Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates generally to potato
processing and more particularly to a method for preparing
skin-on "potato boats," which are hollowed out potato halves
used in making so-called "potato skins."
The serving of "potato skins" has been steadily
increasing in restaurants and other eating establishments.
Potato skins are formed from hollowed-out potato halves or
"potato boats" which typically are fried in hot oil and filled
with condiments, such as cheese and the like.
Such potato boats traditionally have been prepared
at the restaurant by baking and thereby partially cooking
whole potatoes, slicing the potatoes in half, scooping out
the center portions of the potato halves and then oil frying
and/or broiling them. Prior to the slicing, the whole
potatoes are indistinguishable from "baked potatoes" commonly
served for dinner, although at this stage the potato boat
product is partially cooked in the sense that a subsequent
oil fry it desired to give the product a fried character.
Similarly, potato boats have been prepared commercially for
shipment to restaurants and the like by baking and thereby
partially cooking whole potatoes, slicing the potatoes in half,
manually or mechanically scooping out the center portions of the
potato halves, and then freezing them. Again, prior to
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frying, the scooped-out potato halves have a cellular
structure like that of a baked dinner potato.
Such processes are unsatisfactory for several
reasons. First, they tend to produce a nonuniform product
having a variable thickness. As a result, uneven cooking
may occur from one potato boat to the next and even within
a single potato boat. A potato boat or portion thereof
that is too ''thin" will overcook and have a texture which
is too hard for desirable consumption. Conversely, a
potato boat or portion thereof that is too "thick" will
undercook and have a texture which is too soft.
Second, a nonuniform product makes it difficult
accurately to control the yield of the product, that is,
the amount of potato product relative to the quantity of
condiments added. A potato boat which is too thick tastes
too much like a baked potato, while a potato boat which is
too thin lacks the desired consistency.
Third, the product when fried in oil is "heavy"
and has a high oil perception, giving it a greasy taste.
Moreover, the product tends to be flaky and prone to
making the frying oil "dirty."
Fourth, the step of scooping out the center
portions of the potato halves is time-consuming, and hence
is not conducive to efficient, inexpensive production of
potato boats in large quantities.
Fifth, the product cannot be reconstituted by
baking, broiling or microwave without sacrificing the
fried character of the product which makes it popular.
Finally, the center portions removed from the
baked potato halves are in a soft, cooked form, and hence
have little value aside from their use as a mashed potato
; product.
foe
Accordingly, there is a need for a process for
making skin-on potato boats having a relatively uniform shell
thickness and improved product characteristics.
It is therefore one object of the invention to
provide a process for preparing potato boats having a
relatively uniform shell thickness.
According to one aspect of the invention there is
provided a method of preparing, from a raw, skin-on potato,
a potato boat having an outer potato layer of predetermined
thickness adjacent the skin, and a hollowed-out center the
method comprising the steps of: slicing a whole, skin-on
potato to form a plurality of potato sections, each having a
portion of the outer potato skin thereon; thereafter removing
a center portion of a section, leaving an outer potato layer
of predetermined thickness adjacent the skin; thereafter
parrying said potato section; and at some stage in the
processing of said potato or potato section prior to parrying,
blanching the outer potato layer thereof to gelatinize the
same and thereafter maintaining the outer potato layer in a
blanched gelatinized condition until parrying is commenced.
According to another aspect of the invention there is
provided a method of preparing a potato boat comprising the
steps of: blanching a raw, skin-on potato to gelatinize at
least an outer layer thereof beneath the skin of predetermined
thickness; thereafter slicing the potato skin into sections
to form a potato section having an outer potato skin; thereafter
removing a center portion of the section, leaving the
gelatinized outer layer adjacent the skin; thereafter parrying
the potato section; and subsequent to blanching, maintaining
the outer layer in a blanched gelatinized condition until
parrying is commenced.
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According to a further aspect of the invention
there is provided a method of preparing, from a raw, skin-on
potato, a potato boat having an outer potato layer of
predetermined thickness adjacent the skin, and a hollowed-out
center, the method comprising the steps of: slicing a whole,
skin-on potato in half to form a potato half having a portion
of the outer skin thereon; thereafter removing a center portion
of the potato half, leaving an outer potato layer of pro-
determined thickness adjacent the skin; thereafter parrying
the potato half at a temperature within the range of about
325-400 F for about 1/2 to 10 minutes such that the resulting
potato half has an oil content of less than about 8% by weight;
and at some stage in the processing of said potato prior
to parrying, blanching the outer potato layer thereof to
gelatinize the same and thereafter maintaining the outer potato
layer in a blanched gelatinized condition until parrying is
commenced.
