Hydrolysis:SaponificationReactions of Triglycerides?Base-catalyzedCH,"OHHydrolysiscleavage of esterH,Oglyceroltriglyceridesdiglycerides, monoglycerides,1linkagesHO-Hglycerol + fattyacids1+1- saponification (base catalyzed)CH2~OH3NPOHOCH2-0-- enzymatic hydrolysis (lipase catalyzed)1- interesterification (randomization)H,O2NOOO-C-RTRHydrogenationHCH2-0一0unsaturated lipidssaturated lipidsN?trans isomersN:Oxidation3 fatty acid saltsHydrolysis: LipasesHydrolysis:Productssn-1.Can also be catalyzed by enzymesR+-hydrolases or lipasesLipases produce small quantities of freeCH2-O-C-R1-found naturallyfattyacidschocolate9in plants and animals- contribute flavors to cheese, milk chocolateR2-C-0-HC:- in vivo digestion cause off-flavors in milk, fruits and vegetablesnsn-3-sn-2-leadtofoamingCH2-0-C-R3. Specific for fatty acid typet- removed during commercial production of food oils?Cleaves sn-1 and sn-3first to form- diacylglycerols + I fatty acidvegetableo1 monoacylglycerols + 2 fatty acids
1 Reactions of Triglycerides • Hydrolysis triglycerides diglycerides, monoglycerides, glycerol + fatty acids – saponification (base catalyzed) – enzymatic hydrolysis (lipase catalyzed) – interesterification (randomization) • Hydrogenation unsaturated lipids saturated lipids trans isomers • Oxidation H2O H2 Hydrolysis: Saponification • Base-catalyzed cleavage of ester linkages glycerol C CH2 CH2 H OH OH HO + C CH2 CH2 H C O O R1 C O O R3 C O O R2 C O O R1 _ 3 fatty acid salts C O O R2 _ C O O R3 _ Na+ Na+ Na+ _ + 3 Na OH H2O Hydrolysis: Lipases • Can also be catalyzed by enzymes – hydrolases or lipases – found naturally in plants and animals – in vivo digestion • Specific for fatty acid type • Cleaves sn-1 and sn-3 first to form – diacylglycerols + 1 fatty acid – monoacylglycerols + 2 fatty acids C CH2 CH2 H C O O R1 C O O R3 C O O R2 sn-1 sn-2 sn-3 Hydrolysis: Products • Lipases produce small quantities of free fatty acids – contribute flavors to cheese, milk chocolate – cause off-flavors in milk, fruits and vegetables – lead to foaming • removed during commercial production of food oils vegetable oil chocolate
LyesoapHydrolysis:Products(high melting point free fatty acids):Fatty acids,monoglycerides and diglyceridesareCarboxyltsurface activegroupWaterLoving produced commercially for food and cleansing materials(hydrophilic)endCH-OH9HCOCH-OHHydrocarbonhydrophobic tailschainO=Oil LovingCC-O(hydrophobic)endhydrophilic headsHistoryofHydrogenationEnergy and Health:MetabolismDuring the late 1800s, as solid fats became increasingly scarceandexpensive,it becamethe dream oftheoil chemiststofindaOHmonoglyceridelipasessolution to the problem of converting oleic acid (a liquid) into00C00cstearic acid (a solid) simply by the addition of hydrogen, so as toOOCOHmakevaluable hardfats fromrelativelyinexpensiverawmaterials like plant oils.OC'O0CItwasin1897twoFrenchfoodchemistsdiscoveredthatthefluidfattyacidconsistency of vegetable oils is due to their having a lower"0chydrogen content than solid fats such as butter,tallow, and lard.fattyacidThey showed that the hydrogenation was a major new chemicaltechnique which could convert plant oils to fats.sn-2chain largely consenved
2 Lye soap (high melting point free fatty acids) Water Loving (hydrophilic) end Oil Loving (hydrophobic) end Hydrolysis: Products • Fatty acids, monoglycerides and diglycerides are surface active – produced commercially for food and cleansing materials C CH2 H OH OH C O O C O O CH2 hydrophobic tails hydrophilic heads _ Energy and Health: Metabolism OOC OOC OOC OH OOC OH monoglyceride - OOC fatty acid - OOC fatty acid sn-2 chain largely conserved lipases History of Hydrogenation During the late 1800s, as solid fats became increasingly scarce and expensive, it became the dream of the oil chemists to find a solution to the problem of converting oleic acid (a liquid) into stearic acid (a solid) simply by the addition of hydrogen, so as to make valuable hard fats from relatively inexpensive raw materials like plant oils. It was in 1897 two French food chemists discovered that the fluid consistency of vegetable oils is due to their having a lower hydrogen content than solid fats such as butter, tallow, and lard. They showed that the hydrogenation was a major new chemical technique which could convert plant oils to fats
