668

FATMODIFICATION

Companiesin Canada haveintroduced a numberof nonhydrogenatedsoft margarinesthat incorporatepalm andlor palmkernel oil forhardening.

Tools: hydrogenation, interesterification

Hydrogenation and interesterifi-cation are among the tools theindustry uses to give fats and

oils desired functionality for specificproducts.

Approximately one-third of all edi-ble fats and oils in the world arehydrogenated, while approximately10% are fractionated or interesterified,according to data from UnichemaInternational that was presented at theFourth Latin American Congress heldin 1992. Interesterification currentlyhas limited application in the UnitedStates. However, interest is growing inwhether interesterification can be usedto lower trans fatty acid isomers infood products.

Unresolved nutritional questionsconcerning trans fany acids are prompt-ing companies in the United States andCanada to consider options other thanhydrogenation to modify oils. Mean-while, increasing palm oil production inLatin America may increase use ofinteresterificationin that region.

Currently, fonnulators can raise themelting point and solid fat content offats by (a) hydrogenating oils to dif-ferent degrees of hardness or (b) inter-esterifying a liquid oil with a moresaturated oil. The U.S. industry useshydrogenation predominantly. InEurope, companies use interesterifica-tion for a wider variety of products,including margarines.

This article was writtenby Barbara Fitch Haumann,senior editodwriter for INFORM.

Hydrogenation is a chemical pro-cess for adding hydrogen to unsaturat-ed triglyceride esters. Interesterifica-tion is a rearrangement of the fauyesters on the glycerol molecule. Somein the industry see an advantage inusing both.

"It's best to use them together:'according to Alan R. McCurdy, a pro-fessor at the University ofSaskatchewan in Canada. To do this,formulators fully hydrogenate an oiland interesterify it with a nonhydro-

INFORM, Vol. 5. no. 6 (June 1994)

669

genated fat or oil to gel a particular Margarine-type products today are not rnance. The P crystal is desirable formelting characteristic. hydrogenated to the same extent as in fluid or pumpable shortenings for fry.

"Hydrogenation and interesterifica- the past and contain more liquid oils. ing and breadmaking.tion sometimes arc used together to resulting in fewer saturates in the final Hardness of a fat often is measuredgel products with specific highly products. However. this has led to by its melting point. However, for a fatdesired functionalities," according to more trans isomers in the products. or fat blend to be plastic, it must con-Robert Hasten, president of Hastech Average ranges of trans fany acid slst of both solid and liquid phases.Corp. However, when both are used. content of margarines are 11-30% in The ratio of these two phases at differ-"You add cost," Hestert pointed out. the United States, 11-39% in the Unit- ent temperatures is measured and"The improvement in runcuonalny ed Kingdom. 7-32% in Western expressed as Solid Fat Content {SFC}must be desirable enough to offset the Europe and 7-32% in Eastern Europe. or Solid Fat index (SFI). The resultshigher price required for the product." according to data published by consul- are similar. but the methodology is

Hasten and Kenneth F. Carlson, rant Kurt Berger in the March/April different.president of RBD Technologies, pre- 1993 issue of Lipid Technology. A The common practice for preparingdieted there will be more use of inter- recent article on "Properties of Mar- U.S. margarines is direct blending.esterification in the United States and garines Available in the U.S. Market" Table spreads are usually a blend ofmodifications to the hydrogenation by M. Kohiyama and colleagues pro- one or more partially hydrogenatedprocess for such products as mar- vided detailed analysis of 93 mar- basestocks with an unhardened oil orgarines because of interest to reduce garines and spreads available in the with a blend of two or more hydro-trans fauy acid in products. U.S. market. The article. published in genated oils. Stick margarines can be

