阅读说明：本技术 一种含有1,3-二油酸-2-棕榈酸甘油三酯的组合物的制备方法 (A method for preparing composition containing 1, 3-dioleoyl-2-palmitic acid triglyceride ) 是由 叶长青 翁志坚 黄镇平 徐胜荣 于 2019-07-03 设计创作，主要内容包括：本发明公开了一种含有1,3-二油酸-2-棕榈酸甘油三酯(OPO)的组合物的制备方法,包括：将碘值(IV)＜8的棕榈油硬酯精和油酸或油酸低碳直链酯进行酶促酯交换,所述酶促反应体系的水含量小于0.1％；分离去除棕榈酸或棕榈酸非甘油酯的酯,得到含1,3-二油酸-2-棕榈酸甘油三酯的组合物；其中,酶促酯交换反应所用的酶为非1,3位特异性脂肪酶。以本发明提供的方法制备的含有OPO甘油三酯组合物,其组成按重量计,OPO为45～56.2％,Sn-2为60～65％,PPP％<6.11％；与人乳脂肪组成中S<Sub>n</Sub>-1位和S<Sub>n</Sub>-3位主要是油酸,约60～70％的棕榈酸位于甘油三酯的S<Sub>n</Sub>-2位更接近。(The invention discloses a preparation method of a composition containing 1, 3-dioleic acid-2-palmitic acid triglyceride (OPO), which comprises the following steps: carrying out enzymatic ester exchange on palm oil stearin with an Iodine Value (IV) of less than 8 and oleic acid or oleic acid low-carbon straight-chain ester, wherein the water content of an enzymatic reaction system is less than 0.1%; separating and removing palmitic acid or non-glyceride esters of palmitic acid to obtain a composition comprising 1, 3-dioleoyl-2-palmitoyl triglyceride; wherein the enzyme used in the enzymatic transesterification reaction is a lipase which is not specific for 1, 3-position. The composition containing OPO triglyceride prepared by the method provided by the invention comprises 45-56.2% of OPO, 60-65% of Sn-2 and PPP%<6.11 percent; with the human milk fat component S n -1 and S n Oleic acid is predominant in the-3 position, and about 60-70% of palmitic acid is locatedS of triglycerides n The-2 bits are closer.)

1. A method for preparing a composition comprising triglycerides of 1, 3-dioleoyl-2-palmitate, comprising: carrying out enzymatic ester exchange on palm oil stearin with an iodine value less than 8 and oleic acid or oleic acid low-carbon straight-chain ester, wherein the water content of an enzymatic reaction system is less than 0.1%; separating and removing palmitic acid or non-glyceride esters of palmitic acid to obtain a composition comprising 1, 3-dioleoyl-2-palmitoyl triglyceride;

wherein the enzyme used in the enzymatic transesterification reaction is a lipase which is not specific for 1, 3-position.

2. The method of claim 1, 3-dioleoyl-2-palmitoyl triglyceride-containing composition, wherein the step of controlling the water content of the enzymatic reaction system to less than 0.1% comprises:

carrying out vacuum pumping dehydration on palm oil stearin with an iodine value less than 8, non-1, 3-site specific lipase and oleic acid or oleic acid low-carbon straight-chain ester at the temperature of 60-70 ℃, controlling the vacuum degree to be less than 1000Pa, and carrying out vacuum pumping for 1-3 hours; or the like, or, alternatively,

vacuumizing palm oil stearin with an iodine value less than 8 and oleic acid or oleic acid low-carbon straight-chain ester at the temperature of 150-160 ℃, controlling the vacuum degree to be 2-20 kPa, and vacuumizing for 0.5-1 hour; then cooling the system to below 70 ℃, and adding non-1, 3-site specific lipase; or the like, or, alternatively,

palm oil stearin with an iodine value less than 8 and oleic acid or oleic acid low-carbon straight-chain ester are put at the temperature of 150-160 ℃, after the water content of a system is controlled to be less than 0.1% by inert gas partial pressure, the system is cooled to below 70 ℃, and non-1, 3-site specific lipase is added; wherein the flow rate of the inert gas per 100 g of the material is controlled to be 10-100 ml/min.

3. The method for preparing a composition containing 1, 3-dioleoyl-2-palmitoyl triglyceride according to claim 1 or 2, wherein the enzymatic reaction is performed in an inert gas atmosphere, the water content of the reaction system is 0.01 to 0.05%, the temperature of the enzymatic reaction is 55 to 60 ℃, and the end point is that the content of palmitic triglyceride in the total triglyceride is less than 8%.

