Accepted for podium presentation at CRS 2011

1. Performance of a Novel Crystalline Encapsulation System in Chewing Gum Application
M. Sillick C.M. Gregson J. Barra and D. Zampieri
Firmenich, Inc, Princeton, NJ, 08536, USA
Christopher.Gregson@firmenich.com
ABSTRACT SUMMARY
Flavor compounds can be encapsulated before adding
to a chewing gum formulation in order to prevent
partitioning into the hydrophobic gum base and promote
release on mastication. However, the hot and plasticizing
nature of the chewing gum manufacturing process may
challenge the integrity of many encapsulates. This report
details the performance of a novel encapsulate that
consists of droplets of a liquid flavor dispersed within a
crystalline sugar alcohol matrix. Microscopy was used to
show that at least some of the encapsulate particles did
indeed remain intact throughout the gum processing.
Sensory panel evaluations found chewing gums that
contained the novel encapsulate significantly stronger in
mint impact than similar preparations made using iso-
Figure 1 Gum section showing remnants of a crystalline encapsulate
flavor loadings of either the corresponding liquid flavor or particle embedded in a matrix of gum base and fine sorbitol particles. At
a version processed via conventional spray dry higher magnification (insert) droplets are visible within the structure of
encapsulation. the encapsulate particle.
INTRODUCTION EXPERIMENTAL METHODS
The structure of chewing gum consists of dispersed The crystalline encapsulate powders were produced
regions of both solid and liquid sweeteners within a by emulsifying a liquid mint flavor (885106NT,
continuous gum base matrix. While hydrophilic Firmenich Inc.) into a molten sugar alcohol carrier
sweeteners mix quickly with saliva, flavor chemicals are (erythritol, Cargill Inc.) and then spraying the
released much more slowly as they partition out of the melt/emulsion through a pressure nozzle. The sprayed
hydrophobic gum base [1]. Significant fractions of the droplets landed in a bath of an immiscible quench fluid
flavor ingredients with low partition coefficients are (limonene at 0°C) wherein the erythritol quickly
retained within the gum base even after long chewing crystallized. The hardened particles were collected and
times. Thus, in order to promote release, it is necessary to laid on a paper towel overnight to allow the remaining
use a larger dose than would be required if interaction quench fluid to evaporate off. This yielded a free flow
with the gum base could be avoided. powder with a minty character.
One way of preventing flavor chemicals from A comparative spray dried sample (505951 TP0504,
interacting with the gum base is to use an encapsulation Firmenich Inc.) was attained. This product contains mint
system. For example, if the flavor ingredients were flavor 885106NT within a glassy maltopolymer carrier.
embedded within a carbohydrate matrix, they could be Both the crystalline encapsulates and the spray dried
prevented from reaching the gum base. Release might encapsulate were analyzed for liquid flavor content by
then occur very rapidly with fracture of the particles by low-field time-domain nuclear magnetic resonance (TD-
chewing and with dissolution of the carbohydrate carrier LF-NMR) as described by Andrade et al. [3]. A Bruker
in saliva. However, for this to be successfully Optics Minispec 20 Mhz spectrometer was used to
implemented, the encapsulate needs to remain intact measure 4 scans of the 90°/180° spin-echo signal with a
throughout the gum manufacturing process. This can be a 3.5ms delay time, 0.5ms acquisition window and a 20
challenge as the process involves high temperature (45°C second recycle delay. The spin-echo signal was
to 100°C), high shear and plasticizing ingredients such as proportional to the mass of the liquid mint flavor in the
glycerol, sorbitol and water (in the form of polyol syrups sample and therefore could be calibrated using carefully
for example). Glassy carbohydrate carriers may be measured mixtures of the mint flavor and the appropriate
dissolved or become dispersed under such conditions. carrier.
Glassy solids are often described as more soluble and Unflavored chewing gum bases were prepared by
have been found to dissolve faster than chemically similar combining preheated gum bases (12.44% Solsona T and
crystalline solids [2]. Thus, one might expect a crystalline 12.44% Vega) with 56.5% crystalline sorbitol, 11.5%
encapsulation system to show a difference in dissolution maltitol syrup, 6.92% glycerol 0.12% aspartame and
and/or plasticization performance compared to a 0.08% acesulfame K by weight. The ingredients were
conventional glassy carbohydrate encapsulate. mixed in a sigma blade mixer at 45°C to 65°C for 8
minutes.

