CN104186701A - Preparation method of human milk substitute fat based on triglyceride composition and evaluating method of human milk substitute fat - Google Patents

Abstract

The invention discloses a preparation method of a human milk substitute fat based on a triglyceride composition and an evaluating method of the human milk substitute fat. The preparation method comprises the following steps: with lard oil as a base raw material, adding sunflower seed oil, canola oil, palm kernel oil, palm oil, microbial oil and algae oil in the lard oil according to a certain proportion in accordance with composition and distribution of fatty acid of human milk fat to obtain mixed oil similar to the human milk fat on the composition and distribution of the fatty acid; and by adopting specific lipase at 1 and 3 sites as catalysts, and similarities between of mixed oil and human milk fat in aspects of composition and distribution of the fatty acid, composition of polyunsaturated fatty acids and triglyceride as indexes, adjusting the composition of the triglyceride of the mixed fat by using a manner of lactone exchanging to obtain a product with relatively high similarity to the human milk fat on the composition of the triglyceride. The human milk substitute fat is obtained by adopting physical mixing and enzyme catalysis ester exchange manners, the production cost can be greatly reduced, and the relatively high similarity is achieved for the product and the human milk fat.

Description

Preparation method and evaluation method of human milk substitute fat based on triglyceride composition

Technical Field

The invention belongs to the technical field of grease, and particularly relates to a preparation method of a substitute similar to human milk fat in triglyceride composition and an evaluation method of the obtained human milk substitute fat.

Background

Human milk is the best food for newborn infants, providing them with a variety of nutrients including protein, fat, carbohydrates, minerals, vitamins, etc. Fat accounts for 3-5% of breast milk and provides about 50% of energy. The content of triglyceride in breast milk fat exceeds 98%, and the chemical composition varies with lactation period, dietary habits, seasons, race, and other factors. Human milk fat has a very specific molecular structure with most of the saturated fatty acids (mainly palmitic acid) distributed in the 2-position and unsaturated fatty acids in the 1, 3-positions. This particular fatty acid composition and distribution allows a large portion of the triglycerides in breast milk fat to be present in the USU form, such as OPO and OPL. These triglycerides are ingested by the infant and hydrolyzed by the action of gastric and pancreatic lipases into sn-2 monoglycerides and free fatty acids. The sn-2 monoglycerides can be absorbed directly by the small intestine. Thus, saturated fatty acids in the sn-2 position of triglycerides can improve absorption while avoiding the formation of calcium soaps and other side effects. In addition, after the fat is absorbed and recombined, more than 70% of the sn-2 fatty acid is retained in the original position, so that the special structure of human milk fat affects the fat metabolism and distribution in infants.

Human milk fat contains medium-chain fatty acids such as caproic Acid, caprylic Acid and long-chain polyunsaturated fatty acids such as Docosahexaenoic Acid (DHA), Arachidonic Acid (AA), and the like. The medium-chain fatty acids are mainly distributed in the sn-3 position of human milk fat, and the duodenal lipase has high activity on the medium-chain fatty acids at the position. The hydrolyzed medium carbon chain fatty acid can be absorbed by the portal vein to provide immediate energy for the infant, while the 1, 2-position diglyceride is beneficial to the digestive absorption in the duodenum by increasing the solubility of triglyceride. Long carbon chain polyunsaturated fatty acids are less abundant in human milk fat, but are important for infant development, particularly DHA and AA. DHA and AA are highly concentrated in human retina and brain, and play an important role in the development of human visual system and central nerve. However, for some infants, the synthesis of DHA and AA has certain difficulties due to the lower dehydrogenase activity. Therefore, based on the specific functions of medium-chain fatty acids and long-chain polyunsaturated fatty acids, appropriate supplementation of these fatty acids in human milk replacement lipids will be beneficial to the healthy development of infants.

