, but the embodiments of the present application are not limited thereto. The raw materials involved in the present application can be directly purchased from the market. For the process parameters not specifically mentioned, the conventional technology can be referred to. The lipase used in the examples is purchased from Novozymes. The peanut oil used in the examples is purchased from Kingfisher peanut oil of Yihai Kerry Goldilocks Foodstuff Co., Ltd.

[0021] The present application aims to realize the preparation of diglyceride isomer composition by controlling the glycerolysis degree and fractionation process. Compared with other processes, the present application controls the glycerolysis degree, fractionation conditions, especially the diglyceride content and the 1,3 / 1,2 diglyceride ratio of the diglyceride oil, so that the oxidative stability of the diglyceride oil as thermal processing cooking oil is significantly improved, and the production of risk factors is significantly reduced. In the following examples, the experimental data and comparative test data of the characteristics analysis of the diglyceride oil are studied, and the methods are as follows: (1) thermal treatment: in the process of static heating, 300 mL of oil sample is heated to 180 °C in a 500 mL triangular round-bottom flask. The temperature is maintained for 120 min, and the sample is collected for further analysis. Before determination, all samples are stored at-20 °C.

[0022] (2) Glycerol diester content determination was performed using an Agilent Technologies (Palo Alto, CA) equipped with a capillary column DB-1HT (15 m x 0.25 mm x 0.1 pm). The oven temperature was maintained at 380 °C, the pressure was maintained at 20.0 psi, nitrogen gas was used as the carrier gas at a flow rate of 4.41 mL / min, and the constant flow pressure was 30.0 psi. The sample was dissolved in 2 mL of n-hexane and filtered through a 0.45 pm filter. A 20: 1 split mode and a 0.5 pL injection volume were used, and the injection and detector temperature were set to 380 °C. The initial oven temperature was set to 50 °C for 1 min. It was then increased to 100 °C for 2 min, then to 220 °C at a rate of 80 °C / min, and finally to 380 °C at a rate of 50 °C / min for 3 min. The yield of each type of acylglycerol was expressed as a percentage of peak area.

[0023] (3) Glycerol diester isomer content determination was performed using an Agilent Technologies (Palo Alto, CA) equipped with a capillary column DB-1HT (15 m x 0.25 mm x 0.1 pm). The oven temperature was maintained at 380 °C, the pressure was maintained at 20.0 psi, nitrogen gas was used as the carrier gas at a flow rate of 4.41 mL / min, and the constant flow pressure was 30.0 psi. The sample was dissolved in 2 mL of n-hexane and filtered through a 0.45 pm filter. A 20: 1 split mode and a 0.5 pL injection volume were used, and the injection and detector temperature were set to 380 °C. The initial oven temperature was set to 50 °C for 1 min. It was then increased to 100 °C for 2 min, then to 220 °C at a rate of 80 °C / min, and finally to 380 °C at a rate of 50 °C / min for 3 min. The yield of each type of acylglycerol was expressed as a percentage of peak area. 1 H–NMR technique was used to determine the isomer ratio of 1,3 DAG and 1,2 DAG in the sample: 20 mg of sample was weighed, and 0.5 mL of CDCl3 was used to dissolve the sample before and after purification, and then the dissolved sample was transferred to a nuclear magnetic tube for testing. The test conditions were: acquisition time 3.17 s, scan number 80, pulse width 12.76 ps, spectral width 10330.6 Hz, and temperature 25 °C.

[0024] (4) Acid value (AV), peroxide value (PV), and total oxidation value (TOTOX) determination AV, PV, and p-AV were determined according to AOCS official methods Cd3d-63, Cd8-53, and Cd18-90, respectively. To determine AV, 10 g of oil sample was dissolved in a conical flask containing a petroleum ether-ethanol mixture (1:1 v / v, 100 mL), a few drops of phenolphthalein indicator were added, and titration was performed with a potassium hydroxide standard solution (0.1 M).

[0025] To determine PV, 5 g of oil sample was dissolved in a conical flask containing a glacial acetic acid-chloroform solution (3:2 v / v, 30 mL), 0.5 mL of saturated potassium iodide solution was added and shaken well, allowed to stand for 1 min, and then 30 mL of distilled water was added. Titration was performed with a sodium thiosulfate solution (0.01 M).

