1.3 Nutrition and food tests Flashcards
what elements make up carbohydrates
Carbon , Hydrogen , Oxygen
What elements make up protein
Carbon Hydrogen Oxygen and Nitrogen
What elements make up fat
Carbon Hydrogen Oxygen
What are simple sugars and their function
Glucose (a monosaccharide - 1 sugar) and Lactose (a disacharide - 2 sugars)
Function - immediate energy
What are the 3 complex carbohydrates and function of each
Cellulose - cell walls
Starch - energy store in plants
Glycogen - energy store in animals
What are the building blocks of protein
amino acids
What are fats or lipids made of
Fatty acids and glycerol
What are proteins needed for
Structural - growth and repair
Functional - enzymes and antibodies
What are lipids used for
Energy storage
How do you test for starch
To food sample (crush if solid food and add water)
Add iodine
Turns yellow-brown to blue-black
How do you test for a reducing sugar
To food solution add BENEDICTS and HEAT in water bath
Turns blue to brick red precipitate
How do you test for protein
Add biuret reagent to food sample and shake
Turns blue to purple
How do you test for fat
To food solution add same amount of ethanol and water and shake
cloudy white emulsion -fat present
how do you find energy from food - describe practical
Add 20cm3 water to boiling tube and add thermometer -record temperature of water
clamp
measure mass of food to burn
light food in bunsen flame and then hold under boiling tube
if food goes out - put in bunsen flame and relight
once food completely burned take final temperature
How to find the energy from food
mass of water x temp increase x 4.2
to find per gram divide by mass of food