"Awareness concerning possible the March 1994 issue of the Journal of divided into soft stick and hard stick.nutritional implications of trans fatty the Japan Oil Chemists' Society (Yllk· Virtually all hard stick margarines areacids is bringing increased interest in agaku], includes trOllSand cis data. hydrogenated. and soft stick mar-etremauves to our current way to Feedstocks for formulated products garines and soft tub spreads are ahydrogenate." Carlson said. "For range from soybean and canola oils. blend of liquid oil and hard besesrock.instance. people in the industry are which are high in polyunsaturated Fluid shortenings are flowable suspen-working on ideas to make the hydro- fatty acids, to coconut and palm slons of solid fat in liquid oil. and thegenauon process smoother. using gen- stearin. which are highly saturated. liquid oil phase mayor may not betier designs 10 more evenly distribute with coconut oil being approximately partially hydrogenated.the hydrogen in the oil. Companies 90% saturated fatty acids. The selection of oils availablealso are experimenting with catalysts "What you do to make the products domestically often influences whatto lower trans content. In addition. depends on the perfonnance you want techniques will be used. For instance.companies are trying 10 find alternate and what feedstocks you have avail- hydrogenation is widely used in thefeedstocks by exploring the use of able at an affordable price," according United States due to the availability ofinteresterification. " to Hasten. such oils as soybean. in countries

Fats exist in three crystal forms: c. where palm and coconut oils are moreFormulation criteria ~' and ~. W is the preferred crystal available. interesterification is moreFormulation changes during the past form for most margarines and shorten- apt to be used.30 years have concentrated on making ings because it produces a smooth rex- Hard fats such as palm kernel andmargarine products less saturated. ture and an enhanced creaming perfor- palm oils are readily available in trop-

I Hydrogen I Catalyst Bleaching eanhgo>

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INFORM, Voi. 5, no. 6 (June 1994)

670

FATMODIFICATION

ical regions. Palm oil can be fraction-ated into palm stearin (harder fraction)and palm olein (softer fraction), Palmoil also can be hydrogenated. Otherhard fat choices arc lard or tallow.However. with the trend away fromanimal fat usage in products. lard andtallow are nOI generally chosen inNorth America.

"So often the best formulations aresome of this feedstock and some ofthai," Hasten said. The practice ofusing palm oil in some U.S. formula-tions. however. was curtailed after anenritropical oils campaign launchedduring the 19805. As a result, (annul a-tors began substituting hydrogenatedcottonseed oil for palm in shorteningswhere P' characteristics are needed forfunctionality.

"I! didn '( make sense for technicalor nutritional reasons," Hastert said.noting that the tropical oils conuover-sy never became an issue in Europe."Palm oil will begin to be used againin the United States. but it will take along time to recover from this pseu-doscare," he added.

However. because palm oil crystal-lizes somewhat more slowly than cot-tonseed hard fat. switching to palm oilmight require slowing down or modi-fying existing production lines.

HydrogenationLiquid-phase hydrogenation of veg-etable oils was developed by WilhelmNonnann in the early 1900s. The pur-pose is to change the molecular com-position and structure of an oil.

Hydrogenation is done generally toincrease the hardness of an oil. Theresult is improved oxidative stabilityand functionality for use in mar-garines. solid cooking fats and bakingshortenings.

During the reaction, hydrogen gasis intimately mixed with the oil inthe presence of a catalyst (Figure I).After hydrogenation, the catalyst isfiltered out. The oil is bleached withadsorbent clays. and residual tracesof nickel are chelated with citricacid. Temperature, hydrogen pres-sure, type and amount of catalyst.and agitation affect the hydrogena-tion reaction. In commercial prac-tice. for economic reasons. compa-nies seek to use the least amount of

catalyst required to achieve theeffect they want.

A partially hydrogenated oil willhave different properties, dependingon whether hydrogenation was per-formed selectively or nonselectively,Simply stated, selective hydrogena-

"So oftenthe best

formulationsare some

of this feedstockand someof that."

-Rastert

mote formation of trans isomers.High concentration of hydrogen gasresults in low selectivity and lowisomer content, while low concen-tration of hydrogen gas results inhigh selectivity and high trans iso-mer content. Other conditions, suchas catalyst activity, catalyst selectiv-ity and agitator speed, also are Iac-tors.

