阅读说明：本技术 一种抑制二位单甘酯2-mag酰基转移的方法 (Method for inhibiting acyl transfer of di-monoglyceride 2-MAG ) 是由 王小三 高亮 王笑寒 赵彧 王兴国 金青哲 黄健花 于 2019-10-08 设计创作，主要内容包括：一种抑制二位单甘酯2-MAG酰基转移的方法,涉及油脂技术领域。所述方法为将2-MAG、水与饱和盐溶液溶剂混合,保持混合体系内水活度为0～0.50,存储的温度为-30℃～70℃,该方法有效的抑制了2-MAG在贮存过程中发生的酰基转移,简单实用,可应用在工业生产中。(A method for inhibiting acyl transfer of di-monoglyceride 2-MAG relates to the technical field of grease. The method is characterized in that 2-MAG, water and a saturated salt solution solvent are mixed, the water activity in a mixed system is kept to be 0-0.50, the storage temperature is-30-70 ℃, and the method effectively inhibits the acyl transfer of the 2-MAG in the storage process, is simple and practical, and can be applied to industrial production.)

1. A method for inhibiting acyl transfer of di-position monoglyceride 2-MAG is characterized in that 2-MAG, water and a polar solvent are mixed, the water activity in a mixed system is adjusted to be 0-0.50, and the storage temperature is-30-70 ℃.

2. The method for inhibiting acyl transfer of di-monoglyceride 2-MAG as claimed in claim 1, wherein the 2-MAG is an unsaturated fatty acid 2-MAG, including monounsaturated fatty acid 2-MAG, polyunsaturated fatty acid 2-MAG.

3. The method of claim 1 for inhibiting acyl transfer of di-monoglycerides 2-MAG, wherein the method for modulating water activity comprises: drying or adding saturated salt solution into the mixed system.

4. The method of claim 3, wherein the saturated salt solution comprises LiCl saturated salt solution, Mg (NO)₃)₂Saturated salt solutions or K₂SO₄Saturated salt solution.

5. The method of claim 1, wherein the polar solvent is a solvent having a solvent hydrophobicity parameter log P of less than 1.5.

6. The method for inhibiting acyl transfer of bin-monoglyceride 2-MAG as claimed in claim 1 or 5 wherein said polar solvent comprises one or more of acetonitrile, acetone, ethanol, tert-butanol, methanol, acetic acid, propanol, propionic acid, butanone, tetrahydrofuran, butanol, pentanone, ethyl acetate, diethyl ether, ethyl chloride, methyl butylamine, pentanol.

7. The method for inhibiting acyl transfer of di-monoglycerides 2-MAG according to claim 1, wherein the water activity in the mixed system is 0-0.25.

8. The method of claim 1 for inhibiting acyl transfer of di-monoglycerides 2-MAG, wherein the ratio of 2-MAG to polar solvent is 1: 1 to 30 m/v.

9. The method of claim 1 for inhibiting acyl transfer of di-monoglycerides 2-MAG, wherein the ratio of 2-MAG to polar solvent is 1: 2 to 20 m/v.

Technical Field

The invention relates to the technical field of grease, in particular to a method for inhibiting acyl transfer of di-monoglyceride 2-MAG.

Background

Starting in the twentieth of the nineteenth century, scientists discovered that fatty acids located on the MAG glycerol backbone could be spontaneously transacylated. Acyl transfer refers to the intramolecular transfer of one acyl group to an adjacent unoccupied hydroxyl group on the glycerol backbone. The acyl transfer of 2-MAG is a bimolecular nucleophilic substitution reaction.

The rate of acyl transfer is influenced by factors that alter the charge dispersion of the transition state of the nucleophilic substitution reaction. In the presence of protons, the electrophilic character of the carbonyl increases, and the adjacent hydroxyl group acts as a nucleophile to attack the carbonyl carbon, forming a five-membered ring transition state intermediate, i.e., the orthoester. The hydroxyl oxygen attacks the carbon atom again, opening the five-membered ring and forming 1-MAG. When the reaction conditions favor charge dispersion in the transition state of the reaction, the transition state energy is low, the activation energy is reduced, and the acyl transfer rate of the 2-MAG is increased.

However, the literature reports that the reaction process is a research on acyl transfer, and during the storage process, the acyl transfer of 2-MAG can also occur spontaneously without the catalysis of enzyme, namely the transfer of 2-MAG to 1-MAG. Therefore, there is a need to develop a method for inhibiting acyl transfer of 2-MAG during storage.

Disclosure of Invention

Aiming at the problem of acyl transfer during the storage of 2-MAG, the invention aims to provide a method for inhibiting the acyl transfer of 2-MAG, which comprises the steps of mixing 2-MAG, water and a polar solvent, adjusting the water activity in a mixed system to be 0-0.50 and storing at the temperature of-30-70 ℃.

The water activity represents a parameter of the energy state of water in the system, namely the ratio of the vapor pressure of water in the system to the vapor pressure of pure water at the same temperature. When the water activity in the system can reach 1 to the maximum, the state of the water is close to free water, and the water activity of the system cannot be improved by increasing the water content of the system. The detection method and the calculation method of the water activity are obtained by adopting the international standard ISO 417-.

In one embodiment, the 2-MAG is an unsaturated fatty acid 2-MAG, including monounsaturated fatty acid 2-MAG, polyunsaturated fatty acid 2-MAG.

In one embodiment, the method of regulating water activity comprises: drying or adding saturated salt solution into the mixed system.

In one embodiment, the saturated salt solution comprises a LiCl saturated salt solution, Mg (NO)₃)₂Saturated salt solutions or K₂SO₄Saturated salt solution.

In one embodiment, the polar solvent is a solvent having a solvent hydrophobic interaction parameter log P value of less than 1.5.

Generally, in the chemical reaction involving an organic solvent as a reaction medium, the strength of the organic solvent can be represented by a polar coefficient log P, where P refers to the partition coefficient of the solvent in both phases of n-octane and water. The larger the polarity coefficient, the smaller the polarity is; conversely, the smaller the polarity coefficient, the stronger the polarity.

In one embodiment, the polar solvent comprises one or more of acetonitrile, acetone, ethanol, tert-butanol, methanol, acetic acid, propanol, propionic acid, butanone, tetrahydrofuran, butanol, pentanone, ethyl acetate, diethyl ether, ethyl chloride, methylbutylamine, pentanol.

In one embodiment, the water activity in the mixed system is 0 to 0.25.

In one embodiment, the ratio of 2-MAG to polar solvent is 1: 1 to 30 m/v.

In one embodiment, the ratio of 2-MAG to polar solvent is 1: 2 to 20 m/v.

Advantageous effects

The method for inhibiting 2-MAG acyl transfer provided by the invention mixes 2-MAG, water and a polar solvent, and effectively inhibits the 2-MAG from generating acyl transfer in the water activity range of 0-0.5 and under the storage condition of the temperature of minus 30-70 ℃.

In chemical reactions, organic solvents are used as a reaction medium and generally do not participate in the reaction, and in addition, the organic solvents are divided into hydrophobic solvents and hydrophilic solvents, which affect the acyl transfer of glycerides. Depending on the effect of the organic solvent on the acyl transfer in the chemical reaction, the addition of the organic solvent and the inhibition of the acyl transfer at a certain water activity during storage is an effective method.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with examples are described in detail below.

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 detection method and the calculation method of the water activity of the following experiments are obtained by adopting the international standard ISO 417-.