Beverage Stabilizers
By Paula Gerlat
Contributing Editor, Food Product Design Magazine
Contents
In the beginning
Juicing up stability
Stabilizing by gum
Weighty matters
Healthy stabilizers
Stabilzers in CSDs
For creamy beverages
Beverage processing became increasingly sophisticated during the 20th century,
allowing manufacturers to successfully add nutrients, minerals and herbs
without compromising the product's flavor, appearance or texture. The
advent of the 21st century spawned the development of a wide variety of
drinks to appeal to a wide variety of consumer tastes, from "natural"
products to beverages with unique colors and textures never found in nature.
As a result, beverage formulators are now faced with the increasingly difficult challenge of developing new or reformulating old products to suit the latest consumer trends. To accomplish this goal, the selection of appropriate and economical beverage stabilization systems becomes a crucial part of the formulation process. These systems largely depend on the type of beverage formulated, the ingredients used and the desired end product.
In the beginning
Because there are
a multitude of beverage stabilizers available to food designers, several
questions should be considered:
What is the age of the product's target audience? Children will want a sweet, juicy product
and will not be as sensitive to viscosity and hazy appearance as adults.
However, the adult purchasing the beverage will be aware of the nutrient
quality and ingredients, so the stabilizer system becomes important to
the production of an acceptable end product.
What are the nutritional expectations of the target audience? Many consumers expect fruit drinks to be high in vitamins, "New Age" beverages are assumed to be made from pure and natural ingredients and health food consumers want health benefits from their beverages. Because of these expectations, ingredients, such as fiber, vitamins and herbs, often are added to beverages sold in health food stores. These factors all influence the type and level of stabilizer needed.
Is the beverage going to be "lite," having reduced sugar and calories? Without sugar's bulk, viscosifying and mouthfeel effects must be supplied by the stabilizer system.
What finished product characteristics, such as clarity or pH, will influence the type of stabilizer needed?
What type of processing, packaging and distribution is the product expected to undergo?
What is the target price of the product? Target price will have a significant influence on the amount and type of juice used in the product, as well as what stabilizers will be required.
Once all of these questions are answered, formulation can begin. After working with various combinations of water, sweetener and juice concentrates to select an appropriate base, or set of bases, the viscosity modifier should be identified next.
Although antioxidants and anti-microbial agents are not considered true stabilizers, they should be considered as part of the formula. Often, extreme conditions encountered during distribution will lead to flavor oxidization or microbial growth.
After a stabilizer system is chosen, other ingredients, such as color and flavor, can be added. These also may require the addition of a stabilizing ingredient to achieve desired finished-product characteristics. Color can give a beverage a more "natural" appearance. For example, orange drinks can be colored with natural colors, such as beta-carotene, or with FDC dyes. But to get the look of a natural juice, often colors can be blended with other ingredients that will act as clouding agents.
Once all of the beverage's ingredients have been decided upon, processing, packaging and storage studies should be run to ensure that the beverage will be stable in the market.
Juicing up stability
Until the late 1860s, fermentation was the only means of preserving fruit drinks. Commercial
juice production began in 1869, when the Welch Company, now located in Concord, MA, introduced pasteurized bottled
Today, the Nutrition and Labeling Education Act of 1990 (NLEA) requires the percentage of juice
in a beverage to be stated above the nutrition panel. For a beverage to
be labeled a "fruit juice," it must contain 100% juice. Often,
these are blends of juice concentrates combined to produce economical
products with traditional tastes.
Most 100% juices will not require carbohydrate stabilizers to supply viscosity. The normal solids
content is sufficient. However, in some cases, a stabilizer, such as xanthan
gum, is needed to suspend particulate matter such as fruit pulp.
Some juices, such as grapefruit juice, are naturally hazy or cloudy, but juice extraction
and processing often removes the natural compounds present in the juices
that contribute to haze. Therefore, if a cloudy beverage is desired, a
clouding agent, such as certain polysaccharides, proteins, polyphenols,
pulp or polyvalent cations, must be added to the juice. Typical polysaccharides
used for this application include pectin, starch and gums. Polyphenols
are primarily pigments and astringency compounds. Polyvalent cations, such as iron, copper, aluminum and calcium, form insoluble complexes with
proteins.
