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Topics for Today  What is a trans fat?. Readings For Today (Review)  11.3 Fat & Oils: Part of the lipid family  11.4 Saturated and Unsaturated Fats.

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Presentation on theme: "Topics for Today  What is a trans fat?. Readings For Today (Review)  11.3 Fat & Oils: Part of the lipid family  11.4 Saturated and Unsaturated Fats."— Presentation transcript:

1 Topics for Today  What is a trans fat?

2 Readings For Today (Review)  11.3 Fat & Oils: Part of the lipid family  11.4 Saturated and Unsaturated Fats & Oils

3 Topics for Friday  “Acid” Rain  Quiz 10

4 Topics  pH and acid rain  Effects of acid rain  SO 2 and NO x revisited

5 Readings for Friday  6.4 Introducing pH  6.5 Measuring the pH of rain  6.6 In search of the extra acidity

6 Readings for Friday  6.7 Sulfur dioxide (review)  6.8 Nitrogen oxides (review)  6.9 SOx and NOx  6.10 Acid deposition and its effects on materials

7 Announcements! Exam #3 regrades Please have to me by Friday!

8 Announcements! Exam 4 next Friday (May 4)!! Optional!

9 Topics for Today  What is a trans fat?

10 Topics for Today  What is a trans fat? What is a fat?

11 Fatty Acids + Alcohol Triglyceride + Water H+H+ ThreeTriple FatsOils A triple ester!

12 Figure 11.8 (p. 497) Figure 11.8 (p. 497)

13 Figure 11.8 (p. 497) Figure 11.8 (p. 497)

14 Butter 29% Palmitic Acid 9% Stearic Acid 31% Other Saturated About 69% saturated fat! Very high level of saturation!

15 In general…  Saturated fats = Solid (Crisco, lard) WHY?

16 Saturated fatty acids pack better!

17 In general…  Saturated fats = Solid (Crisco, lard)  Animals usually have more saturated fatty acids than plants  Unsaturated fats = liquids

18 Whale blubber 10-20% palmitic acid 2-5% stearic acid 5-10% other fatty acids ~ 25% saturated fatty acids Medium level of saturation

19 Speaking of whales…

20 What do you do with a dead 8 ton, 45 foot whale that beached itself? In 1970…

21

22 Video!  “The infamous exploding whale.”

23 “’It went just exactly right,’ Thornton said. Except the blast funneled a hole in the sand under the whale.” “Where the whale had been, there was a large hole”

24 A small boy ran down the beach ahead of his father. “Look,” the boy cried. “A piece of the whale.”

25 After the large pieces had fallen, it began to rain small particles of foul-smelling blubber. Many in the crowd ran for their cars and drove away. But they wouldn’t be rid of the nauseating odor until they bathed and washed their clothes and cars. Where did the odor come from?

26 1) Amines! Putrescine Cadaverine Products from the breakdown of amino acids

27 2) Rancid fats! Oxidation of fatty acid chains…

28 A colorless, odorless, tasteless gas Oxygen, O 2 Reacts with fatty acids Mainly the unsaturated ones WHY?

29 Fats going rancid Double Bond = Reactive!

30 Oxygen and ROS will help “split” the fatty acid at the double bond Creates two smaller carboxylic acids!!

31 Carboxylic Acids!!  Propanoic Acid (Propionic Acid)  CH 3 CH 2 COOH Limburger cheese smell… C OH O CH 2 CH 3

32 Butanoic Acid (Butyric Acid) Rancid Butter C OH O CH 2 CH 3

33 Butyric Acid Locker Room Smell C OH O CH 2 CH 3

34 Unsaturated fats go rancid quicker than saturated. Reactive!!

35 How do we remove the double bond? The same goes for the products in our kitchen!

36  Hydrogenation – The process of adding hydrogen to a double bond. Creates a saturated molecule from an unsaturated one!

37  Hydrogenation – The process of adding hydrogen to a double bond. Creates a saturated molecule from an unsaturated one!