[0026] TOTOX value is the best indicator to measure the overall oxidation state of oil, and the calculation formula is as follows: TOTOX = 4*PV + p-AV (1) where PV represents the PV value (mmol / kg), and p-AV represents the p-AV value.

[0027] (5) Measurement of risk factors (3-MCPDE, GEs) The 3-MCPDE and GEs of the oil sample were analyzed according to the AOCS official method Cd 29a-13. The oil sample was weighed, d5-3-MCPDE standard was added, and tert-butyl methyl ether-ethyl acetate was used for dissolution. Then, methanol-sodium methoxide was added for hydrolysis, followed by purification using acidified sodium chloride and n-hexane. Next, ethyl acetate was added for extraction, followed by benzene boronic acid derivatization and nitrogen drying, and then re-dissolution with isooctane. The sample was filtered with a membrane and subjected to GCMS analysis. The chromatographic conditions were: injection volume of 1 μL, nitrogen flow rate of 1.18 mL / min, column initial temperature of 80 °C, and temperature increase to 300 °C by programming. The mass spectrometry conditions were: EI+SIM mode.

[0028] Example 1 (1) 100 g of peanut oil and 60 g of glycerol were weighed, heated, melted, mixed uniformly, and then placed in a reactor, and the reaction temperature was set to 75 °C. When the temperature was constant, 2.5 g of lipase Lipozyme CALB was added, and a magnetic stirrer was used for stirring (speed 500 r / min), and the reaction was carried out under the condition of water circulating pump vacuum (absolute pressure = 5000 Pa) to make the oil and enzyme fully react to complete the ester exchange. After 60 min of reaction, the reaction liquid was centrifuged to separate the glycerol layer and the lipase, and the oil sample was collected as a crude glycerol diester oil.

[0029] (2) The crude glycerol diester oil was purified by molecular distillation: the distillation temperature was 180 °C, the vacuum degree was 0.5 Pa, the scraper speed was 200 rpm, the condenser temperature was 40 °C, and the feeding flow rate was 0.5 mL / min. The light phase oil was collected.

[0030] (3) 100 g of the purified peanut glycerol diester oil sample was weighed in a beaker and melted, the beaker was immersed in a 5 °C water bath and stirred, and the stirring was immersed for 90 min to precipitate the solid material, the stirring speed was 100 r / min, and a Buchner funnel was used to filter the solid part and the liquid part. The liquid part was collected to obtain the final glycerol diester oil sample.

[0031] It was calculated that the glycerol diester content in the glycerol diester oil product was 85%, among which the 1,3 glycerol diester: 1,2 glycerol diester = 6.5:3.5, the initial total oxidation value of the glycerol diester oil was 18.08, the peroxide value was 2.87 mmol / kg, the acid value was 0.65 mg / g, the 3MCPDE content was 179 ug / kg, and the GEs content = 97 ug / kg. After heating at 180 °C for 120 min, the total oxidation value = 108.5, the peroxide value = 10.7 mmol / kg, the acid value = 0.70 mg / g, the 3MCPDE content = 184 ug / kg, and the GEs content = 122 ug / kg.

[0032] Example 2 This example is the same as example 1 except for the following technical features: Step (1) set the reaction temperature to 60 °C, and the reaction time to 60 min.

[0033] The calculated diacylglycerol content of the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 6:4, the initial peroxide value of the diacylglycerol oil was 17.58, the peroxide value was 2.89 mmol / kg, the acid value was 0.58 mg / g, the 3MCPDE content was 170 ug / kg, and the GEs content = 109 ug / kg. The diacylglycerol oil was heated at 180 °C for 120 min, the peroxide value = 98.0, the peroxide value = 9.3 mmol / kg, the acid value = 0.90 mg / g, the 3MCPDE content = 177 ug / kg, and the GEs content = 123 ug / kg.

[0034] Example 3 This example is the same as example 1 except for the following technical features: Step (1) set the reaction temperature to 80 °C, and the reaction time to 60 min.

[0035] The calculated diacylglycerol content of the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 7.2:2.8, the initial peroxide value of the diacylglycerol oil was 18.10, the peroxide value was 2.99 mmol / kg, the acid value was 0.70 mg / g, the 3MCPDE content was 133 ug / kg, and the GEs content = 102 ug / kg. The diacylglycerol oil was heated at 180 °C for 120 min, the peroxide value = 108.7, the peroxide value = 7.0 mmol / kg, the acid value = 0.80 mg / g, the 3MCPDE content = 151 ug / kg, and the GEs content = 185 ug / kg.

