CA1078251A - Process for the preparation of a frozen potato product - Google Patents
Process for the preparation of a frozen potato productInfo
- Publication number
- CA1078251A CA1078251A CA253,710A CA253710A CA1078251A CA 1078251 A CA1078251 A CA 1078251A CA 253710 A CA253710 A CA 253710A CA 1078251 A CA1078251 A CA 1078251A
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- Canada
- Prior art keywords
- pieces
- cuttings
- potato
- minutes
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
- A23L19/10—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops
- A23L19/12—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops of potatoes
- A23L19/14—Original non-roasted or non-fried potato pieces
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- Health & Medical Sciences (AREA)
- Nutrition Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Preparation Of Fruits And Vegetables (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a process for the preparation of a frozen potato product, characterized by (a) peeling potatoes;
(b) if necessary, cutting the potatoes to pieces of roughly equal thickness or sizes; (c) heating the pieces of potato in water until the hearts of the potato pieces have acquired a temperature of 60-80°C; (d) cooling the preheated pieces of potato until the hearts of the pieces have acquired a temperature below 25°C; (e) heating the pieces of potato in hot water or steam having a temperature of 95-130°C for such a time that when the temperature T in °C, measured in the hearts of the pieces is plotted in a graph against the heating time t in minutes, the area which is represented by the definite integral amounts to 300-900°C minutes; (f) cooling the heated pieces of potato, if desired; (g) comminuting the pieces of potato to cuttings; (h) mixing the cuttings with a fat if desired, and with salt and/or cheese, bacon or onions, if desired; (i) cooling the cuttings obtained in step (g) or (h), if desired, and frozen in a deep-freeze while being kept in continuous movement; or (j) slightly braising the cuttings obtained in step (h), cooling them while being kept in continuous movement to prevent cohering of the cuttings, if desired, and freezing them in a deep-freeze;
or (k) forming the cuttings obtained in step (h) into a cake by slightly pressing, frying the cake on one side or on both sides, if desired, cooling the cake, if desired, and freezing it in a deep-freeze.
The present invention provides a process for the preparation of a frozen potato product, characterized by (a) peeling potatoes;
(b) if necessary, cutting the potatoes to pieces of roughly equal thickness or sizes; (c) heating the pieces of potato in water until the hearts of the potato pieces have acquired a temperature of 60-80°C; (d) cooling the preheated pieces of potato until the hearts of the pieces have acquired a temperature below 25°C; (e) heating the pieces of potato in hot water or steam having a temperature of 95-130°C for such a time that when the temperature T in °C, measured in the hearts of the pieces is plotted in a graph against the heating time t in minutes, the area which is represented by the definite integral amounts to 300-900°C minutes; (f) cooling the heated pieces of potato, if desired; (g) comminuting the pieces of potato to cuttings; (h) mixing the cuttings with a fat if desired, and with salt and/or cheese, bacon or onions, if desired; (i) cooling the cuttings obtained in step (g) or (h), if desired, and frozen in a deep-freeze while being kept in continuous movement; or (j) slightly braising the cuttings obtained in step (h), cooling them while being kept in continuous movement to prevent cohering of the cuttings, if desired, and freezing them in a deep-freeze;
or (k) forming the cuttings obtained in step (h) into a cake by slightly pressing, frying the cake on one side or on both sides, if desired, cooling the cake, if desired, and freezing it in a deep-freeze.
Description
a7s~sl The invention relates to a process for the preparation ` of a frozen potato product.
Applicants Canadian Patent No. 913,985 describes a process for the preparation of a frozen slightly fried ("braised") potato product from which after thawing may be prepared a "Rosti" by heating the product. According to this process peeled potatoes are, if necessary, cut to pieces of roughly equal sizes, the pieces are heated in water until the hearts of the pieces have acquired a temperature of 60-80C., the preheated pieces are cooled until the hearts of the pieces have acquired a temperature below 25C, the pieces are heated in water or steam of 100C for such a time that when the temperature T in C, measured in the hearts of the pieces, is plotted in a graph ,' against the heating time t in minutes, the area which is ~t represented by the definite integral O~ Tdt amounts to 300-900C
minutes, the heated pieces are cooled, if desired, and comminuted to cuttings, e.g. by grating, the cuttings, with the addition of fat and, if desired, salt, cheese, bacon or onions, are slightly braised, the slightly braised cuttings are formed into a cake, and the cake is frozen. Although according to this - process the preheated and subsequently cooled potato pieces areheated, this is no normal cooking. After thawing the product obtained in this way is not yet equal to a "Rosti" but it becomes only a "Rosti"
' , ~ 30 . ' ", ~()78251 after ~eatin~ or frying. Th~ product obtained by the process i5 a frczen "preliminary" product. Alternatively, according to the known P~Ocess the cake may be ~ried ~ on both sides before freezing. In this way the product ; 5 obtains an attrac~ive appearance and is then a "Rosti"
ready for use, whic~ is frozen. Af~er thawing it is ; mer-ely heated and not fried.
