B1.3 Nutrition and food tests - Food tests

Question 1

Qualitative reagent

Answer 1

A substance used in chemical analysis to test for the presence of specific molecules

Question 2

Qualitative

Answer 2

Relates to measuring the quality of something rather than its quantity

Question 3

Benedict’s reagent

Answer 3

When heated will turn from blue to a brick-red precipitate in the presence of reducing sugars

Question 4

Results for Benedict’s reagent

Answer 4

The solution will change from blue to green to yellow to brick-red depending on the level of reducing sugars present

Question 5

Biuret reagent

Answer 5

Turns from blue to lilac/purple in the presence of proteins

Question 6

Iodine test

Answer 6

Turns from yellow-brown or orange to blue-black in the presence of starch

Question 7

Ethanol and water

Answer 7

When shaken will turn from colourless to a milky-white emulsion in the presence of lipids

Question 8

Sudan III

Answer 8

When shaken will turn from brick-red to a red-stained oil layer in the presence of lipids

Question 9

Carbohydrates

Answer 9

Provide energy for chemical reactions and can break down into sugars

Question 10

Reducing sugars

Answer 10

A sugar such as glucose or fructose that can act as a reducing agent

Question 11

Lipids

Answer 11

An energy store of fats and oils that can break down into glycerol and fatty acids

Question 12

Proteins

Answer 12

The building blocks of cells and tissues that can break down into amino acids

Question 13

Precipitate

Answer 13

Deposits of solid in a solution

Question 14

Mortar and pestle

Answer 14

Devices used for crushing and grinding up food substances

Question 15

Water bath

Answer 15

A container of water heated to a given temperature for control purposes

Question 16

Positive result

Answer 16

A result that shows the presence of a specific substance

Question 17

Negative result

Answer 17

A result that does not show the presence of a specific substance