Most commercial hydrogenationplants use batch slurry reactor equip-ment and supported nickel catalysts.The reaction is carried OUI atl5(}""'225°C, with hydrogen gas pres-sure ranging from 0.5-4 atmospheres(5-50 pstg). Continuous systemswould have desirable attributes, bUIhave not achieved significant com-mercial use at this point.

A review paper by Jonas Edvards-son and Said Irandoust, published inthe March 1994 issue of the Journalof the American Oil Chemists' Soci-ety, discusses reactors used for hydro-genating edible oils.

Recent advancesWork continues on improving thehydrogenation process.

One aspect has been research todecrease the amount of degradationproducts and trails isomers produced.

Associate professor Peter N. Pin-tauro and his graduate students atTulane University, for instance, havedeveloped a low-temperature elect-ro-catalytic process for hydrogenatingedible oils that results in less trailsisomer formation.

In this electrocatalytic reactionscheme, atomic hydrogen is producedon an active Raney nickel powdercathode surface by the electrochemi-cal reduction of water molecules fromthe electrolytic solution. Adsorbedhydrogen reacts with the oil's triglyc-erides to fonn hydrogenated product.The operation does not require hightemperatures or pressures.

The electro-hydrogenated oil hashigher stearic acid content and lowertrans isomers than oil produced viatraditional hydrogenation, Pintauroand his students have reponed. Pintau-ro has sent samples of (he resulting oilto the U.S. Department of Agricul-

INFORM, Vol. 5. no. 6 (June 1994)

(continued on page 672)

tion is a steering of the reactionstoward a step-by-step reduction oflinolenic acid to linoleic acid. andlinoleic to oleic acid, stopping shortof stearic acid. In nonselectivehydrogenation, more linolenic andlinoleic acids go directly to stearicacid.

"Wherever possible, manufacturersaim more toward higher activity forhigher turnaround, which is nonselec-tive," according to David R. Erickson,a consultant based in SI. Louis, Mis-souri.

Isomerization occurs during hydro-genation, with many of the cis doublebonds migrating along the fany acidchain. Some of the cis double bondsare then converted to the trans config-uration. The trans fany acids havehigher melting points than the cis fattyacids, and many cis isomers have ele-vated melting points compared to theoriginal cis fatty acids that were pre-sent in the oil.

High reaction temperatures pro-

672

FATMODIFICATION

(continuedfrom pag~670)

lure's National Center for AgriculturalUtilization Research (NCAUR) forodor and flavor stability analyses.

"Preliminary sensory evaluationsshow this oil has less characteristichydrogenated odor/flavor than con-ventlonafly hydrogenated oils,"according to NCAUR's KathleenWarner, explaining, "Thus. this prod-uct may be good not only because ithas lower Irons content but alsobecause it has less characteristichydrogenated flavor."

Pintauro has obtained a patent onthe process, and Tulane University isactively seeking industrial collabora-tion in the hopes that the process canbe commercialized. Original fundingfor the research came from the U.S.Department of Energy (DOE). Cur-rently, the project is funded in part bythe Slate of Louisiana as well as DOEand Lou Ana Foods Inc.

"If and when it will be commer-cialized will depend on funding andcompany interest." Pintauro said. not-ing that processing COSls based on cur-rent reactor designs are somewhathigher than traditional hydrogenationmethods.

Other research to improve hydro-genation performance has centered. inpart, on new generations of catalysts.designed to improve activity andselectivity while maintaining good fil-terability. This has included increasingthe pore size and decreasing the parti-cle size of the catalysts.

"To a certain extent. the level oftrans isomers (created) can be con-trolled by selecting adequate harden-ing conditions. particularly reactiontemperature and catalyst. Low levelsof trans are obtained if hydrogena-tion is perfonned at low temperatureusing fresh catalyst. while re-use ofcatalyst. high reaction temperatureand. in particular, a sulfur-promotedcatalyst will increase trails isomerformation and steepness of the solidline," Leo Lips of Unichema Interna-tional said in a presentation at theFourth Latin American Congress inArgentina in 1992.

In other work. Peter H. Berben andcolleagues at Engelhard De MeernB.V., De Meern. The Netherlands.

have investigated which reaction con-ditions and catalyst systems wouldproduce the fewest trans isomers dur-ing hydrogenation in a batch reactor.

