Section 2 - Human Nutrition Flashcards
Protein Structure
- made up of amino acid chains
- they all contain Carbon Hydrogen Oxygen and Nitrogen (CHON) atoms
amino acids -> proteins
Lipids structure
- built from fatty acids and glycerol
- contain Carbon, Hydrogen and Oxygen (CHO) atoms
glycerol&fatty acids -> lipids
carbohydrates structure
- carbohydrates are made up of simple sugars
- contain Carbon, Hydrogen and Oxygen (CHO) atoms
- starch and glycogen are long complex carbohydrates made up of simple sugars such as maltose or glucose joined together in a long chain
maltose -> starch
glucose -> glycogen
Make a food sample
- break piece of food with pestle and mortar
- transfer to beaker and add distilled water
- stir with glass rod to dissolve food
- filter with funnel to get rid of solid bits of food
What is the glucose test?
Benedict’s Test
What is the Starch test?
Iodine Solution
What is the Protein Test
Biuret Test
What is the Lipid test
Sudan III Test
Benedict’s Test
GLUCOSE
- prepare food sample and transfer 5cm³ to a test tube
- prepare water bath at 75º
- add benedicts solution to test tube (10 drops) using a pippet
- place test tube in water bath and leave for 5 minutes (tube pointing away from you)
- if food sample contains glucose then solution will change from BLUE to GREEN or YELLOW in low concentrations or BRICK-RED in high concentrations
Iodine solution
- make food sample and transfer 5cm³ to test tube
- add iodine solution and gently shake
- if it contains starch it will change from BROWNY-ORANGE to BLACK or BLUE-BLACK
Biuret Test
- prepare food sample and transfer 2cm³ to a test tube
- add 2cm³ of biuret solution and mix by gently shaking
- if protein is present solution will turn from BLUE to PINK or PURPLE
Sudan III Test
- prepare food sample (without filtering it) and transfer 5cm³ to a test tube
- use pipette to add three drops of Sudan III stain solution to test tube and gently shake
- if sample contains lipids the mixture will separate out into TWO LAYERS. the top layer will be bright RED
Carbohydrates
found in - pasta, rice, sugar…
function - provide energy
Lipids
found in - Butter, oil, fish…
function - provide energy and act as energy store and provide insulation
Proteins
found in - meat, fish
function - needed for growth and repair of tissue and to provide energy in emergencies
Vitamin A
found in - Liver
function - improve vision and keep skin and hair healthy
Vitamin C
found in - Fruit
function - prevent scurvy