Lard has the most similar chemical composition and molecular structure with human milk fat in nature. Approximately 65% of the palmitic acid in lard is reported to be in the sn-2 position and therefore has a high content of USU-type triglycerides. However, lard contains less linoleic and linolenic acids and no medium and long carbon chain polyunsaturated fatty acids than human milk fat. In order to improve the similarity of lard with human milk fat, some researchers have obtained a substitute similar to human milk fat in fatty acid composition and distribution by acid hydrolysis of lard with 1, 3-specific lipase as a catalyst. However, human milk fat is ingested by infants in the form of triglycerides, and it is not known whether the type of triglyceride has an effect on the digestion, absorption and metabolism of infants. Since the chemical composition and structure based on human milk fat are the gold principle for preparing human milk substitute fat, triglyceride composition should be the final index for preparing and evaluating human milk substitute fat. At present, the human milk substitute fat produced industrially is mainly prepared by using palm stearin as an initial raw material and mainly adopting acid hydrolysis as a production mode because the palm stearin has a large amount of palmitic acid on sn-1 and 3 positions. However, in the case of lard, palmitic acid naturally exists in the sn-2 position, and by selecting appropriate vegetable oils and addition ratios, the fatty acid composition and distribution requirements similar to those of human milk fat can be met, and by changing and adjusting the triglyceride composition in the mixed oil in a certain manner, the purpose similar to that of human milk fat triglyceride can be achieved. The mode of mixing and readjusting triglyceride can greatly reduce the cost and increase the yield.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made in view of the above and/or problems with existing methods for the preparation of alternatives to human milk fat in triglyceride compositions and the evaluation of the resulting human milk alternative fat.

Therefore, one of the objects of the present invention is to provide an economically feasible method for preparing human milk substitute fat based on triglyceride composition using lard as raw material.

To solve the above technical problem, according to an aspect of the present invention, the present invention provides the following technical solutions: a preparation method of human milk substitute fat based on triglyceride composition comprises the steps of taking lard as a raw material, mixing vegetable oil with the lard to prepare a product similar to human milk fat in fatty acid composition and distribution, taking 1, 3-site specific lipase as a catalyst, taking the triglyceride similarity of the human milk fat as an index, and performing lactone exchange to obtain the human milk substitute fat similar to the human milk fat in triglyceride composition; wherein the vegetable oil comprises sunflower seed oil, canola oil, palm kernel oil, palm oil, microbial oil containing arachidonic acid and algae oil containing docosahexaenoic acid, and the mixing ratio is lard oil: sunflower seed oil: canola oil: palm kernel oil: palm oil: the microbial oil comprises 1 (0.06-0.14) to 0.42-0.59 (0.12-0.14) to 0.12-0.18): 0.02 (0.02-0.03); the 1, 3-site specific lipase is used as a catalyst, the enzyme adding amount is 6-12 wt%, the temperature is 40-65 ℃, and the reaction time is 2-4 hours.

As a preferred embodiment of the method for preparing human milk substitute lipids based on triglyceride composition of the present invention, wherein: after the lactone exchange, the obtained reaction substrate is centrifuged to remove the enzyme, and then the free fatty acid is removed by molecular distillation.

As a preferred embodiment of the method for preparing human milk substitute lipids based on triglyceride composition of the present invention, wherein: the evaporation temperature of the molecular distillation is 180-185 ℃, the temperature of the heat exchanger is 55-60 ℃, and the absolute pressure is 2 Pa.

As a preferred embodiment of the method for preparing human milk substitute lipids based on triglyceride composition of the present invention, wherein: the mixing proportion is lard oil: sunflower seed oil: canola oil: palm kernel oil: palm oil: microbial oil algae oil 1:0.14:0.59:0.14:0.18:0.02: 0.03.

As a preferred embodiment of the method for preparing human milk substitute lipids based on triglyceride composition of the present invention, wherein: the mixing proportion is lard oil: sunflower seed oil: canola oil: palm kernel oil: palm oil: microbial oil algae oil 1:0.1:0.5:0.13:0.12:0.02: 0.02.

It is still another object of the present invention to provide a method for evaluating human milk alternative lipids based on triglyceride composition.

