CZ9902671A3 - Oils for cooking and frying exhibiting reduced energy value, enhanced hydrolytic stability and process of their preparation - Google Patents

Abstract

The present invention relates to a process for preparing cooking and frying oils reduced energy value that contains indigestible polyol polyesters, have improved color stability and improved stability to hydrolysis during frying. Said the process comprises, in a first stage, processing of the crude polyol polyester with an ion-exchange ligand contained in the aqueous phase where the divalent is converted by this treatment metal soaps contained in the crude polyol-polyester on monovalent soaps. These movalent soaps and ionic the exchange ligands are then removed from the polyol polyol and recovered so processed polyol-polyester for use as an oil for cooking and frying, which contains less than about 550 ppb divalent metal ions. Said oil, further processed it has free content in the usual industrial ways fatty acids of less than about 500 ppm. They preferably have further cooking and frying oils prepared as per solution a Lovibond red value of less than about 6 preferably less than about 4.

Description

Cooking and frying oils with reduced energy value, improved hydrolytic stability and process for their preparation

Technical field

BACKGROUND OF THE INVENTION The present invention relates to energy-reduced cooking and frying oils containing non-digestible polyol polyesters and having improved hydrolysis stability and to a process for preparing these oils.

BACKGROUND OF THE INVENTION

In the food industry, much attention is currently focused on the production of polyol-polyesters of fatty acids for their use as low-energy fats in food products. As a result, there remains a need for economical and efficient processes for producing relatively high purity polyol polyester and fatty acid.

Certain non-digestible polyol fatty acid polyesters have been found to be useful as a low energy substitute for triglyceride oils. For example, Mattson et al. (US Pat. 3,600,186, issued Aug. 17, 1971) discloses low-energy cooking and frying oils in which at least a portion of the triglyceride oil is replaced by a non-absorbable, non-digestible fatty acid sugar ester or fatty acid alcohol sugar ester containing at least 4. fatty acid ester groups wherein each fatty acid has 8 to 22 carbon atoms. Bernhardt (European Patent Application 236,288 published September 9, 1987) and Bernhardt (European Patent Application 233,856, published August 26, 1987) disclose certain medium melting polyol polyesters that can be used to replace at least a portion of triglyceride oils in cooking and cooking oils. frying to reduce passive fat loss. The limitations of passive fat loss has also been proposed a mixture of completely liquid polyol polyesters with completely solid polyol polyester hardstocks, preferably esterified with C ₂ to Cio saturated fatty acids (e.g. sucrose oktastearat or oktabehenat). See, for example, Jandacek, US Pat. 4,005,195 and Jandacek / Mattson, US Pat. 4,005,196; both published January 25, 1977.

Another type of indigestible polyol-polyester composition that can be used to replace some or all of the triglyceride oil in cooking oil or frying oil comprises combinations of liquid polyol polyesters and certain types of other particulate solids selected such that the composition has a a substantially flat solid fat (SFC) curve versus a temperature ranging from room temperature to body temperature. Generally, the solid component is present in the compositions in the form of very small particles (1 micron or less) and at a relatively low concentration. Often, the solid, particulate material serving as a means to reduce passive fat reduction is a solid polyol polyester crystallizing in the desired particularly small particles. Examples of polyolpolyester compositions of this type and cooking and frying oils containing them include, for example, Young, U.S.Patent 5,085,884, issued Feb. 4, 1992; Letton et al., U.S. Patent 5,306,514, issued April 26, 1994, and Letton et al., U.S. Patent issued June 1, 1995; and Corrigan et al., U.S. Patent 5,534,284, issued July 9, 1996.

The polyol fatty acid polyester can be prepared by reacting the polyol with a lower alkyl fatty acid ester in the presence of a basic catalyst. In general, the polyols are readily soluble in an aqueous medium, for example water, while the lower alkyl esters of the fatty acid are soluble in the organic medium. Typically, therefore, an emulsifier, a solvent, and a phase-phase catalyst should be used. · ♦ «« «« «« «« «« «« «« «« « Or a mixture thereof to allow physical contact between the polyol and the lower alkyl ester of the fatty acid and their chemical reaction. The resulting fatty acid polyol polyester is soluble in the organic medium.

Non-digestible polyol polyesters are usually prepared without the solvent by essentially two-step transesterification of the polyol (e.g., sucrose) fatty acid esters with an easily cleavable alcohol (e.g., fatty acid methyl esters). In the first step, a mixture of sucrose, methyl esters, a soap such as an alkali metal salt of a fatty acid and a basic esterification catalyst is heated until melt formation. In a second step, an excess of said methyl esters is added to the melt, and then the mixture is heated to convert the partially esterified sucrose to a highly esterified sucrose polyester. See, for example, Rizzi et al., U.S. Patent 3,963,699, issued June 15, 1976 /, and Volpenhein, U.S. Patent 4,517,360, issued May 21, 1985.

Alternatively, highly esterified polyol polyesters may be prepared by two-step solvent methods (see, for example, Masaoka et al., US Pat. No. 4,954,621, issued Sep. 4, 1990), or by a one-step process in solvent or solvent-free processes (see, for example, Van der Plank, USPatent 4,968,791 Nov. 6, 1990; Meszaros Grechke et al., US Patent 5,079,355, issued Jan. 7, 1992; or Van der Plank et al.

U.S. Patent 5,071,975, issued Dec. 10, 1991).

As expected, the polyol-containing fatty acid reaction product-containing stream containing the polyol-polyester fatty acid product may therefore contain various components in addition to the desired polyol-polyester fatty acid. This stream may contain, for example, residual input weak reactions, such as unreacted lower alkyl fatty acid ester and / or unreacted polyol, emulsifier, solvent, and the like. Phase transfer catalyst and / or basic catalyst · · «fáz přenosu fáz fáz přenosu přenosu fáz fáz fáz fáz fáz fáz fáz fáz fáz . In addition, the stream may contain a plurality of by-products of the reaction itself. In addition to the transesterification of the polyol and the formation of the polyol-polyester fatty acid, numerous side reactions can take place. By side reactions, one chemical component can be cleaved into two or more by-products and / or the starting reactants, catalysts, emulsifiers and solvents can chemically react with each other to form undesirable by-products, for example dia triglycerides, beta-ketoesters, di (fatty acid) - ketones, and saturated and unsaturated fatty acids and / or soaps. These unsaturated and saturated fatty acids and soaps may be formed by hydrolysis of the polyol-polyester and the starting methyl esters. In addition, the feed reactants and other reaction components often contain trace amounts of impurities, for example, traces of metal, including calcium and magnesium ions, which is particularly undesirable in the final product intended for use as a food supplement. Thus, the stream containing the reaction product of the polyol and lower alkyl esters of fatty acid may contain, in addition to the desired polyol-polyester fatty acids, various undesirable components such as impurities which need to be substantially removed to obtain the desired, purified polyol-polyester fatty acids. These impurities may contribute to instability and / or discoloration of the polyol-polyester, especially during cooking and / or frying. It is therefore generally necessary to further refine or purify the crude polyol-polyesters of fatty acids as reaction products of these conventional syntheses.

Typical purification methods include water washing, organic solvent extraction and / or salting out. In US Patent č.4,334,061 shows the preparation of sucrose polyesters in which the reaction product is washed using _{alkalického'vodného%} solution of pH 7-12 in the presence of a polar organic solvent. Van Lookeren, US Pat. 5,055,571, issued Oct. 8 • ·· · «9 ··

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1991, discloses a process for purifying crude polyol polyesters by contacting polyol polyesters with alkali metal ions under alkaline conditions to reduce the alkali metal ion content to less than 5 ppm calculated on the weight of the polyol polyesters. In this process, the content of the monovalent soap present in the raw polyester is preferably reduced by centrifuging or filtering the crystallized soap and / or washing with water in an almost neutral environment.

Watanabe, U.S. Pat. No. 4,973,681, issued November 27, 1990, discloses a purification method for increasing the polyol-polyester's oxidation stability, which comprises contacting the polyol polyesters with a polyhydric oxyacid (e.g., citric acid) and subsequently separating the polyol polyesters from the polybasic acid. It is disclosed that this process removes trace amounts of metal catalyst that may be present in the crude polyol-polyesters.

However, the non-digestible polyol polyesters are not as stable to hydrolysis as conventional triglyceride oils during frying as described above. Therefore, cooking and frying oils containing these indigestible polyol polyesters change the taste and olfactory perceptions more quickly and often change color more quickly. It is therefore desirable to provide non-digestible polyol-polyester cooking and frying oils that are equivalent to triglyceride oil in terms of hydrolytic stability and color development. The more stable the polyol-polyester composition is, the longer the frying oil availability will be.

It has been found that in addition to the monovalent soaps mentioned above, polyol polyesters may contain a significant amount of divalent and multivalent metal soaps (e.g., calcium soaps) and that these divalent and multivalent metal soaps have a deleterious effect. The influence on the hydrolytic stability of polyol polyesters if free fatty acids are present in addition to them. These divalent and multivalent metal ions usually enter the polyol polyester as impurities from the starting methyl esters. Free fatty acids can be introduced into the polyol polyester from the food to be processed, or by hydrolysis of the polyol polyesters, or both.