Juice beverages containing less than 100% juice can be called various names including beverage, drink,
cocktail, ade or nectar. All of these must state the percent of juice.
Most "New Age" beverages contain 5% to 10% juice, lemonades
Stabilizing by gum
Propylene glycol alginates (PGA), made by esterifying alginates with propylene glycol, are a good
hydrocolloid choice for fruit beverages. The ester groups make it harder
for the polymer chains to self-associate in the presence of relatively
high concentrations of hydrogen and calcium, so they are not as sensitive
to calcium ions as sodium and potassium alginate. They are effective in
a pH range of 3 to 6 and have emulsifying, stabilization and suspending
capability. The degree of esterification (DE) determines each form's viscosity
and emulsification levels. The hydrophobic ester groups allow the PGA
molecules to associate slightly with the surface of oil droplets dispersed
in water, so it sometimes acts as a "secondary" emulsifier.
Blends of PGA and xanthan gum have been successfully used in fruit-juice
beverages that require particle suspension, calcium fortification and
viscosity control.
High methoxyl (HM) pectins make good viscosity-control agents for fruit beverages. They have
the advantage of being considered a natural part of many juices. HM pectins
have over 50% DE. This refers to the percentage of acid groups present
in the pectin molecule as the methyl ester. In a product with levels of
less than 55% solids, this pectin acts as a thickener, rather than forming
a gel. A dilute pectin solution mimics the viscosity of a 15% sugar solution.
Microcrystalline cellulose, or cellulose gel, and sodium carboxymethyl cellulose, or cellulose gum,
are used in beverages as suspending aids, thickeners and stabilizers.
These stabilizers are generally considered natural and can provide a source
of fiber. Also, they are stable to a pH of 3.0, allowing them to remain
functional in most acidic fruit beverages during storage.
The previously mentioned hydrocolloid stabilizers must be fully dispersed and hydrated before they
are effective in beverage systems. Often, they can be dispersed using
another dry ingredient, such as sugar, as a carrier; addition to a vortex
during rapid mixing will disperse the gum. Gum suppliers often suggest
making a separate solution of the gum and part of the formula water to
ensure complete hydration of the gum. One of the causes of failure during
scale-up of a beverage system is improper gum handling.
Also, it is wise to try a scale-up run once the stabilization system is chosen. Often, mixing
and heating during processing is quite different from lab or even pilot
plant conditions. Because of this, a processing check at this stage will
reduce future scale-up problems.
Weighty matters
To prevent ringing — the colored ring at the top of a beverage caused by the separation of
the oil from the beverage — brominated vegetable oil (BVO) has been used
to weight the oil. However, in 1970, studies determined that BVOs were
possible mutagens and consequently they were disallowed in many countries,
including the EU, Japan and Australia. The United States has limited BVO
to a maximum of 15 ppm in finished beverages. In most cases, this level
is not sufficient to prevent ringing.
Glyceryl esters of wood rosin, also known as ester gums, have also been used for many years
in certain countries. They often produce a distinctive rosin-like taste,
have low oxidative stability and a slow dissolution rate into flavoring
oils.
Sucrose acetate isobutyrate (SAIB) is another weighting agent that has been used for over 25 years
in more than 40 different countries. Stephen Byrd, technical service technologist,
Eastman Chemical Company, Kingsport,
TN, says that SAIB was approved for use in the United States on June 4,
1999 and its maximum allowed use level is 300 ppm in finished beverages.
Eastman produces food-grade SAIB by controlled esterification of sucrose
with acetic and isobutyric anhydrides. According to Byrd, SAIB is stable
to homogenization and to room-temperature storage and makes a very effective
weighting agent. Its specific gravity of 1.15 allows greater flexibility
than with other weighting agents. It is very safe, does not contribute
any off-flavors or odors and is priced competitively with other currently
available weighting agents. SAIB can also be combined with glyceryl esters
of wood rosin or BVO if the finished beverage requires increased cloud.
If a no-sugar-added version of the beverage is being considered, it's time to consult with
the flavor supplier. Many flavors, such as natural flavor oils, are formulated
for either sugar or no-sugar-added products. The amount of weighting agent
will vary significantly between these two systems and different flavor
systems should be used in each.
