Structural fat for improving cognitive impairment in the elderly and a method for preparing the same

Abstract

The application discloses a structural fat for improving cognitive impairment in the elderly and a preparation method thereof. The immobilized lipase is filled into a continuous flow biocatalytic reaction column and subjected to nitrogen filling treatment; triglyceride with the mass content of DHA at the sn-2 position being above 65% is uniformly stirred and mixed with n-octanoic acid to obtain a reaction liquid; the reaction liquid is pumped into the continuous flow biocatalytic reaction column to obtain mixed lipids, which are subjected to deacidification and dehydration treatment to obtain the structural fat. The structural fat significantly improves the rancid smell of n-octanoic acid and the fishy smell of DHA, and improves the flavor acceptance. Meanwhile, the structural fat effectively overcomes the defects of strong irritation of high-dose n-octanoic acid, poor oxidation stability of DHA and low absorption rate, and enhances the functional safety and quality stability of the product. The structural fat shows a synergistic effect in improving cognitive impairment, is suitable for nutritional intervention of aging or neurodegenerative diseases, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of functional lipid biosynthesis processing, and particularly relates to a structural lipid for improving senile cognitive impairment and a preparation method thereof. BACKGROUND

[0002] The detection rate of cognitive impairment of people aged 60 and above in China is as high as 30.59%, and senile cognitive impairment related to neurodegenerative diseases has become a major challenge in the field of nutrition. Unlike external pathogen infection, cognitive impairment is mainly caused by energy metabolism imbalance and neural function degradation in the brain. Although traditional early drug intervention can alleviate some symptoms, it may damage the normal function of the body's genes or proteins, and there is a certain risk of side effects. In contrast, dietary nutritional supplements provide a safer and more economical intervention program by regulating the overall nutritional environment and improving signal transduction pathways.

[0003] Structural lipids are a class of functional lipids obtained by redistributing or modifying the composition of fatty acids of glycerol triesters through chemical or enzymatic methods, and have specific fatty acid positioning structures at the molecular level. Among them, medium-long chain triglycerides (MLCT) as an important type of structural lipids have a wide range of applications in ordinary food, dietary supplements and special medical food. MLCT structure contains both medium-chain fatty acids (C8-C12) and long-chain fatty acids (>C12). However, current MLCT products generally have problems such as inaccurate structure positioning and low bioavailability, making it difficult to meet the precise intervention of specific nutritional needs.

[0004] Octanoic acid (C8:0) can more effectively promote brain energy metabolism compared to other medium-chain fatty acids, but excessive intake can easily cause dose-dependent gastrointestinal discomfort. In addition, traditional DHA glycerides containing a single component have limited effects on improving age-related neural function degradation, and have defects such as obvious fishy smell and poor oxidative stability. Studies have shown that when C8:0 is located at the sn-1 / 3 position of glycerides, the metabolic rate of C8:0 can be effectively increased while reducing the intake dose, thereby promoting the energy metabolism homeostasis of brain neurons; and when DHA is located at the sn-2 position of glycerides, the sn-2-DHA hydrolyzed by pancreatic lipase in the body can be more quickly absorbed by the intestinal epithelial cells, and the absorption efficiency is 2 times that of ordinary sn-1 / 3-DHA, and can significantly enhance the protection of neural function. Based on the above evidence, the synthesis of structural lipids rich in sn-1,3-C8:0-sn-2-DHA can meet the dual needs of "energy homeostasis and neural protection" in the intervention of senile cognitive impairment, and realize precise nutritional intervention.

[0005] The limitations of the existing MLCT synthesis technology include two aspects of raw material structure and synthesis method. In addition to the long-chain fatty acid in the infant formula MLCT being limited to C14-C18 saturated fatty acid, other MLCTs are generally not explicitly limited to the type and position of C8:0 or DHA. One of the main reasons is that the oil and fat source of high-purity C8:0 is scarce, and the existing technical route generally fails to effectively utilize the rapid energy supply advantage of C8:0; secondly, due to the low content of sn-2 DHA in conventional oil and fat, or the poor selective enrichment effect of the selected technology on sn-2 DHA, the structural lipid yield or purity of the sn-2-DHA position distribution is low, which ultimately restricts the efficacy of the existing MLCT in improving cognitive impairment in the elderly. In addition, the synthesis of MLCT mainly uses traditional chemical method or immobilized enzyme method, and the reaction mode mainly relies on static kettle reaction. Chemical method uses strong alkaline catalyst, which has environmental pollution hazard; and traditional enzyme method has long reaction time and low unit productivity, which is the bottleneck of industrialization.