Thus, there remains a need to improve the separation and purification of the reaction product comprising a polyol fatty acid polyester, in particular the product obtained by transesterification of the polyol. More specifically, it is desirable to provide an economical and efficient separation method to remove divalent and multivalent soaps, and metal traces such as calcium and magnesium, as well as fatty acid methyl esters and fatty acids.

SUMMARY OF THE INVENTION

Surprisingly, it has been found that it is possible to prepare cooking and frying oils of reduced energy value containing polyol-polyesters and which are equivalent to triglyceride oils in terms of hydrolytic stability, reducing the proportion of said divalent and multi-valent (polyvalent) soaps in polyol-polyesters. Preferably, the amount of polyvalent metal ion is reduced to about 550 ppb or less.

It is believed, without being limited in any way, by the present invention that the detrimental effect of divalent metal soap on the stability of the polyol-polyester frying oils is to administer the hydrolysis of the polyol-polyester with this divalent soap. In other words, a divalent soap may catalyze the hydrolysis of the polyolpolyester, thereby causing instability and discoloration by the formation of free polyol-soluble fatty acids. · · · · ·

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% of the polyester and therefore accumulates in the polyol-polyester.

The invention relates to an improved indigestible polyol polyester intended for use as cooking and frying oils with reduced energy value, and to a process for preparing such an oil which exhibits improved color stability and improved stability to frying hydrolysis. The oil preferably contains less than about 550 ppb divalent and multivalent (i.e. polyvalent) metal ions.

The process of the invention comprises the step of 1) thoroughly mixing a) an aqueous washing solution comprising an ion exchange ligand with b) a crude polyol-polyester comprising a polyvalent soap containing a polyvalent ion; 2) ion exchange, wherein the polyvalent ion of the polyvalent soap is exchanged with the ion exchange ligand ion; 3) monovalent soap formation; and 4) removing the polyvalent ion exchange ligand from the crude polyol-polyester. The indigestible polyol-polyester prepared by the process of the invention preferably contains less than about 550 ppb of divalent and multivalent metal ions. In cooking and frying oils prepared by the process of the invention, color impurities and contaminants in the form of free fatty acids are formed much more slowly than in oils containing divalent soaps at higher concentrations.

DETAILED DESCRIPTION OF THE INVENTION.

Definition:'

Indigestible means that only about 70% or less of such a food is consumed by the body. Preferably, it spends only about 20% or less of such foods, or less than about 20% φ φ φ · · · · · · · · · · φ φ φ φ φ φ φ Even more preferably, only about 1% or less of such foods are digested.

The term polyol as used herein includes any aliphatic or aromatic compound containing at least two free hydroxyl groups. Suitable polyols may be selected from the group consisting of: straight and branched chain saturated and unsaturated linear aliphatic compounds; saturated and unsaturated cyclic aliphatic compounds, including heterocyclic aliphatic compounds; or monocyclic or polycyclic aromatic compounds including heterocyclic aromatic compounds. Suitable monosaccharides for use in the present invention include, for example, mannose, galactose, arabinose, xylose, ribose, apiosis, rhamnose, psicose, fructose, sorbose, tagatose, ribulose, xylulose and erythrulose. Oligosaccharides suitable for use in the invention include, for example, maltose, cojibiosis, nigerose, cellobiosis, lactose, melibiosis, gentibiosis, turanose, rutinose, trehalose, sucrose and raffinose. Polysaccharides suitable for use in the invention include, for example, amylose, glycogen, cellulose, chitin, inulin, agarose, zylanes, mannan, and galactans. Although alcohol sugars are not carbohydrates in the strict sense, their use according to the invention is also preferred. Natural alcohol sugars suitable for use in the present invention are sorbitol, mannitol, and galacticol.

Particularly preferred classes of compounds suitable for use in the invention include monosaccharides, disaccharides, and sugar alcohols. Preferred non-esterified polyols include glucose, fructose, glycerol, polyglycerols, sucrose, zylotol, and sugar ethers. A particularly preferred polyol is sucrose. Preferred non-esterified polyols also include alkoxylated polyols such as alkoxylated glycerin, alkoxylated polyglycerols, sorbitol, alkoxylated polysaccharides, and coupled alkoxylated polyols such as coupled polyols.

X ΦΦ · · φ φ φ φ φ φ φ φ φ · · · φ φ φ φ φ φ φ φ φ alko alko alko alko alko alko alko alko alko alko alko φ φ φ φ φ φ φφ φ These polyols can be alkoxylated C ₃ -C ₆ epoxides such as propylene oxide, butylene oxide, isobutylene oxide, and pentene oxide, thus forming the extended polyols having epoxy groups epoxylace index of at least 2, preferably in the range 2-8 as shown in US Patent č.4,816,613 that is incorporated herein by reference. Polyols may also be epoxide alkoxy, preferably C ₃ -C ₀ l, 2-alkylene oxide, in the presence of a polymerization catalyst otvírajícího ring as shown in US Patent 5,512,313 and č.5,399,729 which is incorporated herein by reference.

Suitable alkoxylated polyols for use in the present invention are disclosed in U.S. Patent Nos. 4,983,329; 5,175,323; 5,288,884;

5,298,637; 5,362,894; 5,387,429; 5,446,843; 5,589,217; 5,597,605; 5,603,978 and 6,641,534, all of which are incorporated herein by reference. Suitable alkoxylated polyols include alkoxylated sugar alcohols, alkoxylated monosaccharides, alkoxylated disaccharides, alkoxylated polysaccharides, alkoxylated C ₂ -C ₁₀ aliphatic diols, and alkoxylated C ₃ -C ₂ aliphatic triols. Preferred alkoxylated C ₃ -C ₁₂ aliphatic triols are alkoxylated glycerols, and particularly preferred are propoxylated glycerols containing from about 3 to about 21 moles of propylene oxide per mole of glycerol. Preferred alkoxylated polysaccharides are alkoxylated polysaccharides containing anhydromonosaccharide units, and even more preferred are propoxylated polysaccharides containing anhydromonosaccharide units as disclosed in US Patent No. 5,273,772, which is incorporated herein by reference. Preferred coupled alkoxylated glycerins include those containing the polyether glycol linker segments disclosed in US Patent No. 5,374,446, which is incorporated herein by reference, and those comprising the polycarboxylate linkers disclosed in US Patent Nos. 5,427,815 and 5,516,544, both incorporated herein by reference. herein, reference is made to the compounds disclosed in US Pat. No. 5,516,544.

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The term polyol-polyester fatty acids includes any of the above polyol in which two or more of its hydroxyl groups are esterified with fatty acids. Suitable polyol fatty acid polyesters include sucrose polyesters containing an average of at least four, preferably at least about five, ester linkages per sucrose molecule; fatty acid chains preferably contain about eight to about twenty-four carbon atoms. Liquid indigestible oils include liquid polyol polyesters and fatty acids (see Jandacek, U.S.Patent 4,005,195, issued Jan. 25, 1977); tricarballylic acid liquid esters (see Hamm, U.S. Patent 4,508,746, issued April 2, 1985); liquid diesters of dicarboxylic acids such as malonic and succinic acid derivatives (see Fulcher, U.S.Patent 4,582,927, issued April 15, 1986); alpha branched chain carboxylic acid triglycerides (see Whyte, U.S.Patent 3,579,548, published

May 18, 1971); liquid ethers and ether-esters containing a neopentyl group (see Minich, U.S. Patent 2,962,419, issued Nov. 29, 1960); liquid fatty polyethers of polyglycerol (see Hunter et al., U.S. Patent 3,932,532, issued Jan. 13, 1976); fatty acid fatty acid polyester polyesters (see Meyer et al., U.S. Patent 4,840,815, issued June 20, 1989); liquid polyesters of two ether-linked hydroxypolycarboxylic acids (for example citric acid or isocitronic acid) (see Huhn et al., U.S. Patent 4,888,195, issued December 19, 1988); liquid polydimethylsiloxanes (e.g., Fluid Silicones available from Dow Corning). Solid non-digestible fats or other solid components may be added to liquid non-digestible oils to prevent passive fat loss. Particularly preferred non-digestible fat compositions are those disclosed in U.S. Patent No. 5,490,995 to Corrigan 1996, U.S. Patent No. 5,480,667 to Corrigan et al. U.S. Patent No. 5,451,416 to Johnston et al. 1995 and USPatent 5,422,131 authors • ftp ftft ftft ftftft ftft ftft ftftft * ft ftftft ftftft · ft ···· ······ • ft ftft ftft ··· · Ftft ftftft ftft ftft t

Elsen et al. from 1995. In U.S. Patent No. 5,419,925 to Seiden et al. from 1995, energy-reduced compositions containing triglycerides and polyol polyesters which can also be used in this process are disclosed. However, the present composition can provide a more digestible fat.

