Lower alkyl ester recycling in polyol fatty acid polyester synthesis

Process for synthesizing polyol fatty acid polyesters which includes the steps of reacting an excess of lower alkyl ester with polyol to esterify hydroxyl groups thereof and form polyol fatty acid polyester, separating at least a portion of the unreacted lower alkyl ester from the polyol fatty acid polyester, and recycling the separated unreacted lower alkyl ester for further reaction with polyol or partially esterified polyol. The recycled lower alkyl ester is substantially free of lower alkyl ester degradation reaction products, such as carbonyls and free fatty acids.

TECHNICAL FIELD

This invention relates to a process for synthesizing polyol fatty acids polyesters in which unreacted lower alkyl ester is recovered from the reaction mixture and recycled for use in the polyol fatty acid polyester synthesis. More particularly, this invention relates to such a process wherein good product quality of polyester synthesized with the recycle ester is maintained by minimizing alkyl ester degradation reactions such as oxidation, hydrolysis, pyrolysis, and saponification.

BACKGROUND ART

The food industry has recently focused attention on polyol polyesters for use as low-calorie fats in food products. Triglycerides (triacylglycerols) constitute about 90% of the total fat consumed in the average diet. One method by which the caloric value of edible fat can be lowered is to decrease the amount of triglycerides that is consumed, since the usual edible triglyceride fats are almost completely absorbed in the human system (see Lipids, 2, H. J. Deuel, Interscience Publishers, Inc., New York, 1955, page 215). Low calorie fats which can replace triglycerides are described in Mattson, et al., U.S. Pat. No. 3,600,186. Mattson, et al. disclose low calorie, fat-containing food compositions in which at least a portion of the triglyceride content is replaced with a polyol fatty acid polyester having at least four fatty acid ester groups, with each fatty acid having from eight to twenty-two carbon atoms.

Rizzi and Taylor, U.S. Pat. No. 3,963,699, disclose a solvent-free transesterification process in which a mixture of polyol (such as sucrose), a fatty acid lower alkyl ester (such as a fatty acid methyl ester), an alkali metal fatty acid soap (emulsifier), and a basic catalyst is heated to form a homogenous melt. Excess fatty acid lower alkyl ester is added to the melt to form the higher polyol fatty acid polyesters. The polyesters are then separated from the reaction mixture using various separation procedures; distillation or solvent extraction are preferred.

Volpenhein, U.S. Pat. Nos. 4,517,360 and 4,518,772, discloses a solvent-free transesterification process in which a mixture of polyol (such as sucrose), fatty acid ester selected from the group consisting of methyl esters, 2-methoxy ethyl esters, and benzyl esters, an alkali metal fatty acid soap, and a basic catalyst is heated to form a homogenous melt, to which is added excess fatty acid ester to form the higher polyol fatty acid polyesters. The polyesters are then separated from the reaction mixture using various separation procedures; distillation, water washing, conventional refining techniques or solvent extraction are preferred.

Bossier (III) U.S. Pat. No. 4,334,061, discloses a process in which a mixture of polyol, fatty acid ester, alkali metal fatty acid soap, and basic catalyst is heated to form a homogenous melt, to which is added excess fatty acid ester to form the polyol fatty acid polyesters. The polyesters are then recovered by contacting the crude reaction product with an aqueous washing medium while maintaining the resulting mixture at a pH of from 7 to about 12, in the presence of an emulsion decreasing organic solvent. The alkali metal fatty acid soaps and the color-forming bodies are dissolved in the aqueous phase. The polyol fatty acid polyester is recovered from the organic phase by solvent extraction to remove excess fatty acid lower alkyl esters and steam stripping to remove trace amounts of residual fatty acid lower alkyl esters and solvent.

