1.3 Nutrition And Food Tests Flashcards
What are the main nutrients needed in balanced diet
Carbohydrate
Fats
Protein
Vitamins
Minerals
Fibre
Water
What are the two types of carbohydrates
Simple sugars and complex carbohydrates
Give two examples of simple sugars, what foods they can be found in and what they are needed for
Glucose - in soft drinks, sweets.
Lactose - in milk
Used for immediate energy source
What are the 3 main types of complex carbohydrates
Cellulose
Starch
Glycogen
What are starch and glycogen used for
Give examples of foods that contain them
Starch - energy store in plants
Examples - bread, flour, rice
Glycogen - energy store in animals
Examples - red meat
What is cellulose used for
Structural - production of cell wall in plant cells
What elements are carbohydrates made up of
Carbon, hydrogen, oxygen
What are the building blocks of carbohydrates called
Monosaccharides
What are the building blocks of proteins called
Amino acids
What elements are found in proteins
Carbon.
Hydrogen
Oxygen
Nitrogen
What are proteins needed for
Structural - growth and repair of tissues
Functional - produce antibodies and enzymes
What elements are lipids made from
Carbon
Hydrogen
Oxygen
What are the building blocks of lipids
Fatty acids
Glycerol
What are lipids needed for
Energy store
What is the food test for starch
Add iodine
Turns yellow brown to blue black
What is the test for glucose or a reducing sugar
Add Benedict’s
Heat in water bath
Turns blue to brick red precipitate
What is the test for protein
Add Biuret (add sodium hydroxide and copper sulfate)
Turns blue to purple
What is the test for lipids
Add ethanol and water (equal amounts) and shake
Cloudy suspension if lipids are present
How to test for energy in foods
Add set volume of water in test tube
Record temperature of water
Record mass of food to burn
Light and burn food - hold same distance under boiling tube
WHen finished record final temperature
calculate rise in temperature
How do you calculate energy in food
Mass of water x Temperature rise x 4.2
then divide by mass of food used
Answer in Joules
What are 2 reasons why the energy calculated when burning foods is not the same as the energy given in the nutritional label
Some of the energy released is used to heat the surrounding air and the glass of the boiling tube so does not heat up the water
