This article was taken from the March issue of Wired UK magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content bysubscribing online
Each month Wired's chemist Dr John Emsley, award winning author of nine books and 110 research papers, deconstructs an everyday product. This month: Shape "Feel Fuller" strawberry yogurt.
IngredientsSkimmed milk, strawberries (6 percent), skimmed milk powder, milk powder, guar gum, oligofructose, modified maize starch, carrageen, flavouring, sodium citrate, citric acid, yogurt cultures, cochineal, aspartame, acesulfame K.
FibreThis is carbohydrate which our digestive enzymes cannot break down, so making the stomach feel fuller for longer. Here it comes in the form of guar gum (aka E412) which is extracted from the beans of the guar bush - these are grown mainly in India and Pakistan. Guar gum consists of long chains of mannose molecules with galactose molecules attached. These are the carbohydrates that resist being digested.
Guar gum also finds use in paper making and oil recovery. It strengthens the former and increases production of the latter. It is used to make a slurry with sand which is pumped under high pressure down into oil-bearing rocks. This breaks them up, releasing more oil. The other carbohydrate is oligofructose, which can be extracted from chicory or made from sugar. This carbohydrate feeds the good or "friendly" bacteria that live in our intestines. It also has a creamy "mouth-feel".
MilkThis comes in the form of skimmed milk, skimmed milk powder and milk powder.
StabilisersThese prevent the other ingredients from separating. They include modified maize starch and carrageen, which is extracted from seaweed and is used in fire-fighting foams.
Acidity regulatorThis consists of citric acid (aka E330) and its sodium salt, sodium citrate, which together prevent the pH of the yogurt from changing and becoming too acidic. Citric acid is the natural acid found in citrus fruits. Its chemical formula is C6H8O7 and its molecule contains three acid groups.
ColourThe pink colour of the yogurt derives from cochineal (E120) obtained from the female scale insect (Dactylopius coccus) which lives on cacti. The insects produce the intensely red carminic acid molecule to protect themselves against predators. They are harvested by hand and it takes 150,000 insects to yield a kilo of dye. The insects are killed by heating and then ground to powder. The dye is extracted with ammonia or sodium bicarbonate. Cochineal is back in fashion as a "natural" food dye because of the belief that artificial food dyes cause hyperactivity in children.
SweetenersThese provide the sensation of sweetness, without adding calories. Aspartame (Canderel, E951) is based on two amino acids of the kind which make up proteins, whereas acesulfame K (E950) is entirely synthetic and is a molecule containing sulphur and nitrogen atoms. The two chemicals boost each other's sweetness.
This article was originally published by WIRED UK
