CN107751418A - A kind of preparation method of human milk fat structure fat substitutes - Google Patents

Abstract

The invention discloses a preparation method of a breast milk fat structural lipid substitute, which belongs to the field of food additives and structural lipid preparation. The method uses palm stearin as raw material, increases the content of palmitic acid at the sn-2 position through random transesterification, and then utilizes sn-1,3-specific lipase to catalyze the palm stearin and mixed fatty acids through random transesterification, To prepare a structural fat similar to breast milk fat, namely 1,3-dioleic acid-2-palmitic triglyceride (OPO)-based breast milk fat structural fat substitute. The enzymatic reaction in the present invention adopts a solvent-free system, and the enzyme preparation has a high reuse rate and good safety. Therefore, the method provided by the present invention has the advantages of stable source, low price, simple reaction process and short reaction time in the production of structured lipids. , the content of the product is high, the composition and ingredients of the obtained product and breast milk fat have reached 84.33% similarity, the quality is controllable and other advantages, and it is suitable for large-scale industrial production.

Description

A kind of preparation method of breast milk fat structural lipid substitute

technical field

The invention belongs to the field of food additives and structural fat preparation, and relates to a food additive-breast milk fat substitute, in particular to a breast milk fat structural fat substitute mainly composed of 1,3-dioleic acid-2-palmitic triglyceride The method of preparation of the product.

Background technique

Breast milk contains about 4% to 4.5% fat, which provides 50% energy for infants and young children, 98% of which is triglyceride. The special structure of breast milk fat is that saturated fatty acids represented by palmitic acid are mainly distributed in the sn-2 position of triglycerides, while unsaturated fatty acids represented by oleic acid are mainly distributed in the sn-1 and 3 positions of triglycerides, namely The OPO structure is mostly. The sn-2 palmitic acid glyceride is the most representative and important glyceride in breast milk, and the sn-2 position accounts for more than 68% of the total palmitic acid content.

Influenced by various reasons such as modern life style, work pressure, and personal factors, there are situations such as insufficient breast milk, lack of breast milk nutrition, and the need to increase complementary foods. At this time, infant formula milk powder becomes one of the best foods available as a breast milk fat substitute one. As mentioned above, in breast milk fat, palmitic acid is mostly distributed on the sn-2 position. However, it is obviously different from breast milk fat. The content of palmitic acid in vegetable oil, milk fat and other ingredients commonly used in compound formula milk powder can be close, but palmitic acid is often distributed on the sn-1 and sn-3 of triglycerides, that is, the POP structure . After POP structural lipids enter the human body, under the hydrolysis of pancreatic lipase, free palmitic acid lipids are formed, which easily form calcium soaps with calcium ions in food, resulting in the loss of calcium and energy. In addition to poor utilization, it is also easy to Make the baby constipated, which is not conducive to the health of the baby. And when the palmitic acid is located at sn-2, it shows the OPO structure. Under the action of pancreatic lipase, OPO is hydrolyzed into monoglyceride palmitate, which can be combined with bile salts in the body to form chylomicrons, which are easily absorbed by the human body. Improve the body's absorption and utilization of fatty acids. Thus, the location of palmitic acid in triglycerides is of physiological importance for the infant's nutrient absorption. Therefore, providing breast milk fat structure and oil substitutes, making its structure and nutritional value similar to breast milk, has become one of the main goals of developing infant formula milk powder.

The existing patent zl201410407944.0 provides a method for synthesizing structural lipids based on enzymatic acidolysis of palmitic triglycerides. Although the enzymatic reaction is realized, solvents are required, and the safety is limited. Patent CN201510528796.2 introduces an enzymatic mixture of fatty acids in microwaves to synthesize breast milk fat substitutes and its preparation method. Both the substrate and the enzyme need to strictly control the water activity of the reaction, the equilibration time is long and microwave treatment is required, and personnel exposure must be considered. ; Patent CN201210279472.6 introduces a method for preparing breast-emulsified structured lipids, which also uses mixed fatty acids, but n-hexane is still used as a solvent in the enzymatic reaction system. Also reported in scientific research literature is the method for preparing OPO with lard as a substrate, but because of geographical and religious (Muslim) restrictions, it is difficult to be widely used; another document has also reported that palm oil and palm stearin are used as substrates, but the product The content of palmitic acid in the middle sn-2 position is low, and the type and quantity of fatty acids cannot be similar to breast milk fat.

