Dehydrated Apples -Adaptable, Appealing, and Attractive
ARTICLE SUMMARY: In this white paper, we will review the selection, processing, shelf life, nutrition, and practical
aspects of the use of evaporated and low moisture apple products in snacks, bars, cereals and bakery products.
AUTHORS: Doug Webster, Director of Product Development, Tree Top, Inc.
Kevin Holland, Senior Food Scientist, Tree Top, Inc.
"A" is for apple and the apple in today's menu
is adaptable, appealing and attractive. Bakery
and snack professionals are finding the apple an
attractive accent to their bread, cake, pie, snacks,
breakfast and nutritional bars. Tree Top has good
news for food development professionals. Apple
production is increasing and technology for
processing is becoming more innovative, meeting
the future needs of the baking, cereal and snack
Many bakers will remember the days when hand
preparation of apples was common. The apple
was chosen for clean, sound quality and then
peeled, cored, sliced or diced, and included
in their favorite apple pie formula. The baker was
pleased with the result because he had controlled
every step of the process. However, with the growth
of bakeries, on-site processing became impractical
and the processed apple industry was able to meet
the needs of the baker with quality fresh, frozen,
canned, or dehydrated apple products.
The total U.S. annual production
of apples is about 248 million
boxes, or 5,208,000 tons.
Raw Material Selection and Handling
In today's market, apples selected for processing in
a dehydration operation depend on the varieties
grown in the region and customer need. Most of
the United States production is accounted for by
20 varieties. The total annual production of apples
is about 248 million boxes, or 5,208,000 tons.
The apples that are not sent to the fresh market
are processed into all different ingredient forms.
Washington State is the largest producer of apples,
growing over 60% of U.S. apples.
As noted, apples chosen for dehydration vary
according to the availability in the region and
the suitability of the variety for dehydration, and
commercial use. Figure 1 summarizes the production
of fresh apples in Washington State.
The predominant apple variety chosen for dehydration
is Gala. Gala apples are sweet and mellow in taste, have a
semi-firm texture, and are vertically striped or mottled -
overall blush in color. Since it stores fairly well in cold and
controlled atmosphere storage, it is available almost year-round
to the processor. It is uniformly round in shape
and, therefore, processes well on automated peelers.
Fuji apples, also popular for dehydration, are typically
round and range from large to very large, averaging
75 mm in diameter. They contain between 11–18%
sugars by weight and have a dense flesh that is sweeter
and crisper than many other apple cultivars, making
them popular with consumers around the world. Fuji
apples also have a very long shelf life compared to other
apples, even without refrigeration. With refrigeration, Fuji
apples can remain fresh for up to a year and are typically
available from October through June or July.
The Granny Smith is still in the top 5 of total tons
harvested in Washington State, both in fresh fruit
production and as a dehydrated product. It is a tart
apple with white-green flesh and is firm in texture.
Granny Smith is one of several apple cultivars that are
high in antioxidant activity, and they boast the highest
concentration of phenolics amongst the apple breeds.
Honeycrisp apples are rapidly becoming a prized
commercial variety known for their sweetness, firmness,
and tartness. They have much larger cells than most
apples, which rupture when bitten to fill the mouth with
juice. This apple is becoming so popular, several snack
and bar manufacturers are highlighting “made with
Honeycrisp apple” on their retail package. Honeycrisp
apples lose their crisp texture during prolonged storage
which reduces their availability during the months of
March through September.
Golden Delicious apples are sweet and mellow with a
tender golden skin, and its flesh stays white after slicing
for longer than other varieties. With refrigeration Golden
Delicious are typically available from September through
August, however this variety has been declining in
production and, as a result, not as readily available for
processing as traditionally seen.
The field representatives for dehydration companies
pay close attention to quality as they deal with each
fresh apple packing house in the contracting of
peeler fruit for a processing season. Defects, such
as bruising, bitter pit, and hail damage, can severely
affect the quality of the fruit.
A peeler quality apple is a superior apple to the
apple that goes to the juice process. Peeler quality
apples must meet certain size criteria to be suitable
for production equipment and certain appearance
quality specifications to be considered for an
evaporated (regular moisture) apple product. It
also must meet certain pressure test requirements,
depending on customer requirements for a soft or
firm apple dice in their product.
