WO2016176988A1 - Preparation method combining enzymatic acid hydrolysis and physical mixing for breast milk fat substitute - Google Patents

Abstract

A preparation method combining enzymatic acid hydrolysis and physical mixing for a breast milk fat substitute. The method primarily comprises two steps, where step one being regulation of bulk fatty acid composition of catfish oil or an extract thereof by acid hydrolysis, and step two being regulation of trace fatty acid composition of the hydrolyzate by physical mixing. The raw material catfish oil and the extract thereof used in the method are available from a wide variety of sources and inexpensive, contain an increased content of sn-2 palmitic acid and a reduced overall content of palmitic acid. A small proportion of free fatty acids is used in the acid hydrolysis reaction. Emphasized simultaneously in the process are the bulk fatty acid composition and distribution thereof and trace fatty acid composition comprising medium-chain and long-chain polyunsaturated fatty acids. The product produced has a high degree of similarity to breast milk fat and has great market application prospects.

Description

Preparation method of human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing Technical field

The invention relates to a preparation method of human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing, and belongs to the technical field of oils and fats.

Background technique

Fat accounts for 3-5% of human milk and is the main source of energy for newborns (>50%), of which triglycerides account for over 98%. Human milk fat contains about 200 kinds of fatty acids, including medium carbon chain fatty acids, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, odd carbon chain fatty acids, branched chain fatty acids, trans fatty acids and hydroxy fatty acids. Among these fatty acids, fatty acids having a content of more than 1% are oleic acid (25-35%), palmitic acid (20-30%), linoleic acid (10-20%), stearic acid (5-9%), Myristic acid (4-9%), lauric acid (3-7%), and palmitic acid (1-3%). The fatty acid distribution of triglyceride in human milk fat is unique. More than 60% of palmitic acid is distributed in the sn-2 position of triglyceride, and other unsaturated fatty acids are mainly distributed in sn-1, 3 position. Due to this special fatty acid distribution, although human milk fat contains more than 200 fatty acids, its TAG type is much smaller than the random distribution of ^3,200 species. Among human milk fats, the most TAG content is USU, such as OPO and OPL. Triglycerides of this structure are important for the digestion, absorption and metabolism of fat in infants and young children. About 10 to 30% of the fat ingested by infants and young children is hydrolyzed into sn-1,2-diglycerides, most of the glycerol by the tongue lipase and gastric lipase (the lipase selective for triglyceride sn-3). The triester is hydrolyzed into a sn-2 monoglyceride in the small intestine by pancreatic lipase (a lipase selective for triglyceride sn-1,3). The sn-2 monoglyceride can be absorbed in the initial form in combination with the bile salt and re-esterified into triglycerides in the intestinal epithelial cells, and finally converted into chylomicrons into the lymphatic circulation to provide energy to the body tissues. During this process, 60 to 70% of the sn-2 fatty acid remains in its original position. Therefore, the presence of saturated fatty acids in the sn-2 position of triglycerides will facilitate the absorption of infants and young children, while avoiding the loss of energy and calcium ions due to the formation of soap by the combination of free saturated fatty acids with calcium and magnesium ions in the body. In addition, the effects of two isomers of OPO and POO on infant lymphocytic granules have been studied. The average particle size of chylomicrons formed by OPO is larger than the average particle size of chylomicrons formed by OOP. This shows that OPO is more efficient than OOP. Therefore, more and more infant formula companies pay more attention to fat structure in addition to the fat composition of fat in milk powder.

The medium carbon chain fatty acids in human milk fat are mainly caproic acid, caprylic acid and lauric acid. The long carbon chain polyunsaturated fatty acids are mainly docosahexaenoic acid (DHA, Arachidonic Acid). )Wait. The medium carbon chain fatty acids are mainly distributed in the sn-3 position of human milk fat, and the duodenal prolipase has higher activity on the medium carbon chain fatty acids at this position. Hydrolyzed medium-chain fatty acids can be absorbed by the portal vein to provide immediate energy to infants, while 1,2-disaccharide facilitates digestion and absorption in the duodenum by increasing the solubility of triglycerides. Long carbon chain polyunsaturated fat Fatty acids are less abundant in human milk fat, but they are important for infant development, especially DHA and AA. DHA and AA are highly concentrated in the human retina and brain, and play an important role in the development of the human visual system and central nervous system. However, for some babies, the synthesis of DHA and AA has certain difficulties due to the lower dehydrogenase activity. Therefore, based on the special functions of medium-chain fatty acids and long-chain polyunsaturated fatty acids, proper supplementation of these fatty acids in human milk substitute fats will be beneficial to the healthy development of infants and young children.