4. The method for preparing a composition containing 1, 3-dioleoyl-2-palmitoyl triglyceride according to claim 1, wherein the non-1, 3-specific lipase is Novozym 435 or Lipozyme TMIM, and the amount of the lipase is 2 to 30% of the total mass of all materials in the enzymatic reaction.

5. The method for preparing a composition containing 1, 3-dioleic acid-2-palmitic acid triglyceride according to claim 1, wherein the weight ratio of palm oil stearin to oleic acid or oleic acid low carbon straight chain ester is 1: 1-10; wherein the lower straight chain of the oleic acid lower straight chain ester is a saturated hydrocarbon with 1-6 carbon atoms.

6. The process for the preparation of a composition comprising triglycerides of 1, 3-dioleic acid-2-palmitic acid according to claim 1, characterized in that the enzymatic transesterification reaction is carried out in a batch or continuous manner, optionally in an organic solvent system or a solvent-free system.

7. The method for preparing a composition comprising triglycerides of 1, 3-dioleic acid-2-palmitic acid according to claim 6, wherein the enzymatic transesterification is carried out in a batch mode, comprising the following steps:

(i) palm olein with iodine value less than 8 and oleic acid or oleic acid low-carbon straight-chain ester are subjected to enzymatic ester exchange under the action of non-1, 3-site specific lipase 1 to prepare a composition containing 1, 3-dioleate-2-palmitic acid triglyceride;

(ii) separating excessive oleic acid and palmitic acid generated by the reaction, and then repeating the operation of the step (i) on the separated high-boiling triglyceride component and new oleic acid or oleic acid low-carbon straight-chain ester under the action of non-1, 3-site specific lipase 2 to obtain a high-content 1, 3-dioleic acid-2-palmitic acid triglyceride composition;

wherein the non-1, 3-position specific lipase 1 and the non-1, 3-position specific lipase 2 are the same or different.

8. Application of the composition containing 1, 3-dioleate-2-palmitic acid triglyceride prepared by the preparation method according to any one of claims 1 to 7 in preparation of infant dairy products.

Technical Field

The invention relates to a product capable of replacing human milk fat oil, in particular to a preparation method of a composition containing 1, 3-dioleoyl-2-palmitic acid triglyceride (OPO), and particularly relates to a method for preparing a composition containing OPO triglyceride by using palm oil stearin with low iodine value as a raw material.

Background

Human milk fat is an important component in breast milk, and only accounts for 3.6-4.5% of breast milk, but provides nearly 50% of energy for infants. About 60-70% of palmitic acid in the fat composition of human milk is located in the S of triglycerides_n-2 position, and S_n-1 and S_nThe-3 position is predominantly oleic acid. That is, human milk fat composition is very close to 1, 3-dioleoyl-2-palmitoyl triglyceride (commonly referred to as OPO).

At present, the more common method for producing a composition containing triglycerides of 1, 3-dioleoyl-2-palmitate is: (1) providing grease with rich palmitic acid at the Sn-2 position; (2) providing an oleic acid acyl donor which may be a fatty acid non-triglyceride ester of oleic acid such as oleic acid, methyl oleate or ethyl oleate; (3) and finally, completing the directional transesterification reaction under the catalysis of 1, 3-position selective enzyme (specific lipase) to synthesize the OPO triglyceride, wherein the essence of the directional transesterification reaction catalyzed by the specific lipase is the substitution reaction of unsaturated fatty acid on Sn-1/3-position fatty acid in the Sn-2-position palmitic acid-rich grease, and the composition of the Sn-2-position fatty acid is not influenced.

At present, the grease rich in palmitic acid at the Sn-2 position is mainly derived from triglyceride rich in palmitic acid obtained by performing random transesterification reaction on palm oil extract palm oil stearin or a mixture of triglyceride derived from plants, for example, patent CN101679909A discloses that one or more palm oil stearin components with iodine value of 18-40 are used for performing random transesterification reaction to obtain triglyceride rich in palmitic acid at the Sn-2 position, and then the triglyceride rich in palmitic acid is subjected to specific lipase-catalyzed transesterification reaction with oleic acid or non-triglyceride thereof to prepare a composition containing OPO glyceride.