Nickel catalysts and precious metalcatalysts were used at various temper-

"Precious metalcatalysts openthe possibility

of hydrogenatingunder

a wider rangeof operatingconditions. "

-Okonek

are very interesting since these cata-lysts are already active at much lowertemperatures," Berben said, notingthat in the Engelhard studies. preciousmetal catalysts were used at 6O"c.

Meanwhile. J.B. Rivers Jr., presi-dent of RIMECO Inc. based in Okla-homa City. believes the current hydro-genation process needs 10 be revised.

"We need to adopt a continuous,ubiquitous process," Rivers said. Hiscompany has designed a reactor that iscompamnentalized to help control thefollowing factors along each step ofhydrogenation: hydrogen concentra-tion in solution, catalyst strength andconcentration, temperature, uniformshear on all incremental volumes ofthe mixture. and pressure.

"As the finished oil quality is theobject of the process, the ideal reactormust have the capability of Sloppingthe reaction at the desired degree ofunsmurauon," Rivers said, explaining."With the highly reactive small grainoils, it is desirous to reduce thepolyunsaturates to monounsaturateswithout creating saturates or trans iso-mers."

His company's process is con-trolled with a patented oil qualitymonitor designed to give near-instan-taneous results for iodine value, solidfat index and melting point to regulatethe process at several steps along itsprogression.

Rivers is seeking funding throughthe U.S. Department of Commerce'sAdvanced Technology Program tobuild a prototype of his system. "It isa question of money, lime and supportto build a continuous plant," Riverssaid. noting he has approached largeoil processing companies as well asequipment manufacturers but has yetto get support for the project.

"There is interest in the idea, butthere is reluctance in the food industry10 invest in making changes." he said.

InteresterificationUnlike hydrogenation, interesterifica-tion neither affects the degree of saru-ration nor causes isomerization of thefatty acid double bond. Thus, it doesnot change the fatty acid profile of thestarting material. Instead, it rearranges

..INFORM. Vol.5, no. 6 (June 1994)

(conlinut!d on pugt! 675)

arures and hydrogen pressures. Bychanging the reaction conditions, theylowered the amount of trans isomersformed with nickel catalysts by30-40%, without considerablyincreasing the amount of saturates.They also found that platinum cata-lysts hardly produced any trans iso-mers, but the amount of saturatesincreased dramatically. Addition ofammonium as a reaction modifierbrought the amount of saturatesfonned back to normallevels.

"Whether ammonia or other modi-fiers may be used in food products orto produce food products is anotherquestion. however," Berben pointedout.

"The thrust of our research is toexplore alternative catalysts for lower-ing trans," according to DouglasOkonek, product technology managerfor Engelhard Corp. "Precious metalcatalysts open the possibility ofhydrogenating under a wider range ofoperating conditions." Nickel catalystsmust be used at temperatures aboveI30-140°C. "Precious metal catalysts

675

FATMODIFICATION

[continued from page 672)

the fatty acids on the glycerolmolecule.

lnteresteri fieation can be carriedOUI at significantly lower temperaturesthan hydrogenation, depending on theType of catalyst used. Temperaturesfor interesterification can range from240°C down to Ir'C. The most com-monly used catalyst is sodium methy-late.

Some interesterification catalystsregroup the fatty acids randomly.Specific enzymic catalysts, however,can be used to rearrange fatty acidson selected positions of the triglyc-eride only. In either situation, theoil's melting profile is changed. Inmost applications. interesterificationis used to generate Sleeper meltingblends. Nutritional functionality, par-ticularly absorption characteristics,also can be altered by interesrerifica-tion.