Healthy stabilizers
To be accepted by the consumer, these products have to be perceived as natural, taste good
and "refreshing," and have an appropriate mouthfeel. Also, like
any other beverage, they must be processed and packaged to withstand the
rigors of a distribution system. One of the more popular stabilizers,
added to teas and other healthy beverages, is HM pectin. Not only does
this ingredient add viscosity and stability to the beverage, it also provides
a good source of fiber.
Many other beverages combine minerals, herbs, antioxidants and fiber to quell consumers' health
concerns. Some of these healthful ingredients can also play a stabilization
role. For example, inulin, a natural fiber extracted from many plants
and vegetables — most usually commercially extracted from chicory or Jerusalem
artichoke — is a natural stabilization ingredient. It has many of the
formulation benefits of pectins and cellulose, as well as some unique
health benefits. Inulin, a source of fructooligosaccharide (FOS), is fermented
in the colon and stimulates the growth of beneficial bacteria. Caution
is needed when formulating with this ingredient, because it produces some
laxative effects. Therefore maximum use levels must be considered.
Another new fiber source for beverages is FIBREGUM from Colloides
Naturels International, Bridgewater, NJ. According to Guido Fetta,
national sales manager at the company, the product is 100% vegetable and
is processed using physical extraction only — no chemical or enzymatic
processing is used. Fetta says that the product is 80% soluble fiber and
has probiotic properties without having a laxative effect. The product
is available in a water-dispersible, granular form.
Guar can also play a dual role in high-fiber beverages. For example, TIC Gums, Belcamp, MD, offers Nutriloid GuarNT Bland, an all
natural, odorless, tasteless form of guar that contributes approximately
80% fiber. This ingredient is both cold- and hot-water soluble, making
it an option for instant as well as ready-to-drink beverages. It provides
medium viscosity without excessive gumminess, enhances mouthfeel and helps
to evenly suspend particulates, such as fine-ground herbs or insoluble
nutrients.
Juice beverages exemplify the changes in technology that allow consumers to enjoy "fresh"
juice throughout the year. It also shows why there is an increased need
for formulators to use various ingredients and processing techniques to
achieve consumer satisfaction.
grape juice. During the 1940s and 1950s, new processes, such as flash
pasteurization and frozen concentrates, helped make fruit juices an integral
part of the American diet. Other processing changes, such as the use of
enzymes to increase the yield of juice pressing and ultra-high temperature
(UHT) sterilization, allowed for the economical production of "healthy"
beverages.
generally contain 10% to 15% juice, and many health-food beverages contain
as much as 80% juice, as well as other ingredients, such as herbs, vitamins
or minerals. Some fruit beverages do not contain any fruit juice and must
be labeled"fruit-flavored" beverage.
Polysaccharides generally reduce flavor impact and should be added to the system before final flavoring
is complete. There are many possible products to choose from.
Flavors can be either natural or artificial and, depending on the amount of juice in the beverage,
they can work as top-notes to add life to the product, or provide the
entire flavor to a beverage. Many natural flavors are based on extracted
oils from fruit, such as citrus oils, or other oil extracts. For these
flavor oils to stay dispersed in the beverage, a weighting agent must
be added. Weighting agents are lipophilic compounds with a specific gravity
greater than 1.0 that are used to equilibrate the specific gravities of
beverage components. Water and water-soluble ingredients have specific
gravities of about 1.03, while the flavor oil is usually about 0.87.
One of the fastest growing segments of the beverage industry is "healthy-lifestyle"
beverages. These range from teas to sports drinks to exotic combinations
of herbs and vitamins that claim to have health benefits. The benefits
of teas are just being explained — they are high in antioxidants and many
other beneficial compounds. Isotonic beverages, formulated to restore
athletes' depleted minerals, have been available for more than two decades.
At first, these were considered special beverages to be consumed by athletes
or people suffering with the flu. As part of the healthful-lifestyle attitude
adopted by many consumers in the 1990s, these beverages have gained a
much wider acceptance by the general public and have paved the way for
other healthful-beverages in the general marketplace.