[0006] Therefore, in order to realize the synergistic effect of C8:0 and DHA, to develop a sn-1,3-C8:0-sn-2-DHA structural lipid with clear structural characteristics and effectively improve cognitive impairment in the elderly, and a high-efficiency green preparation method thereof, is a technical problem that needs to be broken through in the field. SUMMARY

[0007] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0008] As one aspect of the present application, the present application provides a preparation method of a structural lipid for improving cognitive impairment in the elderly, and the reaction route is as follows:

[0009]

[0010] The preparation method of the structural lipid for improving cognitive impairment in the elderly comprises the following steps,

[0011] The immobilized lipase is filled into a continuous flow biocatalytic reaction column and subjected to nitrogen filling treatment;

[0012] The triglyceride with a mass content of sn-2 DHA of more than 65% is uniformly stirred and mixed with n-octanoic acid to obtain a reaction liquid;

[0013] The reaction liquid is pumped into the continuous flow biocatalytic reaction column to obtain a mixed lipid, which is subjected to deacidification and dehydration treatment to obtain the structural lipid.

[0014] As a preferred scheme of the preparation method of the structural fat for improving cognitive impairment in the elderly according to the present application: the immobilized lipase comprises one or more of lipase Lipozyme TL IM, lipase R IM-03 or lipase IM-NE100.

[0015] As a preferred scheme of the preparation method of the structural fat for improving cognitive impairment in the elderly according to the present application: the mixing is uniform, and the mixing temperature is 30-60℃.

[0016] As a preferred scheme of the preparation method of the structural fat for improving cognitive impairment in the elderly according to the present application: the mixing is uniform, and the mixing temperature is 45-55℃, and the mixing time is 10-30 min.

[0017] As a preferred scheme of the preparation method of the structural fat for improving cognitive impairment in the elderly according to the present application: the reaction solution is pumped into the continuous flow biocatalytic reaction column, and the reaction column temperature is 30-60℃.

[0018] As a preferred scheme of the preparation method of the structural fat for improving cognitive impairment in the elderly according to the present application: the reaction solution is pumped into the continuous flow biocatalytic reaction column, and the reaction column temperature is 45-55℃.

[0019] As a preferred scheme of the preparation method of the structural fat for improving cognitive impairment in the elderly according to the present application: the reaction solution is pumped into the continuous flow biocatalytic reaction column, and the flow rate is 0.25-1.0 mL / min.

[0020] As a preferred scheme of the preparation method of the structural fat for improving cognitive impairment in the elderly according to the present application: the molar ratio of the triglyceride with a DHA mass content at the sn-2 position of more than 65% to n-octanoic acid is 1:2-6.

[0021] The present application has the following beneficial effects: the present application constructs a structural fat rich in sn-1,3-C8:0-sn-2-DHA triglyceride type, which positions DHA with strong neuroprotective function at the sn-2 position in the molecular structure, and introduces n-octanoic acid (C8:0) with a fast metabolic rate and rapid energy supply at the sn-1,3 position, realizing the dual nutritional synergistic intervention effect of "energy homeostasis and neuroprotection", and effectively overcoming the limitations of DHA and n-octanoic acid when used alone. The specific performance is as follows:

[0022] (1) The obtained structured fat has DHA positioned at the sn-2 site with high efficiency, and the absorption efficiency is twice that of ordinary DHA, thereby significantly improving the bioavailability of DHA; at the same time, n-octanoic acid is positioned at the sn-1,3 site, which can effectively reduce the dosage strength by about 33% compared with traditional trioctanoic acid glyceride, and can be rapidly hydrolyzed under the action of gastrointestinal pancreatic lipase, thereby promoting the energy metabolism homeostasis of brain neurons. The molecular structure has high absorption, high energy supply and high safety, and in an animal model of senile cognitive impairment, the effect of significantly improving the movement ability and perception ability is better than that of DHA or n-octanoic acid alone, and has a clear synergistic advantage.