Virtually all of the polyol fatty acid polyester synthesis processes require that the polyol fatty acid polyester be separated from a reaction mixture comprising products, by-products, and unreacted ingredients. Additionally, many polyol polyester synthesis processes require the use of excess lower alkyl ester, in particular excess methyl ester, so that a significant amount of unreacted lower alkyl ester is contained in the reaction mixture from which the polyol polyester product is recovered. The polyol fatty acid polyester synthesis would therefore be more economically efficient if the excess methyl esters could be reused in the polyol fatty acid polyester synthesis. However, because significant degradation of the lower alkyl esters can occur in conventional processing steps employed to separate and purify the polyol polyester product or in separation of the unreacted lower alkyl ester from the reaction mixture, reuse of the degraded lower alkyl ester can result in the synthesis of inferior polyol polyester product. Consequently, there remains a need to develop a process which can recycle the excess lower alkyl ester from a polyol fatty acid polyester synthesis without adversely affecting product quality of polyesters synthesized from the recycled ester.

SUMMARY OF INVENTION

Accordingly, it is an object of this invention to obviate problems encountered in the prior art and provide improved processes for synthesis of polyol fatty acid polyesters.

It is another object of this invention to minimize the side reactions which degrade lower alkyl esters during such processes to allow the recycle of excess lower alkyl ester without adversely impacting the quality of polyol fatty acid polyester produced therefrom.

It is yet another object of this invention to provide a novel process for the production of polyol fatty acid polyesters, which process recycles unreacted ingredients and improves the economics of the polyol synthesis.

It is a related object of this invention to provide a novel process for the production of polyol fatty acid polyesters, which process eliminates the need to dispose of significant amounts of unused excess reactants.

In accordance with one aspect of the present invention, there is provided a novel process for synthesizing polyol fatty acid polyester comprising the steps of reacting lower alkyl ester and polyol, partially esterified polyol or mixtures thereof to esterify hydroxyl groups thereof and form polyol fatty acid polyester comprising partially and/or fully esterified polyol in admixture with unreacted lower alkyl ester; separating at least a portion of the unreacted lower alkyl ester from the polyol fatty acid polyester; and recycling the separated unreacted lower alkyl ester for further reaction with polyol or partially esterified polyol, wherein the recycled lower alkyl ester is substantially free of lower alkyl ester degradation reaction products.

In accordance with another aspect of the present invention there is provided a novel transesterification process for synthesizing polyol fatty acid polyester comprising the steps of heating a mixture of polyol, fatty acid lower alkyl ester, basic reaction catalyst, and optionally an alkali metal fatty acid soap to form a reaction mixture; subsequently adding to the reaction mixture excess fatty acid lower alkyl ester; reacting a portion of said fatty acid lower alkyl ester with polyol to obtain a product mixture; separating unreacted fatty acid lower alkyl ester from the product mixture; and recycling the separated unreacted fatty acid lower alkyl ester for further reaction, wherein the recycled lower alkyl ester is substantially free of degradation reaction products.

It has been found that unreacted lower alkyl esters can be recovered from the product mixture of product, by-products and unreacted ingredients, and recycled for use in the polyol fatty acid polyester synthesis with no adverse impact on the polyol fatty acid polyester reaction or on the quality of the polyester produced. Potential degradation reactions, such as oxidation, hydrolysis, pyrolysis, and saponification, are minimized so as to recycle directly back to the synthesis reactor the unreacted lower alkyl ester which is substantially free of degradation reaction products. The recycling of unreacted lower alkyl esters according to the invention improves the economics of the synthesis reaction, since separated unreacted fatty acid lower alkyl esters which contain high levels of degradation product would need to be further processed to remove substantial amounts of the degradation products from the ester recycle, or otherwise would need to be discarded, either of which can be expensive.

Additionally, it has been found that the same basic compounds which are used to catalyze the polyol fatty acid polyester synthesis can also be used to neutralize fatty acids in the recycled ester, thereby further improving the economical aspects of the synthesis processes employing ester recycle.

These and additional objects and advantages will be more filly apparent in view of the following detailed description.

