Citric acid

Foods like oranges, lemons, yogurt and apples have a sharp taste because they contain naturally occurring acids. Citrus fruits contain citric acid, apples contain malic acid and yogurts are rich in lactic acid. In this text-based activity, students summarise the functions and uses of citric acid as a food additive.

Baking scones

Foods containing flour must be baked before they can be eaten, to enable the starch in the flour to become digestible. Cakes and bread contain a raising agent that contains an acid and an alkali. These react to liberate carbon dioxide, which makes the baking flour rise.
Students investigate different combinations of raising agents in the baking of scones.