The main raw materials for the synthesis of human milk substitute lipids reported in the literature are palm stearin and lard. Palm stearin is used as a raw material, and the amount of acid hydrolyzed fatty acid used is large, and post-treatment is difficult, resulting in high cost. Lard has similar fatty acid composition and distribution to human milk fat, but it is difficult to obtain universal use because lard itself is not suitable for people of some national beliefs. Therefore, it is necessary to find a fat having a higher palmitic acid content and a lower total palmitic acid content at the sn-2 position, and to develop a method for preparing a human milk substitute fat having a fat composition and a structure close to human milk.

Summary of the invention

The object of the present invention is to provide an economical and feasible method for preparing human milk substitute fat by enzymatic acid hydrolysis and physical mixing using salmon oil as a raw material.

In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing, comprising:

(1) Melt the salmon oil at 50-60 ° C for 30-60 min, and cool down to 15-30 ° C at a cooling rate of 1 ~ 5 ° C / min, and keep the eel oil at this temperature for 5 ~ 48 h, The liquid oil is removed by filtration to obtain a solid fat component of salmon oil rich in palmitic acid at the sn-2 position;

(2) using sn-1, 3-position specific lipase as a catalyst, using oleic acid-rich vegetable oil-derived free fatty acids and linoleic acid-derived vegetable oil-derived free fatty acids as acyl groups for preparing human milk substitute fat products Body, acidifying the fat component of the salmon oil, removing lipase and free fatty acid to obtain an intermediate product;

(3) According to the difference of the intermediate milk fat in the content of medium carbon chain fatty acids and long carbon chain polyunsaturated fatty acids, under the guidance of the physical mixing model of fats and oils, the medium carbon chain fatty acids and long carbons of intermediate products are regulated by adding oils and fats. Chain polyunsaturated fatty acid content, thereby further improving the similarity of the product to human milk fat in fatty acid composition and distribution;

(4) The similarity of the final product to the human milk fat in the fatty acid composition and distribution was evaluated by the human milk replacement lipid evaluation model.

In one embodiment of the present invention, the oleic acid-rich vegetable oil-derived free fatty acid of step (2) and the free fatty acid of a common vegetable oil rich in linoleic acid are used as an acyl donor for preparing a human milk substitute fat product. The mass ratio is 1:1 to 4.

In one embodiment of the present invention, the oleic acid-rich vegetable oil of the step (2) is tea seed oil, olive oil, and vegetables. Seed oil or the like; the linoleic acid-rich vegetable oil is corn oil, soybean oil, sunflower oil, and the like.

In one embodiment of the invention, the catalyst of step (2) is Lipozyme RM IM and/or Lipozyme TL IM.

In one embodiment of the present invention, the acid hydrolysis is carried out in the step (2), and the reaction temperature is from 40 ° C to 70 ° C.

In one embodiment of the present invention, the acid hydrolysis in the step (2) is a batch reaction, and the molar ratio of the salmon oil to the free fatty acid is 1:1 to 5, and the enzyme amount is 3% to 15%, and the reaction time is The stirring rate is from 300 r/min to 800 r/min for 1 h to 5 h.

In one embodiment of the present invention, the acid hydrolysis in the step (2) is a continuous reaction, wherein the molar ratio of the salmon oil to the free fatty acid is 1:1 to 6, and the substrate residence time is 0.5 h to 4 h, and the reaction temperature is It is 40 ° C ~ 70 ° C.