Random interesterification. the pre-dominant form used, changes the crys-tal form of an oil or blend to producedesired solid fat content curves or toproduce blends with high levels ofpolyunsaturated fatty acids. A 1969West Gennan patent. for instance, wasgranted for a zero trans product pro-duced by interesterifying 30% palmoil, 30% palm stearin and 40% palmkernel oil and by blending 27.5% ofthe interesterified fat with 72.5% ofpolyunsaturated vegetable oils.

lnteresterificatjcn involves oil pre-treatment. reaction with a catalyst anddeactivation of the catalyst. The pro-cess usually uses a batch reactor withan agitator, and includes hearing andcooling, sparging and vacuum steps.Figure 2 depicts a typical batch inter-esterification vessel.

The effect on melting and solidifi-cation propenies ultimately dependson the type and mixture of the startingmaterials, according to Michael D.Erickson, senior research scientist atKraft Food ingredients (KFI), in achapter on interesterification preparedfor the Handbook of Soy Oil Process-ing and Utilization, 2nd Edition, to bepublished later this year.

Chemical interesterificaticn alsocan be directed. Known as the EckeyProcess, directed interesterificarion

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produces the desired array of triglyc-erides through temperature manipula-tion. The reaction is conducted atlower temperatures than random inter-esterification. ''The triglycerides solid-ify because their melting point isabove the reaction temperature,"Erickson wrote, noting, "This pro-vides the opportunity to selectivelyfractionate a mixture to obtain desiredfunctional properties."

Interesterification was a significantmodification process before animalfats were displaced by vegetable oilsin products, he added.

Forty years ago, researchers atSwift & Co. in the United Statesdeveloped interesterification to modi-fy lard to function as a shortening forsuch baked goods as cake. After thediscovery by Karl Mattil, Frank Norrisand colleagues, Swift installed thisprocess at its plants during the I950s.It then began interesterifying itsSwifl'ning household lard-basedshortening.

Today, with less use of animal fatsin foods, industry experts said theyknow of no U.S. companies usinginteresterification to produce mar-garine and shortening feedstocks. Theprimary, and limited, use of interester-ification in the United States is to pro-duce high-value specialty fats. such ascocoa butter substitutes and confec-tionery fats.

Outside the United States, inter-esterification is used to produce spe-cialty fats as well as hardened fatswithout trans fatty acids. For instance,Unilever's Becel margarine, an inter-esterified margarine, is available inCanada and continental Europe.

To make Becel, hard fractions ofpalm and palm kernel oil are inter-esterified and blended with liquid oil.The hard fraction represents approxi-mately 12-15% of the formula. Cur-rently, Becel has approximately10-15% of the Canadian margarinemarket.

In India and Pakistan, consumersuse vanaspati, a shortening based onhydrogenated vegetable oil. However,vanaspati of satisfactory consistencyand no trans acids can be made usinginteresterificaricn, according to Bergerin the March/April 1993 issue ofLipid Technology. He noted that S.Majumdar and D.K. Bhattacharyahave obtained products of satisfactoryconsistency by interesterifying palmstearin with a variety of vegetableoils. M.S.A. Kbeiri and co-workersalso have prepared similar products ona larger scale.

Interesterification drawbackslnteresterification is not preferred bythe U.S. industry for a number of rea-sons.

For one, it is not a very clean pro-

INFORM. Vol. 5. no. 6 (June 19Q4)

676

FATMODIFICATION

cess. "The reactions are very sensitiveto moisture," according to NCAUR'sGary List. He said that if the sodiummethcxide catalyst reacts with mots-ture in the air. "you gel saponification.not interesterification." The resullingsoap has to be washed out of the oil,resulting in oil loss.

"You don't end up with a 100%triglyceride, but you also gel smallamounts of digJycerides and some-limes traces of monoglycerides. Thismeans the oil yield from interesterifi-cation is nOI as good as hydrogena-tion," List said. Another concern isusing a fresh catalyst.

"lmeresterification is a messy reac-tion," List said.

David Erickson. who at one timeworked for Swift. agreed that inter-esterification is not as versatile ashydrogenation. '" f interesteri Iication

were an economical and versatile pro-cess. industry would have switchedover to it many. many years ago whenthe first concerns over trans werevoiced," he pointed out.

Enzymatic intertSterificationChemical interesterificaticn, however,is not the only route for this process.Also gaining scrutiny is enzymaticinteresterification. now used commer-cially 10 produce high value-addedproducts. such as structured trigfyc-erides for confectionery usc.

