Candies' shocking flavor sensation
By Paula Frank
Technical Editor, Food Product Design
Contents
Sweet synergy
Sweet sensations
Cool reception
Pucker up
Flavor power
Gumming up on flavor release
Hyper colors
Remember when we were kids and used to have a contest with our friends to see who
could keep an Atomic FireBall in their mouth the longest without
spitting it out before getting to the sweet core? Nowadays, kids as well
as adults have many intensely flavored confections to choose from: the
cinnamony-hot Atomic FireBall made by Ferrara Pan Candy Company, Forest
Park, IL; super-minty candy and chewing gum; hyper-flavored fruit chews
and gummies; and extremely sour confections, such as the Mega Warheads‚
Sour Ooze Chewz, The Foreign Candy Co., Inc., Hull, IA. — complete
with "Wally's Secret Sour Potion Inside."
Many of these confections blend sweeteners and flavors to give the desired effect, be it minty, cinnamony or super-sour. Bright, intense colors often factor into the equation as well. After all, one would expect a hyper-flavored confection to be hyper-colored as well. Ingredient selection not only influences flavor perception, but duration and intensity as well. Other factors, such as the polarity of flavor chemicals and the emulsifying property of the flavor dispersion, also impact flavor delivery.
Sweet synergy
During concept planning, determining desired flavor duration depends largely on the type of confection.
Any candy that dissolves in the mouth will sustain its flavor from beginning
to end. On the other hand, with chewing gum, "it's important to consider
how the product is typically used," says Nonaka. "The average
consumer would probably not want to be chewing the same piece of gum all
day, so there is little value for the gum manufacturer to make a product
that had a flavor duration of much more than 15 to 20 minutes." Jaw
fatigue isn't normally a consideration in food product design, yet in
the determination of chewing gum's flavor duration, it certainly could
be a factor.
Nutritive sweeteners differ in both onset and duration. Relative-intensity curves plot either
sweetness intensity in relation to temperature, and/or intensity in relation
to time. The latter curve tracks onset time, maximum intensity, duration
of maximum intensity, and time of dissipation to give the overall sweetness
duration. Sweeteners are almost always compared to sucrose, which is used
as the standard reference at 100% or 1.0.
Fructose has a relative sweetness of 1.1 to 1.7 compared to that of sucrose. "You have a
fast impact with fructose, but the perception of flavor and sweetness
would dissipate very quickly," says Nonaka. "Sucrose would last
longer at the same concentration than fructose would." Corn syrup
has a flatter time-intensity curve then either fructose or sucrose — exhibiting
a slower onset, lower overall intensity and a longer duration than the
other two sweeteners. Corn syrup with a dextrose equivalent (DE) of 42
has a relative sweetness of 0.50 compared to that of sucrose.
Although higher-molecular-weight (MW) carbohydrates, such as corn syrup or maltodextrin, won't provide
high initial-impact, they do linger longer, which helps the flavor last
longer. High-MW sweeteners tend to coat the palate, which blocks some
of the receptors, creating a masking effect, notes Nonaka. As a result,
flavors are less spiky, yet longer in duration. This masking ability is
particularly useful for subduing off-flavors, metallic notes or bitterness
that result from certain high-intensity sweeteners, or other flavoring
materials used at high levels.
Sweet sensations
Saccharin, used as a sugar substitute for many years, is reportedly 300 to 400 times sweeter
than sugar. It dissolves readily in solvents such as glycerol or propylene
glycol — the same solvents used in flavor manufacturing. Saccharin is
often combined with nutritive sweeteners, because it has a bitter aftertaste
when used alone at higher usage levels. In addition, different flavor
profiles result from combining saccharin, which has a slow flavor release,
with sweeteners that have quicker flavor-release times.
In 1999, sucralose was approved by the FDA for general-purpose use, allowing its use in all
food categories, including candy and gum. It is 600 times sweeter than
sugar. According to the product's manufacturer, McNeil Specialty Products
Company, a wholly owned subsidiary of Johnson & Johnson, New Brunswick, NJ, the sweetener is actually made from
sugar by replacing three OH-groups on the sugar molecule with chlorine
atoms. Sucralose is neither metabolized nor broken down by the body. With
a taste similar to that of sugar, sucralose can in fact be used wherever
sugar is used. It is stable under high-temperature processing and acidic
conditions, highly water soluble, and will not interact with other ingredients.