DETAILED DESCRIPTION OF THE INVENTION

The present invention encompasses processes for recycling lower alkyl esters in the synthesis of polyol fatty acid polyesters. Lower alkyl ester recycling can be used in conjunction with any polyol fatty acid polyester synthesis method which utilizes lower alkyl esters. Such processes are disclosed in U.S. Pat. Nos. 3,963,699; 4,517,360; 4,518,772; 4,806,632 and 5,491,226, incorporated herein by reference. One suitable polyol fatty acid polyester synthesis process is a solvent-free transesterification reaction which can be performed in two steps. In the first step of the transesterification synthesis process, polyol, fatty acid lower alkyl ester, basic reaction catalyst, and optionally soap are combined to form a heterogeneous mixture.

As used herein, the term polyol is intended to include any aliphatic or aromatic compound containing at least two free hydroxyl groups. Suitable polyols can be selected from the following classes: saturated and unsaturated straight and branch chain linear aliphatics; saturated and unsaturated cyclic aliphatics, including heterocyclic aliphatics; or mononuclear or polynuclear aromatics, including heterocyclic aromatics. Carbohydrates and non-toxic glycols are preferred polyols. Monosaccharides suitable for use herein include, for example, mannose, glucose, galactose, arabinose, xylose, ribose, apiose, rhamnose, psicose, fructose, sorbose, tagatose, ribulose, xylulose, and erythrulose. Oligosaccharides suitable for use herein include, for example, maltose, kojibiose, nigerose, cellobiose, lactose, melibiose, gentiobiose, turanose, rutinose, trehalose, sucrose and raffinose. Polysaccharides suitable for use herein include, for example, amylose, glycogen, cellulose, chitin, inulin, agarose, zylans, mannan and galactans. Although sugar alcohols are not carbohydrates in a strict sense, the naturally occurring sugar alcohols are so closely related to the carbohydrates that they are also preferred for use herein. Natural sugar alcohols which are suitable for use herein are sorbitol, mannitol, and galactitol. Particularly preferred classes of materials suitable for use herein include the monosaccharides, the disaccharides and sugar alcohols. Preferred polyols include glucose, fructose, glycerol, polyglycerols, sucrose, zylotol, sorbitol, alkoxylated glycerines, alkoxylated polyglycerols, and sugar ethers; particularly preferred is sucrose.

As used herein, the term polyol fatty acid polyesters is intended to include fatty acid esters of polyols, in which one or more of the hydroxyl groups are replaced with esters of fatty acids. Preferred polyol fatty acid polyesters are those wherein at least half of the hydroxyl groups have been replaced with esters of fatty acids. Particularly preferred are sucrose polyesters with at least five ester linkages per sucrose molecule, in which the fatty acid chains have from about eight to about twenty-four carbon atoms. As used herein, the term lower alkyl ester is intended to include fatty acid esters of lower alkyl alcohols, in which the hydroxyl groups are replaced with esters of fatty acids. Suitable lower alkyl alcohols include C1-C6 mono-alcohols. Especially preferred lower alkyl esters are methyl esters.

Suitable fatty acid esters can be derived from either saturated or unsaturated fatty acids. Suitable preferred saturated fatty acids include, for example, capric, lauric, palmitic, stearic, behenic, isomyristic, isomargaric, myristic, caprylic, and anteisoarachadic. Suitable preferred unsaturated fatty acids include, for example, maleic, linoleic, licanic, oleic, linolenic, erythrogenic acids. In a preferred embodiment of the invention, the fatty acid chains have from about two to about twenty-four carbon atoms. Hydrogenated or unhydrogenated lower alkyl esters obtained from soybean oil, palm kernel oil, coconut oil, sunflower oil, safflower oil, corn oil, cottonseed oil, peanut oil, canola oil, high erucic acid rapeseed oil, and mixtures thereof are preferred.

