South Pasadena • Chemistry
Name
Period
Date
3 · Organic Chemistry
INTERESTING
ORGANIC
COMPOUNDS
Retinal
CH3 CH3 H
H
C
C
C
H
H
C
C
C
H
H
C
C
C
C
H
CH3
C
H
CH3 CH3 H
H
C
H
H
C
CH3
H
H
H
C
H
C
C
CH3
H
C
C
C
C
H
11-cis-retinal
H
C
C
H
O
CH3
CH3
C
H
C
C
C
C
C
C
H
H
H
H
O
CH3
H
all-trans-retinal
Upon absorption of a photon in the visible range, 11-cis-retinal can isomerize to all-trans-retinal. In the 11-cis
isomer, the hydrogens are on the same side of the double bond between carbon atom 11 and carbon atom 12. In
the all-trans isomer, the hydrogens are on opposite sides of the double bond. In fact, all of the double bonds are in
the trans-configuration in this isomer: the hydrogens, or hydrogen and -CH3, are always on opposite sides of the
double bonds (hence, the name "all-trans-retinal"). Note how the size and shape of the molecule change as a result
of this isomerization.
Source: http://www.chemistry.wustl.edu/~edudev/LabTutorials/Vision/Vision.html
Sour Candy Acids
Name
Citric Acid
C6H8O7
Structural Formula
O
O
Description
Citric acid was one of the first acids isolated. In 1784,
Carl Wilhelm Scheele, a Swedish chemist,
crystallized the substance from lemon juice.
H
C
H
O
C
H
O
C
H
H
C
O
C
H
H
O
C
O
H
Citric acid is used for flavoring candy, and also for ice
cream, sherbet, fruit drinks and carbonated beverages.
It is also used as a preservative. Webster's dictionary
defines citric acid as a weak, water-soluble acid found
in many fruits, especially citrus fruits and berries. It is
most often extracted from lemons, gooseberries and
currants as a crystalline substance that is used when
an acidic or sour taste is needed in foods and
beverages.
The Center for Science in the Public Interest describes
citric acid as a versatile, inexpensive, safe substance
used as both a flavoring and an antioxidant.
Name
Malic Acid
C4H6O5
Structural Formula
H
O
C
H
Tartaric Acid
C4H6O6
O
H
O
C
C
H
H
O
C
O
H
H
O
C
H
O
O
H
C
C
H
O
O
C
O
H
H
Lactic Acid
C3H6O3
(Milk Acid)
H
H
H
C
C
H
O
O
C
O
H
H
Fumaric Acid
C4H4O4
H
O
H
O
C
C
C
C
O
H
H
O
Description
Malic acid is an organic food additive that gives food
and beverages a very sour, tart flavor. Malic acid is
found in unripe fruits such as apples, cherries and
tomatoes, and has been called "apple acid," according
to the Center for Science in the Public Interest. This
acid is commonly used in extremely sour hard candy.
It is also used as an additive in salt and vinegar potato
chips, fruit-flavored drinks, lemon-flavored ice-tea
mix, ice cream and preserves.
Malic acid is easily blended and, unlike some other
food acids, its flavor is long-lasting. It is also very
soluble and has a lower melting temperature than
other acids, making it easy to use in confectionery
production.
Tartaric acid is an organic substance that is naturally
present in the juice of fruits like tangerines and
grapes, and coffee beans. It was originally used by the
wine industry to prevent bacterial growth in wine vats.
Tartaric acid has an extremely tart, acidic taste, which
is useful in the production of sour candies. It also acts
as an antioxidant.
Lactic acid is a safe substance that is present in most
living organisms. When used in food production, it
adds tartness to frozen desserts, candy, carbonated
fruit-flavored drinks and other foods. Lactic acid has
to be converted into an encapsulated solid, pure,
crystalline form before it can be used for "acid-sanded
candy." This encapsulated form of lactic acid can
enhance the flavor, color and shelf life of foods.
Fumaric acid is one of the most strongly acidic and
sour organic acids found in nature. According to the
food production company Bartek Ingredients, fumaric
acid "provides more sourness per unit weight than
other acidulants used in dry form." It also extends the
shelf life of sour acid-coated candies, because it does
not absorb moisture while being stored or distributed.
By maintaining a low moisture level, it also slows the
breakdown of sugar, and this results in candy that has
long-lasting sourness and flavor.
Source: http://www.livestrong.com/article/237183-what-kinds-of-acids-does-sour-candy-have