most versatile and widely used organic acid in foodstuffs, citric acid
is a colourless, crystalline organic compound, belonging to the family
of carboxylic acids.
is present in practically all plants, and in many animal tissues and
fluids, but it is in particularly high concentrations in lemons and
other citrus juices and many ripe fruits.
isolated in 1784 from lemon juice, by the Swedish chemist Carl Wilhelm
Scheele, citric acid has been used as a food additive for over 100 years.
is normally manufactured by fermentation of cane sugar or molasses in
the presence of the fungus Aspergillus niger, but it can also be obtained
from pineapple by-products and low-grade lemons.
use as a food additive is wide and varied - as a synergist to enhance
the effectiveness of other antioxidants; as a sharp-tasting flavouring;
as a sequestrant in foods it combines with the naturally occurring trace
metals to prevent discolouration and in wine production it combines
with free iron to prevent the formation of iron-tannin complexes which
cause cloudiness; in brewing to reduce excess losses of sugars from
the germinated barley; to create an acidic environment to discourage
the growth of certain bacteria, yeasts and moulds and in cheese making
it produces a faster and more consistent method of producing the necessary
acidic environment for the enzyme activity than the traditional souring
by lactic acid caused by bacteria.
of this versatility it can be found in a wide range of products, including
non-alcoholic drinks, bakery products, beer, cheese and processed cheese
spreads, cider, biscuits, cake mixes, frozen fish (particularly herrings,
shrimps and crab), ice cream, jams, jellies, frozen croquette potatoes
and potato waffles, preserves, sorbets, packet soups, sweets, tinned
fruits, sauces and vegetables and wine.
problems are that it can be a local irritant and in large amounts can
cause teeth erosion.
there have been erroneous reports that it is a major cause of cancer.
It is thought that this has been brought about by misunderstanding and
confusion over the word Krebs.
acid is one of a series of compounds involved in the physiological oxidation
of fats, proteins, and carbohydrates to carbon dioxide and water.
series of chemical reactions, which is central to nearly all metabolic
reactions and the source of two-thirds of the food-derived energy in
higher organisms was discovered by the German-born British biochemist
Sir Hans Adolf Krebs. He actually received the 1953 Nobel Prize for
Physiology or Medicine for the discovery, and as well as being known
as the tricarboxylic acid cycle (its correct name), it is also known
as the citric acid cycle or the Krebs cycle.
citric acid is fundamental to the Krebs cycle and Krebs is the German
word for cancer!