[0036] Example 4 This example is the same as example 1 except for the following technical features: Step (1) set the reaction temperature to 75 °C, and the reaction time to 30 min.

[0037] The calculated diacylglycerol content of the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 7:3, the initial peroxide value of the diacylglycerol oil was 16.22, the peroxide value was 2.73 mmol / kg, the acid value was 0.72 mg / g, the 3MCPDE content was 153 ug / kg, and the GEs content = 111 ug / kg. The diacylglycerol oil was heated at 180 °C for 120 min, the peroxide value = 85.5, the peroxide value = 8.9 mmol / kg, the acid value = 0.90 mg / g, the 3MCPDE content = 189 ug / kg, and the GEs content = 121 ug / kg.

[0038] Example 5 This example is the same as example 1 except for the following technical features: step (1) set the reaction temperature to 75 °C, and the reaction time to 90 min.

[0039] The calculated diacylglycerol content of the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 7.9:2.1. The initial peroxide value of the diacylglycerol oil was 19.21, the peroxide value was 3.08 mmol / kg, the acid value was 0.69 mg / g, the 3MCPDE content was 141 ug / kg, and the GEs content = 155 ug / kg. The diacylglycerol oil was heated at 180 °C for 120 min, the peroxide value = 96.5, the peroxide value = 7.5 mmol / kg, the acid value = 0.80 mg / g, the 3MCPDE content = 154 ug / kg, and the GEs content = 182 ug / kg.

[0040] Example 6 This example is the same as example 1 except for the following technical features: step (3) the fractionation temperature was 10 °C.

[0041] The calculated diacylglycerol content of the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 6.2:3.8. The initial peroxide value of the diacylglycerol oil was 21.00, the peroxide value was 3.1 mmol / kg, the acid value was 0.60 mg / g, the 3MCPDE content was 156 ug / kg, and the GEs content = 100 ug / kg. The diacylglycerol oil was heated at 180 °C for 120 min, the peroxide value = 98.0, the peroxide value = 9.1 mmol / kg, the acid value = 0.7 mg / g, the 3MCPDE content = 188 ug / kg, and the GEs content = 118 ug / kg.

[0042] Example 7 This example is the same as example 1 except for the following technical features: step (1) the lipase was Lipozyme RM IM.

[0043] The calculated diacylglycerol content of the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 6.5:3.5. The initial peroxide value of the diacylglycerol oil was 22.09, the peroxide value was 2.82 mmol / kg, the acid value was 0.54 mg / g, the 3MCPDE content was 151 ug / kg, and the GEs content = 166 ug / kg. The diacylglycerol oil was heated at 180 °C for 120 min, the peroxide value = 120.0, the peroxide value = 8.2 mmol / kg, the acid value = 0.6 mg / g, the 3MCPDE content = 167 ug / kg, and the GEs content = 199 ug / kg.

[0044] Example 8 This example is the same as example 1 except for the following technical features: step (3) the fractionation time was 120 min.

[0045] The diglyceride oil product was calculated to have a diglyceride content of 85%, with 1,3 diglyceride: 1,2 diglyceride = 7.1 : 2.9, an initial peroxide value of 19.19, a peroxide value of 2.28 mmol / kg, an acid value of 0.71 mg / g, a 3MCPDE content of 101 ug / kg, and a GEs content = 156 ug / kg. The diglyceride oil was heated at 180°C for 120 min, and had a peroxide value = 111.0, a peroxide value = 11.5 mmol / kg, an acid value = 0.9 mg / g, a 3MCPDE content = 110 ug / kg, and a GEs content = 160 ug / kg.

[0046] Example 9 This example is the same as example 1 except for the following technical features: the amount of lipase added in step (1) was 5 g.

[0047] The diglyceride oil product was calculated to have a diglyceride content of 85%, with 1,3 diglyceride: 1,2 diglyceride = 8:2, an initial peroxide value of 19.90, a peroxide value of 2.97 mmol / kg, an acid value of 0.61 mg / g, a 3MCPDE content of 94 ug / kg, and a GEs content = 124 ug / kg. The diglyceride oil was heated at 180°C for 120 min, and had a peroxide value = 107.0, a peroxide value = 11.4 mmol / kg, an acid value = 0.7 mg / g, a 3MCPDE content = 100.5 ug / kg, and a GEs content = 154 ug / kg.