In one embodiment of the present invention, the method for removing the lipase according to the step (2) is centrifugation or filtration, and the method of removing the fatty acid is distillation, and the distillation method is molecular distillation or vacuum distillation.

In one embodiment of the present invention, step (3) is based on the difference between the content of the enzymatic hydrolysate and the human milk fat in the content of the medium carbon chain fatty acid and the long carbon chain polyunsaturated fatty acid, through the palm kernel oil rich in the medium carbon chain fatty acid. And the coconut oil, arachidonic acid-rich algae oil and docosahexaenoic acid microbial oil regulate the intermediate carbon chain fatty acid and long carbon chain polyunsaturated fatty acid content of the intermediate product, thereby further improving the fatty acid composition of the final product. And the similarity of the distribution of the same human milk fat.

In one embodiment of the invention, the physical and chemical mixing model of the grease comprises the formulas (1) to (5):

Wherein, formula (1) represents the fatty acid content of the mixed product, and formula (2) represents the sn-2 fatty acid content of the mixed product. The formula (3) represents the sn-1,3 fatty acid content of the mixed product, and the formula (4) represents the relative content of the sn-2 fatty acid in the mixed product to the total fatty acid.

Wherein Y ₁ and Y _i are the contents of the respective fatty acids of the intermediate product and the selected oil, respectively, and Y _{1 (sn-2)} and Y _i(sn-2) are the intermediate products and the respective fatty acids at the selected fats and oils, respectively. Content, X _i is the molar ratio of the selected oil to the intermediate product;

According to the above formulas (1) to (4), the fatty acid composition and distribution of triglycerides in the system after adding fats and oils to intermediate products can be obtained, and the inequality can be established according to the characteristics of fatty acid composition and distribution of human milk fat, and according to the grease quality formula in the system ( 5), using Matlab R2010a to obtain the maximum amount of oil added under the condition of human milk fat substitute;

M is the mass of the final product; X ₁ is the number of moles of the intermediate product; M ₁ is the molecular mass of the intermediate product, and M _i is the molecular mass of the selected oil;

In one embodiment of the present invention, the human milk substitute fat evaluation model is used to evaluate the similarity of the final product to the human milk fat in the fatty acid composition and distribution according to the step (4), and the evaluation model is:

Among them, G _FA, G _{sn-2FA, and} G _PUFA are the similarities of human milk substitute fat in terms of fatty acid composition, relative content of sn-2 fatty acid, and polyunsaturated fatty acid composition, respectively;

E _i(FA), E _i(sn-2FA), E _i(PUFA) are the fatty acid composition of human milk substitute, the relative content of sn-2 fatty acid or the composition of polyunsaturated fatty acid in the corresponding index of human milk fat. The similarity deducted from the outside;

The relative value of the composition of the fatty acid, sn-2 fatty acid or polyunsaturated fatty acid of human milk fat with its total content;

C _{i (FA/sn-2FA/PUFA)} is a floating coefficient which depends on the total fatty acid content of the human milk fat substitute, the relative content of the sn-2 fatty acid or the polyunsaturated fatty acid composition;

B _{i (FA/sn-2FA/PUFA)} is the total fatty acid content, the relative content of sn-2 fatty acids or the content of polyunsaturated fatty acids in human milk substitute fat;

A _{i (FA/sn-2FA/PUFA)} is the corresponding total fatty acid, sn-2 relative fatty acid content or polyunsaturated fatty acid composition of human milk fat; when B is higher than A, A selects the upper limit; when B is less than A , A selects the lower limit; if B is within the range of A, C is 0.

The invention uses the squid oil or its extract as raw material, and according to the difference in fatty acid composition and distribution of the same human milk fat, the human milk is prepared by the two-step method, that is, the enzymatic acid hydrolysis and the model-guided oil mixing method. In place of the fat product, the enzymatic acidolysis mainly regulates the fatty acid composition of the salmon oil or its extract, and the oil and fat mix mainly regulates the trace fatty acid composition of the enzymatic hydrolysate, and the final product is evaluated by the human milk replacement lipid evaluation model, not only in a large amount. Fatty acid composition and distribution have a high similarity with human milk fat, and also a large increase in the composition of trace fatty acids.

detailed description

The above described objects, features and advantages of the present invention will become more apparent from the detailed description.