A preferred non-digestible oil is a mixture of liquid and solid sucrose polyesters with fatty acids. Preferred solid fatty acid sucrose polyesters contain saturated and unsaturated fatty acids having 8 to 24 carbon atoms. These products and oils are described in U.S. Patent 5,422,131 to Elsen et al. (1995) and U.S. Pat. No. 5,085,884, to Young et al. U.S. Patent 5,306,514 and U.S. Patent 5,306,516 to Letton et al. (1994), compositions that can be used in this process are also disclosed. These preferred non-digestible oil compositions are preferably products which, upon cooling from the full melt, undergo a substantially quiescent state (i.e., without agitation) at a temperature below 37 ° C to a solidified form. This solidified product is particularly effective for retaining a large amount of liquid non-digestible oil and thereby inhibits or prevents passive loss of the non-digestible oil through the consumer.

Other suitable polyol fatty acid polyesters are esterified coupled alkoxylated glycerins, including those containing the polyether glycol linker segments described in U.S. Patent No. 5,374,446, which is incorporated herein by reference, and including those comprising polycarboxylate linkers, as described in ^; US Patents 5,4227815 and 5,516,544, both of which are incorporated herein by reference; more preferred are the compounds disclosed in US Patent 5,516,544.

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Other suitable polyol fatty acid polyesters include epoxy chain-extended esterified polyols having the general formula P (OH) and + c (EPO) n (EE) bz wherein P (OH) is a polyol, A is 2 to 8 primary hydroxyl groups, C is from about 0 to about 8 total number of secondary and tertiary hydroxyl groups, A + C is from about 3 to about 8, EPO is C ₃ -C ₆ epoxide, N is minimum average epoxylation index, FE is acyl fatty group acid ab is a number which on average is greater than 2 and not greater than A + C as disclosed in US Patent No. 4,861,613 and EP 0324010 A1, which are incorporated herein by reference. The average minimum epoxylation index value is generally equal to or greater than A and is sufficient to convert more than about 95% of the primary hydroxyl groups of the polyol to secondary or tertiary hydroxyl groups. A preferred chain of the acyl group of the fatty acid is a C 7 -C ₂₃ alkyl group.

Preferred esterified polyols with chain extended epoxides include esterified propoxylated glycerols prepared by reacting propoxylated glycerol of 2 to 100 oxypropylene units to glycerol with C ₁₀ -C ₂₄ fatty acids or with C ₁₀ -C ₂₄ fatty acid esters as disclosed in US Patents 4,983,329 and 5,175,323, which are incorporated herein by reference. Also preferred are esterified propoxylated glycerols prepared by reacting an epoxide and a triglyceride with an aliphatic polyalcohol as disclosed in U.S. Patent No. 5,304,665, which is incorporated herein by reference, or with an alkali metal or alkaline earth metal salt of an aliphatic alcohol as disclosed in USPatent. No. 5,399,728, which is incorporated herein by reference. More preferred are acylated propylene oxide extended chain glycerols having a propoxylation index above about 2, preferably in the range of about 2 to about 8, even more preferably above about 5 or more, wherein the acyl Λ 9 9 9 9 99 9 • 9 · 9 · 9 9 9 9 «9 9 9 9 999 99 9

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the compounds have a C ₈ -C ₂₄ chain, preferably C 14 -C 18, as disclosed in US Patent Nos. 5,603,978 and 5,641,534, both of which are incorporated herein by reference. Particularly preferred are fatty acid esterified propoxylated glycerols having a sharp melt transition before about 92 ° F (33 ° C) and having a solid fat dilatation index at 92 ° F (33 ° C) of less than about 30, as described in WO 97 / 2260, or having a solid fat expansion index at 70 ° F (21 ° C) of at least about 50 and at 98.6 ° F (37 ° C) of at least about 10, as described in US Patent Nos. 5,589,217 and 5,597,605, which both are incorporated herein by reference.

Other suitable esterified polyols with an epoxy extended chain include esterified alkoxylated polysaccharides. Preferred esterified alkoxylated polysaccharides include esterified alkoxylated polysaccharides containing anhydromonosaccharide units, even more preferred are esterified propoxylated polysaccharides containing anhydromonosaccharide units described in U.S. Patent No. 5,273,772, which is incorporated herein by reference.

According to another embodiment of the invention, the highly pure lower alkyl esters prepared according to the invention can be advantageously used in methods for the synthesis of coupled alkoxylated polyol esters. These methods are disclosed in U.S. Patent Nos. 5,374,446, 5,427,815 and 5,516,544, which are incorporated herein by reference.

Alkoxylated polyols can be prepared by art-known alkoxylation methods, such as reacting a polyol with an epoxide in the presence of a catalyst such as an alkali metal. The alkoxylated polyol can react with the linker segments to form a lowered alkoxylated polyol. Polycarbonyl linkers may be selected from acid derivatives including free acid, acid anhydrides, acid esters, halides ♦ *

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9 9 9 • 9 9 • 9 i9 acids and mixtures thereof. The polyether glycol linker segments may be selected from polyepoxidically-functionalized polyether glycols; the term polyepoxidically functionalized as used herein means that the compound contains two or more epoxy functional groups capable of participating in ring-opening reactions with ether bonding. Suitable polyepoxidically-functionalized polyether glycols include diepoxide-functionalized polyether glycol. The coupled alkoxylated polyol can react with the lower alkyl esters and transesterify to form the coupled esterified alkoxylated polyol.

A suitable method of preparing a coupled esterified alkoxylated polyol using lower alkyl esters of high purity comprises: a step of converting a fatty acid source into a mixed product comprising lower alkyl esters of fatty acids and by-products; a step of washing the mixed product with water at elevated temperature and elevated pressure to remove at least a portion of the by-products from the mixed product; fractional distillation of the mixed product washed with water to give highly pure lower alkyl esters of fatty acids having an acid number of less than 1.0; reacting the polyol with an epoxide to form an alkoxylated polyol; reacting the alkoxylated polyol with a linker to form a coupled alkoxylated polyol; and transesterifying the coupled alkoxylated polyol with lower alkyl esters of high purity.

Preferred esterified allylated alkoxylated polyols are those compounds comprising at least one polyether glycol linker segment, at least two polyol segments each attached to the polyether glycol segments either directly or through an unesterified oxyalkylene segment, and at least one fatty acid containing substituent that is attached to a polyol segment and comprises fatty acid esters and / or

fatty acid esterified oxyalkylene segments, said compounds being disclosed in US Patent No. 5,373,336; those compounds that comprise at least one polycarbonyl linker segment, at least two polyol segments each attached to the polycarbonyl linker segments either directly or through an oxyalkylene segment, and at least one fatty acid esterified oxyalkylene segment attached to the polyol segment, wherein these compounds are disclosed in US Patent No. 5,427,815; or compounds comprising at least two polycarbonyl linker segments, at least three polyol segments each attached to the polycarbonyl linker either directly or through an oxyalkylene segment, and at least one fatty acid esterified oxyalkylene segment attached to the polyol segment, wherein the compounds are described in US Patent No.5, 516, 544. Especially preferred are esterified alkoxylated polyols coupled with a molecular weight greater than 6000 which contain at least two polykarbonylové coupling segments, at least three glyceryl segments and at least one esterified oxyalkylene segment ₆ C ₂ C 4 fatty acid linked to the glyceryl segment, which are disclosed in US Patent No. 5,516,544.

The term ester group means a group formed by the reaction of a hydroxyl group with an organic acid and / or an acid derivative, which group includes fatty acid radicals and / or other organic radicals containing 2 to about 26 carbon atoms. Typical examples of these fatty acid radicals and other organic acids include fatty acid radicals such as acetic, propionic, butyric, caprylic, capric, lauric, myristic, myristooleate, palmitic, palmitooleate, stearic, oleic, ricinooleate, linoleic, linolearic, eloleic, , arachidic, arachidone, behene, lignoceric, erucic and cerotic and other radicals • · 9 9 ·

9,9999 organic acids including aromatic ester forming acids such as benzoic and toluylic acids; branched-chain acid radicals such as isobutyric, neooctanoic or methylstearic acid; very long chain saturated or unsaturated fatty acids such as tricosanoic and tricosenoic acids; cyclic aliphatic acid radicals such as cyclohexanecarboxylic acid; and polymeric ester-forming acid esters such as polyacrylic acid and dimer fatty acid. These fatty acid and other organic acid radicals may be derivatives of naturally occurring acids or synthetic fatty acids. These acid radicals may be saturated or unsaturated, may include positional or geometric isomers, for example cis or trans isomers, may be straight or branched chain, aromatic or aliphatic, may have the same meaning for all ester groups, or may be a mixture of different acid radicals.