In the drawings:
Fig. 1 is a front elevation Al view of a whole potato
after it has been blanched and sliced lengthwise along its
major diameter.
Fig. 2 is a plan view of a potato half taken along
line 2-2 of Fig. 1, showing a perceptible ring distinguishing
the outer gelatinized layer formed during blanching from the
ungelatinized center portion.
Fig. 3 is a vertical section taken along line 3-3 of
jig. 2.
; Fig. 4 is a front elevation Al view of one embodiment
of the invention showing a potato half being passed on a
conveyor screen over a blasting jet.
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I
36
Ego. 5 is a perspective view of a second embodiment
illustrating -the removal of the ungelatinized center portion
with a scraping device.
Fig. 6 is a perspective view of a potato half after
the ungelatinized center portion has been removed, either by
manual scooping or blasting.
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In accordance with the present invention,
potatoes are held in storage under conventional accepted
conditions, so as not to accumulate excessive amounts of
sugar therein. Potatoes of the Russet Burbank variety
weighing 4 to 8 ounces and having a length of 3 to 4 1/2
inches and a diameter of 1 3/4 to 2 3/4 inches are
preferred. The potatoes are cleaned using a water spray
or some other technique well known in the art.
The potatoes are inspected whereby defective and
misshaped potatoes are removed. The peels of the potatoes
are pierced with about 60-80 small holes to prevent
puffing during later processing.
The potatoes are then blanched to deactivate
enzymes present therein and, as illustrated by Figs. 2 and
3, to gelatinize a 1/8-1/2 inch outer layer or "heat ring"
10 beneath the skin. It has been found that a 1/4 inch
heat ring works well. The heat ring lo is translucent and
hence is visually distinguishable from the white, opaque
ungelatinized center portion 14. The potatoes preferably
are blanched in water at a temperature ranging from about
170F to 210F for about 3-15 minutes. It has been found
that blanching at about 190F for about 7 minutes works
well. After blanching, the ungelatinized center portion
of each potato constitutes about 25~-75% of the potato by
weight depending upon the thickness of the heat ring. For
example, the center portion of a potato having a 1/4 inch
heat ring would constitute about 45~-52% of the potato by
weight.
The blanched potatoes are cut in half lengthwise
along their major diameter to form potato halves having
; cut surface portions 18 (Fig. 3).
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In one embodiment ox the process, the cut surface
portions 18 are then subjected to impingement by a stream
of grit-like particles, as, for example, raw potato starch
particles, carried in air. This may be accomplished by
passing the potato halves on a screen conveyor 22 over one
- or more blasting jets 26, as illustrated in Fig. 4. The
impingement of the starch particles abrades away the
ungelatinized center portions 14 of the potato halves,
leaving intact the heat rings 10.
During the impingement process, a stream flow
rate of about 100 CAM is preferred, although any flow rate
sufficient to abrade away the ungelatinized potato cells
will work. It is believed that the ungelatinized center
portions are effectively removed because the ungelatinized
potato cells shatter when impinged by the potato starch
particles. The gelatinized potato cells forming the outer
heat ring do not abrade away because they are more elastic
and not prone to shattering.
A writ or flail may also be used as the impinging
material, but the use of potato starch is advantageous
inasmuch as it is a non-foreign material and readily
recyclable. Other impinging materials, such as potato
flour and crushed bulgur wheat, may also be used. A
medium other than air may also be used to carry the
abrasive material. Surface starch, grit or flail
remaining on the potato halves after blasting is rinsed
;~~ off with a water spray. Such starch may be recycled as an
abrasive or used in other food products.
After rinsing, the hollowed-out potato halves,
such as the one shown in Fig. 6, are inspected and those
with excessive defects or undesirable cavities are
removed. Such potato halves may be frozen at this time
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for storage and/or transportation, but preferably are
processed further as provided below.