Aspartame has a relative sweetness of 180 to 200 times that of sucrose. Although aspartame contributes
4 kcal per gram, similar to that of carbohydrates, it is used at such
Acesulfame-K is 200 times sweeter than a 3% aqueous solution of sucrose and has a clean, sweet
taste and a rapid sweetness onset. "Flavor perception is heavily
dependent on good sweetness release," says Delaney-Reed. "Acesulfame-K
assures an initial impact of sweetness and thus optimal flavor release
from the first taste." Acesulfame-K works well in confections because
it is water-soluble and stable under heat processing and storage conditions.
Deciding on whether to blend nutritive and non-nutritive sweeteners together often depends
on the target market. Some parents object to feeding very young children
alternative sweeteners, particularly in light of media attention focused
on unsubstantiated adverse health effects. Yet there are other reasons
beyond public image that help determine whether using an alternative sweetener
is in order. For example, Corn Products International debuted its "layered
chocolate mint" candy at IFT 2000 in Dallas, complete with formulation,
which contains both dextrose and acesulfame-K.
The reason to use dextrose and acesulfame-K was twofold. Since dextrose is only about 80%
as sweet as sucrose, acesulfame-K provided additional sweetening making
the overall level approximately as sweet as sucrose, explains Nonaka.
Secondly, it avoids the potential pitfall of combining two hygroscopic
ingredients such as dextrose and sucrose together, which could negatively
impact shelf life. The mixture of sucrose and dextrose in place of acesulfame-K
and dextrose could have caused stability issues by picking up moisture,
ultimately resulting in sugar crystallization, or graining.
Cool reception
Sugar alcohols or polyols also have a negative heat of solution. Through a hydrogenation
process, a hydroxyl unit replaces the aldehyde or ketone group on the
sugar molecule. For instance, D-glucose (dextrose) is reduced to D-sorbitol.
Polyols, like non-nutritive sweeteners, are non-cariogenic, and used frequently
in "sugarless" products, but like alternative sweeteners, they
are also used for their impact on flavor perception. Polyols most commonly
used in candy and gum include xylitol, sorbitol, mannitol and maltitol.
Xylitol is equivalent to sucrose in sweetness level, while maltitol is
approximately 90%, sorbitol 62%, and mannitol 42% as sweet.
The degree of cooling depends on various criteria, such as heat of solution, solubility and
particle size. The finer the particle, the more quickly it dissolves into
solution, and therefore, the greater the cooling sensation. Xylitol has the highest heat of solution, yet is less soluble than sorbitol. These
two polyols give the strongest cooling sensation. Although mannitol has
a higher heat of solution than sorbitol, its solubility is very low; therefore,
its cooling effect isn't very strong. Maltitol has the lowest heat of
solution of the four polyols, with moderate solubility.
Some polyols have
additional functions. For instance, hydrogenated glucose syrup or maltitol
syrup acts as a stable, sugar-free carrier for flavors and colors, and
is both acid- and heat-stable, although slight hydrolysis can occur below
pH 3.
Other substances, such as l-menthol, act as natural cooling agents by creating the perception
of coldness through a mechanism affecting nerve endings. One issue with
l-menthol is its tendency to give a burning sensation at high concentrations.
In HR Contact, No. 1 and 2, 1998, a publication of Haarmann and Reimer (HR), Teterboro, NJ, the process involved in discovering
additional substances that act similarly to l-menthol in its cooling effects,
yet have additional marketable criteria, is described. Criteria for this
cooling compound include the substances' ability to last longer than menthol's
duration of 15 minutes or less. Also, the substance has to be liquid,
highly soluble, tasteless — so that it can be used in non-mint applications
— and must intensify the flavor profile of its substrate.
According to the data, several conclusions were made about the structure of the cooling substance
based on knowledge of the body's physiological response to cooling stimuli.
The cooling agent must be able to bind calcium at least to the degree
that menthol does; possess a strong hydrogen-binding capacity; have a
compact hydrocarbon skeleton for the body's receptor to recognize it;
exhibit a balance between its hydrophilic and hydrophobic parts; and have
a MW between 150 and 350.
HR developed several prototypes based on the criteria mentioned above and
evaluated them for the following parameters: availability, applicability,
cooling activity, price, overall flavor, freshness, duration, aftertaste
and mouthfeel. The ability of a cooling agent to enhance and intensify
flavors without imparting taste or aroma is beneficial to the developers
of hyper-flavored confections.
Pucker up
Symanski is conducting a study in conjunction with Bartek Ingredients, an acid supplier based
in Stony Creek, Ontario, Canada, that he hopes will provide information
on the effect of acids on flavor acceptability in confections. The study
will evaluate a variety of acids used in hard candies, where flavor is
found throughout the substrate, and jelly beans, which have flavor and
acid on the outside surface. Variables to be tested include citric, malic,
a combination of citric and malic, fumaric (jellies) and lactic acids
(hard candies).