It has now been found that a preliminar~ product which is equivalent to the above-mentioned preliminary product, optionally in the form of loose pieces instea~l of in the form of a cake, may be prepared in a smaller ,~ number of steps than according to the above-mentioned ~, known process.
The process according to the invention is charac-; 15 teriz~d in that ; (a) pQtatoes are peeled;
(h) i` necessary, cut to pieces of roughly equal thic~ness or sizes;
(c) heated in water ~til the hearts of the pieces have acquired a temperature of 60-8QC.;
(d) the pieces are cooled with air &nd/or cold water until the hearts of the pieces have acquire~ a temperature below 25C.;
(e) tne pieces are heated in warm water or steam having a temperature of 95-130C. for such a time that when the temperature ~ in C., measured in the ~earts of the pieces, is plotted in a graph against the heating time t in minutes, the area which is represented by the definite integral ~ mdt amounts to ~00-900C. minutes;
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1078ZSl (~) i F ~esirPd~ the heatsd pieces are cooled;
(~) the pieces are comminuted to cuttings;
(h) i~ desired, the cuttings are mixed with a fat ard, if desired, salt and/or cheese, bacon or onions;
(i) the cuttings obtained in step (g) or (h) are cooled, if desired, and frozen while being kept in continuous movement; or (j) the cuttings obtained in step (h) are slightly ~ braised, cooled while being kept in continuous movement to prevent cohering of the cuttings, if desired, and frozen; or (k) the cuttings obtained in step ~h) are formed into a cake by slightly pressing, the cake is fried on one side or on both sides, if desired, the cake is cooled, if desired, and frozen The above-mentioned freezing treatments are carried out in a deep-freeze.
~lthough the product obtained in step (k) of the process according to the invention is in the form of a cake, it is obtained with the omission of slightly braising the cuttings mixed with fat and of cooling of the slightly braised cuttings. In tnis respect the ; process according to the invention is more simple from a technical point of view and therefore more economical than the known process.
It is still more economical when the forming of a cake before freezing is omitted, which is the case ... .
in the embodimçnt according to step (i) or (~).
According to step (;) the cuttings have been slightly braised before freezing; according to step (i) sligh'ly ... . .
, ~3--1078ZSl . . .
bra sir.g is also omitted. In both c~ses the product is obtained in the form of loose cuttings. This is particular-- ly advantageous from the YieW-point of packaging of the product. A cake has to be packaged o~ a packaging machine which has been constructed especially for this purpose, whereas loose cuttings can be packaged on a ; usual packaging machine, for instance in bag~ or pouches~
~`~ For carrying out the process according to the invention potatoes having a specific gravity of no more than 1.090 are preferably used as starting material, ,:
because then a product having the desired palatable texture is obtained. ~he optimal specific gravity depends on the variety of potato.
~he potatoes are peeled, and the eyes and damaged or diseased parts are cut away. ~o achieve an effèct ; which i8 as homogeneous as is possible of the pre-heating step (c) and the heating step (e), it is desirable for the potatoes to be cut into as regular pieces as is possible, which pieces have about equal size5 or at least equal thickness, for example, by cutting them into slices. The thickness of the slices ~ay be up to 25 mm The lo-~er limit of the thickness :, .
of the slices may be equal to the thickness of the cuttings to be made therefrom in step (g). ~his thick-; 25 ness may be about 1 mm. It is also possible to use ; small potatoes of sizes of no more than 25 mm. provided they are of about equal siæe Preferably, the thickness ; of the slices or the size of the pieces Qr of whol-potatoes is 15-25 mm. because then heating is controlled easily.
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~ ~078ZSl I)uring the fo7lowillg preheating step it is essential for the heart of each of the pieces of potato to reach a temperature of 60-80C., and ; preferably 65-75C. ~o obtain this effect the piecesof potato are put in hot water, the temperature of - which is not essential, so lon~ as it is high enough SG that the desired temperature in the heart of the pieces of potato will be obtained and the starch in the cells will be gelatinized. It takes about 15 minutes for the desired te~perature bO be oDtained when deali~g with pieces having a thickness of 15 mm, and about 22 minutes with pieces having a thickness of 25 mm, when water is used having the temperature to be reached i~ the pieces.