The fresh apple packing house personnel are
educated on the importance of careful handling of
the apples that go to the processor. The sorting bins
are sometimes water-filled. Since the apples float in
water, the incidence of bruising is reduced.
Bins of fruit destined for the processor are stored in
cold storage or controlled atmosphere rooms until
they are needed. Controlled atmosphere is a low temperature,
low-oxygen (1%), low-carbon dioxide
(1.5%) storage room where fruit is, essentially, "put
to sleep" in regards to respiration and ripening
When the apples are received at the processing
plant, they are graded for quality then transferred
into water-filled tanks. The apples are washed and
sized to remove very large and small apples that are
more suitable for other processes. As they enter the
process, apples are inspected visually and sorted for
Peeling and Coring:
Typically, a mechanical peeler removes the skin, then
a tube removes the core, and finally small curved
blades remove the seed cell pocket from the apple.
Dicing and Slicing:
The peeled and cored apples are then diced or
sliced to customer specification. In most processes,
the dices are optically sorted removing additional
blemishes, seeds, stems, or carpel from the product
Sodium sulfite, potassium metabisulfite, and sulfite
alternative blends (ascorbic acid, citric acid, sodium
chloride, and calcium chloride) have been the
traditional agents used to minimize enzymatic and
non-enzymatic browning and microbial spoilage
in dried fruit. The freshly peeled apples are dipped
or sprayed with the chosen solution prior to
Tree Top has developed a proprietary blend of sea
salt and lemon juice to minimize enzymatic browning without the need for sulfites. The treatment protects
color during drying and maintains a bright color in
low moisture food systems. For dried apples with
no treatment, Tree Top dries the apples to a water
activity (aw) below 0.60 where spoilage organisms
do not grow.
Most processes use a continuous gas-fired air
dryer to reduce the moisture of a fresh apple from
85% to 14-24%. At this moisture, they are shelf
stable and typically referred to as evaporated or
regular moisture. They can be further dried to an
intermediate moisture range of 10 – 14% moisture
or dried to below 3.5% for low moisture food
applications. Evaporated (regular moisture) apples
are typically used for high moisture food systems
such as fruit fillings and baked goods, however
the snacking industry is using more evaporated
apples with the increase of consumer snacking.
Intermediate moisture is best suited for snack bars
ranging in water activity (aw) of 0.40 – 0.60, while
low moisture is best used for low aw pastry fillings,
crispy snacks/bars and cereal. Drying apples reduces
freight costs, increases shelf life, and increases the
versatility of use in food systems.
The air flow, bed depth, temperature, and time in
each stage are crucial to maintaining quality color and moisture levels in the final product. See fig. 2.
The dices may be subjected to an equalization step
after dehydration to assure proper moisture levels in
the final product.
Evaporated (regular moisture) products are custom
manufactured to meet customer needs. In the case
of a “dry cut,” an additional cutting of the evaporated
(regular moisture) apple dice is required to produce
chips, granules, grind or low moisture powder. These
products are used in various bakery fillings and
Packing/Storage and Shelf Life:
The evaporated (regular moisture) apple products
are typically packed in 40-50 pound fiberboard
cases, and low moisture apples, depending on the
product type, are typically packed in a 15-30 pound
case, although other pack sizes are available. Product
is packed within a polyethylene case liner which is
either folded or heat sealed to protect the product.
The case is sealed with tape and stacked on a pallet.
Storage temperature for dried apples is very crucial
to the preservation of quality (flavor and color).
Sulfites dissipate at different rates, depending on
temperature of storage. Figure 3 shows these typical
dissipation rates under different conditions.
Storage/Shelf Life Recommendations
|Evaporated Apples / Intermediate Moisture Apples
|Contains Sulfites (500-1500 ppm)
|Low Moisture Apples
|Contains Sulfites (500-1500 ppm)
|Low Moisture Powders*
|Standard (with Calcium Stearate)
|Other Flow Agents (silicon dioxide or
|*Low moisture fruit powders are susceptible to clumping with temperature swings, for best handling
properties, please maintain refrigerated storage conditions
Grades and Quality
Dried apple manufacturers work closely with each
customer to develop a specification that meets
their product requirements. Common attributes
are moisture, water activity, sulfite level (if used),
sieve analysis, color, maximum allowable vegetative
materials (VM) and blemishes (visual defects).
