2009_Book_FoodChemistry

856 18 Fruits and Fruit Products
invert sugar) and has to contain at least 65% of
soluble solids.
18.2.12 Fruit Powders
Fruit powders are produced by drying juices,
juice concentrates or slurries. The hygroscopic
powders contain less than 3–4% moisture.
Addition of drying aids (such as glucose, maltose
or starch syrup) in amounts greater than 50% of
the dry matter can efficiently control clumping
or caking due to the presence of fructose in the
drying process. Freeze-drying, vacuum foamdrying
(0.1–1 kPa, 40–60 ◦ C) and foam-mat
drying are suitable drying processes. In the last
mentioned process, the material to be dried is
foamed with foam stabilizers and inert gas and
then dried. Spray drying is also applied. It has the
disadvantage that often strong color and aroma
changes occur.
The sugar added to lemonades has to be at least
7% based on the finished beverage.
Tonic water is also considered a lemonade. It contains
about 80 mg quinine/l to provide the characteristic
bitter taste.
18.3.3 Caffeine-Containing Beverages
These are also considered as “lemonades”
(particularly in Europe). The most popular are
the cola drinks, which contain extracts from
the cola nut (Cola nitida) or aromatic extracts
from ginger, orange blossoms, carob and tonka
beans or lime peels. Caffeine is often added (6.5–
25 mg/100ml). Phosphoric acid is sometimes
used as an acidulant (70 mg/100ml). The sugar
content of cola drinks averages 10–11%. The
deep-brown color of the drink is adjusted with
caramel.
18.3 Alcohol-Free Beverages
18.3.1 Fruit Juice Beverages
Fruits mostly provide only the taste in fruit juice
beverages. These drinks are prepared from fruit
juices or their mixtures or from fruit concentrates,
with or without addition of sucrose or glucose,
and are diluted with water or soda or mineral water.
A minimum amount of fruit juice is stipulated:
30% of seed fruit juices or grape juice, 6%
of citrus juice or citrus juice mixtures, and 10%
of other juices or juice mixtures.
18.3.2 Lemonades, Cold and Hot Beverages
These drinks are prepared with or without the use
of fruit juice or fruit extracts by the addition of
natural fruit essences and sugar (sucrose or glucose),
fruit acids and soda or mineral water. They
are also consumed without added carbon dioxide,
either cold or warmed. The drinks are usually
colored. Lemonades made with the addition
of fruit juices contain at least half the amount of
fruit juice normally contained in fruit juice drinks.
18.3.4 Other Pop Beverages
Some effervescent pop drinks are imitations of
fruit juices and lemonade-type drinks, however,
their sugar content is fully or partially replaced
by artificial sweeteners and the natural essence
of flavoring ingredients are replaced by artificial
or artificially-enhanced essences. Coloring substances
are usually added.
18.4 Analysis
As a result of the numerous raw materials and
processes involved, the analysis of fruit products
is difficult and tedious. Information on the following
is important for an evaluation:
• Type, amount, and origin, if necessary, of the
fruit and additives used (e. g., acids, sugar).
• Constituents that determine quality (e. g.,
aroma substances, vitamins).
• Method of processing.
Information of this type is provided by the quantitative
analysis of various constituents, determination
of species-specific compounds, and by the
determination of abundance ratios of isotopes.