The palm oil stearin is rich in palmitic acid triglyceride (PPP) structure, the lower the iodine value of the palm oil stearin is, the higher the PPP content is, and the higher the OPO content in the theoretically synthesized OPO-containing glyceride composition is; for example, patent CN101258230B discloses a process for the preparation of a composition comprising 1, 3-dioleoyl-2-palmitoyl glyceride (OPO) using a localized enzymatic transesterification of palm oil stearin having an Iodine Value (IV) of 8 to 12 with oleic acid or a non-glyceride ester thereof, as a result of which C₅₂40-42% (detected by gas phase internal standard), and the proportion of the palmitic acid in the Sn-2 is about 52-56%, and the effect accords with theoretical expectation. However, this patent also unexpectedly found that: the lower the iodine value of the raw material palm oil stearin, the less the OPO-containing composition prepared using the prior art method is rather unsatisfactory, which is not in line with theoretical expectations, and no exact reason has been found at present. The fatty acid composition required by infant nutrition prepared by mixing the product obtained in the patent with other vegetable oil has a large difference with the milk fat structure of breast milk.

Disclosure of Invention

The invention provides a method for preparing a composition containing OPO triglyceride by using palm oil stearin with low iodine value as a raw material, which overcomes the prejudice of the prior art that the OPO content in the OPO triglyceride composition prepared by using the palm oil stearin with low iodine value as the raw material is low, and the method has simple process and low cost and is suitable for industrial production.

A method for preparing a composition comprising 1, 3-dioleoyl-2-palmitoyl triglyceride (OPO), comprising: carrying out enzymatic ester exchange on palm oil stearin with an Iodine Value (IV) of less than 8 and oleic acid or oleic acid low-carbon straight-chain ester, wherein the water content of an enzymatic reaction system is less than 0.1%; separating and removing palmitic acid or non-glyceride esters of palmitic acid to obtain a composition comprising 1, 3-dioleoyl-2-palmitoyl triglyceride;

wherein the enzyme used in the enzymatic transesterification reaction is a lipase which is not specific for 1, 3-position.

The palm oil stearin is obtained by fractionating palm oil or a derivative thereof, the palm oil being selected from the group consisting of crude palm oil, refined palm oil, palm oil fractions (e.g. fractions obtained by Lanza fractionation), palm oil derivatives or mixtures thereof.

The role of non-1, 3-specific lipase in enzymatic reaction is different from that of specific lipase only substituting Sn-1/3 fatty acid, and at the same time, the composition of Sn-2 fatty acid is not affected, intermolecular or intramolecular acyl redistribution of triglyceride under the action of non-1, 3-specific lipase is randomly distributed according to probability, so after random ester exchange reaction, the probability of distribution of one fatty acid on any site of triglyceride is the same, which is not good for preparing high content OPO triglyceride composition, therefore, the prior art mostly adopts grease rich in palmitic acid at Sn-2 position and acyl donor, and prepares high content OPO triglyceride composition by ester exchange under the catalysis of 1, 3-selective enzyme.

However, the present inventors have unexpectedly found that the content of OPO produced by transesterification using an oil or fat rich in palmitic acid at the Sn-2 position and an acyl donor as raw materials can be increased by controlling the water content of the reaction system to 0.1% or less and using a lipase other than the 1, 3-position specific lipase.

Wherein, the invention controls the water content of the enzymatic reaction system to be less than 0.1 percent, and comprises the following process steps:

carrying out vacuum pumping dehydration on palm oil stearin with an iodine value of less than 8, non-1, 3-site specific lipase and oleic acid or oleic acid low-carbon straight-chain ester at the temperature of 60-70 ℃, controlling the vacuum degree to be less than 1000Pa, and further preferably controlling the vacuum degree to be less than 500Pa for 1-3 hours; or the like, or, alternatively,

vacuumizing palm oil stearin with an iodine value less than 8 and oleic acid or oleic acid low-carbon straight-chain ester at the temperature of 150-160 ℃, controlling the vacuum degree to be 2-20 kPa, and vacuumizing for 0.5-1 hour; then cooling the system to below 70 ℃, and adding non-1, 3-site specific lipase; or the like, or, alternatively,

palm oil stearin with an iodine value less than 8 and oleic acid or oleic acid low-carbon straight-chain ester are put at the temperature of 150-160 ℃, after the water content of a system is controlled to be less than 0.1% by inert gas partial pressure, the system is cooled to below 70 ℃, and non-1, 3-site specific lipase is added; wherein, the flow rate of the inert gas per 100 g of the material is controlled to be 10-100 ml/min, and the material is preferably not carried out.