Mechanical removal of peel, core, seeds, calyx,
and stems from apples is not 100%. Although this
material is not harmful, most manufacturers have
maximum allowable limits that are set in the
specification. If the apples are bruised during
harvesting, packing or in the manufacturing process,
these can develop into a visual blemish, which also
has limits set forth in the specification. Product
grading is performed during the process. Blemishes
are monitored from beginning to end so the
equipment operators can make changes to reduce
the blemish level if necessary.
Typical Uses and Functionalities
|Evaporated (Regular Moisture) Apples
||Piece identity, flavor extender
||Fruit fillings, fried pies, danishes,
||Extenders, texture, apple sauce,
||Cookie filling, granola bars, fruit bars
||Large piece identity
||Baked goods, snacks, pies
|Chops (whole chopped apple dices)
||Piece integrity, flavor, inexpensive
||Mincemeat, apple butter
|Low Moisture Apples
||Piece identity, flavor
||Cereals, granola bars, dry mixes
||Rapid rehydration, piece identity
||Cereals, instant hot cereals,
||Refrigerated doughs, cereals
||Small piece identity, appearance, flavor
||Cake mixes, muffins, granola bars, cereals, toppings
|Powders, Flake Powders
||Texture, flavor, prevent “boil out,” extender
||Apple sauce, cookie fillings, cake mixes, fruit leather
Typical applications for the various evaporated (regular moisture) and low moisture apples and their
functions are presented in Table 1. Low moisture apples are low in water activity (aw =0.15 -0.25) and are
used in dry cereal, bakery, and snack products where controlled water activity (aw) is crucial to prevent
oxidative rancidity, microbial deterioration, and color degradation. A crisp, crunchy apple texture may be a
necessary attribute to the product.
Low moisture apples are used primarily in the cereal,
and snack food industries. The cereal industry
utilizes mostly low moisture apple products as
granules, flakes, and dices in ready-to-eat, cooked, or
instant-type breakfast cereals. The apples can also
be colored and flavored with other fruit flavors, such
as strawberry, peach, and blueberry, to increase their
versatility in cereal products.
The baking industry uses custom-made fillings
(apple, raspberry, blueberry, etc.) which are
formulated using evaporated (regular moisture)
apples for flavor, texture, piece identity, and
extending other higher cost fruit. A baker may
also develop his own formulation for a pastry
filling. The apple fillings are deposited on Danish
pastries, strudels, or in soft cookies or filled fruit
bars. Evaporated (regular moisture) or intermediate
moisture apples may also be added to a dry mix
suitable for cakes, cookies, or muffins.
A rapidly growing use of dehydrated apples is in the
snack food industry, specifically fruit and nut granola
bars and fruit rolls. Intermediate or low moisture
apple granules or dices in combination with
cinnamon or various fruit flavors are a great snack for
lunch, coffee breaks, picnics, or athletic activities.
Reconstitution for Bakery Production
Evaporated (regular moisture) apples can be
reconstituted with either hot or cold water. See
fig. 4. Although the most popular method for
reconstitution is to heat the evaporated (regular
moisture) apples with 3-5 parts water, apples may be
slowly reconstituted using a cold water soak. These
cold water reconstituted apples can be worked
into a cold or hot starch filling if a firm texture and
piece integrity are desired. Customers may want to
experiment with cook time and quantity of water
addition to determine the ideal texture for their
Effect of Variety
Varietal differences in sugar/acid ratios determine
the perceived sweetness and tartness of the fruit.
The higher acid apples (Granny Smith, etc.) will taste
tarter. Also, the malic acid content can interfere
with applications incorporating a leavening agent
(sodium bicarbonate, etc.), requiring adjustments
in the amount of apples, the type of apples, or
the amount of leavening acids (sodium acid
pyrophosphate, potassium acid tartrate, sodium
aluminum sulfate, anhydrous monocalcium
phosphate, sodium aluminum phosphate, etc.).
Excess carbon dioxide production prior to baking
can produce an undesired texture in muffins or
cakes. Refrigerated doughs for biscuit or muffin
products require limited initial carbon dioxide
release during preparation and packaging and
considerable gas release during baking. Thus,
sweeter apple varieties such as Golden Delicious, Fuji
and Gala have been used, since the titratable acidity
is lower than Granny Smith apples.
