Thursday Lecture –Vegetable Oils and Waxes

1. Thursday Lecture –Vegetable Oils and Waxes Reading: Textbook, Chapter 9

2. A Plethora of Peppers “Black Pepper” – Piper nigrum (Asia) “Red Pepper” – Capsicum spp. (Mexico/South America) “Melegueta Pepper” – Aframomum (Africa) “Brazilian (or Pink) Pepper” – Schinus Drupe of member of Anacardiaceae – some people exhibit allergic reaction

3. Quiz • Two different plants both give us a spice called “pepper” – Chili pepper (Capsicum) and Black pepper (Piper) – which is native to the Old World and which to the New World? • Name a major vegetable oil crop. Where is it originally native?

4. Vegetable Oils Figure 9.3, p. 221 Plant oils – mostly acylglycerides Glycerol – 3-carbon “backbone”

5. Vegetable Oils Figure 9.3, p. 221 Plant oils – mostly acylglycerides Glycerol – 3-carbon “backbone” Acyl groups – mostly fatty acids = chain of carbon atoms

6. Triacylglyceride structure Figure 9.3, p. 221

7. Vegetable Oils Figure 9.3, p. 221 Plant oils – mostly acylglycerides • Glycerol – 3-carbon “backbone” • Acyl groups – mostly fatty acids = chain of carbon atoms • Properties of acyl groups: • Length – longer = higher melting point

8. Vegetable Oils Figure 9.3, p. 221 Plant oils – mostly acylglycerides • Glycerol – 3-carbon “backbone” • Acyl groups – mostly fatty acids = chain of carbon atoms • Properties of acyl groups: • Length – longer = higher melting point • Unsaturation – the presence of double-bonds between carbons

9. Vegetable Oils Figure 9.3, p. 221 Plant oils – mostly acylglycerides • Glycerol – 3-carbon “backbone” • Acyl groups – mostly fatty acids = chain of carbon atoms • Properties of acyl groups: • Length – longer = higher melting point • Unsaturation – the presence of double-bonds between carbons • - monounsaturated = has 1 double bond

10. Vegetable Oils Figure 9.3, p. 221 Plant oils – mostly acylglycerides • Glycerol – 3-carbon “backbone” • Acyl groups – mostly fatty acids = chain of carbon atoms • Properties of acyl groups: • Length – longer = higher melting point • Unsaturation – the presence of double-bonds between carbons • - monounsaturated = has 1 double bond • - polyunsaturated = has 2 or more double bonds

11. Vegetable Oils Figure 9.3, p. 221 Plant oils – mostly acylglycerides • Glycerol – 3-carbon “backbone” • Acyl groups – mostly fatty acids = chain of carbon atoms • Properties of acyl groups: • Length – longer = higher melting point • Unsaturation – the presence of double-bonds between carbons • - monounsaturated = has 1 double bond • - polyunsaturated = has 2 or more double bonds • Double bonds  generally lower melting point of compound

12. Triacylglyceride structure Figure 9.3, p. 221

13. Vegetable Oils – The Plant View Why do plants produce oils?

14. Vegetable Oils – The Plant View Why do plants produce oils? Answer: high energy content (caloric value)  compact way to store energy

15. Vegetable Oils – The Plant View Why do plants produce oils? Answer: high energy content (caloric value)  compact way to store energy Where do plants produce and store oils?

16. Vegetable Oils – The Plant View Why do plants produce oils? Answer: high energy content (caloric value)  compact way to store energy Where do plants produce and store oils? Answer: seeds, particularly endosperm or cotyledon(s)

17. Vegetable Oils – The Human View Why do people consume vegetable oils (and other fats)? Box 9.1, p. 222

18. Vegetable Oils – The Human View Why do people consume vegetable oils (and other fats)? Answer: high energy content – we retain a craving for fats that was an advantage for our ancestors at a time when it was difficult to obtain fats Box 9.1, p. 222