Contents of the invention

In order to overcome the shortcomings and deficiencies of the prior art, the object of the present invention is to provide a method for preparing a breast milk fat structural lipid substitute. The preparation method uses a wide range of sources of raw materials, a simple reaction process, no solvent residue, and high product content. The composition and components of the obtained product and breast milk fat have a similarity of 84.33%, and the safety is good, which is suitable for large-scale industrial production.

The object of the present invention is achieved through the following technical solutions:

A method for preparing a breast milk fat structural lipid substitute, which uses palm stearin as raw material, increases the content of palmitic acid at the sn-2 position through random transesterification, and then utilizes sn-1,3-specific lipase to catalyze the transesterification through random transesterification The exchange reaction of palm stearin and mixed fatty acids prepares a structural fat similar to breast milk fat, that is, a breast milk fat structural fat substitute.

The preparation method of the breast milk fat structural lipid substitute specifically comprises the following steps:

1) Random transesterification reaction of palm stearin: take palm stearin as raw material, heat, remove water in vacuum, then add catalyst, heat to 110-115°C, stir for 50min-70min; after the reaction is completed, cool to 70±5°C, add 12±2% citric acid solution to wash and shake, wash three times, separate the oil layer, and obtain palm stearin through random transesterification;

2) Enzymatic acid hydrolysis reaction: prepare a mixed fatty acid composed of lauric acid: myristic acid: oleic acid: linoleic acid with a mass ratio of 3:3:14:5 as an acyl donor, and sn-1,3-specific The lipase is used as a catalyst to carry out the acid hydrolysis reaction, and the molar ratio of palm stearin after random transesterification: acyl donor is 1:2～1:6;

3) The acid hydrolysis reaction product in step 2) is separated and refined by an alkali neutralization method to obtain a breast milk fat structural lipid substitute mainly composed of 1,3-dioleic acid-2-palmitic acid triglyceride (OPO).

The catalyst described in the step 1) is sodium methoxide with a concentration of 0.4-0.6%.

The sn-1,3-specific lipase described in step 2) is Lipozyme RMIM or TMLM.

The amount of the sn-1,3 specific lipase in step 2) is 4%-12% of the total mass of the material; preferably 8%.

The condition of the acid hydrolysis reaction described in step 2) is 55° C. to 70° C. for 0.4 to 4 hours; preferably 65° C. for 1 hour.

The molar ratio of the random transesterified palm stearin: acyl donor described in step 2) is preferably 1:4.

The catalyst after acidolysis reaction in step 2) can be reused 8-10 times.

The alkali used in step 3) is KOH ethanol solution with a concentration of 0.5mol/L-0.6mol/L, and the ethanol solution is formed by mixing 30% volume of ethanol and 70% volume of water.

The amount of alkali used in step 3) is 1.5 to 2.0 times the volume of the free fatty acid in the acid hydrolysis reaction product.

The conditions of the alkali neutralization method described in step 3) are 50-60° C., 150-200 r/min for 10-20 minutes.

A breast milk fat structural lipid substitute prepared by the above preparation method.

The innovation of this method is that by pretreating the substrate palm stearin, the content of palmitic acid at the sn-2 position of the substrate is greatly increased, and a certain proportion of mixed fatty acids is used as an acyl donor to make the type of fatty acid of the obtained product The structure is close to breast milk fat, and at the same time, it can be used repeatedly without solvents and catalysts. It has the advantages of simple process, wide source of raw materials, short reaction time, low production cost, and improved safety.

Compared with the prior art, the present invention has the following advantages and effects:

The preparation method of the present invention prepares the substrate required for the production of OPO through random transesterification of palm stearin, and then adopts reactions such as enzyme-catalyzed transesterification to generate 1,3-dioleic acid-2-palmitic acid triglyceride (OPO) Main breast milk fat substitute. Palm stearin is a by-product of palm olein, which contains a high proportion of palmitic acid. After transesterification, it can be used as a starting material for acidolysis to produce breast milk fat substitutes, and the enzymatic reaction in the present invention uses solvent-free system, the enzyme preparation has a high reuse rate and good safety, so the method provided by the invention has the advantages of stable source, low price and controllable quality in the production of structured lipids.