Cooling the preheated pieces of potato until the hearts of the pieces have acquired a temperature below 25C may be achieved by immersion in, or spraying .
with cold water. Air may also be allowed to flow along the pieces, in combination with coGling with cold ~ater, if desired.
; Then the cooled piecPs of potato are heated in hot water or steam having a temperature of ~5-1~,0C
To determina whether the heat treatment was sufficient, the course of the te~perature ~ in C. is tak.en in the . .
heart of the pieces of potato and plotted on a graph against the heating time t in minutes. There is thus a curve obtained which includes, with the abscissa of time, the ordinate of temperature and a line drawn through a given point on the abscissa of time parallel with the ordinate of temperature, an area which is . ' ' .
`. ~07825~
measursd in C~ minutes by the definite integral indicated in step (e). ~his area should be 300-900C.
minutes ~he best results are obtained with an area '!:
of 450~750C minutes. For slices having a thickness ; 5 of 15 mm and being heated in steam of 100C an area was determined of 532C. minutes after 8 minutes, and for slices having a thickness of 25 mm an area of 550C minutes after 10 minutes. It is to be understood that these calculations need not be repeated at each heating process. When, after a ; number of measurements during the heating process of pieces or slices having a given thicknes in a given heating apparatus, the shape of the heating curve is sufficiently accurately known, it may be determined from the plotted graph how long the heating process should be continued in future runs for pieces with that predetermined thickness to obtain a desired value of the area included.
Measuring the temperature in the heart of the , ., - 20 pieces of potato during preheating, cooling and further heating is suitably carried out with a thermocouple.
After this heating treatment the pieces o~ potato may be cooled. ~he advantage of cooling is that the heated material may be s~ored for some time, and it is also easier to handle during the subsequent comminuting step, Comminuting may be effectively carried out with the aid of a grate or a similar apparatus. Suitable si3es for the cuttings are a length of 20-60 mm, a width of 4-6 mm, and a thickness of 1-3 mm . .
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The cuttings obtained may be further treated in several ways.
The most simple treatment is freezing the cuttings in a deep-freeze either directly or after cooling. During freezing the moist cuttings have to be kept in continuous movement to prevent them from freezing together. It is also possible to mix the cuttings with a fat, e.g., lard, margarine or butter, and . .
optionally also with cooking salt and/or pieces of cheese, bacon or onion before freezing.
Furthermore, the cuttings mixed with fat and optionally -; other additives may be slightly braised for 2-lO minutes on a heated surface, preferably in the apparatus described in Dutch ~ patent 141,079. This braising, also called "browning" in practice, may also take place in a rotating drum, the wall of which is externally heated, or in a mixing trough, a ribbon mixer, a conveyor oven or a conveyor chute. The longer the braising process, the shorter the heating process in step (e) should be.
In other words, a lower value of the area included by the temperature-time curve within the given limits should be kept on, and vice versa, when braising is carried out shorter or is completely omitted a higher value of this area should be kept on.
, After the cuttings have been braised, they are cooled , .;
while being kept in continuous movement to prevent them from ~ cohering by the fat present on the cuttings. The most efficient ;~ method of cooling is blowing or sucking cold air upwardly through a layer of braised cuttings in such : .
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~; a way that they attain a fluidized state, In thls ^ way the heat is carried off quickly and due to the movement the cuttings do not cohere but form a loose :. . .
mass, After the cooling process, the pieces are deep-frozen, Finally, the cuttings optionally mixed with fat and other additives may be formed into a round cake, without braising, The cake is formed by slightly pressing a quantity of cuttings, Suitably, the diameter of the cake is about 25 cm. for the cake to be easily transferred to a frying pan, The thickness may be about 3 cm, ~he cake is froze~ in a deep-freeze, ~he surface of the loose cuttings or of the cake may not dry out, and this may be prevented by ,.,:, '` sealing the cuttings or the cake from the air in a ;- .
known manner, Preferably, the cuttings are packaged in bags of plastic foil or of aluminum foil, and the ~ cake is wrapped in plastic foil or aluminum foil, ': 20 Preferably~ the cake is formed during packaging and ~l before the optional cooling step and before freezing, :..
because then packaging and forming the cake can take place simultaneously, ~he packaged frozen product may ~! be s~ored for quite a time in the deep-freeze compart-ment for frozen foodstuffs.
. .
In order to make the product prepared according to the invention ready for consumption it need only ., .
to be thawed and slightly fried, In so far as the product consists of loose cuttings, it is made into - 30 a cake by slightly pressing after slightly frying, ; -8-, . .