All Purpose Filling
A common use of evaporated (regular moisture)
apples is in a typical cooked filling. The apples are simmered for five to ten minutes or until the
desired reconstituted texture is obtained. The
blend of sugars and spices can be varied to meet
the expectations of the bakery professional and are
added after the apples have been cooked to limit
competition with the apples for the available water.
The proper amount of starch (to give the desired
consistency) is added as a slurry with water and
cooked until the mixture thickens. The starch type
must be acid stable, freeze-thaw stable for specific
applications, smooth in consistency, and bland in
flavor. For a fried pie application, the starch may have
to be increased to stabilize the pie during and after
the frying operations.
Effect of Season:
Evaporated (regular moisture) apples vary in their
reconstitution ratio with the time of year when
processed. Early season (August – September) fruit
is higher in acid, lower in sugar solids, and firmer in
texture. The cook times may have to be increased
to produce the desired texture. The level of water in
the formulation may have to be decreased to allow for lower absorption. The level of citric
acid and/or lemon juice may have to
be decreased to produce the desired
tartness level. The piece integrity
of early season fruit in a filling is a
consistent, firm, intact apple dice.
Late season fruit (late October – late
November) tends to be softer when
reconstituted. A greater reconstitution
ratio is likely to be seen in mature fruit
requiring an increased level of water in
the formulation to achieve the desired
consistency. The acidity is lower and
sweetness or sugar solids are higher
than early season fruit. Some dices
may lose their piece integrity if cooked
excessively. The length of cooking
time may have to be increased to
minimize loss of texture. Controlled
atmosphere fruit (January – July)
typically has intermediate firmness.
Effect of Variety:
The variety of apples chosen for a filling will make a
difference in the characteristics of that filling. Red
Delicious apples tend to cook up to a sweeter, softer
dice. Golden Delicious apples allow flexibility in
texture and flavor. Granny Smith apples are typically
a firm, tart dice in a filling.
At times a phenomenon known as “boil out” will
occur in fruit pies due to low soluble solids. Moisture
can be bound and soluble solids increased through
the use of apple powder or apple flake powder to
help reduce boil out.
These are average values and should be used only to approximate the nutritional composition of any food
formulations. Nutritional data not found on this list are present in levels not required by NLEA standards.
About the Authors
Doug Webster, Director of Product Development, Tree Top, Inc.
Doug Webster has been with Tree Top, Inc. since 2000 and is currently
Director of Product Development. In this role, he leads a research and
development team, creating custom fruit solutions for customers of Tree
Top. Doug earned a B.S. in biology at Western Washington University and
a M.S. in food science from Washington State University. After completing
his masters, he moved to the Yakima Valley focusing his endeavors in the
hop, wine, and fruit industries. Doug is a wine maker and, until recently,
owned his own winery. He now only makes wine for family and friends.
Kevin Holland, Senior Food Scientist, Tree Top, Inc.
Kevin has been with Tree Top, Inc. since 2011 and is currently a
Senior Food Scientist. In this role, he focuses on process research,
troubleshooting existing products and processes, providing technical
support to internal and external customers, and maintaining research
projects. Kevin earned a B.S. in biology with a minor in philosophy at
the University of Pittsburgh at Bradford and a Ph.D. in food science from
Virginia Tech. After completing his doctorate, he worked for a year as
a postdoctoral associate at Virginia Tech investigating antimicrobial
alternatives to sodium benzoate in beverages. Kevin has three children, all
under the age of five. He is our in-house cider expert and enjoys demoing
his hard cider creations with the Tree Top team.
Charlotte L. Deuel Tree Top August 1986
Yepsen, Roger (1994). Apples. New York: W. W. Norton & Co
Lee, C.Y.; N.L. Smith (2000). Apples: An Important Source of Antioxidants in the American Diet
Granny Smith is healthiest apple, Retrieved 2013-02-27
Cabe, Paul R.; Baumgaten, Andrew; Onan, Kyle; Luby, James J.; Bedford, David S. (2005).
Dried apples are a versatile fruit addition to many bakery,
cereal and snack applications. Technical service and sales
representatives are ready to assist the bakery professional with
For filling, snack bar or other recipes/formulations, visit www.
Contact Tree Top at (800) 367-6571 Ext. 1435
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