CA1244707A - Process for preparing dry food - Google Patents
Process for preparing dry foodInfo
- Publication number
- CA1244707A CA1244707A CA000460845A CA460845A CA1244707A CA 1244707 A CA1244707 A CA 1244707A CA 000460845 A CA000460845 A CA 000460845A CA 460845 A CA460845 A CA 460845A CA 1244707 A CA1244707 A CA 1244707A
- Authority
- CA
- Canada
- Prior art keywords
- frying
- food
- food material
- set forth
- preparing dry
- 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.)
- Expired
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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
- A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
- A23L5/10—General methods of cooking foods, e.g. by roasting or frying
- A23L5/11—General methods of cooking foods, e.g. by roasting or frying using oil
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Health & Medical Sciences (AREA)
- Nutrition Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Preparation Of Fruits And Vegetables (AREA)
- General Preparation And Processing Of Foods (AREA)
- Frying-Pans Or Fryers (AREA)
Abstract
Abstract of the Disclosure:
A process for preparing dry food comprising frying one or more food material(s) under reduced pressure in a frying tank equipped with many steam pipes on the side walls and at the bottom in such a way that these pipes surround the food material(s) to be fried to which a sufficient amount of pressurized steam is sup-plied to provide an appropriate amount of heat for preventing a rapid fall of the temperature at frying.
The process of the present invention makes it possible to dry the food material(s) completely in a short period by the sufficient amount of heat supplied from the steam pipes to thereby prepare crisp food product(s) exhibiting an excellent texture.
A process for preparing dry food comprising frying one or more food material(s) under reduced pressure in a frying tank equipped with many steam pipes on the side walls and at the bottom in such a way that these pipes surround the food material(s) to be fried to which a sufficient amount of pressurized steam is sup-plied to provide an appropriate amount of heat for preventing a rapid fall of the temperature at frying.
The process of the present invention makes it possible to dry the food material(s) completely in a short period by the sufficient amount of heat supplied from the steam pipes to thereby prepare crisp food product(s) exhibiting an excellent texture.
Description
~z~
P~OCESS FOR PREPARING DRY FOOD
Background of the Invention Field of the Invention This invention relates to a process for preparing dry ~ood which exhibi-ts excellent crispness and is Eree from browning.
Description of the Prior Art Numerous processes have been proposed for preparing dry food by frying food materials under reduced pressure.
For example, ~apanese Patent Publication No. 665/1972 has disclosed a process for preparing fried potato in two stages, i.e. frying sliced potato to a water content of 5 to 20 % and -then frying it again under reduced pressure at a temperature not higner than 100C, and Japanese Patent Laid-Open No. 22652/1982 has disclosed another process for preparing dry food by frying slices or strips of various food materials under reduced pressure.
However these processes have been employed only for preventing undesirable phenomena such as browning which may be inhibited by frying at a low temperature and -nsufficient drying which may be avoided by slicing.
As a resul-t of our researches to determine ap-propriate conditions for preparing excellent dry food ,~
47~
in a laboratory, we have found that the aimed excellent dry food may be prepared by frying a food material at a temperature of 80 to 130C depending on the material under pressure of 20 to 100 mmHg.
However, a dry food product prepared under the abovementioned conditions in an industrial scale would not be crisp but somewhat moist. This product does not exhibit crispness nor sufficient expansion. Ad-ditional frying under reduced pressure would dehydrate the product without any expansion. The product thus obtained has a hard surface which hits against teeth and contains a large amount of oil, which means that the preparation is completely unsuccessful.
As a result of detailed examination on the frying of food, we have found that the initial contact of pre-fried food with a heated oil would result in rapid evaporation of moisture accompanied by expansion within the food to thereby form a porous tissue. It is nec-essary to maintain the oil around the food at a tem-perature appropriate for expansion until the completion of the evaporation. The evaporated moisture would generally cause a rapid fall of the temperature of the oil around the food. Therefore the delayed or stopped evaporation of moisture from the food would result in an insufficiently porous tissue to thereby form a - 3 - ~ 7~t7 partially hard or shrinked product, so long as it is allowed to stand as such. Additional frying might contxibute to the completion of dehydration. However the product would be impregnated with the oil and become hard, oily and shrinking.
