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Fats and Fat Substitutes

Fats and Fat Substitutes. What are lipids Function of fats Production of fats and oils Fatty acids-classification Classification of fats and oils Crystallization and melting point Smoke point Saponification and Iodine values Fat substitutes. Asparagus 0.25 Avocado 18

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Fats and Fat Substitutes

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  1. Fats and Fat Substitutes • What are lipids • Function of fats • Production of fats and oils • Fatty acids-classification • Classification of fats and oils • Crystallization and melting point • Smoke point • Saponification and Iodine values • Fat substitutes

  2. Asparagus 0.25 Avocado 18 Walnut 58 Peanut 49 Milk 3.5 Butter 80 Cheese 34 Soybean 17 Coconut 34 Oats 4.4 Rice 1.4 Barley 1.9 Hamburger 30 Beef 10-30 Chicken 7 Ham 31 Cod 0.7 Herring 12.5 Fat content of some foods [%]

  3. Lipids • Sterols and sterol esters (sterol , fatty acid) • Mono, di, triglycerides (glycerol , fatty acids) • Waxes (fatty alcohol,fatty acid), ether esters (fatty acids,fatty acohols,glycerol ), glyceryl ether (glycerol, fatty alcohols] • Phospholipids: Plasmologens, Phosphatidyl esters, Sphingomyelin. (phosphoric acid, amino alcohols, fatty acids, glycerol, fatty aldehydes, sphingosine]

  4. Fatty acids • Short chain - 4-10 carbons ; examples: butyric acid (4 :0]; caprylic acid (8 :0]; capric acid [10 : 0] . • Medium chain - 12-14 carbons; examples: lauric acid [12 : 0]; myristic acid [14:0]. • Long chain > 14 carbons; examples: palmitic acid [16 : 0] ; Linolenic acid [18 : 3];

  5. Fatty Acids • Saturated • Unsaturated • monounsaturated - one double bond (oleic acid, palmitoleic acid} • polyunsaturated [PUFA] - two or more double bonds [linolenic acid -18:3; arachidonic acid-20:4 ; eicopentaenoic acid EPA -20:5; docosahexaenoic acid DHA - 22:6]

  6. Omega Fatty Acids Structures

  7. ω–3 PUFA • Essential fatty acids formed in plants (-linolenic acid, ALA, C18:3 ω –3), fish and algae (Eicosapentanoic Acid, EPA, C20:5 ω –3 and Decosahaxaenoic Acid, DHA, C22:6 ω –3) • Aquatic derived lipids are found in high concentrations in the bodies of fatty fish (tuna, salmon, mackerel, etc.), liver of lean fish and the blubber of aquatic mammals • Conversion of linolenic acid (ALA) to DHA in mammals is small, ~ 2%

  8. Omega-3 PUFA Content of Common Animal Products

  9. Possible Health Benefits of PUFA • Prevention of cardiovascular diseases • Lowering blood pressure and triglyceride level • Prevention of certain cancers • Mental health • Normalization of immune system • Weight regulation

  10. DHA milk in Canada • In 2003 Health Canada announces that it has no objection to the sale of a milk, herein referred to as "DHA milk", and dairy products made from this milk, having a docosahexaenoic fatty acid (DHA) content resulting from the use of a specially formulated dairy cattle feed. • The DHA milk would contain 10 mg and 16 mg of DHA per 250 mL serving for 2% milk and whole milk, respectively • Under the Nutrition Labelling Regulations, the amount of DHA, per serving, cannot be indicated in the Nutrition Facts table but it can be indicated anywhere outside of this table, in grams per serving (e.g. "0.016 g DHA per 250 mL serving"), • In 2006 Health Canada approved DHA omega-3 products produced by Martek Biosciences Corporation for use as food ingredients in most foods. The approval allows for per serving levels of not less than 8 mg and not more than 100mg of Martek's DHA.

  11. Products containing DHA

  12. Lipids • Saponifiables (mono, di, triglycerides, phospholipids) • Unsaponifiables [sterols, terpenic alcohols, hydrocarbons, aliphatic alcohols]

  13. Chemical structures of glycerides • Triglyceride • Diglyceride • Monoglyceride

  14. Sterol Structures Campesterol FA FA Cholesterol β-Sitostanol FA Fatty acid ester β-Sitosterol

  15. Unsaponifiables • Squalene • Terpenic alcohol

  16. Classification of Edible Lipids • Fats • Oils • Visible • Invisible

  17. Function of fats • Flavour • Tenderization • Leavening • Emulsion ingredient • Frying medium

  18. The purchase of oil and fat is affected by: • Individual preferences • Intended use • Special dietary needs • Costs

  19. Fats are important in our diets because they: • are a source of essential fatty acids • are source of energy • are necessary for the palatability in the diet • delay emptying rate of the stomach • are necessary as carriers for fat soluble vitamins

  20. Overall acceptability of beef patties based on fat content

  21. Production of Fats and Oils • Rendering • Pressing • Solvent Extraction

  22. Rendering (Animal fats) • Dry heat rendering • Wet heat rendering • Low temperature rendering

  23. Steps involved wet rendering • Fatty tissue • Heating in hot water/steam • Separation of fat • Removal of residual water from fat • Deodorization of fat

  24. Steps involved in dry rendering • Fatty tissue • Heating under vacuum to evaporate water • Filtration of liquified fat • Deodorization fat

  25. Steps involved in low temperature rendering • Fatty tissue • Grinding • Liquefying fat under mild heat • Separation of fat • Deodorization of fat