SUNLIGHTP&GUnileverSOAPWilliam Procter, a candlemaker, and James Gamble, a soapmakerIn the late 19th Century, at Oss in Brabant, the Netherlands, Jurgens andemmigrated from England and Ireland respectively. They settled in CincinnatiVan den Berghtwo family businesses of butter merchants -have thrivinginitially and met when they married sisters. Their father-in-law called aexport trades to the UK.meeting in which he persuaded his new sons-in-law to become businesspartners. On October 31, 1837, as a result of the suggestion, Procter &Gamble was born.Product innovation, 19th century styleIn the early 1870s, they become interested in a new product made fromThe greatest early potential for the use of hydrogenation lay in the Unitedbeef fat and milk margarine which, they realize, could be mass-States,where a vast production of cottonseed oil was looking for newuses.In1911 Procter & Gamble in Cincinnati began marketing Crisco, the firstproduced as an affordable substitute for butter.hydrogenated shortening, which contained a large amount of cottonseed oil.Later, over in the north of England in the mid-1880s, a successfulLater soy bean oil became the major plant oil used for hydrogenation.wholesale family grocery business run by William Lever starts producing aVegetable shortening, margarine, soap and candles.new type of household soap. The product contains copra or pinekermel oil,Ciscowhich helps it lather more easily than traditional soaps made of animal fats"Soap Box Operas"Unusually for the time, Lever gives the soap a brand name Sunlight andIVORYsells it wrapped in distinctive packs.SNOWSoyBeanOilandHydrogenationUnileverIn1929,"Lever Brothers"and"Margarine Unie"Soy bean oil contains a lot of poly-sign an agreement to create Unilever.Theunsaturated fatty acids (whichmakes it an oil)businesses initially aimedto negotiateanarrangement tokeep out of each other's principal.To make a fat out of soy bean oil, the numberinterestsof soapandmargarineproduction,butof doublebonds must be reduced.ultimately decided on an amalgamation insteadThat is: these unsaturated fatty acids shouldbe saturated with hydrogen!
3 William Procter, a candlemaker, and James Gamble, a soapmaker, emmigrated from England and Ireland respectively. They settled in Cincinnati initially and met when they married sisters. Their father-in-law called a meeting in which he persuaded his new sons-in-law to become business partners. On October 31, 1837, as a result of the suggestion, Procter & Gamble was born. The greatest early potential for the use of hydrogenation lay in the United States, where a vast production of cottonseed oil was looking for new uses. In 1911 Procter & Gamble in Cincinnati began marketing Crisco, the first hydrogenated shortening, which contained a large amount of cottonseed oil. Later soy bean oil became the major plant oil used for hydrogenation. Vegetable shortening, margarine, soap and candles. “Soap Box Operas” Unilever In the late 19th Century, at Oss in Brabant, the Netherlands, Jurgens and Van den Bergh – two family businesses of butter merchants – have thriving export trades to the UK. Product innovation, 19th century style In the early 1870s, they become interested in a new product made from beef fat and milk – margarine – which, they realize, could be massproduced as an affordable substitute for butter. Later, over in the north of England in the mid-1880s, a successful wholesale family grocery business run by William Lever starts producing a new type of household soap. The product contains copra or pine kernel oil, which helps it lather more easily than traditional soaps made of animal fats. Unusually for the time, Lever gives the soap a brand name – Sunlight – and sells it wrapped in distinctive packs. In 1929, “Lever Brothers” and “Margarine Unie” sign an agreement to create Unilever. The businesses initially aimed to negotiate an arrangement to keep out of each other's principal interests of soap and margarine production, but ultimately decided on an amalgamation instead. Soy Bean Oil and Hydrogenation • Soy bean oil contains a lot of polyunsaturated fatty acids (which makes it an oil) • To make a fat out of soy bean oil, the number of double bonds must be reduced. • That is: these unsaturated fatty acids should be saturated with hydrogen!