The term divalent soap or divalent metal soap means divalent and multivalent (i.e. polyvalent) cationic fatty acid soaps. In a divalent soap such as calciumoleate, two chains of fatty acid, oleic acid, are attached to a single calcium ion. For the purpose of determining the concentration of divalent metal cations in the composition, all divalent and polyvalent metal cations are assumed in calcium form, and their concentration is expressed in the form of calcium soap equivalent. For the purpose of determining the concentration of calcium soaps in the composition, all divalent soaps are expressed as calciumoleate.

The term impurity is used to include various components that are undesirable in the purified polyol fatty acid polyester. It will be appreciated that a component, for example a di- or triglyceride, may for one application be a harmless component in a polyol fatty acid polyester product, but on the other hand, may be an undesirable component, i.e. an impurity, in another application. For example, since both di- and triglycerides are calorie-rich fats, their presence in a polyol fatty acid polyester intended for use as a low-calorie fat is undesirable and in this case these glycerides are considered impurities. Similarly, when a given polyol fatty acid polyester is a food product, trace amounts of metals are considered to be impurities if they are considered unsuitable for human consumption. Ingredients such as the degradation products of the reactants in the preparation of a polyol fatty acid polyester (for example, a caramelized by-product derived from sucrose) can be both inert and suitable for consumption by the general consumer. However, by-products such as said caramelized polyol by-product may impart undesirable coloring and / or undesirably to the viscosity in the fatty acid polyol polyester product. Thus, the decomposition product of the feedstock may be considered an impurity, although it is generally inert and edible. The term impurity as used herein is meant to include all other ingredients except the desired polyol fatty acid polyester, soaps and lower alkyl esters of fatty acid as discussed in more detail below.

Oil composition

The present inventors have surprisingly found that said polyol polyesters, both their crude product and the end product, may contain a significant concentration of polyvalent (divalent and multivalent) metal ions, probably present in the form of soaps. The concentration of divalent metal ions found in such polyol-polyester products is typically greater than about 2 ppm. Although known to be divalent

soaps are only slightly soluble in triglyceride oils in the presence of free fatty acids, the present inventors have found that divalent soaps are much more soluble in indigestible polyol polyesters than in triglycerides even when triglyceride and polyol-polyester contain the same amount of free fatty acids. In addition, it has been found that the free fatty acid further increases the solubility of the divalent soap in the polyol polyester. Therefore, when converting divalent soap, it is advantageous to convert the resulting free fatty acid radicals into monovalent soaps, which are then easier to remove by washing with water, etc., as opposed to converting to free acids which solubilize the divalent soaps only and make their removal more difficult.

Energy-reduced cooking and frying oils prepared by the process of the invention typically contain less than about 550 parts divalent and multivalent metal ions in 1000 million parts (ppb) as determined by the atomic absorption method as described in the Analytical Methods section below. Preferably, said energy-reduced cooking and frying oils comprise less than 340 ppb, and more preferably contain less than 100 ppb of divalent and multivalent metal ions.

The divalent soap content is determined and expressed as the metal ion content and does not include the weight of the fatty acid radical as part of the soap. It is believed that all calcium ions and other divalent metal ions present in the polyol-polyester form a complex with the free fatty acids that may be present to form divalent soaps. The method of analysis and calculation thus does not depend on the type (i.e., chain length) of the free fatty acid present in the divalent soap.

Cooking and frying oils prepared by the process of the invention have lower divalent and multivalent metal ion concentrations;

said oils after further processing or finishing by conventional industrial processes (ie bleaching, evaporation and deodorization) result in products which typically contain less than about 0.05% (500 parts per million parts by weight (ppm)) of free fatty acids as determined by the assay method of the free fatty acids set forth in the analytical section of this disclosure. Preferably, the cooking and frying oils prepared by the process of the invention contain less than about 0.01% (about 100 ppm), more preferably less than about 50 ppm and most preferably less than about 10 ppm of free fatty acids.

Ion exchange ligands.

Preferred ion exchange ligands allow for efficient binding and formation of chelates with divalent alkaline earth metal ions (such as calcium and magnesium) and form a solution of sufficiently alkaline phase, or together with such sufficiently alkaline phase, to allow divalent soap radicals to be converted to monovalent soaps of free acid. Compositions having insufficient alkalinity, such as citric acid, and in which the pH of the process according to the invention is not adjusted (e.g. by an alkaline agent), release free fatty acids; these fatty acids further improve the solubility of the divalent soaps in the polyol-polyester, making them more difficult to remove by ion exchange. Accordingly, acid ligands (e.g., citric acid) can chelate and bind certain divalent metal ions from divalent soap when performed without the addition of an alkaline agent, but once the fatty acid is released, the ability of citric acid to chelate other divalent ions will diminish and even stop .

Preferred ion exchange ligands are ligands having an equilibrium constant for Ca ⁺⁺ and Mg ⁺⁺ ions of at least 2, more preferably of at least 3. Preferred chelating agents are fully. Substituted monovalent salts of citric acid and ethylenediaminetetraacetic acid. Other chelating agents that are effective in ion exchange and removal of divalent ions from divalent soaps include fully substituted monovalent salts of nitrilotriacetic acid, tripolyphosphate, diethylenetriaminepentaacetic acid, ethylenediaminetetra (methylenephosphonic acid), and diethylenetriaminpenta (methylenephosphonic acid).

These ion exchange compositions and their equilibrium constants for Ca ⁺⁺ and Mg ⁺⁺ ions are disclosed in Kirk-Othmer, 3rd Edition,

Vol.5, p.348 (Wiley-Interscience, 1979). Preferred monovalent cations for the ion exchange ligands are the sodium, potassium, lithium and ammonium salts. Preferably, these ion exchange ligands are chelating agents that can be used in foods and food supplements that meet the requirements for use in foods.

Preferred ion exchange ligands for use in the invention are those that are in the wash solution in fully deprotonated form and that are sufficiently alkaline to buffer the ligand wash solution during the ion exchange step to a pH of at least 6.5.

The ion exchange ligands of the invention may include monovalent salts of hydroxy acids selected from the group consisting of: glycolic, lactic, hydroxybutyric, glyceric, malic, tartaric, tartronic and citric acid; polycarboxylic acids such as oxalic acid and malonic acid; metaphosphoric acid such as phosphoric acid, pyrophosphoric acid and hexametaphosphoric acid; and ethylenediaminetetraacetic acid; and mixtures thereof. Monovalent salt ions may be sodium, potassium, lithium and ammonium ions or mixtures thereof. Preferred ion-exchange ligands include, for example, potassium citrate, sodium citrate, the sodium tetrasodium salt of the acid.

Ethylenediaminetetraacetic acid (Na ₄ EDTA), and disodium or potassium potassium tartaric and malic acid salts of orthophosphoric acid. The use of potassium citrate is particularly preferred in the process of the invention. Also particularly preferred is the use of a mixture of tri-alkali metal citrate and Na ₄ EDTA.

Ion exchange process

The process comprises, in a first step, thoroughly mixing the aqueous wash solution containing the ion exchange ligand with a crude polyol-polyester containing a polyvalent soap having a polyvalent ion.

To achieve high kinetic dissociation rates of ligand ions, the ion exchange ligand needs to be dissolved in the aqueous phase. In addition, generally, the ion exchange ligand is insoluble in the polyol-polyester oil phase. In the process of the invention, the ligand-containing aqueous phase needs to be intimately mixed with the polyol-polyester oil phase containing divalent soap to increase the surface between the two phases. It is believed that the free fatty acid in the polyolpolyester further increases the solubility of divalent (e.g., calcium) soaps in the polyol-polyester. The improved solubility of the divalent soap in the oil phase makes the reaction between the divalent soap and the ion exchange ligand difficult.

The second step of the process involves ion exchange of the polyvalent ion from the polyvalent soap to the ligand ion, forming a monovalent soap. The ion-exchange ligand is capable of chelating metal ions, especially alkaline earth metals, and thereby converting them to divalent salts of the respective ligand. When the reaction proceeds in an alkaline environment, divalent fatty acid soaps are converted to monovalent soaps. Advantageously, the thorough mixing step a) is continued for a sufficiently long period of time, 4 9 4 9 9 9 9 9 9 9 9 9 9 4 4 4 9 9 9 9 9 9 9 9 9 9 9 9 4 9 4 • 9 «49 4445

444 4444 44 · 44 44 44 sufficient to completely ion exchange and thereby convert divalent soap to monovalent soap.

The ion exchange ligand is added to the crude polyol-polyester in an amount sufficient to convert substantially all of the divalent soap present in the crude polyol-polyester to monovalent soaps. Typically, the ion exchange ligand is added at a concentration ranging from about 0.001% to about 5%. Preferably, the ion exchange ligand is added at a concentration ranging from about 0.05% to about 2%, more preferably from about 0.05% to about 1%, and most preferably from about 0.1% to about 0.5%. Preferably, a molar ratio of ion exchange ligands to divalent soap of at least 1: 1 is used, more preferably at least 1.2: 1.