19. Vegetable Oils – The Human View • Why do people consume vegetable oils (and other fats)? • Answer: high energy content – we retain a craving for fats that was an advantage for our ancestors at a time when it was difficult to obtain fats • What has changed? • widespread availability of fats/oils Box 9.1, p. 222

20. Vegetable Oils – The Human View • Why do people consume vegetable oils (and other fats)? • Answer: high energy content – we retain a craving for fats that was an advantage for our ancestors at a time when it was difficult to obtain fats • What has changed? • widespread availability of fats/oils • increase in human lifespan •  Revealing health issues in high consumption of fats Box 9.1, p. 222

21. Acylglycerides – Health Issues – Consumption Increasing World Consumption Projected to be up 16% - 1998-2001 Figure 9.2, p. 220

22. Acylglycerides – Health Issues – Consumption Increasing World Consumption Projected to be up 12% - 2006-2011 Figure 9.2, p. 220

23. Acylglycerides – Health Issues – 25% of deaths in U.S. due to heart disease (2007) - #1 cause Box 9.1, p. 222

24. Acylglycerides – Health Issues – 25% of deaths in U.S. due to heart disease (2007) - #1 cause – Correlation between blood cholesterol & heart disease Box 9.1, p. 222

25. Acylglycerides – Health Issues – 25% of deaths in U.S. due to heart disease (2007) - #1 cause – Correlation between blood cholesterol & heart disease – Plants do not produce cholesterol Box 9.1, p. 222

26. Acylglycerides – Health Issues – 25% of deaths in U.S. due to heart disease (2007) - #1 cause – Correlation between blood cholesterol & heart disease – Plants do not produce cholesterol – Correlation – saturated dietary fats  arterial plaque formation Box 9.1, p. 222

27. Acylglycerides – Health Issues – 25% of deaths in U.S. due to heart disease (2007) - #1 cause – Correlation between blood cholesterol & heart disease – Plants do not produce cholesterol – Correlation – saturated dietary fats  arterial plaque formation Conclusion: exchange saturated for unsaturated fats in foods Box 9.1, p. 222

28. Acylglycerides – Health Issues – 25% of deaths in U.S. due to heart disease (2007) - #1 cause – Correlation between blood cholesterol & heart disease – Plants do not produce cholesterol – Correlation – saturated dietary fats  arterial plaque formation Conclusion: exchange saturated for unsaturated fats in foods Problem: polyunsaturated fats  linked to production of free radicals, which are carcinogenic Recommendation: mono-unsaturated fats appear best for health, based on currently available information Box 9.1, p. 222

29. Acylglycerides – Health Issues – 25% of deaths in U.S. due to heart disease (2007) - #1 cause – Correlation between blood cholesterol & heart disease – Plants do not produce cholesterol – Correlation – saturated dietary fats  arterial plaque formation Conclusion: exchange saturated for unsaturated fats in foods Problem: polyunsaturated fats  linked to production of free radicals, which are carcinogenic Recommendation: mono-unsaturated fats appear best for health, based on currently available information Problem: saturated fats “taste” better Box 9.1, p. 222

30. Trans Fats Saturated fats (animal fats, tropical vegetable fats)  link to heart disease

31. Trans Fats Saturated fats (animal fats, tropical vegetable fats)  link to heart disease Polyunsaturated fats  vegetable oils, liquid at room temp.

32. Trans Fats Saturated fats (animal fats, tropical vegetable fats)  link to heart disease Polyunsaturated fats  vegetable oils, liquid at room temp. Hydrogenation – bubble hydrogen gas through vegetable oil, increases the saturation

33. Trans Fats Saturated fats (animal fats, tropical vegetable fats)  link to heart disease Polyunsaturated fats  vegetable oils, liquid at room temp. Hydrogenation – bubble hydrogen gas through vegetable oil, increases the saturation Completely saturated  hard, like wax – not useful