[0048] Example 10 This example is the same as example 1 except for the following technical features: the amount of glycerol added in step (1) was 100 g.

[0049] The diglyceride oil product was calculated to have a diglyceride content of 85%, with 1,3 diglyceride: 1,2 diglyceride = 6.2:3.8, an initial peroxide value of 19.22, a peroxide value of 2.88 mmol / kg, an acid value of 0.60 mg / g, a 3MCPDE content of 144 ug / kg, and a GEs content = 113 ug / kg. The diglyceride oil was heated at 180°C for 120 min, and had a peroxide value = 120.0, a peroxide value = 8.6 mmol / kg, an acid value = 0.7 mg / g, a 3MCPDE content = 193 ug / kg, and a GEs content = 128 ug / kg.

[0050] Example 11 This example is the same as example 1 except for the following technical features: the distillation temperature in step (2) was 190°C.

[0051] The calculated diacylglycerol content in the diacylglycerol oil product was 92%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 6.6:3.4, the initial peroxide value of the diacylglycerol oil was 29.22, the peroxide value was 2.9 mmol / kg, the acid value was 0.63 mg / g, the 3MCPDE content was 155 ug / kg, and the GEs content = 102 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 100.5, the peroxide value = 8.7 mmol / kg, the acid value = 0.7 mg / g, the 3MCPDE content = 171 ug / kg, and the GEs content = 123 ug / kg.

[0052] Comparative Example 1 This comparative example is the same as Example 1 except for the following technical features: step (2) is set to a reaction temperature of 50°C and a reaction time of 60 min.

[0053] The calculated diacylglycerol content in the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 5.5:4.5, the initial peroxide value of the diacylglycerol oil was 21.22, the peroxide value was 2.93 mmol / kg, the acid value was 0.60 mg / g, the 3MCPDE content was 155 ug / kg, and the GEs content = 120 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 138.0, the peroxide value = 17.3 mmol / kg, the acid value = 1.3 mg / g, the 3MCPDE content = 370 ug / kg, and the GEs content = 300 ug / kg.

[0054] Comparative Example 2 This comparative example is the same as Example 1 except for the following technical features: step (1) is set to a reaction temperature of 55°C and a reaction time of 60 min.

[0055] The calculated diacylglycerol content in the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 5.9:4.1, the initial peroxide value of the diacylglycerol oil was 20.96, the peroxide value was 3.11 mmol / kg, the acid value was 0.71 mg / g, the 3MCPDE content was 148 ug / kg, and the GEs content = 150 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 158.7, the peroxide value = 19.0 mmol / kg, the acid value = 1.8 mg / g, the 3MCPDE content = 350 ug / kg, and the GEs content = 285 ug / kg.

[0056] Comparative Example 3 This comparative example is the same as Example 1 except for the following technical features: step (1) is set to a reaction temperature of 75°C and a reaction time of 10 min.

[0057] The calculated diacylglycerol content in the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 4:6, the initial peroxide value of the diacylglycerol oil was 28.88, the peroxide value was 3.09 mmol / kg, the acid value was 0.62 mg / g, the 3MCPDE content was 168 ug / kg, and the GEs content = 110 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 230.0, the peroxide value = 19.9 mmol / kg, the acid value = 1.9 mg / g, the 3MCPDE content = 489 ug / kg, and the GEs content = 310 ug / kg.

[0058] Comparative Example 4 This comparative example is the same as Example 1 except for the following technical features: the reaction temperature in step (1) was set to 75°C, and the reaction time was 120 min.

[0059] The calculated diacylglycerol content in the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 8.2:1.8, the initial peroxide value of the diacylglycerol oil was 31.00, the peroxide value was 3.22 mmol / kg, the acid value was 0.60 mg / g, the 3MCPDE content was 159 ug / kg, and the GEs content = 101 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 136.5, the peroxide value = 17.5 mmol / kg, the acid value = 1.2 mg / g, the 3MCPDE content = 354 ug / kg, and the GEs content = 182 ug / kg.