To solve the above technical problem, according to still another aspect of the present invention, the present invention provides the following technical solutions: similarity is obtained by comparing and evaluating the obtained human milk substitute fat and human milk fat in terms of fatty acid composition and distribution, polyunsaturated fatty acid and triglyceride composition, and evaluation models are shown as follows:

<math> <mrow> <msub> <mi>G</mi> <mrow> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> </mrow> </msub> <mo>=</mo> <mn>100</mn> <mo>-</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>E</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>;</mo> </mrow> </math>

<math> <mrow> <msub> <mi>E</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>=</mo> <mn>100</mn> <mo>&times;</mo> <mrow> <mo>(</mo> <msub> <mi>C</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mfrac> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

$C_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}=\frac{|B_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}-A_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}|}{A_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}};$

wherein G is_{FA/sn-2FA/PUFA/TAG}Respectively representing the similarity of the human milk substitute fat with the human milk fat in the aspects of fatty acid composition, sn-2 fatty acid relative content, polyunsaturated fatty acid or triglyceride composition;

E_{i(FA/sn-2FA/PUFA/TAG)}respectively representing the deducted similarity of the fatty acid composition, the sn-2 fatty acid relative content and the polyunsaturated fatty acid or triglyceride composition in the human milk fat substitute fat outside the corresponding index content range of the human milk fat;

<math> <mrow> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>/</mo> <msubsup> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </msubsup> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> </mrow> </math> is the relative value of the composition of fatty acid, sn-2 fatty acid, polyunsaturated fatty acid or triglyceride of human milk fat and the total content thereof;

C_{i(FA/sn-2FA/PUFA/TAG)}is the coefficient of variation, which depends on the total fatty acid content, the relative content of sn-2 fatty acids, the polyunsaturated fatty acid or triglyceride composition of the human milk fat substitute;

B_{i(FA/sn-2FA/PUFA/TAG)}is the total fatty acid content, the sn-2 fatty acid relative content, the polyunsaturated fatty acid or triglyceride content of human milk substitute fat;

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

The product obtained by the method of the invention has the advantages of similarity to human milk fat in fatty acid composition and distribution, and higher similarity to human milk fat in triglyceride composition, and is a product which can more comprehensively simulate human milk fat.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to make the above objects, features and advantages of the invention more comprehensible.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

The raw materials of the invention mainly comprise lard (L), Canola Oil (CO), sunflower seed oil (SFO), Palm Kernel Oil (PKO), Palm Oil (PO), Microbial Oil (MO) rich in AA and Algal Oil (AO) rich in DHA. The fatty acid composition and distribution of the various oils are shown in the following table:

TABLE 1 fatty acid composition and distribution of lard, canola oil, sunflower oil, palm kernel oil, palm oil, microbial oils and algal oils

Example 1

Taking 30kg of lard, mixing the lard with sunflower seed oil, canola oil, palm kernel oil, palm oil, AA-rich microbial oil and DHA-rich algae oil, and mixing the lard: sunflower seed oil: canola oil: palm kernel oil: palm oil: the microbial oil and algal oil were mixed at a ratio of 1:0.14:0.59:0.14:0.18:0.02:0.03, and the fatty acid composition, distribution and triglyceride composition of the resulting product were as shown in the following table:

table 2 fatty acid composition and distribution of mixed fats & oils

Fatty acids	total	sn-2	％sn-2	sn-1,3
					C8:0	0.3	0.1	11.1	0.4
C10:0	0.2	0.1	16.7	0.3
					C12:0	3.2	3.5	36.5	3.1
C14:0	2.3	1.9	27.5	2.5
					C16:0	20.6	40.0	64.7	10.9
C16:1	0.9	1.7	63.0	0.5
					C18:0	7.7	2.6	11.3	10.3
C18:1	41.1	28.6	23.2	47.4
					C18:2	19.5	16.3	27.9	21.1
C18:3	2.4	3.6	50.0	1.8
					C20:3	0.1	0.2	66.7	0.1
C20:4	0.5	0.4	26.7	0.6
					C20:5	0.2	0.1	16.7	0.3
C22:5	0.1	0.1	33.3	0.1
					C22:6	0.3	0.4	44.4	0.3