In the following description, numerous specific details are set forth in order to provide a full understanding of the present invention, but the invention may be practiced in other ways than those described herein, and those skilled in the art can do without departing from the scope of the invention. The invention is not limited by the specific embodiments disclosed below.

Example 1

The fatty acid composition and distribution of salmon oil and typical human milk fat are shown in Table 1:

Table 1. Fatty acid composition and distribution of cod oil and human milk fat

Example 2:

In the batch reactor, the salmon oil was used as the raw material, and the 1,3-position specific lipase Lipozyme RM IM was used as the catalyst. The reaction temperature was 50 degrees, the enzyme amount was 10% by weight, and the stirring rate was 500 rpm. The ratio of free fatty acids in rapeseed oil rich in oleic acid and sunflower oil rich in linoleic acid is 1:3, the molar ratio of salmon oil to free fatty acid is 1:3, and the stirring rate is 600 rpm. After the reaction, the lipase in the reactant is removed by centrifugation, and at the same time, the free fatty acid is removed by distillation to obtain an enzymatic hydrolyzed product. The composition of the mixed fatty acids in different ratios used for enzymatic hydrolysis is shown in Table 2, and the fatty acid composition and distribution of the obtained product (intermediate product) are shown in Table 3.

Table 2. Fatty acid composition of fatty acids derived from rapeseed oil, sunflower oil and a 1:3 mixture

FA type	RSO	SFO	1:3
C12:0	0.90	1.30	1.20
C14:0	1.00	1.70	1.53
C16:0	6.70	6.80	6.78
C18:0	2.70	5.20	4.58
C18:1	58.10	25.40	33.58
C18:2	22.50	59.00	49.88
C18:3	7.80	0.60	2.40

Table 3.1: Composition and distribution of large amounts of fatty acids in enzymatic hydrolysates at a ratio of 3 mixed fatty acids

	FA	sn-2FA	%sn-2	Sn-1,3
C12:0	0.6	0.4	22.2	0.7
C14:0	3.8	3.0	26.3	4.2
C16:0	23.8	48.1	67.4	11.7
C18:0	7.8	5.3	22.6	9.1
C18:1	40.5	33.1	27.2	44.2
C18:2	21.2	9.0	14.2	27.3
C18:3	0.5	0.3	20.0	0.6

According to the composition of the medium carbon chain fatty acid and the long carbon chain polyunsaturated fatty acid of human milk fat, combined with the chemical composition characteristics of the obtained enzymatic hydrolyzed product, palm kernel oil rich in medium carbon chain fatty acid and algae rich in arachidonic acid are selected. The microbial oil of oil and docosahexaenoic acid is added to the enzymatic hydrolysate, and the addition ratio is determined according to the chemical composition of human milk fat, and is optimized by the physical mixing model of the oil. The grease blending model is as follows:

After adding the oil to the enzymatic hydrolysate, the fatty acid composition and distribution of the mixed triglyceride in the system can be calculated by the following formula:

Y ₁ and Y _i are the contents of the respective fatty acids of the intermediate product and the selected oil; respectively; Y _{1 (sn-2)} and Y _i(sn-2) are the contents of the respective fatty acids in the intermediate product and the selected oil; X _i is the molar ratio of the selected fat to the intermediate. According to the above formula, the fatty acid composition and distribution of the triglyceride in the system after adding the fat can be obtained. According to the characteristics of fatty acid composition and distribution of human milk fat, the inequality was established. At the same time, according to the formula of fat weight in the system (5), Matlab R2010a (MathWorks, Natick, Massachusetts) was used to obtain the maximum oil addition amount under the condition of human milk fat substitute.

M is the weight of the final product; X1 is the number of moles of the intermediate product; M1 is the molecular mass of the intermediate product, and Mi is the molecular mass of the selected fat.

