Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
apparent discoloration or caking. The control β-CD-free sample begin to cake on
the second day of storage and turn brown on the fourth day. Gelation is an important
functional property of starches and starch-containing products as flours. β-CD considerably
modifies gelation of wheat flour. Admixture of 1.5% β-CD increases
swelling power and solubility of wheat starch granules and leaching of the amylose
fraction. The 1.5% β-CD admixture produces a fourfold increase in viscosity of
starch pastes. Probably, β-CD decomposes the amylase–lipid complexes, because
after flour defatting the effect of CD is strongly reduced.
17.4.3 CYCLODEXTRINS AS TASTE MODIFIERS
β-CD has a taste. Its taste threshold values are lower than that of sucrose: detection
0.039% c.f. 0.27% and recognition 0.11% c.f. 0.25 %. A 0.5% aqueous solution of
β-CD is as sweet as sucrose and a 2.5% β-CD solution is as sweet as a 1.71%
sucrose solution. The sweetness of β-CD should not be ignored in food processing.
Moreover, the sweetness of β-CD and sucrose is additive.
The free-to-complexed guest ratio in an aqueous CD solution depends on several
factors, the important being stability or dissociation constant of the complex, temperature,
and concentrations of both components. In cold concentrated solutions the
equilibrium is shifted toward complexation and crystallization, whereas in warm,
diluted solutions included guest molecules are released from the complexes. Therefore,
when flavoring complexes contact the taste buds in the mouth as warm, diluted
aqueous solutions, elimination of tastes and odors is fairly unlikely. Successful efforts
were claimed in elimination of the phenol-like, unpleasant bitter components from
coffee and tea liberated at 90°C by addition of 0.1% β-CD to the hot drinks. Although
these advantageous results could not be reproduced elsewhere, unpleasant tastes and
odors can be covered by CD complexation at lower temperature and at higher CD
concentration.
Milk casein hydrolyzate is a readily digestible protein source, but its bitter taste
limits its utilization. The bitter taste can be eliminated with a 10% admixture of β-
CD. This method opens a route to the utilization of proteins otherwise useless for
alimentary purposes. Similarly, the bitter taste of ginseng extract has also been eliminated
with CD. The specific odor of mutton and fish, and the nonacceptable odors of
bone powder used as the calcium supplement in animal fodder, sodium caseinate
solution, and other products can be suppressed by CD. Soybean products free of the
grassy smell and stringent taste are obtained by admixing CDs. Soybean lecithin
kneaded with β-CD forms an odorless powder that can be used in nutrition. The bitter
taste of grapefruit and mandarin juices decreases substantially when 0.3% β-CD is
added prior to a 10-min heat treatment at 95°C because bitter naringin and limonin
are complexed in β-CD. A partial complexation of chlorogenic acid and polyphenol
components of coffee with β-CD provides an improvement of the taste and retardation
of precipitate formation; the effect is particularly useful in canned coffee.
17.4.4 SELECTIVE COMPLEXATION AND SEQUESTRATION
Extraction of roasted coffee (ground beans) is more efficient in the presence of β-
CD. β-CD-containing instant coffee powder produced by spray-drying or freeze-