Page 85 - General Biochemistry

Properties of sugar: sweetness...

• Some sugars are sweeter than others. In taste tests of pure sugars, fructose is
the sweetest, and then decreasing in order of sweetness is sucrose, glucose,
maltose, and finally lactose.

• Factors such as concentration, consistency, temperature, and pH affect how
sweetness is judged. For example, fructose seems sweeter when used in cold
foods and in slightly acidic drinks. The fructose tastes less sweet when
warm.

• When the apple is baked, it needs brown sugar added.
• Sucrose seems sweeter when used in the same recipes as small amounts of

salt.

Properties of sugar: carmelization...

Carmelization is the browning reaction that can occur with any kind of sugar. It
requires either an acidic or alkaline pH. As sugar is heated, its molecular
structure is changed, and the new molecules with a higher concentration of
carbon create the distinctive caramel color.

Sugars differ in the degree to which they carmelize and the temperature at which
they react. Sucrose and glucose carmelize at 170ºC (338 ºF) , and fructose
carmelizes at (230ºF).

Onions carmelize when cooked slowly up to 230ºF; the process brings out the
sweetness.

Properties of sugar: solubility...

Sugars are highly soluble in water because they contain many hydroxyl groups,
which form hydrogen bonds with water molecules. The solubility of sugar
increases as the temperature of water rises.

You can make a ‘supersaturated’ solution: Dissolve more sugar in water than
would normally be possible…by heating the water, changing volume, and/or
adding pressure. Then, with absolutely no agitation, cool the solution. This is
a ‘supersaturated’ solution.

A carbonated beverage is a supersaturated solution of carbon dioxide gas in sugar
water.

Rock candy is made from a supersaturated solution of sugar and water

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