The hollowed-out potato halves may be blanched
again so as to remove any high sugars that may have
developed during storage and to gelatinize any starch not
converted on the initial blanching of the whole potatoes.
Such blanching may be at a temperature ranging from about
150F to about 210F and for about 2-10 minutes. It has
been found that blanching at about 190F for about 5
minutes works well.
The blanched potato halves are next air cooled at
ambient temperature for about 2-10 minutes to stop the
blanching action and, if necessary, to remove some of the
moisture from the product and facilitate retrograding of
the starch. Air cooling the potato halves at any
temperature below 150F will stop the blanching, but
cooling at about 70F for about 5 minutes is preferred.
The potato halves may be cooled with a water spray or bath
instead of air
The cooled potato halves are then parried in hot
oil at a temperature ranging from about 325F to 400F for
about 1/2-10 minutes preferably at about 375F for about
5 minutes.
If prepared according to the foregoing
parameters, the processed potato halves or potato boats
will have a solids content of about 30~ to 42%, including
about 4% 7% oils, by weight, with "thinner" potato boats
tending to fall into the higher end of both ranges and the
"thicker" products into the lower end. They are firm,
hold their shape and have a palatable texture for
consumption. For purposes of storage and/or shipment they
may be frozen at a temperature ranging from about -30F to
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I
-10F for about 15-30 minutes, and preferably at about
-20F for about 20 minutes.
The frozen potato boats may be reconstituted by
frying them in oil at a temperature of about 360F for
about 3 minutes, or by other conventional methods, such as
broiling or baking. They may also be reconstituted in a
microwave oven, but in that event, they should be
processed by a longer parrying so that their solids
content, when frozen, is greater than the 30~ to 42% range.
In a second embodiment of the process, the
potatoes are processed exactly as set forth above, except
that the ungelatinized center portion 14 is manually
scooped out with a scraping or cutting device 30, as shown
in Fig. 5, rather than being subjected to a stream of
starch particles. The ring 12 provides a distinct visual
guideline debarking the outer heat ring from the
ungelatinized center portion, thereby enabling the scraper
to produce a product having a markedly uniform product
thickness in comparison to prior manually and mechanically
scooped products.
Because the uncooked center portion is relatively
hard, a substantial portion thereof suitable for a wide
; variety of uses may be removed in a single piece. A few
touch-up passes with the scraping device to remove small
fragments of the uncooked center portion adjacent ring 14
may be necessary.
Russet type potatoes having a length of about
3 I inches and a major diameter of about 2 l/2 inches
were washed, pierced and blanched at a temperature of
about 190F for about 7 minutes. The potatoes were sliced
in half lengthwise along their major diameter, exposing
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cut surfaces. Such cut surfaces were then subjected to a
stream of starch particles carried in air.
A standard blasting gun or jet was used. It had
a Jo. 6 (6/16 inch) nozzle opening positioned about 3
inches away from the cut surfaces and a No. 7 (7/32 inch)
orifice. A stream flow rate of about 100 CAM at about 120
psi was utilized. A standard mixture of starch granules
ranging in size from 10 to 100 microns was drawn into the
air stream through a venturi located between the orifice
and nozzle. The stream removed the ungelatinized center
portions of the potato halves, leaving the outer heat
rings intact.
The resulting hollowed-out potato halves were
rinsed with a water spray and blanched at a temperature of
about 190F for about 5 minutes. They were then cooled at
ambient temperature for about 5 minutes. Thereafter, they
were parried at a temperature of about 375F for about 5
minutes and subsequently frozen. The frozen potato halves
were reconstituted by frying them in oil at a temperature
of about 360F for about 3 minutes.
The resulting potato boats had crisp surfaces,
mealy potato interiors, low oil perception and golden
coloration. They had an average solids content of about
43%, including about 6% oils.
Russet-type potatoes having a length
predominantly between 3 and 4-1/2 inches (average of about
3-3/4 inches) and a major diameter predominantly between
1-3/4 and 2-3/4 inches (average of about 2-1/8 inches)
were washed and blanched at a temperature of about 190
for about 7 minutes. The potatoes were sliced in half
lengthwise along their major diameter, exposing cut
surfaces.
I
The center portions were manually removed with a
scraping device, using the ring as a visual guideline.