Detailed ways

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

The pretreatment of embodiment 1 palm stearin raw material and random transesterification

Put 100g of 52-degree palm stearin into a 500mL Erlenmeyer flask, place it in a temperature-controlled heating device, connect it to a vacuum device, connect a condenser tube, vacuumize, stir and heat to 100°C, and carry out vacuum dehydration for half an hour to remove grease moisture contained in it. Next, add 0.5% sodium methoxide as a catalyst into the reactor connected with a vacuum device, heat at 110°C, and stir for 50 minutes to catalyze the random transesterification of palm stearin. After the reaction, the PA content at the sn-2 position reaches the highest. After the oil is cooled to 70°C, add the prepared 12% citric acid solution to rinse and shake the sodium methoxide in the oil for 3 times, separate the oil layer, and obtain palm stearin through random transesterification.

The determination of the molar ratio of the fatty acid mixture of embodiment 2.

The main fatty acids in breast milk are capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid and linolenic acid. For comparison with the existing fatty acids in palm oil, sn-1,3-specific lipase was used to catalyze the acidification reaction between a single fatty acid and the oil obtained in Example 1. Furthermore, it is determined that the mass ratio of lauric acid: myristic acid: oleic acid: linoleic acid = 3:3:14:5 is mixed to form an acyl donor as a substrate.

Embodiment 3 enzyme catalyzed acid hydrolysis reaction

Using sn-1,3-specific lipase Lipozyme RMIM as a catalyst, using a mixed fatty acid with a mass ratio of lauric acid: myristic acid: oleic acid: linoleic acid = 3:3:14:5 as an acyl donor, Example 1. The palm stearin and mixed fatty acid obtained through random transesterification are mixed in a molar ratio of 1:4, the reaction temperature is 65°C, the catalyst dosage is 8% (w/w total mass of the substrate), the reaction time is 1h, and the sample is determined Composition of total fatty acids and sn-2 fatty acids, wherein the content of palmitic acid in the total fatty acids decreased from 58.56% to 28.10%, and the content of sn-2 palmitic acid accounted for 17.01% of the 52-degree palm stearin (raw material) % increased to 50.61% in breast milk fat structural fat substitutes.

The repeated use of embodiment 4 catalyst

After the acidolysis reaction is finished, the catalyst is centrifuged, and the remaining grease on the surface is cleaned with acetone, air-dried, and then added to the next round of reaction substrate to continue the catalytic reaction. The content of oleic acid in the reaction product triglyceride is used as According to the measurement standard, from the analysis of the obtained data, lipase RMIM can be reused 9 times, and the incorporation rate of oleic acid is not significantly reduced.

Embodiment 5 alkali treatment refines product

A 0.5 mol/L KOH ethanol solution is prepared, wherein the ethanol solution is formed by mixing 30% by volume of ethanol and 70% by volume of water. The enzymatic hydrolysis reaction product obtained in Example 3 in a solvent-free system was centrifuged to remove the enzyme and the preserved sample was taken out, melted in a water bath at 60°C, and KOH ethanol solution of about 1.5 times the volume of free fatty acids was added to neutralize the free fatty acids in the product. Fatty acid, 60°C, 150r/min water-bath shaker reacted for 10min, then stood in a 60°C water bath for 5min, took the upper light yellow organic phase, which was the separated triglyceride, that is, 1,3-Dioleic acid -2-palmitic acid triglyceride (OPO)-based breast milk fat structure lipid substitute. According to the calculation analysis and evaluation of the OPO scoring principle, the overall score of the product under the best conditions is 84.33 (out of 100), references for the OPO scoring principle, Jiang Yuyan, Jin Zi, Lin Ying, Zheng Suiping, Han Shuangyan, enzymatic catalytic production 1,3 -Dioleic acid-2-palmitic acid triglyceride, Modern Food Science and Technology, 2013, 29(5): 1048-1052. The higher score indicates that under the optimal reaction conditions, the structure of breast milk fat substitute obtained by catalytic reaction is similar to that of breast milk fat.