To ensure that calcium soaps are converted to monovalent soaps and not to free fatty acids, the ion exchange of divalent metal ions should take place in a wash solution having a pH sufficiently high to deprotonate the ion exchange ligands and free fatty acids in the polyol referred to. in contact with the washing solution. Preferably, the pH of the ion-exchange ligand-containing aqueous phase is maintained at a pH of about 6.5, more preferably at about 7, and most preferably at about 7.5 and above in the ion-exchange ligand exchange reaction with divalent soap. To sufficiently promote complete conversion to monovalent soaps, it is preferred to maintain the pH of the solution above the pKa of the free fatty acid, most preferably about 1.5 pH units or more above the pKa of the free fatty acid which is about 5 (see Handbook of Biochemistry and Molecular Biology, 3. Ed., Vol. I, pp. 157-269, CRC Press, Clevelend, OH (1976)). An alkaline agent may be used to increase the alkalinity and pH of the wash solution to the desired value. Preferred alkaline compositions include alkali metal hydroxides, preferably sodium hydroxide and potassium hydroxide.

• · · »· ······ φ φ φφφ φφφφ

................

These alkaline compositions are usually added in the form of dilute aqueous solutions.

Preferably, at most 1% by weight of the free fatty acid radicals are present in the polyol-polyester. Most preferably, the concentration of free fatty acids remaining in the polyol-polyester is negligible (substantially none).

Further, the process of the invention comprises a third step comprising removing the polyvalent ion exchange ligand, the monovalent soap and other water-soluble impurities from the treated polyol-polyester. Methods for removing polyvalent ion exchange ligand and monovalent soap include water washing, filtration, centrifugation, and a combination of these methods. A preferred method of removing these components from the polyolpolyester is by washing with water. When using the water wash method, the wash solution and the treated polyolpolyester need to be well mixed so as to increase the interface between the two phases and maximize the mass transfer of the monovalent soap into the aqueous wash solution. The treatment methods and apparatuses used to wash the treated polyolpolyester with water are similar to the treatment methods and apparatuses used to well mix the aqueous ion exchanger solution and the crude polyol-polyester in the first stage.

In a preferred embodiment, the same embodiment and the same devices are used in all three steps of the process according to the invention.

In the process according to the invention, the unpurified polyol-polyester fatty acid and the aqueous ion exchange solution are introduced into a mixing and reaction vessel. The term mixing vessel and reaction vessel as used herein includes any tank, column or other processing apparatus and / or vessel allowing the solutions to interact well. Examples of suitable mixing vessels include single-stage columns, multistage columns, batch vessels, static mixers and bubbling columns, and other suitable mixing vessels and combinations thereof known to those skilled in the art.

A preferred mixing and reaction vessel for the described process of the invention is a multistage column allowing mixing. For multistage columns, both co-current and counter-current methods can be used. However, from the water treatment point of view, the downstream process is less efficient than the countercurrent process, although the downstream columns are more easily adapted to increase production than countercurrent columns. After loading into the column, the wash solution containing the ion exchanger and the unpurified polyol-polyester fatty acids are mixed to form a well mixed mixture, but the process is controlled appropriately to avoid the formation of stable emulsions. This thorough mixing is continued for a period of time sufficient to convert the divalent soaps to monovalent soaps. In addition, this thorough mixing should be continued for a time sufficient to allow other impurities, including the color components, to be transferred from the treated polyester phase to the aqueous wash solution. Then, the aqueous phase formed by the wash solution and the treated polyol-polyester phase are allowed to separate into two phases. The treated polyester phase is then further refined to give the final polyol-polyester product.

The process is carried out at a temperature at which the polyol-polyester remains in a liquid state and the polyol-polyester feed component and the aqueous wash solution are maintained at this temperature. If indigestible oil contains a solid oil (having a complete oil)

9 9 • 99 99 9 9 * 9 9

9 9

9 9 9

If the melting point is above about 37 ° C), higher temperatures are required so that the solid oil is in the molten or liquid state.

In a preferred embodiment of said treatment system, the mixture of the polyol fatty acid to be treated and the ion exchange wash solution used in the mixing vessel is preferably maintained at a temperature of from about 20 ° C to about 100 ° C, more preferably from about 40 ° C to about 95 ° C, and most preferably from about 65 ° C to about 90 ° C. The pressure in the mixing vessel may be lower or higher than atmospheric pressure. One of the advantages of using a pressure higher than atmospheric pressure is that the temperature of the mixture can be increased somewhat because the pressure increase also increases the boiling points of the components present. Higher temperatures may be suitable to maximize the solubility of the resulting monovalent soaps, divalent ligand salt, and other impurities in the ion exchange wash solution, resulting in the highest possible purity of the processed polyol-polyester fatty acid. In this way, the process in the mixing vessel can take place at higher temperatures without boiling its contents. When treating non-digestible oil, if it contains solid polyol-polyester components, it is generally necessary to maintain the temperature of the feed components and the temperature of the process sufficiently high so that the solid polyol-polyester remains in the molten state during processing.

The advantages of the described treatment in the mixing vessels under reduced or elevated pressure should be considered in terms of additional equipment and processing costs compared to the atmospheric pressure treatment. For efficiency and economic reasons, it is preferred to perform the described treatment in the mixing vessels at atmospheric pressure.

It is often necessary to premix the wash solution and the crude polyol-polyester fatty acids before introducing them into the mixing vessel. Using a single input stream containing a pre-current * · * * * * * * * * * * * * * * * * * * * * * * * * * * A mixed crude polyol-polyester fatty acid and ion exchange wash solution can be advantageous in design and can also be economically advantageous compared to using two inlet streams introduced separately into the mixing vessel.

After introduction of the ion exchange wash solution and the crude polyol-polyester fatty acid into the mixing vessel, both components are sufficiently dispersed to achieve a shear ratio allowing the formation of a perfectly blended mixture but not yet allowing the formation of a stable emulsion. The above mixture typically contains droplets of one solution dispersed in the other solution. Preferably, the composition comprises droplets of wash solution in the polyol-polyester phase. Preferably, on average, these droplets have a diameter in the range of about 5μ to about 3000μ, more preferably about 5μ to about 70μ, and most preferably about 5μ to about 20μ. The composition of the mixture depends largely on the mass flow of each feed solution into the mixing vessel as detailed below.

Said dispersion is dependent, among other processing parameters, on the size and shape of the mixing vessels, on the mass flow rates of the solutions supplied to the mixing vessel on the type and size of the mixing. The term mixing is used herein to refer to any means of making a mixture of a wash solution and a crude polyol-polyester with a fatty acid. Mixing can be accomplished by a variety of commonly used methods with conventional types of equipment. For example, rotary agitators and rotating disks can be used for dynamic agitation, while gas injection (i.e., bubbling), static agitators, and feed current pulsation can provide acceptable non-dynamic agitation of the mixture in the mixing vessel. For use in the above mixing containers, it is preferable to use rotary stirrers, although other mixing methods are also suitable for use in the invention.

As is evident, when using rotary stirrers as mixing means, their speed and shape are important to promoting mixing and transfer of mass comprising impurities from the processed polyol-polyester fatty acid to the wash solution. By sufficiently dispersing the mixture and achieving a shear ratio that does not allow the formation of stable emulsions, the reaction of the ion exchange ligand with divalent soaps and subsequent mass transfer including impurities and monovalent soap from unpurified polyol-polyester fatty acid into the wash solution can be optimized. As mentioned above, other forms of mixing are suitable for use in the present invention as long as these types of mixing are sufficient to achieve a shear ratio that prevents the formation of stable emulsions, and at the same time sufficient to form a dispersion containing droplets of declared size.

The residence time of the mixture in the mixing vessel is also important to maximize the extent of the reaction of the ion exchange ligand with divalent soaps and the subsequent transfer of the impurity mass from the unpurified polyol-polyester fatty acid into the wash solution. Preferred residence times of the mixture in the mixing vessel range from about 0.5 minutes to about 30 minutes, more preferably from about 1 minute to about 15 minutes, and most preferably from about 1 minute to about 10 minutes, and are selected based on, for example, concentration impurities and soap emulsifier in the raw and / or processed polyol-polyester as an input to the mixing vessel, based on the concentration of divalent soap to be treated and removed, as well as the permissible concentrations of impurities and monovalent soap in the processed polyol-polyester product.

If a column is used as a mixing vessel, the residence time and degree of purification will necessarily affect the number of columns of the column. The choice of the appropriate number of trays depends on, among other parameters, the height and diameter of the column, the flow rates of each stream, the method and the intensity of mixing. In a co-current feed method with unplasticized polyol-polyester and wash solution, it is preferred that the column have 1 tray up to about 7 trays, preferably about 5 to about 7 trays. In a countercurrent feed method with the unpurified polyol-polyester and wash solution, it is preferred that the column have 5 floors to about 25 floors.