[0023] (2) The product of the present application shows no obvious toxic side effects in in-vivo simulation evaluation, and overcomes the defects of strong irritating odor and poor intake safety of n-octanoic acid alone. At the same time, DHA is placed at the middle sn-2 site of the glycerol skeleton, and the octanoic acid at the side sn-1 / 3 site can effectively protect DHA, reduce the odor and safety risk caused by oxidation. In sensory evaluation, compared with the comparative product, the structured fat exhibits significantly reduced odor caused by octanoic acid or DHA, improves the flavor and consumer acceptance, and has the practical feasibility of food development.

[0024] (3) The present application uses continuous flow immobilized enzyme catalytic reaction to optimize the substrate structure and reaction conditions, and the synthesis time is shortened to 2 hours, the content of sn-1,3-C8:0-sn-2-DHA in the product can reach more than 60%, and the total purity of triglyceride can reach more than 85% detected by HPLC. Compared with the traditional static enzyme method product content <50%, reaction time >5 h process, the efficiency and quality are greatly improved.

[0025] (4) The continuous flow system has good mass transfer and heat transfer performance, and can accurately control the reaction temperature and flow rate, thereby improving the process consistency and safety. The service life of the immobilized enzyme is long and can be repeatedly used for more than 30 times, the process is environmentally friendly and low in cost, and meets the green manufacturing and industrial production needs. The process is controllable, safe and environmentally friendly, and is beneficial to industrialization.

[0026] (5) The sn-1,3-C8:0-sn-2-DHA structured fat prepared by the present application can be widely used in ordinary food, dietary supplements, special medical food and other fields, and is especially suitable for nutritional intervention of the elderly, patients with neurodegenerative diseases and people at risk of cognitive dysfunction, and has good market conversion prospects and social value. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0028] Figure 1 The structural schematic diagram of the continuous flow reaction device used in the present application.

[0029] Figure 2 The effect diagram of the structural lipid of the present application for improving the movement disorder and sensory disorder of C. elegans.

[0030] Figure 3 The HPLC liquid chromatogram of the structural lipid of the present application, which shows that the triglyceride in the structural lipid is the main component, and the proportion reaches 96%.

[0031] Figure 4 The influence of the product of the embodiment and the comparative example of the present application on the development of the body length of C. elegans. ** represents p<0.01.

[0032] Figure 5 The influence of the product of the embodiment and the comparative example of the present application on the movement disorder activity (body swing frequency) of C. elegans. Different lowercase letters represent significant differences, p<0.05.

[0033] Figure 6 The influence of the product of the embodiment and the comparative example of the present application on the sensory disorder activity (chemotaxis index) of C. elegans. Different lowercase letters represent significant differences, p<0.05.

[0034] Figure 7 The QDA radar chart of the product 1 of the embodiment and the products 13 and 14 of the comparative example of the present application. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below.

[0036] The fatty acid composition analysis is carried out according to GB 5009.168-2016 Food Safety National Standard Determination of Fatty Acids in Food.

[0037] The chromatographic conditions for determining the content of triglyceride by HPLC-RID method are as follows: a Sepax HP-Silica column (4.6 mm x 250 mm x 5 μm) is used, the column temperature is 25 °C, the sample concentration is about 20 mg / mL, the injection volume is 20 μL, the mobile phase is n-hexane: isopropyl alcohol: formic acid = 15:1:0.003 (v / v / v), and the flow rate is 1 mL / min. One drop of oil sample is taken into a centrifuge tube, 1 mL of mobile phase is added, oscillation is performed for 30 s, and then the sample is prepared by using a syringe to draw through the membrane. The lipid components are qualitatively determined by using standard samples, the sample concentration is linearly related to the peak area, and the relative composition of each substance is expressed by area normalization method (%).