In the present processes, polyol fatty acid polyester is synthesized and unreacted lower alkyl ester is recycled. In particular, a polyol fatty acid polyester is synthesized by a process comprising the steps of (a) reacting lower alkyl ester with polyol, partially esterified polyol, or mixtures thereof to esterify hydroxyl groups thereof and form polyol fatty acid polyester, the polyol fatty acid polyester comprising partially esterified polyol, fully esterified polyol, or mixtures thereof, and being in admixture with unreacted lower alkyl ester, (b) separating at least a portion of the unreacted lower alkyl ester from the polyol fatty acid polyester, and (c) recycling the separated unreacted lower alkyl ester for further reaction with polyol or partially esterified polyol, wherein the lower alkyl ester which is recycled for further reaction is substantially free of lower alkyl ester degradation reaction products. As used herein, substantially free of lower alkyl degradation reaction products means that the use of the recycled lower alkyl ester will not adversely effect the quality of the polyol polyester product formed from the recycled lower alkyl ester. Degradation reaction products of the lower alkyl ester will be apparent to those skilled in the art and comprise products of oxidation, hydrolysis, pyrolysis, saponification and the like. These degradation reaction products should be minimized or eliminated to permit direct recycling of the lower alkyl ester to the polyol polyester reaction, without resorting to extra cleanup or purification steps for the recycled esters.

This example describes a pilot plant two stage process for synthesizing polyol fatty acid polyesters wherein methyl ester reactant was separated and recycled for further reaction. The polyol fatty acid polyester product comprised sucrose fatty acid polyester (SPE). The methyl ester comprised about 80% soybean methyl ester having about 12% C16 alkyl methyl ester, about 87% C18 alkyl methyl ester, and about 1% other methyl esters; and about 20% cottonseed methyl ester having about 23% C16 alkyl methyl ester, about 76% C18 alkyl methyl ester, and about 1% other methyl esters. One batch of liquid SPE was made using only fresh methyl ester reactant as a control, while six subsequent batches were made using a blend of fresh esters and recycle esters from the previous batch. Each batch employed 36% by weight excess esters. Owing to various process losses, only 22 weight percent of the total ester used was separated and recycled for use in the subsequent batch. All of the lower alkyl ester which was separated and recycled was employed in the first stage of the two-stage transesterification reaction.

In the first stage of each batch, 350 lbs. sucrose, 200 lbs. potassium stearate, 1,530 lbs. methyl ester and 2.8 lbs. potassium carbonate catalyst were charged to a stirred tank reactor, and maintained at a temperature of from about 132 C. to 138 C. and a pressure of from about 1 to about 10 mm Hg. The batch process used a single reactor comprising a tank with an agitator and a recirculation pump. There are two impellers on the agitator; one pitched blade (for solids suspension) and one Rushton turbine (for gas dispersion). A four stage vacuum system capable of pulling 1.0 mm Hg was used to remove methanol by-product from the reactor. Nitrogen sparging was used as a stripping agent to assist in methanol removal. In the second stage of the transesterification reaction, an additional 1,830 lbs. methyl ester and 2.8 lbs. potassium carbonate catalyst were added. Total residence time to achieve 75% octaester was from about 6 to about 10 hours.

The polyol fatty acid polyester product was centrifuged, water washed and bleached with silica gel for refinement. Centrifugation was performed with a disc stack centrifuge; about 95% of the emulsifier (potassium stearate soap) was removed from the crude (unrefined) polyol polyester. Water-washing was done in a stirred tank; the water level was about 18% by weight of the crude polyol polyester, the mixing time was from about 10 to about 30 minutes. The water phase was separated by gravity settling. The crude polyol polyester was then dried to a moisture content of less than about 0.1% in a vacuum dryer. Silica gel bleaching was performed by contacting dry silica with the crude polyol polyester in a stirred tank for 30 minutes; the silica level was about 1% by weight of the crude polyol polyester. The silica gel was separated from the polyol polyester in a filter press. For all six processing batches, the batch reaction time, the soap level after centrifuging and the soap level after water washing were consistent.