Preferably, the enzymatic reaction is carried out in an inert gas atmosphere, the water content of a reaction system is 0.01-0.05%, the enzymatic reaction temperature is 55-60 ℃, and the end point is to measure that the content of palmitic acid triglyceride in the total triglyceride is less than 8%.

The non-1, 3-site specific lipase is Novozym 435 or Lipozyme TM IM and the like, and the dosage of the lipase accounts for 2-30% of the total mass of all materials in the enzymatic reaction.

The weight ratio of the palm oil stearin to the oleic acid or oleic acid low-carbon straight-chain ester is 1: 1-10; wherein the lower straight chain of the oleic acid lower straight chain ester is a saturated hydrocarbon with 1-6 carbon atoms.

Preferably, the oleic acid low-carbon linear chain ester is methyl oleate or ethyl oleate.

Furthermore, the purity of the oleic acid or the oleic acid low-carbon straight-chain ester in the enzymatic reaction is 50-90%.

The enzymatic transesterification is carried out batchwise or continuously, optionally in an organic solvent system or in a solvent-free system, wherein the same or different non-1, 3-specific lipases are used batchwise and in stages.

Further, in one embodiment, the method of the present invention comprises:

(i) palm olein with iodine value less than 8 and oleic acid or oleic acid low-carbon straight-chain ester are subjected to enzymatic ester exchange under the action of non-1, 3-site specific lipase 1 to prepare a composition containing 1, 3-dioleate-2-palmitic acid triglyceride;

(ii) separating excessive oleic acid and palmitic acid generated by the reaction, and then repeating the operation of the step (i) on the separated high-boiling triglyceride component and new oleic acid or oleic acid low-carbon straight-chain ester under the action of non-1, 3-site specific lipase 2 to obtain a high-content 1, 3-dioleic acid-2-palmitic acid triglyceride composition;

wherein the non-1, 3-position specific lipases 1 and 2 are Novozym 435 or Lipozyme TM IM, etc., and the non-1, 3-position specific lipase 1 and the non-1, 3-position specific lipase 2 are the same or different.

The ester exchange step by step can improve the content of the by-product in the low-boiling components needing rectification and separation and greatly reduce the total amount of low-boiling substances, thereby greatly reducing the rectification energy consumption.

In order to increase the OPO content in the 1, 3-dioleate-2-palmitic acid triglyceride composition, the enzymatic reaction product is subjected to separation and refining treatment, specifically vacuum distillation, fractional distillation, molecular distillation and/or chemical refining, so that the enzymatic reaction product is close to the fat with a human milk fat structure.

Further, the absolute pressure of the vacuum distillation, the fractional distillation and the molecular distillation is 1-500 Pa, and the temperature is 140-260 ℃.

Further, the chemical refining adopts dilute alkali refining.

The composition containing OPO triglyceride prepared by the method comprises, by weight, 45-56.2% of OPO, 60-65% of Sn-2 and 6.11% of PPP; meets the quality requirements of the Ministry of public health of the people's republic of China on 1, 3-dioleoyl-2-palmitoyl triglyceride: wherein, the content of Sn-2 in the composition is required to be more than or equal to 52 percent; the content of OPO is more than or equal to 40 percent. Therefore, the method provided by the invention overcomes the defect of low OPO content in the OPO triglyceride composition prepared by taking palm oil stearin with low iodine value as a raw material in the prior art.

The composition containing OPO triglyceride and S in the human milk fat composition prepared by the invention_n-1 and S_nThe-3 position is mainly oleic acid, and about 60-70% of palmitic acid is located in the S of triglyceride_nThe-2 bits are closer. The composition containing OPO triglyceride prepared by the invention can be used as a high-quality fat substrate suitable for replacing infant food, and is applied to preparing infant dairy products.

To better meet the fatty acid composition required by the human body, the composition containing 1, 3-dioleoyl-2-palmitoyl triglyceride obtained in the present invention may be mixed with at least one vegetable oil, the proportion and type of which may be determined according to the dietary and physical needs of the desired composition.

Drawings

FIG. 1 is a flow chart of a stepwise process for preparing a composition containing 1, 3-dioleoyl-2-palmitoyl triglyceride (OPO) in examples 6 to 7 of the present invention.

Detailed Description

For further understanding of the present invention, the following examples are provided to describe the preparation method of a composition containing triglyceride 1, 3-dioleate-2-palmitate (OPO) in detail, but the present invention is not limited to these examples, and those skilled in the art who have the guidance of the core of the present invention will make insubstantial modifications and adjustments, and still fall within the scope of the present invention.