Fatty acids and triglycerides

1. Triglycerides and Chemistry of Fatty acids CHM4201:SPECIAL TOPIC IN ORGANIC CHEMISTRY Group Members: Nur Fatihah binti Abas (154120) Faridah binti Sulaiman (154603) Wan Fatihah Nasuha binti Wan Nor (154115) Lecturer’s Name: Prof. Mawardi Rahmadi

2. Learning outcomes: To understand about fatty acid and triglycerides. To know the physical and chemical properties of fatty acid and triglycerides. To distinguish between fatty acid and triglycerides.

3. Fatty Acids Long straight-chain carboxylic acids no branching Most common chains range from 10–20 carbons in length Usually, an even number of carbons in the chain, including the carboxyl carbon Can be saturated or unsaturated, but usually no other functional groups present Any fatty acid that cannot be synthesized by the body is called an essential fatty acid

4. Structure of fatty acids A fatty acid is nothing more than a long C-H chain with a carboxyl group (COOH) on the end . The COOH gives it an acid property . The 3….dots represent the chain is very long.

5. Physical Properties of Fatty Acids Solubility >Longer chains more hydrophobic, less soluble. >Double bonds increase solubility. Melting points Depend on chain length and saturation Double bonds lead chain disorder and low melting temperature. Unsaturated FAs are solids at Room Temperature.

6. Fatty Acids The most common fatty acids. Higher mp Lower mp

7. Types of fatty acids

8. Medium-chain Fatty Acid (6-10 carbons) Long-chain Fatty Acid (12 or more carbons) Short-chain Fatty Acid (less than 6 carbons) The Length of the Carbon Chain

9. Saturated and Unsaturated FAs Saturated FA s have no double bonds. ( C-C) Double bonds lower the melting temperature Unsaturated FA s have at least one double bond (C=C) in one of the fatty acids

10. Saturated Fatty Acid All single bonds between carbons

11. Monounsaturated Fatty Acid One carbon-carbon double bond

12. Polyunsaturated Fatty Acid More than one carbon-carbon double bond

13. Structure Stearic acid : a typical saturated fatty acid with 18 carbons in the chain Oleic acid : a typical un saturated fatty acid with 18 carbons in the chain

14. Cis -fatty acid : H’s on same side of the double bond; fold into U-like formation; naturally occurring. Trans-fatty acid : H’s on opposite side of double bond; more linear ; occur in partially hydrogenated foods

15. Location of Double Bonds Polyunsaturated fatty acid (PUFA) are identified by position of the double bond nearest the methyl end (CH 3 ) of the carbon chain; this is described as a omega number . If PUFA has first double bond 3 carbons away from the methyl end => omega 3 FA 6 carbons from methyl end => omega 6 FA

16. Omega-3 Omega-6

17. Fatty Acid Nomenclature Nomenclature reflects location of double bonds Also used are common names ( e.g : oleic, stearic, palmitic ) Linoleic is also known as 18:2 n-6 This means the FA is 18 carbons in length, has 2 double bonds, the first of which is on the 6th carbon Arachidonic => 20:4 n-6

18. Classification and Structure-Saturated Fatty Acids Common Name Systematic Name Formula Butyric acid n- butanoic Caproic acid n- hexanoic Caprylic acid n- octanoic Capric acid n- decanoic Lauric acid n- dodecanoic

19. Common Name Systematic Name Formula Myristic acid n- tetradecanoic Palmitic acid n- hexadecanoic Stearic acid n- octadecanoic Arachidic acid n- eicosanoic Behenic acid n- docosanoic Lignoceric acid n- tetracosanoic

20. Naming for Unsaturated FAs 10 9 8 7 6 5 4 3 2 1 Δ 9, 10 - Octadecenoic acid 9 - Octadecenoic acid

21. Common Name of Fatty Acids Common Name Systematic Name Myristoleic 9-tetradecenoic acid Palmitoleic 9-hexadecenoic acid Oleic 9-octadecenoic acid Vaccenic 11-octadecenoic acid Erucic 13-docosenoic acid

22. Chemical Reactions of Fatty Acids Esterification reacts fatty acids with alcohols to form esters and water

23. Fatty Acid Hydrolysis Acid Hydrolysis reverses esterification Fatty acids are produced from esters

24. Saponification Saponification is the base-catalyzed hydrolysis of an ester Products of the reaction are An alcohol An ionized salt which is a soap Soaps have a long uncharged hydrocarbon tail Also have a negatively charged carboxylate group at end Form micelles that dissolve oil and dirt particles

25. Reaction at the Double Bond Hydrogenation is an addition reaction Unsaturated fatty acids can be converted to saturated fatty acids Hydrogenation is used in the food industry

26. Hydrogenation

27. An ester of glycerol with three fatty acids. Also known as triacylglycerols One type of lipid categorised as simple lipid. Triglycerides

28. Structure of Triglycerides Glycerides are lipid esters A triglyceride places fatty acid chains at each alcohol group of the glycerol Glycerol part Fatty acid chains

29. Glycerol Glycerol Always looks the same 3 C’s with 3 OH’s and everything else H’s.

30. Formation of Triglycerides

31. Example of triglycerides Triglyceride derived from one molecule each of palmitic acid, oleic acid, and stearic acid, the three most abundant fatty acids in the biological world .

32. Physical properties of triglycerides Physical properties depend on the fatty acid components . Melting point increases as the number of carbons in its hydrocarbon chains increases and as the number of double bonds decreases. Oils : Triglycerides rich in unsaturated fatty acids are generally liquid at room. Fats : Triglycerides rich in saturated fatty acids are generally semisolids or solids at room temperature .

33. Physical properties of triglycerides Hydrocarbon chains of saturated fatty acids can lie parallel with strong dispersion forces between their chains; they pack into well-ordered, compact crystalline forms and melt above room temperature. Because of the cis configuration of the double bonds in unsaturated fatty acids, their hydrocarbon chains have a less ordered structure and dispersion forces between them are weaker; these triglycerides have melting points below room temperature.

34. Chemical Properties Triglycerides have typical ester and alkene chemical properties as they are composed of these two groups:- Saponification : replace H with salt from a strong base Hydrolysis : produces the fatty acids and glycerol, a reverse of formation Hydrogenation : saturates the double bonds

35. Triglyceride Reactions Triglycerides undergo three basic reactions These reactions are identical to those studied in carboxylic acids Triglyceride Glycerol Fatty Acids Glycerol Fatty Acid Salts More saturated triglyceride H 2 O, H + NaOH H 2 , Ni

36. Hydrolysis

37. Saponification

38. Hydrogenation

39. QUIZ

40. What’s What? Identify the glycerol molecule The fatty acids

41. Thank you