2. Flavoring was dosed as outlined in Table 1. The Table 1: Flavoring dosages for chewing gum samples.
amount of each encapsulate powder was chosen based on
the TD-LF-NMR results for liquid flavor content, which Flavoring Effective Liquid
are shown in parenthesis. Thus, Gums 1 and 2 were dosed Flavor Content (wt%)
to have the same amount of liquid mint flavor. Gum 3 has
the same total dosage as Gum 1, but a much lower amount Gum 1 0.30% of liquid flavor (885106 NT) 0.30%
of flavor. Similarly, Gums 4 and 5 have iso-flavor loading
Gum 2 3.33% of crystal encapsulate 0.30%
despite having different dosages of the respective (x 9.12% liquid flavor)
encapsulate powders. In all cases, the flavoring was added Gum 3 0.30% of crystal encapsulate 0.027%
to the gum base and mixing was then continued for an (x 9.12% liquid flavor)
additional two minutes. The flavored chewing gums were Gum 4 1.73% of spray dried encapsulate 0.25%
discharged, laminated and cut into sticks. (x14.45% liquid flavor)
The gum samples were evaluated by sensory (tasting) Gum 5 3.13% of crystal encapsulate 0.25%
panels. Additionally the microstructure was characterized (x 7.99% liquid flavor)
by microscopy. Sticks of gum were cut into 25 micron
sections using an American Optical 820 microtome.
Sections were collected and examined using an Olympus contained liquid flavor), with extremely intense impact of
BX51 optical microscope. mint flavor and stronger mentholic and cooling character.
Additionally, even though it contains less than 1/10th of
RESULTS AND DISCUSSION the amount of flavor, all panelists also found Gum 3
The chewing gum contains a large proportion of stronger than Gum 1, with a significantly higher impact of
crystalline sorbitol (56%). This is visible as a multitude of mint.
fine particles (<5μm) dispersed throughout the gum base, Gums 4 and 5 were compared by the same
which appear bright under slightly crossed polarized light methodology. All panelists found Gum 5 (with a
(figure 1). The solvents (water and glycerol) are likely to crystalline encapsulate) significantly stronger than Gum 4
be saturated with respect to sorbitol both during and after (with a spray dried encapsulate), with a significantly
the mixing process. A relevant question then is to what higher impact of mint.
degree is the erythritol encapsulate soluble within the
solvent system? If the encapsulate dissolves during CONCLUSION
processing, the hydrophobic flavors will be able to A novel crystalline encapsulation system was used to
interact with the gum base either via direct encounters on limit interaction with a chewing gum base. This enabled a
mixing or by diffusion through the solvent. significantly higher perceived flavor impact. Even when
In addition to fine particles of sorbitol, figure 1 also less than 1/10th the amount of flavor was used, gums
shows a 200μm circular region in which there are other flavored with the crystalline encapsulate tasted more
larger crystalline particles. This region has similar strongly of mint than gums that contained unencapsulated
characteristics (size, shape, and polycrystalline nature) to liquid flavor. Microscopic evidence suggests that the
the erythritol encapsulate particles. At higher crystalline encapsulation system may be better able to
magnification small (~1μm) circular regions of a resist dissolution during a gum manufacturing process
dispersed phase are visible within the crystalline matrix. compared to a conventional spray dried encapsulate.
These features are common in erythritol encapsulate
particles that contain droplets of liquid flavors. As- REFERENCES
received crystalline sorbitol does not show these features. 1. Harrison M. 2000. Mathematical Models of Release and
Thus a significant fraction of the flavor remains Transport of Flavors from Foods in the Mouth to the
encapsulated within the crystalline carrier and isolated Olfactory Epithelium. In: Flavor Release. American
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Similar efforts were made to search for encapsulate 2. Chiou W.L. and Riegelman S., 1971 J. Pharm.Sci.
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dried powders could be found. It is possible that spray
dried encapsulate particles did not survive the gum
mixing process as readily as the crystalline encapsulate.
Six trained panelists assessed the chewing gum
samples for flavor intensity. The samples were presented
blind and following a balanced presentation order. The
flavor intensity was evaluated on a scale of 0 to 10 where
0 denotes no flavor and 10 denotes very strong flavor. All
panelists found Gum 2 (flavored by a crystalline
encapsulate) significantly stronger than Gum 1 (which