TABLE 3 triglyceride composition of the Mixed fats & oils

Triglycerides	Content (wt.)	Triglycerides	Content (wt.)
				OLaLa	0.45	POL	12.51

MMLa	1.22	PPL	11
				LLaO	0.73	PPM	0.83
MOLa	0.27	OOO	15.27
				PMLa	4.98	POO	21.66
LaOO	2.3	PPO	8.25
				POLa	0.95	POS	9.14
PML	2.18

Adding 10 wt% of 1, 3-site specific lipase into the obtained mixed oil, reacting for 3 hours at 60 ℃, stirring at the speed of 250rpm, centrifuging the obtained reaction substrate at the speed of 4000rpm to remove the enzyme, and then removing free fatty acid by molecular distillation, wherein the molecular distillation conditions are as follows: the evaporation temperature is 185 ℃; heat exchanger temperature, 60 ℃; rotational speed, 120 rpm; absolute pressure, 2 Pa. The fatty acid composition, distribution and triglyceride composition of the intermediate product obtained are shown in the following table:

TABLE 4 fatty acid composition and distribution of the product after lactone exchange

Fatty acids	total	sn-2	％sn-2	sn-1,3
					C8:0	0.2	0.2	32.5	0.2
C10:0	0.3	0.1	12.8	0.3
					C12:0	3.2	3.4	35.6	3.1
C14:0	1.9	2.9	49.8	1.5
					C16:0	20.1	35.9	59.4	12.3
C16:1	1.4	2.0	45.7	1.2
					C18:0	7.2	2.6	11.9	9.5
C18:1	43.0	30.2	23.4	49.4
					C18:2	16.9	17.1	33.6	16.9
C18:3	2.9	3.5	40.7	2.6
					C20:3	0.3	0.3	40.3	0.2
C20:4	0.7	0.1	7.0	0.9
					C20:5	0.3	0.1	14.6	0.4
C22:5	0.1	0.2	66.7	0.1
					C22:6	0.3	0.4	44.4	0.3

TABLE 5 triglyceride composition of the product after lactone exchange

Triglycerides	Content (wt.)	Triglycerides	Content (wt.)
				OLaLa	0.33	POL	13.07
MMLa	0.87	PPL	16.98
				LLaO	1.7	PPM	2.99
MOLa	0.56	OOO	9.35
				PMLa	3.72	POO	24.13
LaOO	1.06	PPO	8.06
				POLa	2.13	POS	4.09
PML	3.88

The obtained product is evaluated through a similarity evaluation model respectively, and the product has higher similarity with human milk fat in the aspects of fatty acid composition, distribution, polyunsaturated fatty acid and triglyceride composition. The calculation formula of the evaluation model used is as follows:

<math> <mrow> <msub> <mi>G</mi> <mrow> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> </mrow> </msub> <mo>=</mo> <mn>100</mn> <mo>-</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>E</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>;</mo> </mrow> </math>

<math> <mrow> <msub> <mi>E</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>=</mo> <mn>100</mn> <mo>&times;</mo> <mrow> <mo>(</mo> <msub> <mi>C</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mfrac> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

$C_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}=\frac{|B_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}-A_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}|}{A_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}};$

wherein G is_{FA/sn-2FA/PUFA/TAG}Respectively representing the similarity of the human milk substitute fat with the human milk fat in the aspects of fatty acid composition, sn-2 fatty acid relative content, polyunsaturated fatty acid or triglyceride composition; e_{i(FA/sn-2FA/PUFA/TAG)}Respectively representing the deducted similarity of the fatty acid composition, the sn-2 fatty acid relative content and the polyunsaturated fatty acid or triglyceride composition in the human milk fat substitute fat outside the corresponding index content range of the human milk fat; <math> <mrow> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>/</mo> <msubsup> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </msubsup> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> </mrow> </math> is the relative value of the composition of fatty acid, sn-2 fatty acid, polyunsaturated fatty acid or triglyceride of human milk fat and the total content thereof; c_{i(FA/sn-2FA/PUFA/TAG)}Is the coefficient of variation, which depends on the total fatty acid content, the relative content of sn-2 fatty acids, the polyunsaturated fatty acid or triglyceride composition of the human milk fat substitute; b is_{i(FA/sn-2FA/PUFA/TAG)}Is the total fatty acid content, the sn-2 fatty acid relative content, the polyunsaturated fatty acid or triglyceride content of human milk substitute fat; a. the_{i(FA/sn-2FA/PUFA/TAG)}Is the total fatty acid, sn-2 relative fatty acid content, polyunsaturated fatty acid or triglyceride composition of the corresponding human milk fat; when B is higher than A, A selects the upper limit; when B is smaller than A, A selects the lower limit; if B is within the range of A, C is 0.