[0038] Determination of the composition of fatty acids at the sn-2 position: The composition of fatty acids at the sn-2 position of triglyceride is determined by using pancreatic lipase to specifically hydrolyze the fatty acids at the sn-1,3 positions of triglyceride to obtain 2-MAG. 100 mg of oil is taken into a centrifuge tube, 2 mL of 1 mol / L Tris buffer (pH 8.0), 0.5 mL of a 0.05% cholate solution, and 0.2 mL of a 2.2% calcium chloride solution are added for emulsification. Then, 40 mg of pancreatic lipase is added, the mixture is uniformly mixed, and then oscillation is performed at 40 °C for 3 min. Then, 1 mL of 6 mol / L hydrochloric acid solution is added to stop the reaction, 2 mL of diethyl ether is added to extract the lipids, and then the lipids are concentrated to 200 μL by nitrogen blowing. The concentrated lipids are separated by thin layer chromatography. The developing agent is n-hexane: diethyl ether: acetic acid (50:50:1, v / v / v), the corresponding sn-2 monoglyceride band after separation is scraped off, extracted with diethyl ether twice, and then 2-MAG is obtained by nitrogen blowing, and the composition of the fatty acids is analyzed by GC method.

[0039] Triglyceride (DHA ORIGINS 580): provided by Fermentalg, France, item number 08103, the mass content of DHA at the sn-2 position is about 70%. Caprylic acid: purchased from Shanghai Yinan Chemical Technology Co., Ltd., item number R002004-500 mL, purity ≥ 99%.

[0040] Example 1:

[0041] The immobilized lipase IM-NE100 (2.0 g) was filled into a continuous flow biocatalytic reaction column (Ф1.4 cm x 10 cm) and subjected to nitrogen gas treatment (pressure 0.1 MPa, flow rate 75 mL / min, for 15 min); the triglyceride with a DHA mass content of 70% at the sn-2 position was mixed with n-octanoic acid (molar ratio 1:4) in a preheater, the preheater temperature was 45°C, the mixing time was 15 min, to obtain a reaction liquid; the reaction liquid was pumped into the continuous flow biocatalytic reaction column at a flow rate of 0.5 mL / min, and the circulating temperature of the reaction column was set to 45°C, to obtain a mixed lipid; the collected mixed lipid was subjected to deacidification and dehydration treatment, and the obtained structured lipid had a 1,3-n-octanoic acid-2-DHA mass percentage of 68.5%, and the n-octanoic acid proportion in the triglyceride was 62.4%, and the label 1.

[0042] Example 2:

[0043] Using triglyceride and n-octanoic acid as substrates, the immobilized lipase was replaced with Lipozyme TL IM or lipase RIM-03, respectively, and other synthesis experimental parameters were referred to Example 1. The composition of the obtained structured lipid is shown as follows.

[0044] Table 1. Composition of structured lipids obtained using different lipase types

[0045]

[0046] Example 3:

[0047] Using triglyceride and n-octanoic acid as substrates, the molar ratio of triglyceride to n-octanoic acid was adjusted to 1:2 or 1:6, respectively, and other synthesis experimental parameters were referred to Example 1. The composition of the obtained structured lipid is shown as follows.

[0048] Table 2. Composition of structured lipids obtained using different substrate molar ratios

[0049]

[0050] Example 4:

[0051] Using triglyceride and n-octanoic acid as substrates, the reaction temperature was set to 30°C or 60°C, respectively, and other synthesis experimental parameters were referred to Example 1. The composition of the obtained structured lipid is shown as follows.

[0052] Table 3. Composition of structured lipids obtained using different circulating temperatures

[0053]

[0054] Example 5:

[0055] Using triglyceride and n-octanoic acid as substrates, the flow rate was set to 0.25 mL / min or 1.0 mL / min, respectively, and other synthesis experimental parameters were referred to Example 1. The composition of the structural lipid obtained is shown below.