Unilever Research scientists in theUnited Kingdom developed andpatented a process to make cocoa but-ter equivalents (CBEs) by specificenzyme interesterification of high-oleic sunflower oil and a palm oilfraction. These enzymatic CBEs havebeen tested extensively in chocolate

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INfORM, Vol. 5, 00. 6 (June 1994)

recipes and are completely inter-changeable with cocoa butter, accord-ing to Loders Croklaan B.Y.researchers.

During 1993, Loders CrokJaan putan enzymic interesterification plant online in wormerveer, The Netherlands.to produce fats for confectionery use.

Oil modification by lipases is per-formed under virtually anhydrous con-ditions, at temperatures up to 70°C,according to Paul Quinlan andStephen Moore of the Col worth Labo-ratory, Unilever Research. UnitedKingdom, in an article in the May1993 issue of INFORM.

Interesterification using randomlipases produces fat compositions sim-ilar to those obtainable from standardchemical methods. An advantage isthat these lipases generally are per-ceived as "natural" alternatives tochemical techniques.

Current applications of lipases,however, center around exploitation ofthe sn-I.3 fatty acid specificity ofmost commercially availableenzymes, which allows the manufac-ture of specific triglycerides in highyield. Such triglycerides can improveorganoleptic properties, such as reduc-ing waxiness and imparting cool melt-ing. and can reduce the total saturatedfat content of a product. Also, Quinlanand Moore wrote, low levels canimprove the processing or storageproperties of products, reducingbloom in confectionery products.

"In these applications, the majoradvantages of enzymic interesterifica-tion over existing chemical technolo-gies lie in the range of specificitiesavailable in Jipases and the greaterdegree of control in reactions," theywroie.

Unilever scientists also havedeveloped a novel triglyceride viaenzymatic Inreresrertncauon andbased on vegetable fats to closelymimic the fatty acid distribution inhuman milk fat. "This triglyceridecan only be made with the use of a1,3-specific lipase. by reacting tri-palmitin with unsaturated fattyacids," according to Quinlan andMoore. This product currently isunder commercial development foruse in infant formula under the tradename Betapol.

677

Interesterification researchResearch on interesterifying fats andoils continues as the industry contem-plates possible changes in product For-mulations.

Engelhard laboratories. forinstance, are working on alternate cal-alysts to the widely used homoge-neous catalyst, sodium methylate. forchemical interestenfication.

Meanwhile, at NCAUR, List andcolleagues have randomly interesteri-fied liquid vegetable oils throughchemical interesterification usinghydrogenated soybean and cottonseedhardstocks. This has resulted in blendsof liquid (80%) and solid rriglycerides(20%) with plasticity curves similar tocommercial tub margarine oils pre-pared by blending hydrogenated hard-stocks. They also have shown thaiblending an interesterified basestock:with additional liquid oil results in aproduct with plasticity and meltingpoint suitable for shortening formula-tions.

List originally conducted inter-esterification trials during the 19708 tocreate zero trans fats as a result ofconcerns that dietary trans fatty acidsmight be linked to atherosclerosis.Although those trials were successful,the work was dropped. Promptingrevival of this research were advancesin genetic engineering that promisefuture availability of soybean lineswith altered fatty acid composition.including increased saturated fattyacid content. according to List.

"A lot of these products may endup in margarines in the future," hesaid.

The goal of this latest work hasbeen to build a database characteriz-ing the structures, including the solidfat indices and melting points, result-ing from interesterifying liquid oilswith hydrogenated hardstccks. In thefuture, high palmitic or high stearicsoybean oil might substitute for thefully hydrogenated hardstocks, Listsaid.

At the University of Lund, H.M.A.Mohamed and colleagues have con-ducted studies to produce margarinefat without trans fatty acids by enzy-matic interestenficaucn of cottonseedoil and fully hydrogenated soybeanoil.