The resulting hollowed-out potato halves were blanched at
a temperature of about 190F for about 5 minutes, and then
water cooled at about 70F for about 5 minutes.
Thereafter they were parried at a temperature of about
375F for about 5 minutes and subsequently frozen.
The resulting potato boats after reconstitution
had crisp surfaces, mealy potato interiors, low oil
perception and uniformly golden coloration. They were
slightly thicker than the products of the previous example
and had an average solids content of about 38~, including
about 4.6~ oils.
With each of the foregoing processes, the product
when scooped and parried has an "associated" or
"integrated" cellular structure. The term "integrated" is
intended to refer to a state in which a cohesive cellular
structure exists bonding the potato cells together, as in
the case of raw or moderately blanched (gelatinized)
potato cells. It excludes potatoes having "disassociated"
potato cells, as where the potatoes have been baked or
blanched for a long period of time. In the case of
disassociated potato cells, an integral cellular structure
no longer exists. ale potato cells separate and the bonds
between cells break down. When the disassociation is
caused by baking, the cells also dehydrate, giving them a
mealy character.
It will be apparent to those skilled in the art
that the gelatinized layer or heat ring formed during the
initial blanching of a potato has a uniform thickness
throughout. Thus, after such potato is cut in half and
the ungelatinized center portion removed by the impinging
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particle stream, the resulting potato boat has a uniform
thickness throughout. Moreover, all potato boats blanched
at the same time and temperature parameters have the same
thickness, regardless of variations in size. As a result
of such uniformity in the product, it will be appreciated
- that it is easy to evenly cook and maintain high yield
control during the product's preparation. Furthermore,
the thickness of the product can be easily varied simply
by modifying the initial blanching parameters. For
example, the thickness can be increased by prolonging the
initial blanching period and decreased by reducing such
period.
The manual scooping embodiment does not achieve a
product with quite the same degree of uniformity of
thickness US the impinging particle embodiment. However,
the presence of a visual guideline distinctly defining the
portion of potato half to be removed enables the scraper
to produce a product of relatively uniform thickness and
one which achieves the advantages associated with a
uniform thickness to a large extent.
The impinging particle embodiment enables potato
boats to be produced efficiently and inexpensively in
large quantities through the use of automated conveyors,
blasting jets and potato handling equipment, and therefore
with only a minimal amount of manual labor.
The manual scooping embodiment is advantageous in
that the uncooked center portion is removed substantially
in a single piece. Thus, such center portion is a
valuable by-product suitable for a wide variety of uses
and further processing.
Both embodiments produce a product having
markedly improved oil perception, texture, taste and
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coloration in comparison to prior products. Such
improvement is due primarily to processing the product in
a specified manner and with defined temperature and tire
parameters. For example, during processing the surface of
the product becomes sealed, containing the desired
percentage of oil by weight. Thus, unlike prior products,
very little oil is absorbed into the product during the
oil fry reconstitution. Additionally, the product has a
smooth, non flaky texture. Thus, upon reconstitution there
is little tendency of the product to dirty the frying oil.
In yet a third embodiment of the process, raw
potatoes of the Russet Burbank variety are stored, cleaned
and inspected in the manner earlier described. By virtue
of its raw state, the potatoes have an integrated cellular
structure. The potatoes are sliced in half lengthwise
along their major diameter to form skin-on potato halves.
Thereafter, the center portions of the potato
halves are removed with a mechanical apparatus or
otherwise, leaving preferably a 1/4 inch potato layer
adjacent the skin. The hollowed-out potato halves are
blanched at a temperature ranging from about 150F to
about 210F for about 2-10 minutes, to gelatinize the
potato layer. Though blanched, the potato halves still
have an associated or integrated cellular structure.
Thereafter, the potato halves are air cooled, parried,
frozen and reconstituted in the manner earlier described.
Product prepared in the foregoing manner has an
average oil content after parrying of about 4-7~, by
weight, with virtually all the product within a range of
about I to 8%, and an average solids content within the
range of about 30-42%, typically about 34-38%. Upon
reconstitution, the product has an average oil content of
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about 7-8%, by weight, with virtually all the product
falling within a range of about 6% to 11~, and a solids
content within the range of about 34-48%, typically about
41-43~.