Another optional parameter of this treatment process that can improve the reaction of the ion exchange ligand with divalent soaps and the subsequent transfer of monovalent soap mass and impurities from the polyol-polyester fatty acid to the wash solution is the amount of ion exchange wash solution fed to the column. Preferably, the ratio of the polyol-polyester weight feed stream to the ion exchange wash solution feed stream is in the range of about 2: 1 to about 50: 1, more preferably the ratio is from about 3: 1 to about 50: 1, and most preferably More specifically, the preferred ratio of the polyol-fatty acid fatty acid feed flow to the wash solution feed flow in the co-current multistage column is preferably in the range of about 3: 1 to about 20: 1, and the feed feed weight ratio is about 4: 1 to 20: 1. The flow rate of the polyol-polyester fatty acid to the mass feed flow of the inverter wash solution in the countercurrent multistage column is preferably in the range of about 4: 1 to about 40: 1.

As mentioned above, preferred mixing vessels for use according to the invention are multistage columns equipped with a mixing device. Multistage columns suitable for use in the present invention include, but are not limited to, rotary disk feeders, OldshueRushton extractors, Scheibel extraction towers, Kuhni towers, and the like. These columns are described in Perry et al., Chemical Engineers Handbook, 6th Edition, 1984, pp. 21-77 to 21-79, which is incorporated herein by reference. Columns referred to in

the work of Perry et al. are schematically shown in a countercurrent arrangement. The heavy liquid phase is introduced to the top of the vertical column and removed from the bottom of the column, and the light liquid phase is introduced near the bottom of the column and removed near the top of the column. As mentioned above, the two feed currents of the invention can be fed countercurrently, i.e., the currents pass through the column in the opposite direction or co-current, which means that the currents pass through the column in the same direction. If both streams are introduced at or near the same end of the column, they are usually removed at or near the other end of the column.

Between the individual trays of the column there may be partitions with apertures the size and shape of which are designed to provide the required residence time and other processing conditions. Similarly, each tray may comprise a rotary stirrer, wherein the stirrers are driven by a single shaft passing through the column. Thus, a single shaft can drive all agitators to maintain a constant agitation rate across the various tray trays. However, it should be understood that the inclusion of agitators with independent propulsion engines and / or gears for individual trays or between trays is also possible, so that the corresponding mixing speeds may vary from one tray to the other trays. The speed of mixing in the column and the individual trays, the size and shape of the openings in the baffles separating the trays and the number of trays are among the criteria of the proposed solution that can be varied to achieve the desired cleaning effect.

Multistage columns may also include at either or both ends of quiescent zones in which the treated mixture (ie the mixture obtained after processing at a sufficient shear ratio and residence time to achieve the desired degree of polyol impurity mass transfer into the wash solution) is no longer agitated, and into two phases. In the case of using a rest zone can be mentioned

separating the two phases using two sampling sites, i.e. a first collection site for the first phase and a second collection site for the second phase.

After mixing, the mixture can be separated into two phases based on the general immiscibility of the oily phase containing the purified polyol-polyester fatty acid and the phase consisting of an aqueous solution containing a monovalent soap, a divalent ligand salt and other water-soluble impurities.

All reported drop diameters were measured with a Lasentech scanning laser detector. More specifically, said Lasentech system is based on measuring the reflection of a concentrated beam of light, which system comprises a computer interface, a laser diode, detectors, a 10 meter fiber optic cable, and a measuring probe. The light from the laser diode is led through the fiber optic cable to the probe. The light is focused through a sapphire filter at a very small point of the sample. In the case where the light beam passes through a particle, or in this case a droplet, the light diffuses in the opposite direction. This light is accumulated and fed back to the detection unit where the timer switches. As soon as the light passes through the droplet, the backscattering of the light ceases and the countdown stops. If the light beam speed and backscatter pulse time are known, droplet size can be calculated from these data. For a given series of results, the average drop diameter is calculated by dividing all obtained averages by the number of drops measured.

It will be appreciated that unpurified polyol-polyester fatty acids can be prepared in a conventional manner by reacting the polyol with a lower alkyl ester of a fatty acid. However, this unpurified polyol-polyester fatty acid can be obtained from any available source or by a method of preparation known in the art. Purified polyol-polyester fatty acids can be used, among other methods, as low calorie fat in foods, and practically is purified polyol-polyester fatty acids according to the invention. The invention is particularly advantageous for use as a food supplement due to its improved purity.

The wash solution comprises a solvent, generally immiscible with the polyol-polyester, so as to readily form two phases with it and simultaneously dissolve the ion-exchange ligand. Examples of this solvent for the wash solution include, but are not limited to, water, methanol, acetone, and ethyl acetate. Preferred solvents for use in the disclosed processes include water and, more generally, aqueous wash solutions due to their availability and cost, but other solvents may be considered for such processes and methods when mixed with a non-purified polyol-polyester after mixing. fatty acids under the conditions described herein remove at least a portion of the impurities from the unpurified polyol-polyester fatty acid.

A lower alkyl ester of a fatty acid is a frequently used means for reacting with a polyol and forming a polyol-polyester. In these reactions, a stoichiometric excess of the lower alkyl esters of the fatty acid is used to completely esterify the polyol. The residual lower alkyl ester of the fatty acid remains in the reaction product and is usually not soluble in water, which is the preferred solvent in the process of the invention. Furthermore, since the lower alkyl ester of the fatty acid is the feedstock for the reaction with the polyol to form the polyol-polyester of the fatty acid, it is desirable to separate and recycle the residual lower alkyl ester of the fatty acid. In general, therefore, the lower alkyl ester of a fatty acid is not included in the term impurity in this application. A more detailed description of the direct recycling of lower alkyl esters is given in provisional patent application 08 / 797,018 (Attorney Docket 6506), entitled Lower Alkyl

AND

Ester Recycling In Fatty Acid Polyester Synthesis which is incorporated herein by reference.

Typically, the lower alkyl fatty acid ester cannot be removed by mere contact with the aqueous wash solution alone, although small amounts of both the lower alkyl fatty acid ester and the desired polyol polyester fatty acid remain undesirably retained in the wash solution. Preferably, the lower alkyl esters of the fatty acid are removed from the polyol-polyester of the fatty acid by hot evaporation. However, since the lower alkyl ester evaporates at a temperature lower than the polyol-polyester fatty acid evaporation temperature, all impurities having a boiling point lower than the polyol-polyester fatty acid boiling point can evaporate simultaneously with the lower alkyl ester. In order to obtain a lower alkyl ester of sufficient purity for direct recycling in the polyol-polyester fatty acid manufacturing process, it is often desirable to remove as much monovalent soap and impurities as possible using the washing processes of the invention prior to the evaporation step.

A preferred emulsifier for use in a polyol transesterification reaction to form a polyol-polyester fatty acid is an alkali metal salt of a fatty acid. The term soap emulsifier as used herein means the alkali metal salts of saturated and unsaturated fatty acids of about eight to about twenty-four carbon atoms that are added to the mixture for the transesterification polyol-polester reaction. Suitable soap emulsifiers include, for example, lithium, sodium, potassium, rubidium and cesium salts of fatty acids such as capric, lauric, myristic, palmitic linolenic, oleic and stearic acids, as well as mixtures thereof. Fatty acids derived from soybean oil, sunflower oil, safflower oil, cottonseed oil, palm oil, and the like are suitable for use herein. * * * * * * A a a a a a a a * Corn oil. * Corn oil. A particularly preferred soap emulsifier is, for example, a potassium soap prepared from palmitic acid and stearic acid. In addition to the alkali metal salt soap, other emulsifiers such as sucrose mono-, di- and triesters with fatty acid may also be used. Solid mono- and diglycerides may also be used, although less preferred.

Although generally an emulsifier, specifically a soap emulsifier, is often a desirable component of the reaction, it is undesirable in the final polyol-polyester product. Therefore, it is desirable to remove substantially all of the soap emulsifier and monovalent soap from the reaction mixture prior to hot evaporation to remove excess methyl ester to minimize color degradation during evaporation. In addition, the presence of a soap emulsifier in significant amounts, i.e., greater than about 2000 ppm, can cause problems in the form of stable emulsions of the ion-exchange solution and non-purified polyol-polyester fatty acid. It is preferred that the concentration of the soap emulsifier in the unpurified polyol-polyester fatty acid is less than about 2000 ppm, more preferably less than about 1000 ppm, and most preferably less than about 500 ppm, to prevent the formation of these stable emulsions. In addition, as will be described in more detail below, the treated polyol-polyester fatty acid discharged from the described mixing vessel can be further treated by bleaching and / or filtration to further reduce the concentration of monovalent soap and soap emulsifier below detection limits, i.e. below about 50 ppm. The concentration of soap in the polyol-polyester fatty acid can be determined by neutralizing titration using HCl or other strong acid to a predetermined point.