The methyl ester was separated from the bleached polyester product using evaporation and stripping processes. The evaporation was performed with a wiped film design evaporator operating under a pressure of about 1.0 mm Hg and a temperature of about 425 F. (about 218 C.). The methyl ester which was vaporized and recondensed in the evaporator was recycled. Steam stripping of the polyol polyester completed the methyl ester removal. Steam stripping was performed with a packed column with countercurrent flow of steam and polyol polyester operating under a pressure of about 4.0 mm Hg and a temperature of about 425 F. (about 218 C.).

The methyl ester which was separated for recycle from each batch of liquid SPE exhibited measurements within the acceptable limits for peroxide value, percent free fatty acid, chain length distribution and visual appearance. Results for peroxide value, carbonyl value, percentage of free fatty acid, and chain length distribution are set forth in Table 1.

One method of determining peroxide value is thiosulfate titration. Peroxides reduce the KI to I 2 , and I 2 can complex with starch indicator to create a blue color. A thiosulfate titrant oxides the I 2 , causing the blue color to disappear; 0.5 mole of I 2 is consumed per mole thiosulfate.

A potassium iodide solution of 15 grams KI in 10 ml deionized water and a 0.01N thiosulfate solution were prepared. Samples were prepared by dissolving 20 grams of sample with 30 ml of a 60:40 v:v glacial acetic acid/1,1,2-trichlorotrifluoroethane solution, adding 1 ml of the KI solution, agitating for 1 minute, adding 100 ml of distilled water, mixing, and adding 2 ml of a starch indicator solution (Fisher Scientific, SS408-1). The samples were then titrated with the thiosulfate to a colorless endpoint.

Preferably, the peroxide value is less than about 85 ppm.

One method of determining free fatty acid level is with phenolphthalein titration. One milliliter of phenolphthalein indicator, 50 0.2 grams of sample and 100 ml of warm neutral denatured alcohol w ere mixed. The solution was titrated to a phenolphthalein endpoint using 0.01N NaOH. The percent free fatty acid (%FFA) was reported as % oleic acid, and was calculated according to the equation: % FFA as Oleic = [ ( ml of NaOH ) ( Normality of NaOH ) 28.21 ] Sample Weight .

Preferably, the percentage of free fatty acid is less than about 0.4%, more preferably less than about 0.3%.

One method of determining fatty acid chain length distribution is by gas chromatography. Fatty acid lower alkyl esters can be separated by gas chromatography by chain length. Samples were dissolved in hexane and analyzed on a capillary GC having a 50 m 0.22 id fused column (Supelco SP-2340). The column head pressure was 25 psi, the helium carrier gas flowrate was 2-3 ml/minute, the split vent flow rate was 100 ml/minute, the initial temperature in 175 C., the final temperature was 195 C., the rate was 1.6 C./minute, the air pressure was 40 psi, the air flowrate was 400 ml/minute, the hydrogen pressure was 30 psi, and the hydrogen flowrate was 30 ml/minute. Preferably, chain length distribution remains consistent throughout the recycling; i.e. the chain length varies from the chain length of fresh methyl ester by no more than about 20%, preferably no more than about 15%. Most preferably the chain length for C16 lower alkyl ester varies no more than about 15%, and the chain length for the C18 lower alkyl ester varies no more than about 5%. For soybean methyl ester, the chain length generally comprises from about 8% to about 14% C16 lower alkyl ester, and about 85% to about 95% C18 lower alkyl ester. For cottonseed methyl ester, the chain length generally comprises from about 19% to about 23% C16 lower alkyl ester, and from about 74% to about 84% C18 lower alkyl ester.