The palm kernel oil added to the enzymatic hydrolysate was determined by the fat addition model. The ratio of algae oil and microbial oil was 1: (0.046-0.1314): (0.005-0.011): (0.0076-0.014); the fatty acid composition of the final product obtained And the scope of the distribution is shown in the following table:

Table 4. Fatty acid composition and distribution range of the final product

Fattyacid	Total	Sn-2
C8:0	0.2-0.5
C10:0	0.2-0.5	0.0-0.1
C12:0	3.0-6.8	2.2-5.2

C14:0	4.3-5.1	3.6-4.5
C16:0	21.7-23.0	42.8-46.2
C18:0	7.0-7.5	4.8-5.2
C18: 1n-9	36.6-39.1	31.7-33.4
C18: 2n-6	16.9-18.3	8.6-9.7
C18: 3n-3	0.5-0.6	0.3-0.7
C20:0	0.0-0.1	0.0-0.1
C20: 3n-6	0.0-0.1	0.1-0.7
C20: 4n-6	0.4-0.6	0.6-3.3
C22:0	0.0-0.1	0.0-0.1
C22: 5n-3	0.0-0.1	0-0.1
C22: 6n-3	0.2-0.4	0.2-0.5

The data in Table 4 was taken into the evaluation model of human milk replacement lipid to obtain the fatty acid composition and distribution score of the enzymatic hydrolysate. The model is as follows:

Among them, G _{FA/sn-2FA/PUFA is} the similarity of human milk substitute fat in human milk fat in terms of fatty acid composition, relative content of sn-2 fatty acid or polyunsaturated fatty acid composition;

E _{i (FA/sn-2FA/PUFA)} is the similarity of the fatty acid composition, the relative content of sn-2 fatty acid or the polyunsaturated fatty acid composition of human milk instead of the corresponding content of human milk fat.

The relative value of the composition of the fatty acid, sn-2 fatty acid or polyunsaturated fatty acid of human milk fat with its total content;

C _{i (FA/sn-2FA/PUFA)} is a floating coefficient which depends on the total fatty acid content of the human milk fat substitute, the relative content of the sn-2 fatty acid or the polyunsaturated fatty acid composition;

B _{i (FA/sn-2FA/PUFA)} is the total fatty acid content, the relative content of sn-2 fatty acids or the content of polyunsaturated fatty acids in human milk substitute fat;

A _{i (FA/sn-2FA/PUFA)} is the corresponding total fatty acid, sn-2 relative fatty acid content or polyunsaturated fatty acid composition of human milk fat; when B is higher than A, A selects the upper limit; when B is less than A , A selects the lower limit; if B is within the range of A, C is 0.

Table 5 Model evaluation score range

Score type	fish oil	Final product
G FA	86.5	96.2-97.6
G sn-2FA	83.3	94.9-97.0
G PUFA	45.8	55.7-61.5

The data in Table 5 indicates that the obtained product has a high similarity in fatty acid composition and sn-2 fatty acid composition with human milk fat, and the final product has a certain degree of improvement in PUFA composition compared with fish oil.

Example 3:

In the packed bed continuous reactor, the 30-degree solid fat extract of cod oil was used as the raw material, and the 1,3-position specific lipase Lipozyme RM IM was used as the catalyst. The reaction temperature was 60 degrees and the residence time was 1 h. The selected source was used. The ratio of free fatty acids in oleic acid-rich tea seed oil and linoleic acid-rich corn oil is 1:2, and the molar ratio of the fat residue of the salmon oil to the free fatty acid is 1:4, and the reaction is carried out by centrifugation. The lipase in the reaction is simultaneously freed of fatty acids by distillation. The composition and distribution of fatty acid fatty acids obtained by extracting squid oil at 30 degrees are shown in Table 6. The composition of free fatty acids and mixed fatty acids derived from tea seed oil and corn oil is shown in Table 7, and the obtained enzymatic hydrolysate (intermediate product) The fatty acid composition and distribution are shown in Table 8.