[0060] Comparative Example 5 This comparative example is the same as Example 1 except for the following technical features: the fractionation temperature in step (3) was 15°C.

[0061] The calculated diacylglycerol content in the diacylglycerol oil product was 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 5.5:4.5, the initial peroxide value of the diacylglycerol oil was 28.10, the peroxide value was 2.77 mmol / kg, the acid value was 0.55 mg / g, the 3MCPDE content was 144 ug / kg, and the GEs content = 112 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 148.0, the peroxide value = 19.1 mmol / kg, the acid value = 1.7 mg / g, the 3MCPDE content = 380 ug / kg, and the GEs content = 218 ug / kg.

[0062] Comparative Example 6 This comparative example is the same as Example 1 except for the following technical features: the catalyst in step (1) was NaOH, the addition amount was 0.5% of the mass of the substrate, the reaction temperature was 180°C, and the reaction time was 120 min.

[0063] The diacylglycerol content of the diacylglycerol oil product was calculated to be 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 7:3, the initial peroxide value of the diacylglycerol oil was 29.05, the peroxide value was 2.60 mmol / kg, the acid value was 0.60 mg / g, the 3MCPDE content was 149 ug / kg, and the GEs content = 110 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 210.0, the peroxide value = 25.2 mmol / kg, the acid value = 1.1 mg / g, the 3MCPDE content = 575 ug / kg, and the GEs content = 490 ug / kg.

[0064] Comparative Example 7 This comparative example is the same as Example 1 except for the following technical features: step (3) was not fractionated.

[0065] The diacylglycerol content of the diacylglycerol oil product was calculated to be 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 6.5:3.5, the initial peroxide value of the diacylglycerol oil was 28.80, the peroxide value was 3.00 mmol / kg, the acid value was 0.62 mg / g, the 3MCPDE content was 168 ug / kg, and the GEs content = 158 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 138.5, the peroxide value = 17.0 mmol / kg, the acid value = 1.2 mg / g, the 3MCPDE content = 642 ug / kg, and the GEs content = 900 ug / kg.

[0066] Comparative Example 8 This comparative example is the same as Example 1 except for the following technical features: the amount of lipase added in step (1) was 10 g.

[0067] The diacylglycerol content of the diacylglycerol product was calculated to be 85%, of which 1,3 diacylglycerol: 1,2 diacylglycerol = 8.2:1.8, the initial peroxide value of the diacylglycerol oil was 28.88, the peroxide value was 3.09 mmol / kg, the acid value was 0.60 mg / g, the 3MCPDE content was 147 ug / kg, and the GEs content = 110 ug / kg. The diacylglycerol oil was heated at 180°C for 120 min, the peroxide value = 218.0, the peroxide value = 14.4 mmol / kg, the acid value = 0.9 mg / g, the 3MCPDE content = 400 ug / kg, and the GEs content = 354 ug / kg.

[0068] Comparative Example 9 This comparative example is the same as Example 1 except for the following technical features: the amount of glycerol added in step (1) was 30 g.

[0069] The diglyceride product was calculated to have a diglyceride content of 85%, with 1,3 diglyceride: 1,2 diglyceride = 4.8:5.2, the diglyceride oil had an initial peroxide value of 30.05, a peroxide value of 2.82 mmol / kg, an acid value of 0.52 mg / g, a 3MCPDE content of 160 ug / kg, and a GEs content = 160 ug / kg, the diglyceride oil was heated at 180°C for 120 min, the peroxide value = 130.0, the peroxide value = 19.6 mmol / kg, the acid value = 1.0 mg / g, the 3MCPDE content = 593 ug / kg, and the GEs content = 428 ug / kg.

[0070] Comparative Example 10 This example is the same as Example 1 except for the following technical feature: step (2) distillation temperature is 170°C.

[0071] The diglyceride product was calculated to have a diglyceride content of 73%, with 1,3 diglyceride: 1,2 diglyceride = 6.6:3.4, the diglyceride oil had an initial peroxide value of 28.88, a peroxide value of 3.01 mmol / kg, an acid value of 0.60 mg / g, a 3MCPDE content of 149 ug / kg, and a GEs content = 144 ug / kg, the diglyceride oil was heated at 180°C for 120 min, the peroxide value = 153.0, the peroxide value = 15.7 mmol / kg, the acid value = 0.7 mg / g, the 3MCPDE content = 371 ug / kg, and the GEs content = 323 ug / kg.