A sample of raw Russet-type potatoes were washed
- and sliced in half lengthwise along their major diameter.
The center portions of the potato halves were removed by
hand scooping, leaving skin-on, hollowed-out potato halves
having a potato layer adjacent the skin of about 1/4
inch. The raw hollowed-out potato halves were blanched at
a temperature of about 185F for about 10 minutes,
parried at a temperature of about 360F for about 4
minutes, and then frozen. The frozen potato boats had an
average solids content of about 38.29%, including about
5.39% oils, by weight.
Another sample of potato boats, processed as just
described, were reconstituted by frying them in oil at a
temperature of about 360~F for about 3 minutes. The fried
potato boats had crisp surfaces, mealy potato interiors,
low oil content and golden coloration. They had an
average solids content of about 44.10%, including 7.68%
oils, by weight.
While potato boats processed in the foregoing
manner do not have all the advantages attendant with the
"heat ring" processes illustrated in Examples I and II,
this process is a significant improvement of prior potato
boat processes for several reasons. This embodiment, as
well as the embodiments earlier described, produces a
product having a significantly lower oil content than
prior processes, giving the product a less greasy, more
palatable taste. In theory, because the hollowed-out
potato halves have an integrated cellular structure when
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parried, whether in a raw (Third Embodiment) or blanched
(First and Second Embodiments) state, the cohesive
cellular structure acts as a barrier to minimize the
amount of frying oil absorbed into the product. The
relatively small amount of oil that is absorbed into the
product seals the surface of the product to a certain
extent, thereby minimizing the absorption of any
additional oil by the product when it is finish fried.
Inasmuch as prior potato boat processes bake and then fry
the product, the disassociated potato cells act much like
a sponge to absorb a relatively large amount of frying oil.
The disassociation effect is a function of time
and temperature. The point at which disassociation occurs
is difficult to measure, but the difference between
integrated and disassociated cellular structure is readily
observable. It is roughly estimated that potato cells in
the outermost layers of a potato baked at 450F would
begin to disassociate between about 20-30 minutes. It is
also roughly estimated that potato cells in the outermost
layers of a potato blanched at 190F would begin to
disassociate after about 50 minutes.
Frozen product prepared in accordance with this
embodiment, as well as the other embodiments, may be
reconstituted by baking, broiling or microwave, and still
retain to a large extent its fried character, since the
product is parried before it is frozen and therefore
contains a measurable oil content. Frozen product
prepared in accordance with prior methods is not believed
to contain any measurable oil content and therefore cannot
be reconstituted other than by frying if the product's
fried character is to be retained.
~39306
In addition, product prepared in accordance with
this embodiment, as well as the other embodiments, is
believed to have better storage attributes than prior
products, since the oil content of the frozen product acts
to preserve the product and prevent dehydration.
Moreover, as with the manual scooping embodiment earlier
described, the center portion is removed as a raw,
virtually single piece of potato suitable for further
processing into other potato products.
The foregoing advantages are not believed to be
strongly influenced by omitting the blanching step(s)
before parrying. However, a blanching step is strongly
preferred because it is believed that the blanch and
parry together give the product improved texture, flavor
and coloration.
Those skilled in the art will appreciate that
some deviation from the above procedure, including
elimination of some of the steps, will still result in a
satisfactory product. For example, the product need not
be frozen if it is being prepared for immediate
consumption. As a further example, both a mechanical
scraping device and the impinging starch particles may be
used to hollow-out a potato half after blanching, the
scraping device being used initially to remove the
innermost segment of the gelatinized portion and the
starch particles being used to remove the gelatinized
portion closest to the heat ring. in this way, the amount
of energy used during the starch-impinging step is
minimized. Similarly, the described method can be used to
make "open shell" potato boats, that is, hollowed out
potato boats that have been cut in half or in thirds, or
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lZ3~3~6
whole potatoes that have been sliced in, for example,
thirds or fourths and the center portions removed.
Having illustrated and described the principles
of my invention by what is presently a preferred
embodiment and several suggested alternatives, it should
be apparent to those persons skilled in the art that such
embodiments may be modified in arrangement and detail
without departing from such principles. I claim as my
invention all such modifications as come within the true
spirit and scope of the invention as defined by the
following claims.
