Introducing the Lipids
The term lipids applies to a broad range of organic molecules that dissolve easily in organic solvents such as alcohol, ether, or acetone, but are much less soluble in water.
– Monounsaturated – one point of unsaturation
– Polyunsaturated – two or more points of unsaturation (PUFA)
Saturated versus Unsaturated Fatty Acids
Saturated fats – solid at Fats melt at different room temperature temperatures
② Fats provide most of the energy needed to perform much of the body’s work.
③ Pads of fat surrounding in vital organs serve as shock absorbers.
④ The fat blanket under the skin also insulates that body from extremes of temperature.
⑤ Some essential nutrients are soluble in fat and therefore are found mainly in foods that contain fat.
※Usefulness of fats
in food (P135 key point)
① The energy density of fats makes foods rich in fat valuable in many situations. (P135 Figure 5-2)
feeling full after a meal. P136 Table 5-1
A Close Look at Lipids
Triglycerides (fat) Phospholipids Sterols
Triglycerides: Fatty Acids and Glycerol
95 percent of dietary fat and stored fat Triglyceride – Glycerol + 3 fatty acids
When we say “fat,” we generally mean triglycerides.
※Usefulness of lipid (body and food)
In the body (P134 key point)
① Fat is the body’s chief storage form for the energy from food eaten in excess of need.
Fatty acid
Fatty acids are key building blocks of triglycerides. – Chain length
• Short-chain Fatty Acid (less than 6 carbons) • Medium-chain Fatty Acid (6-10 carbons) • Long-chain Fatty Acid (12 or more carbons)
Saturated versus Unsaturated Fatty Acids
Saturated versus Unsaturated Fatty Acids
Saturated fatty acid – filled to capacity with hydrogen atoms
Unsaturated fatty acid – missing hydrogen
② Fat carries with it many dissolved compounds that give goods enticing aromas and flavors.
③ Fat lends tenderness to foods. ④ Fats provides satiety, the lasting satisfaction of
– Lipids generally are hydrophobic and lipophilic
– Hydrophilic, lipophobic
Lipids in foods and the human body fall into three classes: Triglycerides, Phospholipids, Sterols.
Chapter 5
The lipids Fats, Oils, Phospholipids,
and Sterols
Think about it
How important is fat to the foods you think of as tasty? Can one have too little body fat? What is your take on the difference between fat and cholesterol?
Unsaturated fats – liquids at room temperature
Phospholipids and Sterols
Phospholipid
– Glycerol + two fatty aபைடு நூலகம்ids + phosphorus – Phosphorus part makes it soluble in water – Fatty acids make it soluble in fat – Therefore can serve as an emulsifier – Key role is in cell membranes