1078Z~il .
In household this fryin may take place in a frying pan. After being fried on one side, the cake is turned and fried on the other side. The time of fr~ing is somewhat dependent on the thickness of the cake and from the fact whether step (j) has been carried out. When the thickness is about 3 cm, the first side should be fried during about 8 minutes and the second side during about 6 minutes. If the cake before freezing is fried on one side or on both sides, it is sufficient to heat it up. This may be done ; in a high frequency oven during 2-2.5 minutes, in a hot air oven at 150C during 10-15 minutes, or in an electrical or gas-heated household oven at 250C during 40 minutes.
The following examples illustrate the invention.
EXAMPLES 1 to 16 Potatoes of the Bintje variety (specific gravity 1.084) were peeled in a steam peeler, then the eyes and the unsound parts were removed. The potatoes were then cut to slices having a thickness of 20 mm.
; The slices were heated in water of 75C for 15 minutes, at which time the heart of the slices had acquired a temperature 20 of 70C. The preheated slices were then cooled in flowing cold water until theheartof the slices had acquired a temperature of 19C. This was the case after 19 minutes. Subsequently, the slices were heated in steam of 100C for 10 minutes, the area of ~ the definite integral Ov~ Tdt being 690C minutes, ; .
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` ~078~:Sl The heated slices were divided into portions and each of the portions was processed further as - indicated in the Table. Cutting accordin~ to step(g) as indicated hereinbefore was accomplished in the cutting cylinder of an Alexander-Werk apparatus for kitchen use. This cylinder has a stationary wall with cutting openings, like those of a kitc~.en ~rate, across which openings the p-:tato slices to be cut are guided by a rotor. The cuttings had a crescent-shaped cross section perpendicularly to the longitudinal direction. The width of the cuttings was 4-6 mm, the thickness 1-3 mm, and the length 20-60 mm.
In the head of the Table the letters in parentheses correspond with the steps of the process according to ; 15 the invention indicated hereinbefore by the sane lettersa ...;
In the Table has been indicated whether, and eventually in -~lhich manner a certain step was carried out. The indication "+" means that the step mentioned in the head of the Table wa! carried out; "-" means that it ; 20 was not carried out.
Freezing was carried out in a fluidized bed at -40C., except in the Examples 7, 8, 15 and 16, where n a cake was formed.
In the Examples 3-8 and 11-16, wherein in step (h) the c-~ttings were mixed with fat, 0.1% by weight of antioxidant, calculated on the fat, was additionally added. The antioxidant was a mixture of butylhydroxy-anisole, n-propyl gallate and citric acid, which was dissolved before in a portion Or the quantity of fat i 30 to be mixed with the cuttings~
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,"--lla-78ZSl After two months storage at -20C a Rosti was prepared from each of the products obtained according to the Examples 1 to 6 and 9 to 14 by melting a small pat of margarine in a frying pan, putting 500 g of frozen cuttings in the pan and heating for 3 minutes on a large flame while turning the cuttings. Then a cake was formed by slightly pressing the heated cuttin~s. The cake was fried on both sides on a moderate flame for 3 minutes to give a golden brown crust.
~ rom each of the products obtained according to the ; lQ Examples 7 and lS a Rosti was prepared by frying the cake in a ~rying pan, with the addition of a small pat of margarine, on ,i~ one side for 8 minutes and on the other side for 6 minutes.
Each of the products obtained according to the Examples 8 and 16, which is already a Rosti, was heated. This was done in a high frequency oven for 2.5 minutes, or in a hot air oven at 150C for 14 minutes respectively.
In all these cases a palatable Rosti having the desired texture was obtained. The individual potato cuttings were well :"
perceptible both visually and on the tongue.
It will be understood that the claims are intended to cover all changes and modifications of the preferred embodiment of the invention, herein chosen for the purpose of illustration, which do not constitute departures from the spirit and scope of the invention.