[0056] Table 4. Composition of structural lipid obtained at different reaction flow rates

[0057]

[0058] Comparative Example 1:

[0059] Using triglyceride and n-octanoic acid as substrates, no nitrogen charging was performed, and other synthesis experimental parameters were referred to Example 1. The mass percentage of 1,3-n-octanoic acid-2-DHA in the structural lipid obtained was 52.4%, and the percentage of n-octanoic acid in the triglyceride was 55.2%, labeled 10.

[0060] Comparative Example 2:

[0061] Using triglyceride and n-octanoic acid as substrates, no continuous flow biocatalytic reaction was performed. The enzyme was added to the preheater and directly reacted with the substrate, and other synthesis experimental parameters were referred to Example 1. The mass percentage of 1,3-n-octanoic acid-2-DHA in the structural lipid obtained was 41.1%, and the percentage of n-octanoic acid in the triglyceride was 43.7%, labeled 11.

[0062] Comparative Example 3:

[0063] Using commercially available ordinary algal oil (triglyceride with 40% DHA at sn-2 position) and n-octanoic acid as substrates, other synthesis experimental parameters were referred to Example 1. The mass percentage of 1,3-n-octanoic acid-2-DHA in the structural lipid obtained was 38.2%, and the percentage of n-octanoic acid in the triglyceride was 56.4%, labeled 12.

[0064] Comparative Example 4: n-octanoic acid, labeled 13.

[0065] Comparative Example 5: triglyceride with 70% DHA at sn-2 position, labeled 14.

[0066] Test Example 1: Toxicity and Side Effect Test

[0067] Add 1% of the product from the examples or comparative examples to NGM medium containing 0.001% NP-40 of *C. elegans*. Stir at 50°C for 30 min to fully dissolve in NGM before pouring into culture dishes. After *C. elegans* synchronization, add eggs to M9 buffer and incubate overnight at 20°C for 12 h to hatch L1 larvae. Experimental interventions are initiated using L1 larvae. Wild-type *C. elegans* samples on day 5 are used as healthy models. The *C. elegans* model of age-related sensory dysfunction (Alzheimer's disease) was purchased from the US Nematode Genetic Resource Center. Video recordings of the nematodes were performed using a stereomicroscope, and body length was analyzed using Wormlab software.

[0068] The results are as follows Figure 4 As shown, caprylic acid (CNA) in experiment number 13 significantly reduced the body length of nematodes compared to the blank model group, indicating that CNA restricts the growth and development of *C. elegans* and has certain toxic side effects. In contrast, products 1-12 obtained through the synthetic process did not significantly alter the body length of nematodes, proving that they had no obvious toxic side effects.

[0069] Experimental Example 2: Assessment of Vitality in Improving Movement Disorders

[0070] The nematode culture procedure was performed according to Example 1. Motility was measured by the number of swings of *C. elegans* in M9 buffer solution every 30 seconds. Each experiment was repeated three times, and the average value was taken. The above tests were performed on the products labeled 1-9 prepared in Examples 1-5 and the products labeled 10-14 determined in Comparative Examples 1-5.

[0071] The results are as follows Figure 5 As shown, compared to the products of Comparative Examples 10-14 and the blank group, the wiggling frequency of *C. elegans* with cognitive impairment significantly increased after intervention with the structural lipids 1-9 prepared according to this invention, indicating that the obtained structural lipids all have good efficacy in improving motor impairment. Meanwhile, the effects of all synthesized structural lipids were significantly higher than those of Comparative Examples 1-5 (labeled 10-14), indicating that the structural lipids have a synergistic effect. Furthermore, in Examples 1-5, the higher the mass percentage of 1,3-octanoic acid-2-DHA, the better the overall effect. Among them, structural lipid 1, with the highest proportion of 1,3-octanoic acid-2-DHA (72.5%), showed the best effect in improving nematode motor impairment, indicating that structural lipids of the 1,3-octanoic acid-2-DHA type have a superior ability to improve motor function.

