1. Plant oils What is added to food?

2. Preservation Need to make food last longer – preserve it –Salt (remove water) –Vinegar (pickling) –Alcohol (kill microbes) Knowledge of chemistry Also use chemistry to improve flavours or appearance

3. Food additives Substance added to a food –Food additive Approved for use in Europe –Given an ‘E’ number –Identify them rather than name them Eg.E102 is tartrazine (yellow colouring) E220 is sulphur dioxide (preservative) Six types of additive

4. Food additives E numberAdditiveWhat it doesExample E1xxColoursImprove the appearance of food. Can be natural, brownings or additives E150 – caramel colour E2xxPreservativesHelps food last longer = less wastage E211 – sodium benzoate E3xxantioxidantsHelp stop food reacting with oxygen E300 – vitamin C

5. Food additives E numberAdditiveWhat it doesExample E4xxEmulsifiers, stabilisers and thickeners Help improve the texture of food E440 – pectin E5xxAcidity regulator Helps control pH and tasteE501 – potassium carbonate E6xxFlavouringsBlends flavours of food – sweet, sour, bitter, salt and savory E621 – monosodium glutamate

6. What is a food additive and why might they be used? Challenge question – How does the system used in Europe identify additives?

7. Detecting additives Food scientists – investigate what has been added Complicated versions of simple techniques Chromatography –How well something dissolves in a solvent –Solubility determines how far they move across a surface –Separation technique

8. Investigating food dyes Test a selection of food dyes with chromatography Which dyes are pure and which are mixtures? What are the component colours of each dye? Solvent = water, matrix = paper

9. Identifying ingredients Separated by chromatography Identified by comparing to known ingredients –Compare chromatogram Hi-tech – mass spectrometer –Compares relative atomic mass Chemical make up can be indentified