38 Review! Same as with crude oil!

39 Hydrogenation of ethylene C = C H HH H + H2H2 catalyst C H H HH HH EtheneEthane

40 Hydrogenation of propylene C = C H HCH 3 H + H2H2 catalyst C C H HH HH H H H PropenePropane

41 Hydrogenation of a fatty acid C = C HH + H2H2 catalyst C HH HH C O OH C O Complete hydrogenation !

42 catalyst H 2 + (Oleic Acid) (Stearic Acid)

43 Hydrogenation H 2 + unsaturated fatty acid  saturated fatty acid (usually oil)(usually fat)

44 Why hydrogenate foods?

45 Butanoic Acid (Butyric Acid) C OH O CH 2 CH 3 1) Longer shelf-life!

46 Margarine contains “partially hydrogenated soybean oil.” 2) More spreadable!

47 NOT HydrogenatedHydrogenated

48 NOT HydrogenatedHydrogenated Peanut Oil!

49 NOT HydrogenatedHydrogenated More unsaturated fat (healthier)

50 Hydrogenation H 2 + unsaturated fatty acid  saturated fatty acid (usually oil) “Good” Fats (usually fat) “Bad” Fats Why make the food less healthy?

51 NOT HydrogenatedHydrogenated More unsaturated fat (healthier) Longer Shelf- Life (won’t go rancid as fast) More spreadable More saturated fat Has Trans Fats!

52 Propylene (Propene) CC HH3CH3C HH CC HH CH 3 H Same or different?

53 Butylene (Butene) CC CH 3 H3CH3C HH CH CH 3 Expand! CC HH3CH3C CH 3 H Same or different?

54 CC CH 3 H3CH3C HH CC HH3CH3C H Cis / Trans Isomers! cis-2-butene trans-2-butene

55 Cis / Trans Isomers  Need a double bond cis = groups on SAME side of double bond trans = groups on opposite side of double bond

56 Cis / Trans isomers  Unlike the isomers we have seen before…  The atoms are connected the SAME way, but the structures are still DIFFERENT!!!

57 CC CH 3 H3CH3C HH CC HH3CH3C H Cis / Trans Isomers! cis 2-butene trans 2-butene Different structure = different properties!!!

58 1-butene CH 2 CHCH 2 CH 3 Write out all possible forms CC CH 2 CH 3 H HH cis or trans? Neither!!!

59 New isomer? C = C H CH 3 H YES!!! cis or trans? NEITHER !

60 Isomers of butene (C 3 H 6 ) (non ring) CC CH 3 H3CH3C HH CC HH3CH3C H cis 2-butene trans 2-butene CC CH 2 CH 3 H HH 1-butene C = C H H3CH3C H H3CH3C

61 Cis / Trans isomers  Unlike the isomers we have seen before…  The atoms are connected the SAME way, but the structures are still DIFFERENT!!!

62 Cis / Trans isomers  Unlike the isomers we have seen before…  The atoms are connected the SAME way, but the structures are still DIFFERENT!!!  There MUST be a non-hydrogen group on EACH carbon with the double bond

63 Hydrogenation of a fatty acid C = C HH + H2H2 catalyst C HH HH C O OH C O Complete hydrogenation ! Partially Hydrogenate d?

64 Hydrogenation of a fatty acid C = C HH + H2H2 catalyst C O OH Partially Hydrogenate d?

65 Partially Hydrogenated... C HH HH C O OH OR… C = C H H C O OH Saturated fatty acid trans fatty acid

66 Unsaturated Fats C = C HH C O OH VS C = C H H C O OH cis trans Straight Chain… Packs like a saturated fatty acid!

67 Concerns of trans fats?

68 Saturated Fats  Occur naturally  Increase “bad” cholesterol (LDL) Increase of plaque in arteries (leads to atherosclerosis)

69 Trans Fats Double Whammy!  Occur naturally in very small amounts  Increase “bad” cholesterol (LDL) Increase of plaque in arteries (leads to atherosclerosis)  Decrease “good” cholesterol (HDL)


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