Lo2- Lipids And Fats 🥓🫒🍕 Flashcards
Are Lipids soluble in water?
No they’re insoluble in water
What are lipids soluble in?
Solvents such as alcohol and ether
What do lipids include?
. Fats (triglycerides)
. Fatty acids
. Waxes + sterols e.g cholesterol
. Also compound lipids ➡️ lipids attached to another chemical compound e.g lipoproteins, glycolipids, phospholipids ( lecithin in egg yolk)➡️ all found in animal or plant cells
When is ‘fat’ + ‘oil’ used?
When discussing food prep+ diet
When is ‘lipid’ used?
When discussing metabolism ( chemical processes) involving fats in body
How much energy is in a gram of fat?
9kcal - most energy dense nutrient ➡️ x2 protein or carbs
Is eating fat essential for the diet?
Yes
What are the functions of fats?
- Concentrated energy source
- Provides fat to keep body warm
- Protects vital organs
- Essential component for cell membranes
- Provides fat soluble vitamins
- Provides essential fatty acids - linoleic acid (omega 6) and alpha linoleic acid (omega 3)
What do fats include?
Fats + oils
What state are fats usually in at room temperature?
Tend to be solid at room temperature
What state are oils in at room temperature?
Tend to be liquid at room temperature
What are the functions of fats in food?
- Enhancing flavour
- Enhancing texture
- Enhancing aroma
- Crispness of food
- Tenderness of food
- Used to enrich food products
What can fats also help with in terms of digestion?
. Gastric emptying as fatty food take longer to digest ➡️ prevent hunger sensations for longer so person feels satisfied + fuller for longer
What is fat divided into?
Saturated + unsaturated fats
Is fat a triglyceride?
Yes
What are triglycerides made up of?
Glycerol + 3 fatty acids
What are fatty acids made up of?
Chains of carbon + hydrogen atoms
How many different fatty acids are there in food?
16
What can fatty acids be broken down into?
Single or double bonds
What are the different types of bonding in fats?
. Saturated
. Mono- unsaturated
. Polyunsaturated
What do saturated fats contain?
Many saturated fatty acids
Do saturated fats have a double bond?
Have no double bonds between carbon atoms in carbon chain
Are saturated fats usually solid at room temperature?
Yes
Are saturated fats very stable?
Yes and they are unlikely to react with other chemicals
What shape do saturated fats have?
Packed closely together due to linear shape ➡️ rigid structure
What are some sources of saturated fats?
. Cheese
. Milk
. Bacon
. Butter
. Coconut oil
Do saturated fats have missing hydrogen atoms?
No
Do unsaturated fats have some hydrogen atoms missing?
Yes
When is formed in unsaturated fats when a hydrogen atom is missing?
A double bond between 2 atoms in the chain
. Bend or curve in otherwise straight carbon chains ➡️ allows movement as cannot be packed together
Are unsaturated fats liquid at room temperature?
Yes
What are the 2 groups of unsaturated fats?
- Mono- unsaturated fatty acids
- Polyunsaturated fatty acids
How many double bonds do mono- unsaturated fatty acids have?
One
. Prefix ‘mono’ means one
What are some sources of mono- unsaturated fatty acids?
. Avocados
. Cashews
. Peanuts
. Olive oil ➡️ oelic acid ➡️ 18 carbon atoms + chains ➡️ one double bond between 9th + 10th atom ➡️ clear liquid at room temp but when chilled may become cloudy + solidify
Is the double bond a weakness for mono- unsaturated fatty acids?
Yes - makes it unstable + unlikely to chemically react
.double bond creates opportunity for oxidation
How many double bonds do polyunsaturated fatty acids contain?
2 or more
. Prefix ‘poly’ means 2 or more
What are some sources of polyunsaturated fatty acids?
. Corn
. Soya
. Sunflower oils
What are polyunsaturated fatty acids most likely to react with?
Oxygen due to double bonds in chain which reduce stability of molecule
. Tend to go rancid when exposed to air + sunlight for long periods of time ➡️ oxidation
. Repeated exposure to high temperatures increase oxidative damage
What can polyunsaturated fatty acids be divided into?
. Omega
. Number for omega indicates location of first double bond at one end of chain
. Essential fatty acids = omega 3 and Omega 6 fatty acids
What are some properties of trans fatty acids?
- Hydrogen atoms on opposite sides of double bonds
- Prefix ‘trans’ means across
- More linear appearance like saturated fats = UNHEALTHY
What are some properties of cis fatty acids?
- Hydrogen atoms both on same side of molecule
- Looks like it’s bent in shape like unsaturated fats = HEALTHY
What is hydrogenation?
Used to turn vegetable oil ➡️ solid substance
What does hydrogenation do to shelf life?
Improves shelf life + reduces likelihood of oxygenation
What are the vegetable oils hardened with?
Hydrogen gas
What happens to the bonds during hydrogenation?
Double bonds ➡️ single bonds
UNSATURATED fats ➡️ SATURATED fats
What type of oil is made from hydrogenation?
Partially hydrogenated oil➡️ used in baking, processed foods including fat spreads + cakes
What can artificially created trans fats lead to an increase in?
Coronary heart disease
Where do small amounts of natural trans fats occur?
In milk + beef
. Not seen as being unhealthy compared to artificial trans fats
How does hydrogenation change the molecular structure?
Hydrogen gas + UNSATURATED FAT MOLECULE ➡️ removal of the double bond TRANS FATTY ACID
Which 2 polyunsaturated fatty acids are essential for health?
- Linoleic acid ➡️ Omega 6
- Alpha Linoleic acid ➡️ Omega 3
Can the body manufacture omega 3 and 6?
No, they must be consumed in the diet
What are essential fatty acids converted into?
- Eicosapentaenoic acid (EPA)
- Docosahexaenoic acid (DHA)
What are some sources of Omega 3 (Alpha Linoleic acid)?
- Green leafy vegetables
- Walnuts
- Soya beans
- Grains
- Rapeseed oil
What are some sources of omega 6 (linoleic acid)?
- Found in oils - sunflower, corn, soya
- Cold water
- Oily fish - tuna, salmon, sardines
What is cholesterol?
A type of fat that does not produce energy
Where is cholesterol found?
In all animal + tissue cells
. Not found in plants or vegetables
What is cholesterol essential for?
1.structure of cell membranes
2. Production of bile for absorption of fats
3. Essential component of many hormones
4. Vitamin D
Where is cholesterol produced?
In the liver
How is cholesterol transported around body?
By proteins called lipoproteins
What are the 2 types of lipoproteins?
- Low density lipoproteins (LDL)
- High density lipoproteins (HDL)
What is Low Density Lipoproteins also known as?
Bad cholesterol
Do Low Density Lipoproteins make up most of body’s cholesterol?
Yes
What do high levels of Low density lipoproteins raise risk of?
. Heart disease+ strokes ➡️ clogs up arteries by plague ➡️ narrows coronary arteries
What are some sources of low density lipoproteins?
Foods that contain saturated fats ➡️ beef, bacon, milk
What are High Density lipoproteins also known as?
Good cholesterol
What is the function of high density lipoproteins?
Absorbs cholesterol in blood+ carries it back to liver
. Liver then flushes it from body
What can high levels of high density lipoproteins prevent?
Lower risk of heart disease + stroke
What are some sources of high density lipoproteins?
Foods that contain unsaturated fats ➡️ avocado, olives, fish, nuts, pulses