[0072] Experimental Example 3: Vitality Assessment for Improving Sensory Impairment

[0073] The nematode culture operation refers to Test Example 1. In the center of a 6 cm flat plate, mark O point, on the diameter, mark A and B points on both sides of O point at a distance of 2.5 cm, and mark the front end of A and B points at 0.5 cm. Use the gun head to suck about 50 nematodes and quickly drop them at O point, and record the total number of nematodes N. Place in the incubator for about 10 min, and after the nematodes are scattered, drop isopentanol (attractant) and 1-octanol (repellent) at A and B points respectively, and after adapting for a period of time under the condition of 31% relative humidity and 20°C, use a high-resolution camera to take a 10-second photo. After 1 h, count the number of nematodes at A and B ends. Calculate the chemotaxis index (CI): CI = (N A -N B ) / (N A +N B ), repeat each experiment 3 times, and take the average value.

[0074] wherein N A : the number of nematodes at isopentanol; N B : the number of nematodes at 1-octanol.

[0075] Figure 2 The trajectory diagram of the structural lipid of the present application for improving the movement disorder and sensory disorder of C. elegans shows the influence of different embodiments and comparative examples on the movement ability and sensory ability of C. elegans. Wherein the line segment represents the distance of C. elegans crawling per unit time, and the continuous and long line segment represents good movement ability of C. elegans; A (attractant), B (repellent), and C. elegans crawling to A point rather than B point represent strong sensory ability. The statistical results are shown in Figure 6 Compared with the comparative examples and the model group, the sensory ability of C. elegans after intervention by the structural lipids 1-9 prepared by embodiments 1-5 of the present application is significantly improved, indicating that the obtained structural lipids all have the efficacy of improving sensory disorder. At the same time, in embodiments 1-5, the higher the mass percentage of 1,3-n-octanoic acid-2-DHA, the better the effect, indicating that the structural lipid of 1,3-n-octanoic acid-2-DHA type has better ability to improve sensory ability.

[0076] As can be seen from Test Examples 2 and 3, although the ratio of 1,3-n-octanoic acid-2-DHA in the structured fat prepared in Comparative Example 1 is also relatively high, the improvement effect on the exercise ability and sensory ability is still not significant. This is mainly due to the fact that nitrogen charging is not performed during the reaction, which can cause oxidation of part of the DHA in the structured fat. DHA is a highly unsaturated fatty acid, and the multiple double bonds in its molecule are prone to free radical chain reaction with oxygen, leading to oxidative degradation. After nitrogen charging, the reaction system is in an inert environment, effectively avoiding the oxidation of DHA. DHA is a highly unsaturated fatty acid, which is easily affected by light, heat and oxygen to cause oxidative degradation, generating harmful substances, reducing the nutritional value and possibly producing odor and toxicity. Nitrogen charging replaces the oxygen in the reaction system, reduces the oxygen partial pressure, and inhibits the occurrence of free radical chain reaction, significantly improving the stability of DHA. This measure ensures the structural integrity of DHA during the reaction, further improving the purity and quality of the final product.

[0077] Test Example 4: Sensory evaluation of structured fat

[0078] QDA method was used for sensory evaluation of each product. 30 sensory evaluation personnel were selected from teachers and students of the Food Science and Technology College of Huazhong Agricultural University according to interest and description ability. According to GB / T 16291.1—2012 "General Guidelines for Sensory Analysis Selection, Training and Management of Evaluators Part 1: Optimal Evaluation", the basic sensory ability test was carried out in the standardized sensory analysis laboratory, 15 people were selected to form the optimal evaluation group, and each evaluator was trained for 48h for sensory description analysis. The description words were determined according to the method in GB / T 16861—1997 "Sensory Analysis Identification and Selection of Descriptive Words for Establishing Sensory Profiles by Multivariate Analysis Method". The 15 members of the optimal evaluation group were asked to brainstorm and initially give the description terms of the odor of each structured fat, then the description words obtained were preliminarily screened through group discussion, and the intensity of the description words was evaluated by 5-point scale, the scoring standard was shown in Table 6, the geometric mean M was calculated by formula (1), the odor attributes were sorted and reduced to determine the odor attributes. Finally, the intensity of the odor attributes of the products of each example and comparative example was evaluated by 5-point scale. Each time 3 random number codes were used, and they were randomly presented.