"Exploitation of the varying speci-ficities of different ttpases permitsproduction of a variety of desirableglyceride mixtures that are unobtain-able using conventional chemicalinteresterification processes," theywrote in the November 1993 issue ofFeu Wissenschaft Technologie. They

ever, the amounts of free fatty acidsformed when a lipase is used the firsttime are higher than those formed onrepeated use or after the initial stabi-lization period in a continuous columnprocess. Free fatty acid formation canalso be decreased by operating atlower temperatures or by drying theenzyme preparation and substratefeedstock before use," they wrote.

In a follow-up article published inthe February 1994 issue of Feu Wis-senscnoft Technolagie, Mohamed andK. Larsson, also at the University ofLund, summarized findings concern-ing crystallization behavior and func-tional properties of cottonseed oilinteresterified with fully hydrogenatedsoybean oil by tipases. "The moststriking effect was an increase in therelative stability of the p'-crystal formby interesterificalion, indicating possi-bilities for margarine production with-out trans fany acids:' they wrote.

At the University of Saskatchewan,McCurdy also has made margarinestock using fully hydrogenated palmstearin as well as high erucic acidrapeseed sreertne via enzymatic inter-esterification.

Meanwhile, at the University ofGuelph, John deMan and France Chohave carried out chemical interesterifi-calion and enzymatic interesterifica-lion using hydrogenated canota oiland palm stearin. Some of their find-ings with chemical interesterificationwere published in the Journal of FoodLipids during 1993. Other findingswith enzymatic interesterification areslated to be published in ELAE1S.

"There is an increasing tendency toproduce margarines with higher levelsof unhydrogenated oils. This meansthat the crystal network has to holdlarge amounts of liquid oil," deMansaid.

Cho and deMan have used partialchemical interesterification 10 producesoft margarine formulations with lowIrons content containing 50-70% liq-uid oil. They selected blends of liquidcanola oil as well as hydrogenatedcanola oil and palm stearin for theirexperiments. "You need to make surethe hard components are interesteri-fied to the consistency you need, andthen add the liquid oils," deMan said.adding, "I don', see any drawbacks. If

"There is. .an increasingtendency

to producemargarineswith higher

levels ofunhydrogenated

'l "01 S.

-deMan

noted that chemical interesterificationhad been used to produce zero-rzensmargarines in previous studies.

The Lund researchers said inter-esterification of fats always causesdiglyceride formation, "as diglyc-erides are intermediates in the reac-tion. The high content of diglyceridesis expected to delay crystallizationand lower the solid fat content of theinreresterified fat." However. theynoted. L. Hemqvist and K. Anjouhave used diglycerides to stabilize theW polymorph in margarine containinghydrogenated rapeseed and soybeanoils. "Thus the presence of diglyc-erides produced in the enzymatic reac-tion can be an advantage in the com-mercial production of margarine fatstock," they wrote.

A disadvantage was 4-6% freefuny acid content, which rnust beremoved from interesterified fatstocks to be used in margarine. "How-

INFORM. Vol. 5. no. 6 (June 1994)

678

FATMODIFICAnON

Fat modification to be discussedIndustry representatives said the issue of fat modification will continue 10be of great interest to companies. One opportunity for discussing it willbe a workshop entitled "Developing and Processing Vegetable Oils forHuman Nutrition:' to be held Oct. 2-3. 1994. in Winnipeg, Canada. TheCanadian Section of the American Oil Chemists' Society is organizingthe workshop.

Hastert, Mag and McCurdy will be among the speakers. Topics willinclude the physiological effects of dietary trans isomers and saturatedfatty acids, as well as hydrogenation and interesterification. For moredetails on the workshop. contact W.W. Riley Jr .. Canola Council of Cana-da. 400-167 Lombard Ave., Winnipeg. Manitoba R3B OT6. Canada (fax:204-942-1841).

you can hydrogenate. you can inter-esterify."

deMan also has looked at the per-formance of enzymatic imeresterifica-tion. Its chief advantage over chemicalinteresterification is one can direct thefatty acids to specific positions. How+ever, disadvantages are that it gener-ates some free fatty acids and partialglycerides. and it also is more expen-sive.