34. Trans Fats Saturated fats (animal fats, tropical vegetable fats)  link to heart disease Polyunsaturated fats  vegetable oils, liquid at room temp. Hydrogenation – bubble hydrogen gas through vegetable oil, increases the saturation Completely saturated  hard, like wax – not useful Partial saturation  creamy consistency, useful for spreads also more chemically stable, longer shelf life

35. Trans Fats Saturated fats (animal fats, tropical vegetable fats)  link to heart disease Polyunsaturated fats  vegetable oils, liquid at room temp. Hydrogenation – bubble hydrogen gas through vegetable oil, increases the saturation Completely saturated  hard, like wax – not useful Partial saturation  creamy consistency, useful for spreads also more chemically stable, longer shelf life Problem – creates trans type of bonds – health problems

36. Omega 3, Omega 6 fats “Omega n” – refers to position of double bond relative to methyl end of fatty acid Required in human diet – omega 3, omega 6 types Associated with health benefits

37. Extraction of Vegetable Oils Figure 9.6, 9.7, p. 227 • Basic Approaches • Mechanical Extraction • - cold pressing means no heat applied • - hot pressing means external heart is applied • Note: screw press now widely used – allows continuous processing and separation of residual “cake”

38. Extraction of Vegetable Oils Figure 9.6, 9.7, p. 227 • Basic Approaches • Mechanical Extraction • - cold pressing means no heat applied • - hot pressing means external heart is applied • Note: screw press now widely used – allows continuous processing and separation of residual “cake” • Solvent Extraction • - organic solvent (e.g. hexane) • Notes: more efficient (less oil left behind) but requires processing because solvent must be removed

39. Processing of Vegetable Oils Figure 9.8, p. 229 Refining: use alkali to remove free fatty acids Degumming: extraction with water to remove mucilaginous material Bleaching: removal of pigments that produce color Deodorizing: removal of aromatic compounds through steam heating Winterizing: removal of particles by precipation at low temperature + filtering Hydrogenation: increasing the saturation of fatty acids (use hydrogen gas + catalyst)  raise melting point

40. Common Sources of Vegetable Oils Table 9.4, p. 230-1 • Polyunsaturated • linseed oil (Linum usitatissimum - seeds) • tung oil (Aleurites fordii – seeds) • Unsaturated • Safflower (Carthamus – 1-seeded fruits) • soybean (Glycine max – seeds) • sunflower (Helianthus annuus – 1-seeded fruits) • corn oil (Zea mays – germ) • sesame oil (Sesamum indicum – seeds) • cottonseed oil (Gossypium – seeds) • canola oil (Brassica – seeds) • Moderately saturated • peanut oil (Arachis hypogaea – seeds) • olive oil (Olea europea – fruit pulp)

41. 2005 2007

42. Traditional Vegetable Oil Plants Sesame Oil Linseed Oil - Flax

43. Traditional Oil Crop - Olive Cold Pressing of pulp after seeds removed “extra-virgin” – first press, low oleic acid level – not processed further

44. Traditional Oil Crop - Olive Cold Pressing of pulp after seeds removed “extra-virgin” – first press, low oleic acid level – not processed further “virgin” – first press, higher acid level – not processed further

45. Traditional Oil Crop - Olive Cold Pressing of pulp after seeds removed “extra-virgin” – first press, low oleic acid level – not processed further “virgin” – first press, higher acid level – not processed further “refined” – refining methods used  odor/flavor altered “pure” – mixture of refined and virgin oils

46. Figure 9.21, p. 240 Major Oil Crops - Palm Palm plantation - Thailand Vegetable fat – solid at room temp

47. Major Oil Crops - Soybean

48. Major Oil Crops - Sunflower Figure 9.12, p. 234

49. Major Oil Crops - Canola Brassica napus – “rapeseed”  rape Canada: Canadian oil = Canola

50. Vegetable Oils and Soaps Figure 9.5, p. 223 Hydrolysis of acylglyceride  fatty acids + glycerol Triacylglyceride + alkali (e.g. NaOH – lye)  sodium salt of fatty acid + glycerol + water Soap molecules connect oils with water