One method of determining carbonyl value is based upon reacting fatty acid lower alkyl ester with an ethanolic solution of 2,4-dinitrophenylhydrazine (2,4-DNPH) and hydrochloric acid to form 2,4-dinitrophenylhydrazones, which in the presence of a base produce red color. A 2,4-DNPH stock solution was prepared by dissolving 0.8 0.02 g of 2,4-DNPH in 200 ml of 200 proof (100%) undenaturated ethanol, and then adding 10 ml of concentrated HCI. A KOH solution was prepared by dissolving 118 g of KOH in 500 ml of distilled water, and diluting to 2000 ml with 200 proof undenaturated ethanol. A dodecanal stock solution was prepared by diluting 0.200 0.001 g of odecanal to 50 ml with 200 proof undenaturated ethanol. The carbonyl concentration was calculated as: ppm C O = ug C O in stock ml = weight of dodecanal ( g ) 50 ml 28 184 F 10 6 g ug ;

F % purity of dodecanal/100.

The dodecanal stock was diluted 50-fold with 200 proof undenaturated ethanol to form a working solution; the working solution was used to make calibration standards. Fatty acid lower alkyl ester samples were prepared by diluting 0.1 0.0100 g of sample with 4 ml of ethanol.

Each of the samples, standards, and ethanol blanks was placed in a 25-ml volumetric flask, and 2 ml of the 2,4-DNPH solution was added to each flask. Stoppered flasks were placed in a 75 1 C. water bath for 20 0.5 minutes, cooled to room temperature, diluted to 25 ml with the KOH solution, and mixed well with shaking. After standing at room temperature for 20 0.5 minutes, the absorbance was read at 480 nm using quartz cells. A calibration curve was constructed from the absorbance values of the calibration standards. Preferably, the carbonyl value is less than 200 ppm.

One method of determining the percent of octaester in a polyol polyester is with high performance liquid chromatography. The polyol polyester sample was dissolved in hexane, filtered, and injected into the HPLC where normal phase separation based on the number of free hydroxyl groups takes place. A 80 mm by 4 mm, 5 m Zorbax Reliance silica column was used. The mobile phase is a methyl-t-butyl/hexane step gradient system. The gradient consists of 4.8 minutes of 4% methyl-t-butyl in hexane; 2.9 minutes of 16% methyl-t-butyl in hexane; 1.9 minutes of 25% methyl-t-butyl in hexane; 1.9 minutes of 50% methyl-t-butyl in hexane; and 2.9 minutes of 100% methyl-t-butyl in hexane. Detection was by a light-scattering mass detector. The octaester level was calculated by the integrator as the normalized octaester area percent. Preferably, the octaester level is greater than about 70%.

Color was determined using a Lovibond Automatic Tintometer with a red/yellow calibration standard (2.9 red/12.0 yellow). The color was reported in AOCS red and yellow units. Preferably, the color is less than about 3.7 Lovibond red units.

The level of soap remaining in the polyol polyester reaction product after centrifuging is preferably less than 2000ppm. One method of determining the level of soap is by acid tritiation. Samples were prepared by mixing 0.5 0.01 grams of sample with 50 ml of a 1:1 v:v isopropanol/ deionized water solution. The sample was titrated with 0.01N HCl using an automatic titrator. One equivalence point was observed. % K soap = ( ml HCl ) ( Normality HCl ) 32.0 ** sample weight ** 32.0 = Molecular Weight K soap (g/mol) * 0.001 1 / ml * 100

This example describes a production process for synthesizing sucrose fatty acid polyesters (SPE) with the use of recycle methyl esters in a two step continuous process. The methyl ester comprised cottonseed methyl ester of about 23% C16 alkyl methyl ester, about 76% C18 alkyl methyl ester, and about 1% other methyl esters. In the first stage, the continuous reaction system was made up with 267 lb/hr sucrose, 60 lb/hr potassium stearate, 1,116 lb/hr methyl ester and 9 lb/hr potassium carbonate. The second stage was made up with 1,560 lb/hr methyl ester and 6 lb/hr potassium carbonate. A series of continuous stirred tank reactors (CSTRs) were used for the continuous reaction system; each reactor comprised a tank with an agitator and a recirculation pump. There were two impellers on the agitator; one pitched blade (for solids suspension) and one Rushton turbine (for gas dispersion). The overall process ran for approximately 100 hours, with unreacted methyl ester being recycled for additional reaction after the first 24 hours of the process. The weight percentage of recycle esters was the same as in Example 1 and all of the recycled esters were employed as the methyl ester in the first stage. A four stage vacuum system capable of pulling 1.0 mm Hg was used to remove methanol by-product from the reactor. Nitrogen sparging was used as a stripping agent to assist in methanol removal.