Similarity between the obtained mixed oil and the ester exchange product and the human milk fat in the composition of fatty acid, sn-2 fatty acid, polyunsaturated fatty acid and triglyceride is shown in the following table through similarity model evaluation:

TABLE 6 similarity of fat blends and interesterification products to human milk fat

Degree of similarity	Mixed oil and fat	Transesterification products
			GFA	92.7	92.1
Gsn-2FA	90.4	88.2

GPUFA	61.7	60.2
			GTAG	61.3	69.1

Example 2

Taking 50kg of lard, mixing the lard with sunflower seed oil, canola oil, palm kernel oil, palm oil, AA-rich microbial oil and DHA-rich algae oil, namely lard: sunflower seed oil: canola oil: palm kernel oil: palm oil: the microbial oil and algal oil were mixed at a ratio of 1:0.1:0.5:0.13:0.12:0.02:0.02, and the fatty acid composition, distribution and triglyceride composition of the obtained product were as shown in the following table:

TABLE 7 fatty acid composition and distribution of Mixed fats & oils

Fatty acids	total	sn-2	％sn-2	sn-1,3
					C8:0	0.3	0.1	11.1	0.4
C10:0	0.2	0.1	16.7	0.3
					C12:0	3.1	3.3	35.5	3.0
C14:0	2.5	2.0	26.7	2.8
					C16:0	20.7	43.3	69.7	9.4
C16:1	1.5	1.3	28.9	1.6
					C18:0	7.2	2.8	13.0	9.4
C18:1	40.3	25.6	21.2	47.7
					C18:2	18.2	17.1	31.3	18.8
C18:3	2.3	2.5	36.2	2.2
					C20:3	0.1	0.1	33.3	0.1
C20:4	0.5	0.3	20.0	0.6
					C20:5	0.2	0.0	0.0	0.3
C22:5	0.1	0.1	33.3	0.1
					C22:6	0.3	0.4	44.4	0.3

TABLE 8 triglyceride composition of the Mixed fats & oils

Triglycerides	Content (wt.)	Triglycerides	Content (wt.)
				OLaLa	0.33	POL	11.84
MMLa	1.32	PPL	11.68
				LLaO	0.18	PPM	1.07
MOLa	0.54	OOO	14.61
				PMLa	5.01	POO	24.17
LaOO	1.88	PPO	8.03
				POLa	0.17	POS	10.32
PML	0.62

Adding 12 wt% of 1, 3-site specific lipase into the obtained mixed oil, reacting for 4 hours in a water bath with the temperature of 50 ℃, stirring at the speed of 250rpm, centrifuging the obtained reaction substrate at the speed of 4000rpm to remove the enzyme, and then removing free fatty acid by molecular distillation, wherein the molecular distillation conditions are as follows: the evaporation temperature is 180 ℃; heat exchanger temperature, 55 ℃; rotational speed, 120 rpm; absolute pressure, 2 Pa.

The fatty acid composition and distribution and triglyceride composition of the resulting product are shown in the table below.