Table 6 Fatty acid composition and distribution of squid oil at 30 degrees

Table 7 Composition of fatty acids derived from tea seed oil, corn oil and mixed fatty acids of 1:2 mixture

FA type	Tea seed oil	Corn oil	1:2
C16:0	14.72	12.2	13.04
C18:0	3.68	1.6	2.29
C18:1	58.31	26.51	37.11
C18:2	19.9	56.51	44.31
C18:3	0.97	0.32	0.54

Table 8 Composition and distribution of large amounts of fatty acids in enzymatic hydrolysates

FA type	Total	Sn-2	%sn-2	Sn-1,3
C12:0	0.11	0.2	60.6	0.1
C14:0	2.78	3.9	46.8	2.2
C16:0	27.5	58.5	70.9	12.0
C18:0	8.13	4.22	17.3	10.1
C18:1	38.6	19.1	16.5	48.4
C18:2	18.5	12.3	22.2	21.6
C18:3	0.43	0.3	23.3	0.5

The coconut oil added to the enzymatic hydrolyzed product was determined by the fat addition model. The ratio of algae oil and microbial oil was 1: (0.1057-0.1415): (0.0053-0.0111): (0.008-0.0143); the final product obtained (fat mixed product) The range of fatty acid composition and distribution is shown in Table 9 below:

Table 9 Fatty acid composition and distribution range of the final product

FA type	Total	Sn-2
C8:0	0.4-0.5
C10:0	0.5-0.6	0.0-0.1
C12:0	5.4-6.8	4.2-5.3
C14:0	4.0-4.3	5.1-5.4
C16:0	24.7-25.4	51.4-53.5
C18:0	7.2-7.4	3.8-4.1
C18: 1n-9	34.4-35.5	19.6-20.4
C18: 2n-6	16.2-16.8	11.4-12.4
C18: 3n-3	0.3-0.4	0.3-0.7

C20:0	0.0-0.1	0.0-0.1
C20: 3n-6	0.0-0.1	0.1-0.7
C20: 4n-6	0.4-0.6	0.6-3.3
C22:0	0.0-0.1	0.0-0.1
C22: 5n-3	00-0.1	0.0-0.1
C22: 6n-3	0.2-0.4	0.2-0.5

The data in Table 9 was taken into the evaluation model of human milk replacement lipid to obtain the fatty acid composition and distribution score of the enzymatic hydrolysate as shown in Table 10 below:

Table 10 Model Evaluation Score

Score type	fish oil	Final product
G FA	86.5	97.2-97.8
G sn-2FA	83.3	96.7-97.2
G PUFA	45.8	54.3-60.3

The data in Table 10 shows that the obtained product has a high similarity in fatty acid composition and sn-2 fatty acid composition with human milk fat, and the final product has a certain degree of improvement in PUFA composition compared with fish oil.

Although the present invention has been disclosed in the above preferred embodiments, the present invention is not limited thereto, and various modifications and changes can be made thereto without departing from the spirit and scope of the invention. The scope of protection of the present invention should be as defined in the claims

Claims (9)

1. A method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing, comprising:

   (1) Melt the salmon oil at 50-60 ° C for 30-60 min, and cool down to 15-30 ° C at a cooling rate of 1 ~ 5 ° C / min, and keep the eel oil at this temperature for 5 ~ 48 h, The liquid oil is removed by filtration to obtain a solid fat component of salmon oil rich in palmitic acid at the sn-2 position;

   (2) using sn-1, 3-position specific lipase as a catalyst, using oleic acid-rich vegetable oil-derived free fatty acids and linoleic acid-rich vegetable oil-derived free fatty acids as acyl donors for preparing human milk substitute lipids , acidifying the fat component of the salmon oil, removing lipase and free fatty acid to obtain an intermediate product;

   (3) According to the difference of the intermediate milk fat in the content of medium carbon chain fatty acids and long carbon chain polyunsaturated fatty acids, under the guidance of the physical mixing model of fats and oils, the medium carbon chain fatty acids and long carbons of intermediate products are regulated by adding oils and fats. Chain polyunsaturated fatty acid content, thereby further improving the similarity of the product to human milk fat in fatty acid composition and distribution;