In India, interesterification ofblends of fully hydrogenated rice branoil and rice bran oil has producedplastic fats suitable for zero-transmargarines, according to Ajit Joshi, inan article in the April-June 1993 issueof The Journal of the Oil Technolo-gists' Association of India.

"This type of margarine made frominteresterified products does not havetrans isomers, and a large amount ofliquid oil can be incorporated inthem." Joshi wrote.

The trans dilemmaIndustry representatives agreed thatthe controversy over frons fauy acidsin the diet has forced companies toconsider making changes. However. atleast in Canada, it is hydrogenationthat is under attack, according toTheodore Mag of T. Mag/Associates,Consulting.

"Here in Canada. marketing depart-ments have determined the word'hydrogenated' should be avoided.Consumers don't understand that fullyhydrogenated means there are no transfatty acids. They believe that anything

hydrogenated is bad for them. Compa-nies want to be able to get away fromany mention of hydrogenated fat onproduct labels," Mag said. noting thatas in the United States. labels in Cana-da must stale whether the oil has beenhydrogenated.

The large companies, exceptUnilever-owned Thomas 1. Lipton,Mag said, "seem 10 be silting andwaiting." Several smaller companiesin Canada. however. have introducednonhydrogenated soft margarinesthat use fractionated palm and/orpalm kernel oil in the formula forhardening. These include Nuvel mar-keted by Thibault, Mirage Crystalfrom Mirage Margarina Ltd. andnon hydrogenated margarine fromJ.E. Bergeron & Fils.

CanAmera Foods is supplying oilblends and the actual formulations forthese companies. "They asked us tocome up with formulations usingunhydrogenated oils," according toGeorge Ctenzos. quality assurancemanager for CanAmera Foods.

The Nuvel product contains 60%canola, 27% soybean and 13% modi-fied palm oil. The Mirage Crystal con-tains 51% canola, 34% soybean and15% modified palm oil. Bergeron'snonhydmgenared margarine, which ismainly canola oil but also contains 2%palm kernel oil and modified palm oil.is the cheapest formulation.

Ault Foods, meanwhile, has devel-oped a ncnhydrogenated soft mar-garine now marketed by its Lactantiasection under the name Olivina. This

also uses an oil blend provided byCanAmera. Ollvlna is a more expen-sive product because it containsrefined olive oil, high-oleic sunfloweroil. regular sunflower oil and canotaoil as well as palm and palm kerneloil.

Other soft margarines marketed asnonhydrogenated in Canada includePresident's Choice from Loblaw,Golden Gale and Fleischmann's.

Products deviating from the Becelformulation, which uses largeramounts of palm kernel oil, may notbe equal in quality, Mag said. "Uyoucut down palm kernel in the formula-tion. you cut quality as well," hesaid.

The Irons issue, Mag and Hastenagreed, is far from resolved.

"Currently. if you want a productwith a certain functionality, you haveto interesterify or hydrogenate or youuse a natural saturated fat such aspalm or coconut oil. Then the questionis, do you want a saturated fat or a fatwith frons isomers?" Hasten pointedout.

"There is some indication thattrans have some harmful effects, butnOI as harmful as saturated fat. Mea-suring the long-term health effects isvery difficult. People, however. likethings black or white. They like toask, 'Is this good for me or bad forme?' The old standby answer of mod-eration is probably what's best. It'sprobably not which fat you eat buthow much fat," Hasten said.

KFI's Michael Erickson notedthat pursuing low-trans technology"has limited long-term potential. Thegeneral public will recognize theword 'hydrogenated' as being thesource of yet another percei vedhealth risk. For other-than-liquidapplications. and if tropical fats arenot an option. co-interesterifiedblends of liquid oil and fully hard-ened oil are the only practical alter+native. However, labeling lawsrequire that hydrogenated oil bedeclared even though a product likethis contains no trans fatty acids--orat least not nutritionally significantamounts. This makes crop technolo-gy the only remaining alternative forachieving a domestic nonhydro-genated fat." •

INFORM. Vol. 5. no. 6 (June 1994)