[0079] (1)

[0080] In the formula: F is the ratio of the actual number of times that the description word is mentioned to the total number of times that the description word can be mentioned; I is the ratio of the intensity of the description word actually given by the evaluation group to the maximum possible intensity of the description word.

[0081] Table 6. Sensory attribute odor intensity scoring standard

[0082]

[0083] Results as Figure 7 The sensory evaluation scores show that n-octanoic acid (No. 13) has a higher rancid taste, and the triglyceride with a DHA content of 70% at the sn-2 position (No. 14) has a significant fishy smell. The structural lipid (No. 1) synthesized by the present application has significantly lower scores in greasy taste, rancid taste and fishy smell, indicating that the 1,3-n-octanoic acid-2-DHA triglyceride has better sensory acceptance.

[0084] The present application constructs a 1,3-n-octanoic acid-2-DHA triglyceride structural lipid with precise molecular structure and significant functional synergy. DHA is located at the sn-2 position, and n-octanoic acid is distributed at the sn-1,3 position, realizing the dual functional synergy of neuroprotection and rapid energy supply. The structural lipid can be selectively hydrolyzed by pancreatic lipase in vivo to release sn-2-DHA monoglyceride, significantly improving its absorption efficiency, and rapidly metabolizing n-octanoic acid to generate ketone bodies for energy supply, significantly alleviating the common brain energy metabolism imbalance problem of patients with neurodegenerative diseases. Compared with the problems of oxidative instability, strong irritation or toxic side effects when DHA or n-octanoic acid is used alone, the structural lipid exhibits good physiological safety and significant improvement in motor and sensory function in animal models, demonstrating obvious synergistic advantages.

[0085] The present application uses a continuous flow immobilized enzyme catalytic process, combined with substrate structure optimization and reaction parameter precision control, to successfully realize the efficient synthesis of high-purity structural lipids, with a 1,3-n-octanoic acid-2-DHA content of more than 60% in the product, and a structural lipid purity of more than 85% detected by HPLC. Compared with traditional static kettle enzyme method, the reaction time is shortened to less than 2 hours, and the immobilized enzyme can be reused more than 30 times, with the advantages of high efficiency, green, controllable, easy to scale up, etc., suitable for industrialized scale production of functional foods and special medical nutrition products.

[0086] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, which should be covered by the scope of the claims of the present application.

Claims

1. The application of a structural lipid in the preparation of lipids that improve cognitive impairment in the elderly, characterized in that: The method for preparing the structural lipid includes the following steps: Immobilized lipase was packed into a continuous flow biological enzyme catalytic reaction column and then subjected to nitrogen purging. Triglycerides with a DHA content of over 65% at the sn-2 position were mixed with octanoic acid to obtain a reaction solution. The reaction solution was pumped into a continuous flow bio-enzyme catalytic reaction column to obtain mixed lipids, which were then subjected to deacidification and dehydration to obtain the structured lipids. The immobilized lipase is lipase IM-NE100.

2. The application according to claim 1, characterized in that: The mixture is homogeneous, and the mixing temperature is 30~60℃.

3. The application according to claim 1 or 2, characterized in that: The mixture is homogeneous, with a mixing temperature of 45-55℃ and a mixing time of 10-30 minutes.

4. The application according to claim 1 or 2, characterized in that: The reaction solution is pumped into a continuous flow bio-enzyme catalytic reaction column, and the reaction column temperature is 30-60℃.

5. The application according to claim 1 or 2, characterized in that: The reaction solution is pumped into a continuous flow bio-enzyme catalytic reaction column, and the reaction column temperature is 45~55℃.

6. The application according to claim 1 or 2, characterized in that: The reaction solution is pumped into a continuous flow bio-enzyme catalytic reaction column at a flow rate of 0.25~1.0 mL / min.

7. The application according to claim 1 or 2, characterized in that: The molar ratio of triglycerides with an sn-2 DHA content of over 65% to caprylic acid is 1:2~6.

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