In order for the transesterification reaction of the polyol to the polyol-polyester of the fatty acids to proceed at a temperature below the decomposition temperature of the polyol, a base initiator, also referred to as a basic catalyst, is usually added. Although the basic catalyst is preferred for the reaction itself, it is generally considered an impurity in the polyol-polyester fatty acid product stream. A description of various types of basic catalysts and their function in the transesterification of polyols is disclosed in U.S. Patent No. 3,963,699 to Rizzi et al., And U.S. Patent Nos. 4,517,360 and 4,518,772 to Volpenheim, which are incorporated herein by reference. Said base catalyst is usually a strong base with an affinity for hydrogen and is often referred to as a base initiator because it induces the transformation of the polyol from the stable state of the molecule to a reactive ion. The terms base catalyst and base initiator are therefore interchangeable in this specification. This basic catalyst specifically removes hydrogen from the polyol molecule resulting in the formation of a polyol ion which is in a reactive state. For example, a basic catalyst converts sucrose into a sucrose ion.

Preferred base catalysts include carbonate and methoxide ions in conjunction with alkali or alkaline earth metals such as potassium or sodium.

The term phase transfer catalyst used herein includes any chemical component that can interact with the polyol to form a chemical complex, and wherein the complexed polyol can pass from one phase to the other, and wherein the non-complexed polyol will usually be soluble in the other . The phase transfer catalyst herein is to be distinguished from an emulsifier, such as a fatty acid soap, since it is believed that the emulsifier provides a single phase in which both chemical components are soluble, i.e., the formation of a chemical complex is not necessary. As with the other components of the reaction, as mentioned above, the phase transfer catalyst and any decomposition product thereof, although its use is often desirable in the transesterification of a polyol and the formation of a polyol-polyester fatty acid, is considered in the polyol-polyester fatty acid product. for impurity.

After describing the various solutions and devices suitable for using the described processes, the next step relates to the post-treatment of the mixture. The term treated herein means that the product is treated in a manner in which at least a portion of the impurities and / or soap has been removed from the polyol-polyester fatty acid. Accordingly, the term treated polyol-polyester fatty acid means a polyol-polyester fatty acid which is obtained after removal of at least a portion of the impurities and soap as described herein. Preferably, the treated mixture is removed from the mixing vessel and allowed to settle under gravity and split into two phases. Each of the two phases can then be separately removed as a treated phase with a polyol-polyester fatty acid and a phase containing a wash solution of impurities and a monovalent soap. Other methods of separation are equally suitable and may be preferred in certain cases. For example, if time is decisive and capital and / or operating costs are not, the processed mixture can be transferred from the mixing vessel to a centrifuge where it can be divided into a light phase, which usually contains polyol-polyester fatty acids and a heavy phase, which usually contains a washing solution of dirt and soap.

Although the use of various suitable ion-exchange ligands leads to some small improvements in color quality of the crude polyol-polyester, it has surprisingly been found that the use of an alkali metal citrate salt as an ion-exchange ligand in the wash solution provides a significant improvement in the color quality of the polyolpolyester. . For this reason, the use of alkali metal citrate or the use of citric acid or alkali metal dihydrogen citrate or alkaline is particularly preferred.

metal-hydrogen citrate in conjunction with alkaline agents to increase the alkalinity and pH of the wash solution.

The treated fatty acid polyol-polyesters of the invention preferably have a Lovibond Red Scale value of less than about 6, preferably less than 4, more preferably less than about 2, and most preferably less than about 1.0. The lower the Lovibond Red Scale value, the lower the color level in the polyol. The color is measured using a Lovibond Automatic Tintometer using a red / yellow calibration standard of 2.9 red / 12.0 yellow).

The treated polyol-polyester fatty acid may contain a small amount of ion-exchange wash solution together with residual impurities and monovalent soap, while the ion-exchange wash solution may contain a small amount of polyolpolyester of fatty acid and other organic oils. Preferably, the treated polyol-polyester fatty acid comprises less than a total of about 1% by weight of wash solution and impurities, including less than about 100 ppm monovalent soap, and more preferably less than about 50 ppm monovalent soap. Preferably, the ion exchange solution contains at most about 5% by weight of organic oils. Since residual impurities, monovalent soap and washing solution can remain in the treated polyol polyester of fatty acids even after prior treatment in a mixing vessel, the treated polyol polyester fatty acids can be further purified in further purification steps. For example, the treated polyol polyester can be dried under vacuum to remove the ion exchange wash solution and volatile impurities. The polyol polyester can also be contacted with particulate silica to remove mechanical impurities and monovalent soap. Preferably, the treated polyol-polyester fatty acid is dried under vacuum to remove excess lower alkyl esters of fatty acids so that the concentration of the wash solution is &quot;

9 * 9 9 9 9

9 9 9

9 9 9 * 9 9 9

90

0 9

9 0 0 0 0

0 ·

The monovalent soap and impurities were less than 0.1% by weight. In addition, as mentioned above, an excess of lower alkyl esters of fatty acids can be removed and often desirable if present by hot evaporation

Product use

The polyol polyesters, which are among the frying oils prepared by the process of the invention, can optionally be blended with conventional triglyceride oils. The term triglyceride oil as used herein refers to triglyceride compositions that are liquid or liquid at a temperature above 25 ° C. Although not required, triglyceride oils suitable for use in the present invention may also include those oils which are liquid or liquid at a temperature below 25 ° C. These triglyceride oils mainly contain triglycerides, but may also contain residual levels of other components such as mono- and diglycerides. To maintain a liquid or liquid state at temperatures below 25 ° C, this triglyceride oil contains a minimum amount of glycerides whose melting points are greater than 25 ° C, thereby limiting the increase in solids when cooling the triglyceride oil. Desirably, said triglyceride oil is chemically stable and oxidation resistant.

Suitable triglyceride oils may be derived from naturally occurring liquid vegetable oils such as cottonseed oil, soybean oil, safflower oil, corn oil, olive oil, coconut oil, palm kernel oil, peanut oil, rapeseed oil, canola oil (ie rapeseed oil). low erucic acid), sesame oil, sunflower oil, and mixtures thereof.

Also suitable are liquid oil fractions obtained from palm oil, lard and tallow, for example by salting out or direct interesterification and subsequent oil separation. Oils in which glycerides predominate. preserve aroma and taste, but care should be taken not to increase the proportion of glycerides melting above 25 ° C. If oils are selected which have a larger proportion of solids melting in the range of 25 ° C to 40 ° C than desired, it may be necessary to separate the solids. For example, refined and slightly hydrogenated soybean oil as well as refined cottonseed oil are suitable.

Typically, the cooking and frying oils of the invention contain from 0% to about 90% triglyceride fat or oil. Preferably, the cooking and frying oils of the invention comprise from about 0% to about 70% triglyceride oil, more preferably from about 1 to about 30% triglyceride oil, and most preferably from about 1% to about 10% triglyceride oil.

In the preparation of the energy-reduced cooking and frying oils of the invention, the indigestible polyol polyesters are usually mixed with an optionally selected triglyceride oil, having previously removed divalent and higher soaps from the polyol-polyester as described herein. Alternatively, the triglyceride oil may be separately treated as described above for polyol-polyesters to separate divalent metal soaps from the triglyceride prior to mixing with the polyol-polyester (although divalent soaps are less soluble in triglyceride oils than polyol-polyesters and are therefore included in much smaller concentrations). Alternatively, the non-digestible polyol polyester can be first mixed with the triglyceride oil and the mixture can then be treated as described above to remove divalent soaps from said mixture.

Methods of analysis

Φ · · · · · · · φ · φ · • · • · • · •

A. Determination of free fatty acids

1. Weigh approximately 15,0 g of the test sample into a clean 250 ml beaker.

2. Place a stir bar in the beaker, add 30 ml of ethanol and 15 drops of phenolphthalein solution.

3. Titrate with 0.1 N NaOH solution while stirring until a slightly pink color persists for 30 seconds.

Calculation of free fatty acid content

Percentage of free fatty acids (calculated as oleic acid) = ml 0.1 N NaOH x 2.82 / sample weight (in grams).

B. Lovibond color measurement

1. Use a Lovibond Automatic Tintometer, calibrate to AOAS specification using 2.9R / 12Y standards.

2. Heat sample cell 5-1 / 4 and chamber to 120 ° F.

3. Place the filled cuvette into the instrument and read the staining (AOCS Lovibond).

The instrument used is the Lovibond Automatic Tintometer. Pre-heating is 70 ° C before use.

C. The instrument is calibrated to AOCS calibration standards (i.e. 2.9R / 12Y). The sample is prepared for analysis either by heating to a temperature of 70 ° C followed by direct measurement or by first filtering the sample through a temperature of 70 ° C. filter paper Whatman 40 under nitrogen atmosphere, heat to 70 ° C and then measure. The paper filter removes particles interfering with color measurement. For this reason, filtered samples provide a more accurate measurement of visible staining.

Both 5.25 and 1 cuvettes are used for the sample. The color ratios relative to the cuvettes used are not proportional. Therefore, it is important to compare the corresponding data (i.e. the result of the filtered sample / 1 cuvette is different than the unfiltered sample / 1 cuvette, and other than the filtered sample / 5.25 cuvette).