In order to avoid these undesirable phenomena, the frying oil may be circulated or stirred. However the initial evaporation of molsture under reduced pres-sure is much vigorous than that under atmospheric pressure, which might prolong the lowering o the tem-perature of the oil around the food. Consequently the food product thus obtained might become 'nard and oily.
Our subsequent researches have revealed that a 1~ complete dehydration and frying may be achieved by supplying a large amount of heat while keeping the temperature as it is, i.e. without raising it.
Nothing but steam can supply a large amount of heat at once. Furthermore a conventional heater equipped with steam pipes only at the bottom is unable to supply a sufficient amount of heat. Therefore we have found it necessary to employ a frying tank equipped with many pipes at the bottom and sides and if possible, at the center.
~ 7 Summary of the Invention It is an objec-t of the present invention to provide a process for preparing dry food which comprises frying one or more food material(s) such as vegetables, root-crops, fruits, edible fungi, fishery products, seaweeds, beans, cereals, nuts, livestock meats or processed goods -thereof as it is or in a sliced form(s) under reduced pressure in a frying tank equipped with many steam pipes to which a sufficient amount of pressurlzed steam for providing appropriate amount of heat is supplied to prevent or restore a rapid fall of the temperature o:E the frying oil.
Brief Description of the Drawings Fig. 1 is a vertical section of a frying apparatus l~ used in the present invention wherein 1 is a frying apparatus, 2 is a frying tank, 3 are steam pipes and 10 is a vegetable oil.
Detailed_Description of the Preferred Embodiments According to the process of the present invention, it is possible to fry a food material at any cons-tant temperature from 80 to 130C by supplying a large amount of pressurized steam to many pipes equipped at least at the bottom and on the walls of a frying tank without inhibiting the frying operation to thereby supply a _ 5 _ ~ 2 ~
sufficient arnount of heat to prevent or restore a rapid fall in the temperature of the frying oil. For example, a fried potato which exhibits a complete ex-pansion without undergoing browning and contains 1.8 %
of water may be obtained by frying a potato material at a constant temperature of 120C, although the time required for frying may be somewhat prolonged.
In the process of the present invention, a stirrer may be equipped in the Erying tank in order to circulate the frying oil rapidly to thereby achieve uniform dis~
tribution of the supplied heat. Alternately a basket containing the food material to be fried may be immersed and subjected to a vertical or rotary motion in the oil to stir the oil.
More particularly, the process of the present invention may be carried out by connecting a steam supply apparatus to the steam pipes equipped in the frying tank, setting the apparatus to a desired tem-perature from 80 to 130C and supplying a lar~e amount of steam at the temperature as set above constantly.
The optimum temperature for frying may vary depend~
ing on the food material to be fried. Table 1 shows examples of the food materials used in the process of the present invention and the optimum temperatures thereof for frying.
~2~ 7 Table 1 Optimum temperature for frying (C) Food 80 - 90 Welsh onion ~white part), spinach, okra, cucumber, strawberry 90 - 95 Welsh onion (green part), eggplant, broccoli, lettuce, melon pimento, kidney bean, green pea, asparagus, raw mushroom, burdock, 95 - 100 garlic, apple, banana, kiwi, raisin, boiled fish pastes (kamaboko and chikuwa), raw oyster onion, cabbage, Japanese radish, lotus root, pineapple, persimmon, 100 - 105 lean pork, white meat of chicken, beef, beef liver, tangle, wakame seaweed 105 - 110 carrot, pumpkin, pork skin, chicken skin, potato chip 110 - 130 frozen pineapple, potato stick The pressure of the whole apparatus containing the frying tank may be reduced. In order to remove the moisture of a food material rapidly, it may be fried under reduced pressure of approximately 20 to 100 mmHg, preferably at approximately 20 to 60 mmHg. In order 7 ~2~ Q7 to prevent a rapid decrease in the degree of the reduced pressure caused by the rapid evaporation of moisture at the initial contact of the food with the frying oil, some means such as switching over to a powerful vacuum pump, stirring the frying oil or subjecting a basket containing the food to a vertical or rotary motion may be employed.
Various food materials such as those as such, those cut into various forms or those soaked into liquors optionally containing sugar, table salt or fruit juices may be used in the process of the present invention.