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Applicants Canadian Patent No. 913,985 describes a process for the preparation of a frozen slightly fried ("braised") potato product from which after thawing may be prepared a "Rosti" by heating the product. According to this process peeled potatoes are, if necessary, cut to pieces of roughly equal sizes, the pieces are heated in water until the hearts of the pieces have acquired a temperature of 60-80C., the preheated pieces are cooled until the hearts of the pieces have acquired a temperature below 25C, the pieces are heated in water or steam of 100C for such a time that when the temperature T in C, measured in the hearts of the pieces, is plotted in a graph ,' against the heating time t in minutes, the area which is ~t represented by the definite integral O~ Tdt amounts to 300-900C
minutes, the heated pieces are cooled, if desired, and comminuted to cuttings, e.g. by grating, the cuttings, with the addition of fat and, if desired, salt, cheese, bacon or onions, are slightly braised, the slightly braised cuttings are formed into a cake, and the cake is frozen. Although according to this - process the preheated and subsequently cooled potato pieces areheated, this is no normal cooking. After thawing the product obtained in this way is not yet equal to a "Rosti" but it becomes only a "Rosti"
' , ~ 30 . ' ", ~()78251 after ~eatin~ or frying. Th~ product obtained by the process i5 a frczen "preliminary" product. Alternatively, according to the known P~Ocess the cake may be ~ried ~ on both sides before freezing. In this way the product ; 5 obtains an attrac~ive appearance and is then a "Rosti"
ready for use, whic~ is frozen. Af~er thawing it is ; mer-ely heated and not fried.
It has now been found that a preliminar~ product which is equivalent to the above-mentioned preliminary product, optionally in the form of loose pieces instea~l of in the form of a cake, may be prepared in a smaller ,~ number of steps than according to the above-mentioned ~, known process.
The process according to the invention is charac-; 15 teriz~d in that ; (a) pQtatoes are peeled;
(h) i` necessary, cut to pieces of roughly equal thic~ness or sizes;
(c) heated in water ~til the hearts of the pieces have acquired a temperature of 60-8QC.;
(d) the pieces are cooled with air &nd/or cold water until the hearts of the pieces have acquire~ a temperature below 25C.;
(e) tne pieces are heated in warm water or steam having a temperature of 95-130C. for such a time that when the temperature ~ in C., measured in the ~earts of the pieces, is plotted in a graph against the heating time t in minutes, the area which is represented by the definite integral ~ mdt amounts to ~00-900C. minutes;
--2~
.
:
1078ZSl (~) i F ~esirPd~ the heatsd pieces are cooled;
(~) the pieces are comminuted to cuttings;
(h) i~ desired, the cuttings are mixed with a fat ard, if desired, salt and/or cheese, bacon or onions;
(i) the cuttings obtained in step (g) or (h) are cooled, if desired, and frozen while being kept in continuous movement; or (j) the cuttings obtained in step (h) are slightly ~ braised, cooled while being kept in continuous movement to prevent cohering of the cuttings, if desired, and frozen; or (k) the cuttings obtained in step ~h) are formed into a cake by slightly pressing, the cake is fried on one side or on both sides, if desired, the cake is cooled, if desired, and frozen The above-mentioned freezing treatments are carried out in a deep-freeze.
~lthough the product obtained in step (k) of the process according to the invention is in the form of a cake, it is obtained with the omission of slightly braising the cuttings mixed with fat and of cooling of the slightly braised cuttings. In tnis respect the ; process according to the invention is more simple from a technical point of view and therefore more economical than the known process.
It is still more economical when the forming of a cake before freezing is omitted, which is the case ... .
in the embodimçnt according to step (i) or (~).
According to step (;) the cuttings have been slightly braised before freezing; according to step (i) sligh'ly ... . .
, ~3--1078ZSl . . .
bra sir.g is also omitted. In both c~ses the product is obtained in the form of loose cuttings. This is particular-- ly advantageous from the YieW-point of packaging of the product. A cake has to be packaged o~ a packaging machine which has been constructed especially for this purpose, whereas loose cuttings can be packaged on a ; usual packaging machine, for instance in bag~ or pouches~
~`~ For carrying out the process according to the invention potatoes having a specific gravity of no more than 1.090 are preferably used as starting material, ,:
because then a product having the desired palatable texture is obtained. ~he optimal specific gravity depends on the variety of potato.
~he potatoes are peeled, and the eyes and damaged or diseased parts are cut away. ~o achieve an effèct ; which i8 as homogeneous as is possible of the pre-heating step (c) and the heating step (e), it is desirable for the potatoes to be cut into as regular pieces as is possible, which pieces have about equal size5 or at least equal thickness, for example, by cutting them into slices. The thickness of the slices ~ay be up to 25 mm The lo-~er limit of the thickness :, .
of the slices may be equal to the thickness of the cuttings to be made therefrom in step (g). ~his thick-; 25 ness may be about 1 mm. It is also possible to use ; small potatoes of sizes of no more than 25 mm. provided they are of about equal siæe Preferably, the thickness ; of the slices or the size of the pieces Qr of whol-potatoes is 15-25 mm. because then heating is controlled easily.