The polyol fatty acid polyester product was centrifuged, water washed and bleached with silica gel for refinement. Centrifugation was performed with a disc stack centrifuge; about 95% of the emulsifier (potassium stearate soap) was removed from the crude (unrefined) polyol polyester. Water-washing was done in an agitated tray column; the water level was about 18% by weight of the crude polyol polyester, the mixing time was from about 2 to about 10 minutes. The water phase was separated by centrifugation. The crude polyol polyester was then dried to a moisture content of less than about 0.1% in a vacuum dryer. Silica gel bleaching was performed by contacting dry silica with the crude polyol polyester in a stirred tank for 30 minutes; the silica level was about 0.5% by weight of the crude polyol polyester. The silica gel was separated from the polyol polyester in a filter press. The in-process measurements, including reactor residence time, soap level after centrifuging and soap level after water washing, were also consistent during the entire production run.

The methyl ester was separated using evaporation and stripping processes. The evaporation was performed with a wiped film design evaporator operating under a pressure of about 1.0 mm Hg and a temperature of about 425 F. (about 218 C.). The methyl ester which was vaporized and recondensed in the evaporator was recycled. Steam stripping of the polyol polyester completed the methyl ester removal. Steam stripping was performed with a packed column with countercurrent flow of steam and polyol polyester operating under a pressure of about 4.0 mm Hg and a temperature of about 425 F. (about 218 C.).

The peroxide value, carbonyl value, percentage of free fatty acids, chain length distribution and visual appearance for the recycle ester were within acceptable limits during the entire production run. Results for peroxide value, carbonyl value, percentage of free fatty acid, and chain length distribution are set forth in Table 3. Additionally, percent of SPE octaester, flavor, color and residual soap after centrifuging for the liquid SPE product were within acceptable limits during the entire production run. Results for percentage octaester, color and residual soap after centrifuging are set forth in Table 4. The analytical measurements were performed as discussed in Example 1.

TABLE 3 Comparison of Fresh and Recycled Methyl Ester Peroxide Carbonyl % Free % C16 % % C18 % Value Value Fatty Chain variation Chain variation Methyl Ester (ppm) (ppm) Acid Length from fresh Length from fresh Acceptable <85 <200 <0.4 19 to / 20 60 to / 20 Limits 27 79 Fresh(Day 1) 10 196 0.04 22.5 75.5 Recycled Day 2 15.2 102 0.11 N.A. N.A. N.A. N.A. Day 3 20 122 0.11 21.5 4.7 76.5 1.3 Day 4 14.8 100 0.12 20.9 7.1 77.1 2.1 Day 5 14 128 0.12 19.3 14.2 78.7 4.2 N.A. Not Available TABLE 4 Comparison of Sucrose Polyester Quality Using Fresh and Recycled Methyl Ester Substrate Methyl Ester Residual Soap After Final Color Substrate % Octaester Centrifuging (ppm) (Lovibond Red) Acceptable Limits >70 <2000 <3.7 Fresh (Day 1) 76 483 1.7 Recycled Day 2 78 900 1.1 Day 3 77 600 1.5 Day 4 75 600 1 Day 5 76 400 1.5 Having described the preferred embodiments of the present invention, further adaptations of the processes described herein can be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. A number of alternatives and modifications have been described herein, and others will be apparent to those skilled in the art. Accordingly, the scope of the present invention should be considered in terms of the following claims, and is understood not to be limited to the details of the processes described in the specification.