TABLE 9 fatty acid composition and distribution of the product after lactone exchange

Fatty acids	total	sn-2	％sn-2	sn-1,3
					C8:0	0.2	0.1	16.7	0.3
C10:0	0.2	0.1	16.7	0.3
					C12:0	3.4	3.1	30.4	3.6
C14:0	2.1	2.4	38.1	2.0
					C16:0	20.1	38.0	63.0	11.2
C16:1	1.8	1.1	20.4	2.2
					C18:0	6.7	2.4	11.9	8.9
C18:1	42.5	28.6	22.4	49.5
					C18:2	18.2	18.9	34.6	17.9
C18:3	2.5	2.1	28.0	2.7
					C20:3	0.1	0.1	33.3	0.1
C20:4	0.5	0.2	13.3	0.7
					C20:5	0.2	0	0.0	0.3
C22:5	0.1	0.1	33.3	0.1
					C22:6	0.3	0.4	44.4	0.3

TABLE 10 triglyceride composition of the lactone-exchanged product

Triglycerides	Content (wt.)	Triglycerides	Content (wt.)
				OLaLa	0.4	POL	11.93
MMLa	0.8	PPL	16.84
				LLaO	1.6	PPM	3.06
MOLa	3.18	OOO	8.73
				PMLa	0.55	POO	24.79
LaOO	1.15	PPO	7.86
				POLa	2.2	POS	4.5
PML	3.85

Similarity between the obtained mixed oil and the ester exchange product and the human milk fat in the composition of fatty acid, sn-2 fatty acid, polyunsaturated fatty acid and triglyceride is shown in the following table through similarity model evaluation:

TABLE 11 similarity of fat blends and interesterification products to human milk fat

Degree of similarity	Mixed oil and fat	Transesterification products
			GFA	93.8	92.5
Gsn-2FA	91.2	90.3
			GPUFA	62.1	61.5
GTAG	59.7	71.9

The preferred embodiment of the present invention is divided into two steps:

firstly, according to the fatty acid composition and distribution of human milk fat, taking lard as a basic raw material, mixing the lard with sunflower seed oil, canola oil, palm kernel oil, palm oil, microbial oil rich in AA and algal oil rich in DHA, and adjusting the fatty acid composition to ensure that the mixed oil has the fatty acid composition and distribution similar to the human milk fat;

and the second step is based on the fatty acid composition and distribution of human milk fat, the composition of polyunsaturated fatty acid and triglyceride, 1, 3-site specific lipase is used as a catalyst, the triglyceride composition of the mixed oil is adjusted by a lactone exchange mode and the similarity of the triglyceride with the human milk fat is used as an index, and the product is evaluated by a model, so that a substitute with higher similarity of the triglyceride composition with the human milk fat is finally obtained.

The specific process is as follows:

first step mixing of different vegetable oils with lard

According to the fatty acid composition and distribution of human milk fat, the lard oil is mixed with the canola oil, the sunflower seed oil, the palm kernel oil, the microbial oil rich in AA and the algae oil rich in DHA in the mixing proportion of the lard oil: sunflower seed oil: canola oil: palm kernel oil: palm oil: the microbial oil is algae oil 1 (0.06-0.14): 0.42-0.59): 0.12-0.14):0.02 (0.02-0.03), the relative content of sn-2 fatty acid in the mixed oil is controlled between 65% and 75%, and simultaneously the composition and distribution of other fatty acid are ensured within the range of corresponding fatty acid in the human milk fat.

Second step 1, 3-site specific lipase-catalyzed lactone exchange

And carrying out lactone exchange on the obtained mixed oil by using 1, 3-site specific lipase. The addition amount of the enzyme is 6-12 wt%, the reaction temperature is 40-65 ℃, and the reaction time is 2-4 hours.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims (6)

1. A preparation method of human milk substitute fat based on triglyceride composition is characterized in that:

the method comprises the following steps of mixing lard serving as a raw material with vegetable oil to prepare a product similar to human milk fat in fatty acid composition and distribution, and then performing lactone exchange by using specific lipases at 1,3 sites as catalysts and using triglyceride similarity of the same as the human milk fat as an index to obtain human milk substitute fat similar to the human milk fat in triglyceride composition; wherein,

the vegetable oil comprises sunflower seed oil, canola oil, palm kernel oil, palm oil, microbial oil containing arachidonic acid and algae oil containing docosahexaenoic acid, and the mixing ratio is lard oil: sunflower seed oil: canola oil: palm kernel oil: palm oil: the microbial oil comprises 1 (0.06-0.14) to 0.42-0.59 (0.12-0.14) to 0.12-0.18): 0.02 (0.02-0.03);

the 1, 3-site specific lipase is used as a catalyst, the enzyme adding amount is 6-12 wt%, the temperature is 40-65 ℃, and the reaction time is 2-4 hours.