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~ ~078ZSl I)uring the fo7lowillg preheating step it is essential for the heart of each of the pieces of potato to reach a temperature of 60-80C., and ; preferably 65-75C. ~o obtain this effect the piecesof potato are put in hot water, the temperature of - which is not essential, so lon~ as it is high enough SG that the desired temperature in the heart of the pieces of potato will be obtained and the starch in the cells will be gelatinized. It takes about 15 minutes for the desired te~perature bO be oDtained when deali~g with pieces having a thickness of 15 mm, and about 22 minutes with pieces having a thickness of 25 mm, when water is used having the temperature to be reached i~ the pieces.
Cooling the preheated pieces of potato until the hearts of the pieces have acquired a temperature below 25C may be achieved by immersion in, or spraying .
with cold water. Air may also be allowed to flow along the pieces, in combination with coGling with cold ~ater, if desired.
; Then the cooled piecPs of potato are heated in hot water or steam having a temperature of ~5-1~,0C
To determina whether the heat treatment was sufficient, the course of the te~perature ~ in C. is tak.en in the . .
heart of the pieces of potato and plotted on a graph against the heating time t in minutes. There is thus a curve obtained which includes, with the abscissa of time, the ordinate of temperature and a line drawn through a given point on the abscissa of time parallel with the ordinate of temperature, an area which is . ' ' .
`. ~07825~
measursd in C~ minutes by the definite integral indicated in step (e). ~his area should be 300-900C.
minutes ~he best results are obtained with an area '!:
of 450~750C minutes. For slices having a thickness ; 5 of 15 mm and being heated in steam of 100C an area was determined of 532C. minutes after 8 minutes, and for slices having a thickness of 25 mm an area of 550C minutes after 10 minutes. It is to be understood that these calculations need not be repeated at each heating process. When, after a ; number of measurements during the heating process of pieces or slices having a given thicknes in a given heating apparatus, the shape of the heating curve is sufficiently accurately known, it may be determined from the plotted graph how long the heating process should be continued in future runs for pieces with that predetermined thickness to obtain a desired value of the area included.
Measuring the temperature in the heart of the , ., - 20 pieces of potato during preheating, cooling and further heating is suitably carried out with a thermocouple.
After this heating treatment the pieces o~ potato may be cooled. ~he advantage of cooling is that the heated material may be s~ored for some time, and it is also easier to handle during the subsequent comminuting step, Comminuting may be effectively carried out with the aid of a grate or a similar apparatus. Suitable si3es for the cuttings are a length of 20-60 mm, a width of 4-6 mm, and a thickness of 1-3 mm . .
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The cuttings obtained may be further treated in several ways.
The most simple treatment is freezing the cuttings in a deep-freeze either directly or after cooling. During freezing the moist cuttings have to be kept in continuous movement to prevent them from freezing together. It is also possible to mix the cuttings with a fat, e.g., lard, margarine or butter, and . .
optionally also with cooking salt and/or pieces of cheese, bacon or onion before freezing.
Furthermore, the cuttings mixed with fat and optionally -; other additives may be slightly braised for 2-lO minutes on a heated surface, preferably in the apparatus described in Dutch ~ patent 141,079. This braising, also called "browning" in practice, may also take place in a rotating drum, the wall of which is externally heated, or in a mixing trough, a ribbon mixer, a conveyor oven or a conveyor chute. The longer the braising process, the shorter the heating process in step (e) should be.
In other words, a lower value of the area included by the temperature-time curve within the given limits should be kept on, and vice versa, when braising is carried out shorter or is completely omitted a higher value of this area should be kept on.
, After the cuttings have been braised, they are cooled , .;
while being kept in continuous movement to prevent them from ~ cohering by the fat present on the cuttings. The most efficient ;~ method of cooling is blowing or sucking cold air upwardly through a layer of braised cuttings in such : .
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~; a way that they attain a fluidized state, In thls ^ way the heat is carried off quickly and due to the movement the cuttings do not cohere but form a loose :. . .
mass, After the cooling process, the pieces are deep-frozen, Finally, the cuttings optionally mixed with fat and other additives may be formed into a round cake, without braising, The cake is formed by slightly pressing a quantity of cuttings, Suitably, the diameter of the cake is about 25 cm. for the cake to be easily transferred to a frying pan, The thickness may be about 3 cm, ~he cake is froze~ in a deep-freeze, ~he surface of the loose cuttings or of the cake may not dry out, and this may be prevented by ,.,:, '` sealing the cuttings or the cake from the air in a ;- .
known manner, Preferably, the cuttings are packaged in bags of plastic foil or of aluminum foil, and the ~ cake is wrapped in plastic foil or aluminum foil, ': 20 Preferably~ the cake is formed during packaging and ~l before the optional cooling step and before freezing, :..
because then packaging and forming the cake can take place simultaneously, ~he packaged frozen product may ~! be s~ored for quite a time in the deep-freeze compart-ment for frozen foodstuffs.
