CS269749B1 - A method for producing higher fatty acid esters of sucrose - Google Patents

Abstract

The method of producing sucrose esters with higher fatty saturated or unsaturated acids with a degree of esterification of 5 to 8 consists in that after alkaline esterification, the reaction mixture is diluted with water in a mass ratio of 1:1 to 10, the pH of the reaction mixture, or only its hydrophobic organic part, is adjusted to a value of 4 to 10. By adding 0.1 to 5 l by mass of a biocatalyst exhibiting esterase or Upas activity, the mixture, or its hydrophobic organic part, is hydrolyzed until the alkyl esters of higher fatty acids disappear. The product contained in the organic layer is separated from the aqueous phase. The obtained sucrose esters act as non-caloric fat substitutes. They can be used in medicine and in the food industry.

Description

The invention relates to a method for producing sucrose esters with higher fatty saturated or unsaturated acids with a degree of esterification of 5 to 8. These esters have the physicochemical and organoleptic properties of fats, but unlike them, they are not hydrolyzed by lipases in the gastrointestinal tract and also act as a lipophilic solvent for cholesterol. Therefore, they are recommended as non-caloric fat substitutes, or as a means for reducing cholesterol levels in blood plasma.

The most technologically feasible route for their production is based on the base-catalyzed transesterification of sucrose with alkyl esters of higher fatty saturated or unsaturated acids. This transesterification can be carried out in a sucrose solution in high-boiling aprotic solvents or without the presence of a solvent. However, it is always necessary to work with an excess of alkyl esters of higher fatty saturated or unsaturated acids so that the reaction proceeds in a satisfactory yield and with a sufficiently high degree of esterification. With regard to the required physicochemical and organoleptic properties of the final product and its hygienic safety, it is necessary to completely remove excess alkyl esters of higher fatty acids and sucrose esters and these acids with a degree of esterification lower than 5. This has so far been carried out by extracting the product of the transesterification reaction of sucrose with alkyl esters of higher fatty saturated or unsaturated acids with alcohol, most often methanol or ethanol. This extraction is time-consuming, requires working with a flammable solvent, and involves the costs of safety gear and solvent regeneration. In addition, the reaction product is partially extracted into the alcohol, which reduces the reaction yield.

These disadvantages are eliminated by a method for producing sucrose esters with higher fatty saturated or unsaturated acids with a degree of esterification of 5 to 8, prepared by base-catalyzed transesterification of sucrose, characterized in that the reaction mixture after esterification is diluted with 1 to 10 times the mass amount of water and mixed. After mixing the reaction mixture, the aqueous phase is optionally separated and the pH of the reaction mixture, optionally only its hydrophobic organic part, is adjusted to a value of 4 to 10 and then 0.1 to 5% by mass of a biocatalyst exhibiting esterase or Upase activity is added and the mixture is incubated at 2 to 45 °C. An isolated enzyme, whole cells or subcellular particles can be used as a biocatalyst, as such or in immobilized form. Under the action of the biocatalyst, alkyl esters of higher fatty saturated or unsaturated acids and sucrose esters with these acids with a degree of esterification lower than 5 are hydrolyzed and the hydrolysis products pass into the aqueous layer, while sucrose esters with higher fatty saturated or unsaturated acids with a degree of esterification higher than 5 are not hydrolyzed and form an organic layer. After filtering off the biocatalyst and separating the aqueous layer, a product is obtained, which, after possible decolorization with bleaching clay and deodorization, can be directly applied to dietetic products or pharmaceutical preparations.

The pH of the reaction mixture is adjusted with organic or inorganic acid, such as phosphoric or citric acid, to the range specified above. The pH of the organic layer is adjusted by adding 1 to 10 times the amount of buffer with a pH of 4 to 10. If the biocatalyst is used in immobilized form, it can be reused in the next production batch after being separated from the reaction mixture and washed with buffer.

The invention and its effects are further illustrated by the following examples, which in no way limit its scope.

Example 1 . .