The present invention uses palm stearin as raw material for the first time, through random transesterification, increases the content of palmitic acid at the sn-2 position to increase its ratio, and then the mass ratio is: lauric acid: myristic acid: oleic acid: linoleic acid = 3:3:14:5 mixed fatty acids as acyl donors, through acid hydrolysis to obtain breast milk fat structure lipid substitute mainly 1,3-dioleic acid-2-palmitic acid triglyceride, sn-2 palmitate The acid content is increased from 17.01% in the 52-degree palm stearin (raw material) to 50.61% in the breast milk fat structured fat substitute.

The raw materials used in the present invention are cheap and come from a wide range of sources. The reaction adopts a solvent-free system, the method is simple, and the safety is good. The breast milk fat substitute produced is closer to the fatty acid composition and distribution of breast milk fat, which is a low-cost development of vegetable oil production. The production of fat provides a theoretical and reference basis, and can be widely used as an additive in infant formula fat.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. a preparation method of breast milk fat structure lipid substitute, is characterized in that: Using palm stearin as raw material, increase the sn-2 palmitic acid content through random transesterification, and then use sn-1,3 specific lipase to catalyze palm stearin and mixed fatty acids through random transesterification to prepare similar Structural fat of breast milk fat, that is, a substitute for structural fat of breast milk fat; The mixed fatty acid is composed of lauric acid: myristic acid: oleic acid: linoleic acid in a mass ratio of 3:3:14:5. 2. The preparation method of breast milk fat structural lipid substitute according to claim 1, is characterized in that specifically comprising the steps: 1) Random transesterification reaction of palm stearin: take palm stearin as raw material, heat, remove water in vacuum, then add catalyst, heat to 110-115°C, stir for 50min-70min; after the reaction is completed, cool to 70±5°C, add 12±2% citric acid solution to wash and shake, wash three times, separate the oil layer, and obtain palm stearin through random transesterification; 2) Enzymatic acid hydrolysis reaction: prepare a mixed fatty acid composed of lauric acid: myristic acid: oleic acid: linoleic acid with a mass ratio of 3:3:14:5 as an acyl donor, and sn-1,3-specific The lipase is used as a catalyst to carry out the acid hydrolysis reaction, and the molar ratio of palm stearin after random transesterification: acyl donor is 1:2～1:6; 3) The acid hydrolysis reaction product in step 2) is separated and refined by an alkali neutralization method to obtain a breast milk fat structural lipid substitute mainly composed of 1,3-dioleic acid-2-palmitic acid triglyceride. 3. the preparation method of breast milk fat structural lipid substitute according to claim 2, is characterized in that: The catalyst described in the step 1) is sodium methoxide with a concentration of 0.4-0.6%. 4. according to the preparation method of claim 1 or 2 described breast milk fat structure lipid substitute, it is characterized in that: The sn-1,3 specific lipase is Lipozyme RMIM or TMLM. 5. The preparation method of the breast milk fat structural lipid substitute according to claim 1 or 2, characterized in that: The amount of the sn-1,3 specific lipase is 4%-12% of the total mass of the material. 6. the preparation method of breast milk fat structure lipid substitute according to claim 2, is characterized in that: The condition of the acidolysis reaction described in step 2) is 55°C-70°C acidolysis reaction for 0.4-4h. 7. the preparation method of breast milk fat structural lipid substitute according to claim 2, is characterized in that: The catalyst after the acidolysis reaction in step 2) is reused 8 to 10 times. 8. The preparation method of breast milk fat structural lipid substitute according to claim 2, is characterized in that: The alkali used in step 3) is KOH ethanol solution with a concentration of 0.5mol/L-0.6mol/L, and the ethanol solution is formed by mixing 30% volume of ethanol and 70% volume of water. 9. The preparation method of breast milk fat structural lipid substitute according to claim 2, is characterized in that: The amount of alkali used in step 3) is 1.5 to 2.0 times the volume of the free fatty acid in the acidolysis reaction product; The conditions of the alkali neutralization method described in step 3) are 50-60° C., 150-200 r/min for 10-20 minutes. 10. A breast milk fat structural lipid substitute, characterized in that it is prepared by the preparation method described in any one of claims 1-9.