. .
In order to make the product prepared according to the invention ready for consumption it need only ., .
to be thawed and slightly fried, In so far as the product consists of loose cuttings, it is made into - 30 a cake by slightly pressing after slightly frying, ; -8-, . .
1078Z~il .
In household this fryin may take place in a frying pan. After being fried on one side, the cake is turned and fried on the other side. The time of fr~ing is somewhat dependent on the thickness of the cake and from the fact whether step (j) has been carried out. When the thickness is about 3 cm, the first side should be fried during about 8 minutes and the second side during about 6 minutes. If the cake before freezing is fried on one side or on both sides, it is sufficient to heat it up. This may be done ; in a high frequency oven during 2-2.5 minutes, in a hot air oven at 150C during 10-15 minutes, or in an electrical or gas-heated household oven at 250C during 40 minutes.
The following examples illustrate the invention.
EXAMPLES 1 to 16 Potatoes of the Bintje variety (specific gravity 1.084) were peeled in a steam peeler, then the eyes and the unsound parts were removed. The potatoes were then cut to slices having a thickness of 20 mm.
; The slices were heated in water of 75C for 15 minutes, at which time the heart of the slices had acquired a temperature 20 of 70C. The preheated slices were then cooled in flowing cold water until theheartof the slices had acquired a temperature of 19C. This was the case after 19 minutes. Subsequently, the slices were heated in steam of 100C for 10 minutes, the area of ~ the definite integral Ov~ Tdt being 690C minutes, ; .
.
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` ~078~:Sl The heated slices were divided into portions and each of the portions was processed further as - indicated in the Table. Cutting accordin~ to step(g) as indicated hereinbefore was accomplished in the cutting cylinder of an Alexander-Werk apparatus for kitchen use. This cylinder has a stationary wall with cutting openings, like those of a kitc~.en ~rate, across which openings the p-:tato slices to be cut are guided by a rotor. The cuttings had a crescent-shaped cross section perpendicularly to the longitudinal direction. The width of the cuttings was 4-6 mm, the thickness 1-3 mm, and the length 20-60 mm.
In the head of the Table the letters in parentheses correspond with the steps of the process according to ; 15 the invention indicated hereinbefore by the sane lettersa ...;
In the Table has been indicated whether, and eventually in -~lhich manner a certain step was carried out. The indication "+" means that the step mentioned in the head of the Table wa! carried out; "-" means that it ; 20 was not carried out.
Freezing was carried out in a fluidized bed at -40C., except in the Examples 7, 8, 15 and 16, where n a cake was formed.
In the Examples 3-8 and 11-16, wherein in step (h) the c-~ttings were mixed with fat, 0.1% by weight of antioxidant, calculated on the fat, was additionally added. The antioxidant was a mixture of butylhydroxy-anisole, n-propyl gallate and citric acid, which was dissolved before in a portion Or the quantity of fat i 30 to be mixed with the cuttings~
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,"--lla-78ZSl After two months storage at -20C a Rosti was prepared from each of the products obtained according to the Examples 1 to 6 and 9 to 14 by melting a small pat of margarine in a frying pan, putting 500 g of frozen cuttings in the pan and heating for 3 minutes on a large flame while turning the cuttings. Then a cake was formed by slightly pressing the heated cuttin~s. The cake was fried on both sides on a moderate flame for 3 minutes to give a golden brown crust.
~ rom each of the products obtained according to the ; lQ Examples 7 and lS a Rosti was prepared by frying the cake in a ~rying pan, with the addition of a small pat of margarine, on ,i~ one side for 8 minutes and on the other side for 6 minutes.
Each of the products obtained according to the Examples 8 and 16, which is already a Rosti, was heated. This was done in a high frequency oven for 2.5 minutes, or in a hot air oven at 150C for 14 minutes respectively.
In all these cases a palatable Rosti having the desired texture was obtained. The individual potato cuttings were well :"
perceptible both visually and on the tongue.
It will be understood that the claims are intended to cover all changes and modifications of the preferred embodiment of the invention, herein chosen for the purpose of illustration, which do not constitute departures from the spirit and scope of the invention.