[0072] Comparative Example 11 This example is the same as Example 1 except for the following technical feature: step (2) distillation temperature is 210°C.

[0073] The diglyceride product was calculated to have a diglyceride content of 80%, with 1,3 diglyceride: 1,2 diglyceride = 6.6:3.4, the diglyceride oil had an initial peroxide value of 31.01, a peroxide value of 3.09 mmol / kg, an acid value of 0.69 mg / g, a 3MCPDE content of 168 ug / kg, and a GEs content = 120 ug / kg, the diglyceride oil was heated at 180°C for 120 min, the peroxide value = 123.0, the peroxide value = 14.0 mmol / kg, the acid value = 0.9 mg / g, the 3MCPDE content = 292 ug / kg, and the GEs content = 300 ug / kg.

[0074] Table 1 Comparative data for peroxide value and acid value after heat treatment for examples and comparative examples used in the present invention Table 2 Comparison of heat stability properties for examples and comparative examples Conclusion: after the peanut oil is subjected to moderate glycerolysis reaction to obtain peanut oil diglyceride oil, and then purified by molecular distillation and modified by fractionation, the peanut oil diglyceride oil is obtained, compared with other processes, the glycerolysis degree, molecular distillation purification and fractionation conditions, especially the glyceride content and the 1,3 / 1,2 glyceride ratio of the peanut oil diglyceride oil are controlled, the oxidative stability of the peanut oil diglyceride oil as a hot processing cooking oil is significantly improved, and the production amount of risk factors is significantly reduced.

[0075] The above embodiment is a preferred embodiment of the present application, but the embodiment of the present application is not limited to the above embodiment, and any change, modification, replacement, combination, simplification made without departing from the spirit and principle of the present application should be an equivalent replacement mode, and all are included in the protection scope of the present application.

Claims

1. A method for producing a stable diglyceride oil, characterized by, The method comprises the following steps: (1) glycerolysis of vegetable oil, and then collecting the oil sample and purifying the raw glyceride oil by molecular distillation; (2) dry fractionation of the raw glyceride oil, and then collecting the fractionated oil to obtain the stable glyceride oil.

2. The method according to claim 1, wherein the vegetable oil in step (1) is a vegetable oil with a sliding melting point of greater than or equal to 4 ℃, preferably peanut oil.

3. The method according to claim 1, wherein the glycerolysis in step (1) is enzyme-catalyzed glycerolysis, and the enzyme is one of lipase Lipozyme CALB, Lipozyme TL IM or Lipozyme RM IM; the mass ratio of vegetable oil to glycerol in glycerolysis is 2:1-1:1; the enzyme addition amount is 1-5% of the substrate mass; the glycerolysis reaction temperature is 60-80 ℃; and the reaction time is 30-90 min.

4. The method according to claim 1, wherein the molecular distillation purification in step (1) obtains the raw glyceride oil in the light phase, and the glyceride content is 80-100%.

5. The method according to claim 1, wherein the molecular distillation in step (1) is operated according to the following parameters: distillation temperature is 180-190 ℃; vacuum degree is 0.5-1.0 Pa; scraper rotation speed is 150-200 rpm; condenser temperature is 30-50 ℃; and feed flow rate is ≤0.5 mL / min.

6. The method according to claim 1, wherein the fractionation in step (2) comprises the following steps: melting the raw glyceride oil, then stirring and immersing at 5-10 ℃ for 90 min or more until the solid matter is precipitated, then performing suction filtration to separate the solid part and the liquid part, and collecting the fractionated oil.

7. The method according to claim 1, wherein the mass ratio of 1,3 glyceride to 1,2 glyceride in the stable glyceride oil is 6:4-8:

2.

8. A stable glyceride oil prepared by the method according to any one of claims 1-7.

9. The stable glyceride oil according to claim 8, wherein the 3MCPDE content growth rate of the stable glyceride oil after heat treatment is ≤34%; and the GEs content growth rate is ≤81.4%, preferably ≤25.8%.

10. Use of the stable glyceride oil according to claim 8 or 9 as a heat-processed cooking oil. ​ ​ ​ ​ ​ ​ ​

Images