"Sensory studies will be conducted to see if people really do have a preference based on
flavor type," says Symanski. "For instance, whether malic is
preferred over citric acid in apple flavor." Developers tend to use
malic acid in apple-flavored confections, since malic is the predominant
acid in real apples. The study should either support or question the theory
behind this approach. The results, expected in April 2001, should help
determine not only what acids are best-suited for specific flavors (i.e.,
citric acid in lemon), but could serve as a guide for confectioners to
set up their own acid/flavor optimization studies.
Flavor power
One method to achieve a specific effect is to use ingredients that impact at different stages
throughout the flavor profile. A flavor developed with a high-intensity
sweetener that hits up front and an acid that has a delayed hit will seem
intensely sweet, compared to a flavor that has an initial onset of acidity
followed by latent sweetness.
Although sweeteners can enhance flavors, they can also compete with them if used at too high
of a level, creating a masking effect. Vanilla is also an effective masking
agent.
Sometimes the substrate causes flavor masking. For instance, in bubble or chewing gum, a lot of the flavor gets absorbed into the gum base, and will not be released,
notes Pullia. "Encapsulated flavors are used extensively these days
in bubble and chewing gum, because they do not get as locked into the
gum base as oil-based flavors do." In addition, since sweeteners
enhance flavor delivery in chewing gum, developers often turn to high-intensity
sweeteners to achieve the desired flavor profile, because there isn't
enough room in the formula to attain the needed sweetness level with additional
bulk sweeteners.
Flavors made with an encapsulant, such as gum acacia or modified food starch, help deliver
added flavor, provide additional stability during shelf life and protect
against harsh conditions such as high acidity. Encapsulation can give
a product a timed or a prolonged release. However, they do not work well
in liquid matrices, notes Pullia.
Gumming up on flavor release
Propylene glycol alginate (pga), another emulsifying gum, also aids in flavor release. Both pga
and gum acacia reduce interfacial tension between the hydrophobic and
hydrophilic phases, without which the tongue would be unable to perceive
flavors, which are primarily concentrated oils, explains Ward.
Flavor perception is also impacted by the polarity of the flavor or aroma compounds. The
polar, or charged end of the compound is hydrophilic, and readily dissolves
in water, whereas the uncharged, or nonpolar moiety is hydrophobic. As
a result, "threshold values of flavors are affected by the lipophilic
and hydrophilic properties of the gum," notes Ward.
In gummy candies, the type of stabilizer affects not only flavor release, but flavor duration.
A line of readily soluble agars combined with other hydrocolloids such
as pectin or carrageenan are available for gummy applications "that
do not require boiling and hence may have better flavor release,"
notes Ward. The speed at which gummy candy dissolves impacts flavor duration.
"High-methoxyl pectin forms irreversible gels and will dissolve more
slowly in the mouth than agar, which has a lower gelling point than most
gums," she says.
Pectin is acid resistant; however, for optimum results, the addition of acid should be delayed until
after the agar system is hydrated, before it gels. The decision to use
agar, pectin, modified food starch or gelatin in gummy candy depends on
the formulation and desired shelf life. "For instance, simply adding
more acid to a gelatin-based gummy can break down the protein gel structure
over time," says Pullia.
Hyper colors
Natural colorants are used primarily when a natural label is required, with the exception
of carmine, which gives a stable, bright red, purple or pink color that
cannot be achieved with the use of Red #3 dye or Red #40 lake pigment.
FDC Red #40, has more of a brick-red hue and FDC #3 fades when
exposed to light, precipitates out of solution at lower pH values and
has a perceived iodine off-note to some individuals, notes Gesford.
FDC Red #3 is not the only color to avoid under acidic conditions. FDC Blue #1
and Blue #2 show significant and slight fading respectively after one
week at pH of 3. "At low pH values, FDC aluminum lakes are more stable than dyes but can bleed off and behave more like dyes. Natural
pigments are generally not stable in highly acidic environments and would
require special handling to have any chance of success in an acidic environment,"
says Gesford.
Diluents improve color handling and minimize cross-contamination during processing. The carrier
is typically chosen for its compatibility to the system it's being used
in, says Gesford. There are a wide variety of diluents that both FDC
dyes and lake pigments can be put in, such as water, alcohol, sugar syrup,
propylene glycol, glycerin or various oils. Water or alcohol can dilute
FDC dyes, while oils are used for FDC lakes. Either type of
synthetic colorant can be dispersed in sugar syrup, propylene glycol or
glycerin.