2. The method of claim 1 for producing human milk substitute lipids based on triglyceride composition, wherein: after the lactone exchange, the obtained reaction substrate is centrifuged to remove the enzyme, and then the free fatty acid is removed by molecular distillation.

3. The method of preparing human milk substitute lipids based on triglyceride composition as claimed in claim 2, wherein: the evaporation temperature of the molecular distillation is 180-185 ℃, the temperature of the heat exchanger is 55-60 ℃, and the absolute pressure is 2 Pa.

4. The method of claim 1 for producing human milk substitute lipids based on triglyceride composition, wherein: the mixing proportion is lard oil: sunflower seed oil: canola oil: palm kernel oil: palm oil: microbial oil algae oil 1:0.14:0.59:0.14:0.18:0.02: 0.03.

5. The method of claim 1 for producing human milk substitute lipids based on triglyceride composition, wherein: the mixing proportion is lard oil: sunflower seed oil: canola oil: palm kernel oil: palm oil: microbial oil algae oil 1:0.1:0.5:0.13:0.12:0.02: 0.02.

6. A method for evaluating human milk substitute lipids according to any one of claims 1 to 5, based on the preparation method of human milk substitute lipids consisting of triglycerides, characterized by: similarity is obtained by comparing and evaluating the obtained human milk substitute fat and human milk fat in terms of fatty acid composition and distribution, polyunsaturated fatty acid and triglyceride composition, and evaluation models are shown as follows:

<math> <mrow> <msub> <mi>G</mi> <mrow> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> </mrow> </msub> <mo>=</mo> <mn>100</mn> <mo>-</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>E</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>;</mo> </mrow> </math>

<math> <mrow> <msub> <mi>E</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>=</mo> <mn>100</mn> <mo>&times;</mo> <mrow> <mo>(</mo> <msub> <mi>C</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mfrac> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

$C_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}=\frac{|B_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}-A_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}|}{A_{i(\mathrm{FA}/\mathrm{sn}-2\mathrm{FA}/\mathrm{PUFA}/\mathrm{TAG})}};$

wherein G is_{FA/sn-2FA/PUFA/TAG}Respectively representing the similarity of the human milk substitute fat with the human milk fat in the aspects of fatty acid composition, sn-2 fatty acid relative content, polyunsaturated fatty acid or triglyceride composition;

E_{i(FA/sn-2FA/PUFA/TAG)}respectively representing the deducted similarity of the fatty acid composition, the sn-2 fatty acid relative content and the polyunsaturated fatty acid or triglyceride composition in the human milk fat substitute fat outside the corresponding index content range of the human milk fat;

<math> <mrow> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> <mo>/</mo> <msubsup> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </msubsup> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mrow> <mo>(</mo> <mi>FA</mi> <mo>/</mo> <mi>sn</mi> <mo>-</mo> <mn>2</mn> <mi>FA</mi> <mo>/</mo> <mi>PUFA</mi> <mo>/</mo> <mi>TAG</mi> <mo>)</mo> </mrow> </mrow> </msub> </mrow> </math> is the relative value of the composition of fatty acid, sn-2 fatty acid, polyunsaturated fatty acid or triglyceride of human milk fat and the total content thereof;

C_{i(FA/sn-2FA/PUFA/TAG)}is the coefficient of variation, which depends on the total fatty acid content, the relative content of sn-2 fatty acids, the polyunsaturated fatty acid or triglyceride composition of the human milk fat substitute;

B_{i(FA/sn-2FA/PUFA/TAG)}is the total fatty acid content, the sn-2 fatty acid relative content, the polyunsaturated fatty acid or triglyceride content of human milk substitute fat;

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