A mixture of 32 g (0.0935 mol) of sucrose, 106 g (0.3732 mol, 4 eq.) of ethyl palmitate, 13.7 g (0.0466 mol, 0.5 eq.) of potassium palmitate and 150 mg of potassium ethoxide was heated to 150 °C under a pressure of 50 Pa with stirring. After 3 h, 160 g of

CS 269 749 B1 (0.5633 mol, 6 eq.) of ethyl palmitate was added and the reaction mixture was stirred for another 6 h at the same pressure and temperature. The vacuum source was then disconnected and the mixture was allowed to cool to 80 °C with stirring. 330 g of water was added to the reaction mixture in portions and the pH of the aqueous phase was adjusted to 7.5 by adding phosphoric acid. 1.5 g of lipase (EC 3.1.1.3) was added to the reaction mixture at 40 °C and the mixture was stirred at this temperature until ethyl palmitate was present according to thin layer chromatography in the ethyl acetate-petroleum system (b. v. 45 to 60 °C) 5:95 (v/v). The mixture was transferred to a heated separator and the lower aqueous layer was separated from the organic; This was filtered through a heated filter funnel with a frit. The yellowish product was decolorized by stirring « with 10 g of bleaching earth at 90 °C and a pressure of 1.5 kPa. 160 g of solid product were obtained, which according to the results of preparative chromatography on a silica gel column (eluent petroleum ether, or petroleum ether-ethyl acetate 100:0.5 to 100:5) contained 60 wt. % octa-O-palmitoyl sucrose and 40 wt. % of a mixture of penta to hepta-O-palmitoyl sucrose.

Example 2

A mixture of 120 g (0.4444 mol, calculated as methyl palmitate) of methyl esters of acids contained in lard (this mixture was prepared by re-esterification of lard with methanol), 120 ml of methanol and 3.9 g (0.0696 mol) of potassium hydroxide was heated to boiling for 75 minutes, then 32 g (0.0935 mol) of sucrose and 3.9 g of potassium carbonate were added and methanol was distilled off with stirring. This gave a mixture of sucrose, potassium salts and methyl esters of fatty acids from lard in the ratio sucrose : methyl ester : K-salt =1:4: 0.75. Then the temperature of the reaction mixture was raised to 145 °C and the pressure was reduced to 1 kPa. After 2.5 h, 152 g (0.563 mol, calculated as methyl palmitate) of a mixture of methyl esters of acids contained in pork fat, 3.9 g of potassium carbonate were added to the reaction mixture and the mixture was heated to 145 to 150 °C under a pressure of 1 kPa for another 6 h. After cooling to 80 °C, the reaction mixture was mixed with a 10-fold excess of water and after 30 minutes of stirring at 80 °C, the aqueous layer was separated from the aqueous layer. 5 kg of 0.1 M phosphate buffer and pH = 7.5 and 0.5% by weight of lipase (EC 3.1.1.3) were added to the organic layer and the mixture was stirred at 40 °C until the methyl esters disappeared. Then the organic layer was separated from the aqueous layer, filtered with carborane and dried at 80°C and 1.2 kPa pressure.

170 g of a product with the consistency of lard was obtained, which contained sucrose esters with a degree of esterification of 5 to 8. *

Example 3..

In the same way and with the same weights as in Example 2, sucrose esterification of a mixture of fatty acid methyl esters present in tallow was carried out. Then 3 kg of water was added to the reaction mixture, the organic layer was separated from the aqueous layer and mixed with 3 kg of 0.3 M borate buffer with pH = 9, containing 40 mmol CaCl^ in dm^ and 5% by weight of a heterogeneous biocatalyst with immobilized lipase (for example, covalently bound to OSTSORB AV or to modified porous glass). The mixture was shaken at 45 °C until the methyl ester content disappeared, then the organic phase was separated from the aqueous phase. The heterogeneous biocatalyst was isolated from the aqueous phase by filtration, which was washed with 0.3 borate buffer with pH = = 9.0 and reused in the next batch. From the organic phase, after decolorization with bleaching clay and drying in vacuum, 160 g of a product containing sucrose esters with fatty acids present in tallow, with a degree of esterification of 6 to 8, was obtained. Example 4

A mixture of 3.2 g (9.35 mmol) of sucrose, 26.6 g (89 mmol, 9.5 equiv.) of n-propyl palmitate and 1.4 g (5 mmol, 0.54 equiv.) of sodium palmitate was heated to 100 °C with stirring. Then 0.3 g of sodium was added portionwise, the temperature was raised to 160 °C and the pressure was reduced.