' .~ , , '~
,`
~ -12-;
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Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. a process for the preparation of a frozen potato product which comprises (a) providing peeled potato pieces;
(b) heating the potato pieces in water until the hearts of the potato pieces have acquired a temperature of 60-80°C; (c) cooling the preheated potato pieces until the hearts of the pieces have acquired a temperature below 25°C; (d) heating the potato pieces in hot water or steam having a temperature of 95-130°C for such a time that when the temperature T in °C, measured in the hearts of the pieces is plotted in a graph against the heating time t in minutes, the area which is represented by the definite integral amounts to 300-900°C, minutes; (e) comminuting the potato pieces to cuttings; and (f) freezing the cuttings in a deep-freeze while being kept in continuous movement.
(b) heating the potato pieces in water until the hearts of the potato pieces have acquired a temperature of 60-80°C; (c) cooling the preheated potato pieces until the hearts of the pieces have acquired a temperature below 25°C; (d) heating the potato pieces in hot water or steam having a temperature of 95-130°C for such a time that when the temperature T in °C, measured in the hearts of the pieces is plotted in a graph against the heating time t in minutes, the area which is represented by the definite integral amounts to 300-900°C, minutes; (e) comminuting the potato pieces to cuttings; and (f) freezing the cuttings in a deep-freeze while being kept in continuous movement.
2. A process as claimed in claim 1 in which the cuttings are mixed with a fat before being frozen.
3. A process as claimed in claim 2 in which the cuttings are mixed with at least one of salt, cheese, bacon and onions before being frozen.
4. A process as claimed in claim 1, 2 or 3 in which the cuttings are slightly braised before being frozen.
5. A process as claimed in claim 1, 2 or 3 in which the heated pieces of potato are cooled before being comminuted.
6. A process as claimed in claim 1, 2 or 3 in which the potato pieces are provided by cutting potatoes into pieces.
7. The process of claim 1, 2 or 3 wherein potatoes are cut to pieces having a thickness or size of 15-25 mm.
8. The process of claim 1, 2 or 3 wherein the heating is continued until the area represented by the definite integral amounts to 450-750°C minutes.
9. The process according to claim 1, 2 or 3 wherein the cuttings are cooled in a fluidized bed prior to freezing.
10. The process according to claim 1, 2 or 3 wherein the cuttings are sealed from the air before or after freezing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7506564.A NL159001B (en) | 1975-06-03 | 1975-06-03 | PROCESS FOR PREPARING A FROZEN POTATO PRODUCT, FROM WHICH A "ROSTI" MAY BE PREPARED, AND FORMED DEEP-FROZEN POTATO PRODUCT OBTAINED BY APPLICATION OF THIS PROCESS. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078251A true CA1078251A (en) | 1980-05-27 |
Family
ID=19823871
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA253,710A Expired CA1078251A (en) | 1975-06-03 | 1976-05-31 | Process for the preparation of a frozen potato product |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1078251A (en) |
| DE (1) | DE2624391C3 (en) |
| GB (1) | GB1495484A (en) |
| NL (1) | NL159001B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109846003A (en) * | 2018-11-07 | 2019-06-07 | 中国农业科学院农产品加工研究所 | A kind of potato staple food processing tailored flour and its production method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8400739A (en) * | 1984-03-08 | 1985-10-01 | Fri D Or B V | METHOD AND APPARATUS FOR PREPARING DEEP-FROZEN MEALS AND PRODUCT, OBTAINED BY THIS PROCESS |
| DE4424100A1 (en) * | 1994-07-08 | 1996-01-11 | Buse Gase Gmbh & Co | Method of producing frozen semi-finished potato products |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3597239A (en) * | 1967-09-25 | 1971-08-03 | Vahlsing Inc | Method of manufacturing frozen oil-blanched diced potatoes suitable for preparing hash brown potatoes |
| NL6817389A (en) * | 1968-12-04 | 1970-06-08 |
-
1975
- 1975-06-03 NL NL7506564.A patent/NL159001B/en not_active IP Right Cessation
-
1976
- 1976-05-31 CA CA253,710A patent/CA1078251A/en not_active Expired
- 1976-05-31 DE DE2624391A patent/DE2624391C3/en not_active Expired
- 1976-06-02 GB GB22812/76A patent/GB1495484A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109846003A (en) * | 2018-11-07 | 2019-06-07 | 中国农业科学院农产品加工研究所 | A kind of potato staple food processing tailored flour and its production method |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2624391A1 (en) | 1977-01-13 |
| NL159001B (en) | 1979-01-15 |
| GB1495484A (en) | 1977-12-21 |
| NL7506564A (en) | 1976-12-07 |
| DE2624391C3 (en) | 1986-05-28 |
| DE2624391B2 (en) | 1980-10-09 |
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