HydrogenationHydrogenationBythelate1970sroughly60%ofalledibleoilsandfatsintheUSwerepartiallyhydrogenatedAndan estimated75%of thesoyoil used in the USwashydrogenatedtomakeshorteningandmargarine,as wellas largeamountsof lightlyhydrogenatedsoycookingandsaladHydrogerLinsafiratedGasSaturatedMoreover,somesoyoilhaslongbeenhydrogenatedtomakenonfoodproducts,suchasPartiai hydrogenation is intended to saturate some but not all the double bonds ofsoaps.poly-unsaturated fatty acids, and here is were the problem begins...HydrogenationofDoubleBondsHydrogenationandIsomerizationofDoubleBondschemisorptionHeterogeneous catalytic hydrogenationM-CH,-CH=CH-CH2-CH,-CH=CH-CH2-CASinvolvesthreereactions:chemisorption1.Doublebondmigration2.Cis-trans isomerization-CH,-CH=CH-CH2--CH=CH-CH2-CH23.Selective hydrogenation of dienes and trienesCisHcisIsomerization-C-CH-C-CH2-isomerization200°CMigrationHMH-CH=CH- + H,No reaction-CH=CH-CH,-CH,-CH,-CH=CH-CH2-transhydrogenationtrans+ metal catalyst (Ni, Pt, Pd, Cu-Cr)room temp-CH,-CH,-CH,-CH2--CH=CH-+ H2-CH,-CH2
4 Hydrogenation By the late 1970s roughly 60% of all edible oils and fats in the US were partially hydrogenated. And an estimated 75% of the soy oil used in the US was hydrogenated to make shortening and margarine, as well as large amounts of lightly hydrogenated soy cooking and salad. Moreover, some soy oil has long been hydrogenated to make nonfood products, such as soaps. Hydrogenation C C H H + H2 C C H H Unsaturated H H Saturated Hydrogen Gas Partial hydrogenation is intended to saturate some but not all the double bonds of poly-unsaturated fatty acids, and here is were the problem begins. Hydrogenation of Double Bonds Heterogeneous catalytic hydrogenation involves three reactions: 1. Double bond migration 2. Cis-trans isomerization 3. Selective hydrogenation of dienes and trienes 200oC -CH=CH- + H2 No reaction + metal catalyst (Ni, Pt, Pd, Cu-Cr) room temp -CH=CH- + H2 -CH2-CH2- Hydrogenation and Isomerization of Double Bonds M -CH2-CH=CH-CH2- CH2-CH=CH-CH2- H H -C-CH-C-CH2- H M H cis -CH2-CH=CH-CH2- trans chemisorption -CH2-CH=CH-CH2- cis isomerization -CH=CH-CH2-CH2- -CH=CH-CH2-CH2- cis trans Isomerization & Migration -CH2-CH2-CH2-CH2- hydrogenation chemisorption
ConsequencesofHydrogenationofFatsEven more about..Double BondsChange in melting behaviorincrease in saturates and / or trans contentCis doublebondsareformed in natureaffects spreadability,oral response, baking qualitylmprovesoxidativestabilitylesspolyunsaturatedfatTrans double bonds areformed by synthetic chemistryReduced nutritionalvalueprocesses called: HydrogenationDueto trans question raised about effects on coronaryheartdisease:lowerHDL,hiqherLDL-Trans fatty acids formed from"HydrogenationPartially hydrogenated fats can haveareasmuchas35%trans."Artificial"the trans content has to be declared on the label."Synthetic"or"Un-Natural"TYPESOFFATHEALTHTrouncingtransfatNOTRANSFATNYCto restaurants:Notrans fatEFFECYSTransNew York City'sboardothealeCanralsFIisodtoapthe nation's SrsNEWYORK-TheBoardofHealthbanontranetats-hamiful arsficiaoils Phat can bereplacod with otheandlowetingrediantsvotedTuesdaytomakeNewYorkbeneficialgoods:pnsoftranoods,margarineerenadult:Saturatothenation's first cityto banWholemili3%Salad1%Cerose.taymet1%.Candyhigh tiooartery-clogging artificial trans fats(bet,larmb,pork,4%Shoteni40%HELPCENTER5%Chipsat restaurants from the cornerpopoorrUntpizzeria to high-end bakeries.potatoes174AnimatBrodcrackors.oouohum.DsaRestaurants hadto eliminateartificialtransfatsfromalloftheirfoodsbyJuly2008
5 Consequences of Hydrogenation of Fats • Change in melting behavior increase in saturates and / or trans content affects spreadability, oral response, baking quality • Improves oxidative stability less polyunsaturated fat • Reduced nutritional value Due to trans question raised about effects on coronary heart disease: lower HDL, higher LDL Partially hydrogenated fats can have as much as 35% trans. the trans content has to be declared on the label. Even more about. Double Bonds • Cis double bonds are formed in nature • Trans double bonds are formed by synthetic chemistry processes called: Hydrogenation – Trans fatty acids formed from “Hydrogenation” are “ Artificial” “Synthetic” or “Un-Natural” NYC to restaurants: No trans fat NEW YORK - The Board of Health voted Tuesday to make New York the nation’s first city to ban artery-clogging artificial trans fats at restaurants — from the corner pizzeria to high-end bakeries. Restaurants had to eliminate artificial trans fats from all of their foods by July 2008