291
as flavors or aromas in the food industry (Buckler et al. 1969). As explained above,
in order to form the cyclodextrin polymers, reagents that possess two or more functions capable of reacting with hydroxyl groups are needed to form an insoluble resin
that can be used as a sorbent matrix.
Some years after the abovementioned patent was filed, a cyclodextrin polymer
made with epichlorohydrin was developed to reduce the bitterness of fruit juices
(Shaw et al. 1984). The purpose of that investigation was to improve the taste of
orange or grapefruit juices using α- or β-cyclodextrin polymers as sorbents to form
a complex with limonin, narangin, and nomilin, three natural bitter components.
Their results were conclusive showing a good absorption of the bitter molecules and
a taste preference of the new bitterless juice over the control juice, without absorbing other flavor or valuable components such as ascorbic acid, and with the possibility to regenerate the cyclodextrin polymer sorbent. A couple of years after that, the
selectivity of these cyclodextrin polymers was tested (Shaw and Buslig 1986), using
γ-cyclodextrin polymer as well, with other juice containing the same bitter components and also caffeine, and proved that cyclodextrin polymers do not complex with
the latter. In the same research paper, they studied the importance of the crosslinking agent used to prepare the cyclodextrin polymers. Their study concluded that
naringin removal was more effective when using β-cyclodextrin polymer resins,
compared to α- and γ-cyclodextrin polymers or a standard Amberlite XAD-4 resin,
which did remove caffeine or limonin in turn.
Two decades later, β- or γ-cyclodextrin were linked to chitosan through succinyl
or maleyl bridges to improve the sorption of bitter compounds (Binello et al. 2004).
This bitter-masking potential was measured by analyzing the bitterness of different
solutions composed of either a single model molecule (caffeine) or natural extracts.
Pure chitosan possesses a good sorption capacity of bitter compounds, better than
those of the α-, β-, or γ-cyclodextrin monomers. However, the chitosan β-cyclodextrin
adducts improve the bitter-masking power in all cases. Besides the batch procedures, Wagner Jr. et al. (1988) reported, also in the 1980s, on the result of a pilotplant fluidized-bed procedure, where the β-cyclodextrin polymer was regenerated
over 20 times without apparent loss of capacity. The debittering of other juices has
also been reported later on (Szejtli and Szente 2005).
In the last decade, another area of application searched in food science and cosmetics is the retention of fragrance or aroma molecules. For example, the encapsulation of two molecules (linalool and camphor) composing Lavandula angustifolia
essential oil using cross-linked cyclodextrin-epichlorohydrin polymers and their
subsequent liberation was studied using a static headspace gas chromatography
technique both in gaseous and aqueous phases and compared to those of the parent
and derivative cyclodextrins (Ciobanu et al. 2012). Cyclodextrin polymers present
different retention profiles depending on cyclodextrin/cross-linker ratios, the phase,
and the volatile compound.
In 2009, cyclodextrin polymers were used in solid-phase extractions to determine
additives in food (Li et al. 2009). Epichlorohydrin was used to cross-link
β-cyclodextrin with soluble starch to evaluate the content of brilliant blue in food.
The detection is feasible between 0 and 12 ppm. As solid-phase extraction research
6 Cyclodextrin-Based Polymers for Food and Pharmaceutical Applications…
as flavors or aromas in the food industry (Buckler et al. 1969). As explained above,
in order to form the cyclodextrin polymers, reagents that possess two or more functions capable of reacting with hydroxyl groups are needed to form an insoluble resin
that can be used as a sorbent matrix.
Some years after the abovementioned patent was filed, a cyclodextrin polymer
made with epichlorohydrin was developed to reduce the bitterness of fruit juices
(Shaw et al. 1984). The purpose of that investigation was to improve the taste of
orange or grapefruit juices using α- or β-cyclodextrin polymers as sorbents to form
a complex with limonin, narangin, and nomilin, three natural bitter components.
Their results were conclusive showing a good absorption of the bitter molecules and
a taste preference of the new bitterless juice over the control juice, without absorbing other flavor or valuable components such as ascorbic acid, and with the possibility to regenerate the cyclodextrin polymer sorbent. A couple of years after that, the
selectivity of these cyclodextrin polymers was tested (Shaw and Buslig 1986), using
γ-cyclodextrin polymer as well, with other juice containing the same bitter components and also caffeine, and proved that cyclodextrin polymers do not complex with
the latter. In the same research paper, they studied the importance of the crosslinking agent used to prepare the cyclodextrin polymers. Their study concluded that
naringin removal was more effective when using β-cyclodextrin polymer resins,
compared to α- and γ-cyclodextrin polymers or a standard Amberlite XAD-4 resin,
which did remove caffeine or limonin in turn.
Two decades later, β- or γ-cyclodextrin were linked to chitosan through succinyl
or maleyl bridges to improve the sorption of bitter compounds (Binello et al. 2004).
This bitter-masking potential was measured by analyzing the bitterness of different
solutions composed of either a single model molecule (caffeine) or natural extracts.
Pure chitosan possesses a good sorption capacity of bitter compounds, better than
those of the α-, β-, or γ-cyclodextrin monomers. However, the chitosan β-cyclodextrin
adducts improve the bitter-masking power in all cases. Besides the batch procedures, Wagner Jr. et al. (1988) reported, also in the 1980s, on the result of a pilotplant fluidized-bed procedure, where the β-cyclodextrin polymer was regenerated
over 20 times without apparent loss of capacity. The debittering of other juices has
also been reported later on (Szejtli and Szente 2005).
In the last decade, another area of application searched in food science and cosmetics is the retention of fragrance or aroma molecules. For example, the encapsulation of two molecules (linalool and camphor) composing Lavandula angustifolia
essential oil using cross-linked cyclodextrin-epichlorohydrin polymers and their
subsequent liberation was studied using a static headspace gas chromatography
technique both in gaseous and aqueous phases and compared to those of the parent
and derivative cyclodextrins (Ciobanu et al. 2012). Cyclodextrin polymers present
different retention profiles depending on cyclodextrin/cross-linker ratios, the phase,
and the volatile compound.
In 2009, cyclodextrin polymers were used in solid-phase extractions to determine
additives in food (Li et al. 2009). Epichlorohydrin was used to cross-link
β-cyclodextrin with soluble starch to evaluate the content of brilliant blue in food.
The detection is feasible between 0 and 12 ppm. As solid-phase extraction research
6 Cyclodextrin-Based Polymers for Food and Pharmaceutical Applications…