   (4) The similarity of the final product to the human milk fat in the fatty acid composition and distribution was evaluated by the human milk replacement lipid evaluation model.
2. The method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing according to claim 1, wherein the oleic acid-rich vegetable oil-derived fatty acid is the same as the common vegetable oil fatty acid rich in linoleic acid source. As an acyl donor for preparing a human milk substitute fat, the mass ratio is 1:1 to 5.
3. The method for preparing a human milk substitute lipid according to claim 1, wherein the catalyst is a lipase selective for the 1,8 and 3 positions of the triglyceride.
4. The method for preparing a human milk substitute lipid according to claim 1, wherein the acid hydrolysis has a reaction temperature of 40 ° C to 70 ° C.
5. The method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing according to claim 1 or 4, wherein the acid hydrolysis is a batch reaction, and the molar ratio of the salmon oil to the free fatty acid is 1: 1 to 5, the amount of enzyme added is 3% to 15%, the reaction time is 1 h to 5 h, and the stirring rate is 300 r/min to 800 r/min.
6. The method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing according to claim 1 or 4, wherein the acid hydrolysis is a continuous reaction, and the molar ratio of the salmon oil to the free fatty acid is 1: 1 to 6, the substrate residence time is from 0.5 h to 4 h.
7. The method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing according to claim 1, wherein the oil and fat mixture is based on an enzymatic hydrolysis product, and the human milk fat has a medium carbon chain fatty acid and a long carbon chain. The difference in the content of unsaturated fatty acids is determined by microbial oils rich in medium carbon chain fatty acid palm kernel oil and coconut oil, arachidonic acid-rich algae oil and docosahexaenoic acid.
8. The method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing according to claim 1 or 7, wherein the oil and fat mixing under the guidance of a physical mixing model of oil and fat, the physical mixing model of the oil is as follows :

   

   

   

   

   Wherein, Y ₁ and Y _i are the content of the intermediate products and each fatty acid selected grease, Y _{1 (sn-2)} and Y _{i (sn-2)} are intermediate products and fats each fatty acid on the two selected Content, X _i is the molar ratio of the selected oil to the intermediate product;

   According to the above formula, the fatty acid composition and distribution of triglyceride in the system after adding fats and oils can be obtained, and the inequality can be established according to the characteristics of fatty acid composition and distribution of human milk fat. At the same time, according to the formula of fat weight in the system (5), Matlab R2010a is used to satisfy people. The maximum amount of oil added under the condition of cream substitute;

   

   M is the weight of the final product; X ₁ is the number of moles of the intermediate product; M ₁ is the molecular mass of the intermediate product, and M _i is the molecular mass of the selected oil;
9. The method for preparing a human milk substitute fat combined with enzymatic acid hydrolysis and physical mixing according to claim 1 or 7, wherein the human milk substitute fat evaluation model is used to evaluate the final product in the fatty acid composition and distribution. The similarity of fat, the evaluation model is:

   

   

   

   Among them, G _{FA/sn-2FA/PUFA is} the similarity of human milk substitute fat in human milk fat in terms of fatty acid composition, relative content of sn-2 fatty acid or polyunsaturated fatty acid composition;

   E _{i (FA/sn-2FA/PUFA)} is the similarity of the fatty acid composition, the relative content of sn-2 fatty acid or the polyunsaturated fatty acid composition of human milk instead of the corresponding content of human milk fat.

   

   The relative value of the composition of the fatty acid, sn-2 fatty acid or polyunsaturated fatty acid of human milk fat with its total content;

   C _{i (FA/sn-2FA/PUFA)} is a floating coefficient which depends on the total fatty acid content of the human milk fat substitute, the relative content of the sn-2 fatty acid or the polyunsaturated fatty acid composition;

   B _{i (FA/sn-2FA/PUFA)} is the total fatty acid content, the relative content of sn-2 fatty acids or the content of polyunsaturated fatty acids in human milk substitute fat;

   A _{i (FA/sn-2FA/PUFA)} is the corresponding total fatty acid, sn-2 relative fatty acid content or polyunsaturated fatty acid composition of human milk fat; when B is higher than A, A selects the upper limit; when B is less than A , A selects the lower limit; if B is within the range of A, C is 0.