CS 269 749 Bl 3 at 0.1 Pa. After 0 h, the reaction mixture was allowed to cool to 80 °C and 150 g of water was carefully added; after 10 minutes, the organic layer was separated from the aqueous layer. 600 g of 0.5 M phosphate buffer pH = 8.5 with 2 * wt. biomass of the yeast Saccharomycopsis lipolytica were added to the organic layer and the mixture was stirred at 30 °C until the disappearance of n-propyl palmitate. Then the mixture was filtered through a frit, the organic layer was separated from the aqueous layer and then dried in a water pump vacuum at 80 °C. 13 g of solid product was obtained, which according to the result of preparative chromatography (see example 1) contained 45 wt. % octa-O-palmitoyl sucrose in addition to the sucrose derivatives esterified below. ·

Example 5 i A mixture of 3.2 g (9.35 mmol) sucrose, 22.3 g (74.8 mmol, 8 eq. based on 2-propyl palmitate) of a mixture of 2-propyl esters of fatty acids contained in coconut oil, 2.6 g (1 eq.) sodium palmitate and 30 mg of sodium hydride was heated under a pressure of 1 Pa to 200 °C for 2 h, then allowed to cool to 70 °C. 250 g of water was added to the mixture and after 10 minutes of stirring at 70 °C the organic layer was separated from the aqueous layer. 100 g of borate buffer with pH ≤ 9 and 1 g of permeabilized Saccharomycopsia lipolytica cells were added to the organic layer and the mixture was stirred at 35 °C until the 2-propyl esters of fatty acids disappeared. The aqueous layer was then separated from the organic layer and the latter was filtered through a frit and dried at 80°C under water pump vacuum. 8 g of product were obtained in the form of a viscous oil which, according to silica gel column chromatography (see Example 1), contained 45% by weight of octa-O-acylsucrose.

Example 6

In the same manner as in Example 2, a mixture of sucrose, methyl esters of fatty acids contained in pork lard and the corresponding sodium salts was prepared by the action of sodium hydroxide in a molar ratio of sucrose; Na salt: methyl ester 1:0.75:12. 0.1% by weight of sodium amide was added to this mixture and the reaction mixture was stirred for 8 h at 160°C and a pressure of 100 Pa. It was then mixed with 10 times the amount of water and after 10 minutes at 70°C the organic layer was separated from the aqueous layer. A 40-fold amount (by weight) of phosphate buffer pH=8.5 and 5% by weight of Saccharomycopsis lipolytica cells immobilized by their incorporation into the carrageenan gene was added to the organic layer. This mixture was shaken at 3B °C until the methyl ester content disappeared, then it was filtered, the aqueous layer was separated from the organic layer. The organic layer was dried at 90 °C and a pressure of 100 Pa to constant weight. With a 32 g sucrose charge, 156 g of a product of lard consistency were obtained, which contained, according to chromatography on a silica gel column (see example 1), 55% by weight of octa-O-acylsucrose.

Claims (4)

SUBJECT OF THE INVENTION 1. A method for producing sucrose esters with higher fatty acids with a degree of esterification of 5 to 8 by esterification of sucrose with 8 to 12 molar equivalents of alkyl esters of higher fatty saturated or unsaturated acids and 0.5 to 1 molar equivalent of alkali salts of higher fatty saturated or unsaturated acids at 140 to 200 °C under a pressure of 0.1 to 1,000 Pa in the presence of 0.1 to 10% by weight of a basic catalyst, characterized in that 1 to 10 times the amount of water is added to the reaction mixture, based on the total weight of the reaction mixture, after adding water and mixing the reaction mixture, the aqueous phase is optionally separated and the pH of the reaction mixture, optionally only its hydrophobic organic parts, is adjusted to a value of 4 to 10 and then 0.1 to 5% by weight of a biocatalyst having esterase or Upase activity, the mixture hydrolyzes at 2 to 45 °C CS 269 749 Bl until the alkyl esters of higher fatty saturated or unsaturated acids disappear, after which the product contained in the organic layer is separated from the aqueous layer including the biocatalyst. 2. The method according to item 1, characterized in that the pH of the reaction mixture is adjusted by adding an organic or inorganic acid, for example citric or phosphoric acid, to a pH value of 4 to 10. 3. The method according to item 1, characterized in that the pH of the hydrophobic organic part is adjusted to pH 4 to 10 by dilution with 0.2 to 2 mol.dm ³ buffer in a mass ratio of 1:1 to 10. AND 4. The method according to points 1 and 2 or 3, characterized in that for the hydrolysis of alkyl esters of higher fatty saturated or unsaturated acids, whole cells or subcellular particles exhibiting esterase or Upase activity or immobilized enzymes, immobilized cells or immobilized molecular particles exhibiting esterase or Upase activity are used, and these are separated from the reaction mixture after the hydrolysis has taken place and reused in the next production batch. .