Fats

What makes up fats?

Carbon, hydrogen and oxygen

Under what circumstances do fats provide more energy than carbohydrates?

When they are oxidised

What are the functions of fat?

1. It is a concentrated source of energy.

2. It surrounds and protects vital organs, e.g kidneys and glands

3. It forms an insulating layer beneath the skin to help preserve body heat and protect the skeleton and organs.

4. It provides sources of fat-soluble vitamins (A, D, E, K)

5. It forms part of the structure of cell membranes throughout the body, especially in the brain

What is the state of fats at room temperature?

Solid

What is the state of oils at room temperature?

Liquid

What are the types of lipids?

1. Triglycerides/triglycerol (simple lipids)

2. Sterols

3. Phospholipids

How are triglycerides/simple lipids formed?

Carbon, hydrogen and oxygen molecules of glycerol and fatty which combine to form these.

What are the categories of fatty acids?

Saturated and unsaturated

How are saturated fatty acids formed?

This is formed when all the carbon atoms are saturated with hydrogen atoms and cannot accept any more.

What are examples of saturated fatty acids and where are they found?

1. Butyric acid found in milk and butter

2. Palmitate acid found in animal fats

3. Lauric acid found in dairy foods and coconut oil

4. Stearic acid found in beef fat

How are unsaturated fatty acids formed?

This is formed when some carbon atoms are joined with others by a double bond, and so are not completely saturated with hydrogen atoms.

Deine the term monounsaturated

This is when fatty acids have only one double bond in their molecule. E.g. oleic acid is found mostly in animal and plant fats and oils

Define the term polyunsaturated

This is when fatty acids have more than one double bond. E.g. linoleic and linolenic acids both found in vegetable oils.

What is the most common form of phospholipids?

Lecithin which is found in egg yolks, soya bean, wheat, peanuts, and liver.

What is the function of phospholipids?

They act as emulsifiers in the body which helps to keep fats suspended in the blood and body fluids.

What is the use of phospholipids in the food industry?

This is used as an emulsifier to mix fat and water into products such as mayonnaise.

What is the most common sterol?

Cholesterol

What are some examples of sterols?

1. Cortisone from the adrenaline glands

2. Sex hormones such as oestrogen

3. Vitamin D

4. Bile acids which help to digest food.

Which of the food groups contain cholesterol.?

Food from animals

What are some foods containing high amounts of cholesterol?

1. Organ meats (offal)

2. Egg yolks

3. Shellfish

4. Poultry

5. Fish

6. Dairy products

How does the body transport cholesterol and triglycerides through the bloodstream?

By using lipoproteins

What are the types of lipoproteins known to have implications on the health of the heart?

1. Low-density lipoproteins (LDLs)- referred to as bad cholesterol

2. High-density lipoproteins (HDLs)'- referred to as good Cholesterol

Why do low-density lipoproteins contribute to heart disease and high-density lipoproteins don't?

This is because LDLs circulate all around the body while HDLs carry cholesterol to the body and then to the liver for breakdown and excretion.

What are the sources of fat and oils?

Plants and animals such as salmon, coconut oil, avocado, chia seeds, sardines, seeds, olive oil, nuts and whole eggs.

What are the forms of fat in foods?

Visible and invisible fat

What are visible fats?

These are fats that are easy to detect in food. Examples include fat on meat, butter, cooking oil, shortening, and margarine.

What are invisible fats?

These are fats that are constituent parts of food and are difficult to detect. Examples include

• Egg yolk

• Lean meat

• Nuts

• Seeds

• Prepared food eg, pastries, biscuits, fritters

• The flesh of oily fish

What are the health effects of fat?

• Obesity

• Heart diseases due to high cholesterol which can cause coronary heart diseases

What are the effects of heat on fats?

When heated, solid fats melt into liquid oils, becoming thinner and bubbling. At high temperatures, fat molecules decompose into glycerol and fatty acids, producing a blue haze in the smoke before igniting and burning quickly.