  26. Pressing/Expelling • Grinding or cracking • Cooking • Pressing/ Expelling • Cold pressing - uncooked seeds. This process is used for specialty oils. • Crude oils

  27. Vegetable oil expeller

  28. Solvent Extraction • Grinding or cracking seeds • Cooking & pressing • Solvent Extraction (hexane) • Evaporation of solvent • Crude oil

  29. Typical oil extraction yield/100kg of seeds Cotton Seed 13 kgMustard 35 kgPalm Kernel 36 kgPalm Fruit 20 kgRapeseed 37 kgSesame 50 kgSoybean 14 kgSunflower 32 kg

  30. Edible oils refinery process steps: • Degumming • Refining • Bleaching • Deodorization • Hydrogenation • Interesterification

  31. Degumming • Water degummingRemoval of phosphatides in seed oils via centrifugal separation, after precipitation with water. A commonly applied pre-treatment prior to further acid degumming. • Acid degummingRemoval of gums and impurities via centrifugal separation after precipitation with acid and water. Commonly applied for low grade oils. • Special degummingRemoval of gums and other impurities via centrifugal separation, after precipitation with acid and water. Applied mainly as starting phase in physical refining of seed oils.

  32. Other processing Bleaching - removal of color pigments, oxidized components and residual gums via absorption in bleaching clay or other absorbents, followed by separation of the spent absorbent. Refining - removal and recovery of substantial quantities of free fatty acids during physical refining. Through the removal of volatile impurities this process also results in deodorization. Deodorization- removal and recovery of residual free fatty acids and other volatile impurities via vacuum steam distillation. The heat treatment also produces a bleaching effect.

  33. Vegetable oil deodorizer

  34. Interesterification • Changes the position of fatty acid radicals on the glycerides. • In the presence of alkaline catalysts (sodium methoxide or alloy of sodium and potassium] and at temp above melting point fatty acids move between hydroxyl position. This results in a new product with a random distribution of fatty acids. • The reaction is used by industry to modify crystallization behavior and the physical properties of fat.

  35. Interesterification S-S-S + 0-0-0  S-S-S S-O-S O-S-S S-0-0 O-S-O 0-0-0 (12.5%] [12.5%] [25%] [25%] [12.5%] [12.5%]

  36. Interesterification (Examples) • Lard has a narrow plastic range, creams poorly and gives poor volume cakes. After interesterification can be used as shortening. • Interesterification of fats with simple acetates and butyrates gives a waxy and translucent material that can be used as edible protective coating and plasticizer. • Fats in presence of a large excess of glycerol produce a mixture of mono, di and triglycerides that after removal of glycerol is used as emulsifying agent in foods.

  37. Hydrogenation • Hydrogenation -addition of hydrogen to a double bonds of unsaturated fatty acids in the presence of catalyst (Nickel, organometallic compounds. • It permits to convert liquid oil into plastic fats for production of margarine and shortenings.

  38. Hydrogenation may be: • Selective -hydrogen is added to the most unsaturated fatty acids. Selectively hydrogenated oils a more resistant to oxidation. • Nonselective • Selectivity is increased by increasing hydrogenation temperature • Selectivity is decreased by increasing pressure and agitation.

  39. Hydrogenation may results in the formation of positional and geometric (trans] isomers: Oleate    Stearate Iso Oleate  Iso linoleate  Linolenate  Linoleate  Iso Oleate  Stearate   Conjugated dienes   ____________________________

  40. Edible Fats • Margarine • Shortening • Butter

  41. Fats and Oils are classified into following groups: • Linolenic acid • Oleic-linoleic acid • Lauric acid • Erucic acid • Vegetable butters • Milk fats • Animal depot fats • Marine oils

  42. Linolenic acid group: • Oils of this group contain appreciable amount of linolenic acid. Example: Soybean oil. • This oils are highly susceptible to oxidation Off flavors are described as grassy, painty or fishy. • Unhydrogenated oils may be used in mayonnaise and salad dressings. • Partially hydrogenated oils are used in production of shortening, margarines, salad dressings.

  43. Linolenic-Oleic acid group: • This group contains a fair amount of oleic and linoleic acids; fewer problems with flavor reversion. • Examples: cottonseed oil, olive oil, palm oil, peanut oil, safflower oil, sunflower oil. • Application: cooking and frying oils, in mayonnaise, salad dressings,

  44. Olive oil • 1300-2000 olives are needed to make a quart of oil. • The term “virgin oil” applies to oils obtai -ned from the first pressing and not subjected to any other processing. • The term “Extra virgin” applies to oils with acidity less than 1% • Term “pure” applies to refined oils and to blends of refined and virgin oils.

  45. Lauric acid group: • The most saturated edible oils. • They are made predominantly of lauric acid and contain smaller amounts of C8, C10, C14 and C18 fatty acids. Solid and ambient temperature and melt over a narrow range 24-27 C. • Examples: Coconut oil, palm kernel oil • Susceptible to hydrolytic rancidity (in the presence of water or lipase) • applications: frying oils, spray coatings for cereals and crackers.

  46. Erucic acid group: • Mustard, rapeseed, canola oils • Oil may contain up to 40-55% erucic acid [22:1w9] unsaturated fatty acid • canola oil contain no more than 2% of erucic acid and is 94% unsaturated . The most unsaturated of all vegetables oils. It is considerably high in oleic acid. • Dressings, margarines, shortenings.

  47. Canola plant

  48. Canola seeds

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