C. Determination of divalent and higher metal ions and determination of soap.

Analysis of the indigestible fat sample to quantitatively determine the concentration of metal ions, including alkaline earth ions such as Ca ⁺⁺ and Mg ⁺⁺ ions, and transition metals such as Fe ⁺⁺ ions, the procedure of EPA SW846 (which is incorporated herein by reference) ). All divalent and polyvalent metal ions are evaluated as calcium ions and based on the same molecular weight.

The detailed description will be more readily apparent in connection with the following example in which polyol-polyesters of fatty acids containing divalent soaps are reacted with ion-exchange ligands in the wash solution and the resulting monovalent soaps are removed while purifying the polyolpolyester. The color of the solution resulting from the presence of color components is measured with a commercially available Lovibond color analyzer.

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DETAILED DESCRIPTION OF THE INVENTION

Example 1

A raw sucrose polyester such as a raw sucrose polyester prepared to produce Oleanu ™ (manufactured by The Procter & Gamble Company, Cincinnati, OH) was prepared by the general two-step procedure described in US Pat. No. 3,963,699 to Rizzi et al., Issued to The Procter & Gamble Company, and issued June 16, 1976. Said crude sucrose polyester containing about 75.4% octaester and about 6.2% soap was prepared by reaction in five sequential and substantially identical batches.

each weighing about 3900 pounds. Processing of each batch took place in two stages and each batch had the following composition: Batch 1 Batch 2 degree 1 degree 1 Cotton methyl esters 1306 lb (592 kg) 1305 lb (592 kg) oils soap 200 lb (90.8 kg) 200 lb (90.8 kg) sucrose 300 lb (136 kg) 300 lb (136 kg) tri-potassium carbonate 2.4 lb (1.09 kg) 2.4 lb (1.09 kg) degree 2 degree 2 Cotton methyl esters 2093 lb (950 kg) 2090 lb (949 kg) oils tri-potassium carbonate 2.4 lb (1.09 kg) 2.4 lb (1.09 kg) Batch 3 Batch 4 degree 1 degree 1 Cotton methyl esters 1310 lbs (595 kg) 1306 lb (595 kg)

99 · ·· · · 4 44 44 4 · 4 4 · 4 · 4 4 4 4

444 4444

4444 ·· 4 44 »4 44 oil

soap sucrose tri-potassium carbonate 200 lb 300 lb 2.4 lb (90.8 kg) (136 kg) 200 lb 200 lb 2.4 lb (90.8 kg) (90.8 kg) (1.09 kg) (1.09 kg) degree 2 degree 2 Cotton methyl esters 2091 lb (949 kg) 2091 lb 949 kg oils tri-potassium carbonate 2.4 lb (1.09 kg) 2.4 lb (1.09 kg) batch 5

degree 1

Cotton methyl esters 1305 lb (592 kg) oils soap 200 lb (90.8 kg) sucrose 300 lb (136 kg) tri-potassium carbonate 2.4 lb (1.09 kg)

degree 2

Cotton methyl esters 2094 lb (951 kg) oils tri-potassium carbonate 2.4 lb (1.09 kg)

Each of the five batches is purified as follows: each batch is washed individually with a small amount of water (about 1 part by weight of water to 5.5 parts by weight of raw sucrose polyester) to hydrate and flocculate the monovalent soap, then centrifuging to remove most precipitated soaps (up to about 447 ppm) and particulate catalyst as sludge. The washed and unbleached sucrose polyester (pH about 7.1) is then introduced into three stainless steel tanks in proportions of substantially the same weight and then washed with a chelating agent. ··· • t · · · · • ·· ··········

9 9 9 9 9

9999999 99 999 99 99 with an aqueous wash solution to obtain a potassium citrate concentration of 4975 ppm in the crude sucrose polyester. The chelating aqueous wash solution contained 3400 lb of water and 97.42 pounds of potassium citrate and had a pH of 8.59. 970 lb of this solution was added to each tank. The crude polyester and the chelating solution were mixed for 10 minutes; after stirring for 5 minutes, the solutions are mixed again for another 5 minutes. The mixture was allowed to settle for 1.5 hours and the aqueous layer was removed. 66 pounds of silica gel are then added to each of the three tanks.

The contents of all three tanks are then filtered to form a silica gel filter cake.

The processed sucrose ester has the following concentration of calcium, free fatty acids, and has the following product color: 540 ppb, 0.22% and 0.83.

A typical commercial product, Olean ™, made without applying the chelating solution wash of the invention, contains about 2200 ppb to 2800 ppb calcium ions and has a Lovibond red index of about 2.3

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PATENTOVÉ

Claims (27)

A process for preparing an indigestible polyol-polyester having improved stability to hydrolysis, comprising the steps of: a. thoroughly mixing the aqueous phase containing the ion exchange ligand wash solution with the polyol-polyester containing a divalent soap with a divalent cation; b. ion exchange of divalent and multivalent ion from a divalent and multivalent ion exchange ligand so-called divalent and multivalent ion exchange ligand, c. monovalent soap formation; d. removing the divalent and multivalent ion exchange ligand and monovalent soap from the processed polyol-polyester, thereby reducing the concentration of divalent and multivalent metal ions in the resulting indigestible polyol-polyester. 2. The method of claim 1 wherein the concentration of divalent and multivalent metal ions is reduced to less than 550 ppb divalent and multivalent metal ions. The method of claim 1, wherein the pH of the aqueous wash solution is maintained at 6.5 or higher during the ion exchange step (b). 4. The method of claim 2 wherein the concentration of divalent and multivalent metal ions is reduced to less than about 340 ppb. • 99 99 99 99 99 5. The method of claim 4, wherein the concentration of divalent and multivalent metal ions is reduced to less than about 100 ppb. 6. The method of claim 1 wherein the resulting indigestible polyol polyester comprises less than about 500 ppm of free fatty acids. 7. The method of claim 6, wherein the resulting indigestible polyol polyester comprises less than about 100 ppm of free fatty acids. 8. The method of claim 6, wherein the resulting indigestible polyol polyester comprises less than about 50 ppm of free fatty acids. 9. The method of claim 1, wherein the ion exchange ligand is used in an amount of from about 0.05% to about 2% by weight of the composition used in step (a). The method of claim 1, wherein the ion exchange ligand is a tri-alkali metal citrate salt, tartaric acid, ethylenediaminetetraacetic acid, or mixtures thereof. The method of claim 10, wherein the ion exchange ligand is selected from the group consisting of potassium citrate, sodium citrate, and mixtures thereof. 12. The method of claim 1, wherein in step (d), the treated polyol polyester is removed using a method selected from the methods comprising: 4 «4 4 4 4 44 * · 4 · 4 4 4 4 4 4 4 4 4 4 4 4 4 445 44 4 44 444 4444 444 4444 · 4 444 * 4 44 water wash, filtration, centrifugation and combinations thereof, monovalent soap and divalent ion exchange ligand. 13. The method of claim 11, wherein the resulting indigestible polyol polyester comprises less than about 100 ppm of free fatty acids, less than 340 ppb of divalent and multivalent metal ions, and has a Lovibond reddish value of less than about 4. 14. The method of claim 13, wherein the resulting indigestible polyol polyester comprises less than about 50 ppm of free fatty acids, less than 100 ppb of divalent and multivalent metal ions, and has a Lovibond red color value of less than about 2. 15. The method of claim 3, wherein the ion exchange ligand is selected from the group consisting of dialkali metal citrate, monoalkali metal citrate, citric acid, and mixtures thereof, and the pH of the aqueous wash solution is adjusted with an alkaline composition. 16. The process of claim 15 wherein the alkali metal is selected from the group consisting of sodium, potassium, and mixtures thereof. 17. The process of claim 16 wherein the pH of the aqueous scrubbing solution is adjusted with an alkali metal hydroxide. 18. An indigestible polyol-polyester composition having improved hydrolysis stability comprising an indigestible polyol-polyester and less than about 550 ppb divalent and multivalent metal ions. 9 · * ·· 99 9 99 ·· • 9 99 9 9 9 9 9 9 9 9 9 9 9 * 99 99 9 * 9 9 9 9 9 99,999 * 4,999 19. The non-digestible polyol-polyester of claim 18, further comprising less than about 500 ppm of free fatty acids. 20. The non-digestible polyol-polyester of claim 19 comprising less than about 340 ppb of divalent and multivalent metal ions and less than about 100 ppm of free fatty acids. 21. The non-digestible polyol-polyester of claim 20 comprising less than about 100 ppb of divalent and multivalent metal ions and less than about 50 ppm of free fatty acids. 22. The indigestible polyol polyester according to claim 19, wherein its Lovibond red color value is less than about 6. 23. The indigestible polyol polyester according to claim 19, wherein its Lovibond red color is less than about 4. 24. The indigestible polyol polyester according to claim 20, wherein its Lovibond red color value is less than about 2. 25. The indigestible polyol polyester according to claim 21, wherein its Lovibond red color value is less than about 1.0. The non-digestible polyol-polyester of claim 18. Characterized in that the polyol component is sucrose. 27. The indigestible polyol-polyester of claim 18 wherein the polyol component is an alkoxylated glycerin.