4.4 the effect of food processing on colour

how do anthocyanins give colour to food?

found in red cabbage, berries, aubergines - colour changes with pH, from red to blue

how do carotenoids give colour to food?

found in carrots, oranges, apricots - stable during heat, give yellow to orange colour

how does chlorophyll give colour to food?

found in green vegetables - gives bright green colour, but unstable during cooking

how do synthetic dyes give colour to food?

lab-made compounds like tartrazine (yellow), quinoline (green), erythrosine (red) used in processed foods

why are natural colours used in food?

to enhance or restore colour lost during processing, appeal to health-conscious consumers

why are synthetic dyes used in food?

to create bright, consistent colours, replace faded natural pigments, improve visual appeal

how does heat affect anthocyanins?

can cause fading or colour change depending on pH and temperature

how do acids affect anthocyanins?

shift colour to deeper red tones

how do alkalis affect anthocyanins?

shift colour to blue or grey tones

how does heat affect chlorophyll?

turns green to olive green, reduces brightness

how do alkalis affect chlorophyll?

make colour greener but damage texture and nutrients

how does heat affect carotenoids?

generally stable, but oxidation during dehydration can fade colour

how do consumers feel about synthetic colours?

some concern over health risks, prefer natural colours, especially in children's foods

how do consumers feel about natural colours?

seen as healthier and safer, but may be less vibrant or consistent

why is food colour important to consumers?

affects perception of freshness, flavour and quality - mismatched colour can reduce appeal

why do countries regulate food colours?

to protect public health, ensure safety, prevent allergic reactions and limit harmful additives

what is an E number in food colouring?

code for approved additives in the EU - e.g. E100 for curcumin, E127 for erythrosine

what does ADI mean in food regulation?

acceptable daily intake - maximum safe amount of a substance consumed per day