When it comes to developing candy and gum flavors for kids, the more extreme, the better, but turning
down the volume a notch may be in order for the older crowd. Unique flavor
intensities and perceptions are achieved by using sweeteners and acids
that have different flavor-intensity curves. Initial impact and duration
of flavor are key parameters to consider, as are the masking and enhancing
characteristics of various flavoring ingredients.
• Photo: Corn Products International
© 2000 by Weeks Publishing Company
Weeks Publishing Company
The fact that sweeteners provide sweetness is a given, but in confections, they actually serve
several functions. However, with respect to flavor, "the role of
the sweetener is to enhance the delivery of the flavors themselves,"
says Henry Nonaka, manager of technical services, Corn
Products International, Inc, Bedford Park, IL. "Generally, and
especially in gum application, the perception of flavor is controlled
somewhat by the release of sweetener. When you run out of sweetener, you
run out of flavor."
At one point in time, high-intensity, non-nutritive sweeteners were used mainly in dietetic,
reduced-calorie products. However, using them for flavor effect, often
in conjunction with nutritive sweeteners, is becoming increasingly popular.
Blending sweeteners often gives a synergistic effect or creates a sucrose-like
profile, says Denise DeLaney-Reed, junior food technologist, Nutrinova
Inc., Somerset, NJ. Plus, high-intensity sweeteners are non-cariogenic
and provide calorie reduction.
low levels that it is non-caloric. Aspartame loses sweetness during prolonged
heat exposure. This limits its application in confections, unless added
to a cold process or post heat processing.
Certain ingredients provide a cooling sensation in the mouth, a trait associated with mint-flavored
gum and candy. That cooling effect is often attributed to ingredients
that have negative heat of solution, such as dextrose.
Acidulants deliver sour impact to candy and gum. Their acidity produces a sour character
that can be extreme or merely complementary to the flavor at hand. Citric
and malic acids are most commonly used in confections, notes Ernie Symanski,
senior food technologist, flavor division, HR.
The choice of acid depends on the profile desired. For instance, citric
acid provides an upfront hit, while malic has a delayed impact. Combining
these two acids is said to give prolonged acidity, but "if anything,
it's the acid level that really makes the difference in terms of intensity,"
notes Symanski. Fumaric, lactic and tartaric acids also find use in candy
and gum — fumaric and lactic acids give a delayed acid hit, and tartaric
acid produces a tartness upfront.
Knowledge of process and product parameters helps in flavor delivery. "Producing hyper-flavored
confections is not always as simple as adding extra flavor," says
Bill Pullia, business development manager, Flavors of North America (FONA),
Carol Stream, IL. "Working with your flavor supplier to supply you
with concentrated flavors can remedy some of the processing problems associated
with solvent/carrier systems. If you're producing a hard candy, you want
it to be 2% moisture or less. If a non-concentrated flavor is used, you're
liable to use twice as much solvent as necessary, which will affect your
moisture content, water activity and things of that nature."
While research has
yet to be conducted on the impact of stabilizer gums on flavor perception
and release, some interesting facts are known. "In candies, gum arabic
(also known as gum acacia) is the gum of choice because of its good flavor
release and ability to protect flavor from oxidation," notes Florian
Ward, Ph.D., vice president, research and development, TIC
Gums, Inc., Belcamp, MD. "Gum acacia contains an arabinogalactan-protein
complex which enhances its emulsifying properties." Gum acacia has
low viscosity and is very water soluble — both beneficial characteristics
in water-based confections.
Bright colors enhance the perception of intensely flavored confections. Selection of a colorant
is based on the desired effect, the formula acidity and shelf-life stability.
At times, combinations work best. For example, FDC aluminum lakes
may be used in combination with FDC dyes, or both types of synthetic
colorants may be combined with natural pigments, although use of natural
(non-certified) colorants is generally minimal in candy and gum.
"FDC aluminum lakes provide stability in more extreme conditions (heat as well as light
exposure) with less bleed or mottling," explains Pam Gesford, manager
technical services, food/confectionery, Colorcon, West Point, PA. "FDC
dyes, on the other hand, provide brightness. Using a combination of FDC
aluminum lakes and dyes can give a more intense color without coloring
the consumers' mouth as much as straight dye. Combining high levels of
FDC Yellow #5 with other synthetics is an option for generating neon-type
colors in hues of yellow, green and orange."
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