In the process of the present invention, it is particularly preferable to soak a food material into an aqueous solution of thick malt syrup in a concentra-tion of 10 to 60 % for 0.5 to 24 hours. By this opera-tion, the moisture within the food would be thoroughly removed ~y the osmotic pressure. Therefore expansion may be completed rapidly at frying to thereby obtain a crisp food product having an excellent texture.
Frying may be continued for 10 to 30 min at an appropriate temperature. It may be somewhat shorter at a higher temperature while it may De somewhat longer at a lower temperature.
After the completion of the frying, the basket containing the food material may be drawn up from the - 8- ~244707 oil and moved vertically to swish the oil off or al-ternately rotated above the oil to swish the oil off by centrifugation, thereby taking out the fried food from the apparatus which has been brought under ordinary pressure.
An example of an apparatus which can be used in the process of the present invention will now be il-lustrated wi-th reference to Figure 1, which is a vertical section of a ~rying appara-tus wherein 1 is a cyllndrical frying apparatus as a whole, 2 is a frying tank, 3 are steam pipes wound around the sides and the bottom of the frying tank three turns densely, 4 is a wire net basket comprising four steps each containing potato chips 5 which would fall into the central space of the frying tank 2 to fry the potato sticks 5, 6 is a shaft for hanging the basket 4 while 7 is a door.
After pulling up the shaft 6, potato sticks 5 are in-troduced into the basket 4 successively from the door 7. 8 and 8 are inlets of steam while 8' and 8' are outlets thereof through which a large amount of pres-surized steam at 150C would be passed. The steam pipes 3 are filled with pressurized steam to thereby heat added vegetable oil 10 to 125C continuously. 9 is a deaerating pipe connected to a condenser and a large vacuum pump ~not shown in the figure~ to maintain ~ 9 ~ 1 2 4 ~ ~ 0 7 a reduced pressure oE approximately 20 to 100 mmHg during the frying period. 11 and 12 are a vertical and a rotary motor, respectively. The vertical motor 11 is used for pulling up the basket 4 above the oil to set the potato sticks 5 and for moving the basket 4 vertically in the vegetable oil during the frying period. The rotary motor 12 is used for rotating the basket 4 clockwise or counterclockwise in the vegetable oil during the frying period and for rotating the basket 4 after pulling up to remove the oil by centrifu-gation.
Although frying of potato sticks has been illustrated above as an example, other food materials may be fried in the same manner. When the material to be fried is amall, a wire net basket of fine meshes-should be employed in order to prevent the escape of the material through the net. In addition, the temperature of steam should be adjusted to the optimum temperature for each food.
In the process of the present invention, food materials can be fried at a low temperature of 80 to 130C continuously by supplying a large amount of pres-surized steam sufficient for providing an appropriate amount of hea-t to prevent or restore the rapid fall of the temperature at the initial stage of frying in - lo - ~4~7 a short period through many steam pipes equipped on the walls and at the bottom of a Erying tank. A large amount of heat supplied in the process of the present invention exhibits many excellent effects such as con-tinuous rapid evaporation of the moisture in a food material at the initial stage of frying which may result in the formation of an excellent porous tissue and the inhibition of intrusion of oil.
To illustrate the present invention, the following examples will be given.
Example 1 A frying apparatus as shown in Fig. 1 was employed.
A vegetable oil was poured into a frying tank.
Steam was supplied from a large pressurized steam genera-tor to steam pipes. The frying temperature was set at 120C and pressurized steam at 150C was continuously supplied to maintain this temperature during the frying period.
Potato sticks (10 mm x 5 mm x 100 mm) were introduced into a basket, the frying apparatus was closed and a vacuum pump was started. When the pressure reached 40 mmHg, the basket containing the potato sticks were immersed in the frying tank.
During the immersion, a slight lowering of the oil temperature was observed. However no significant
P~OCESS FOR PREPARING DRY FOOD
Background of the Invention Field of the Invention This invention relates to a process for preparing dry ~ood which exhibi-ts excellent crispness and is Eree from browning.
Description of the Prior Art Numerous processes have been proposed for preparing dry food by frying food materials under reduced pressure.
For example, ~apanese Patent Publication No. 665/1972 has disclosed a process for preparing fried potato in two stages, i.e. frying sliced potato to a water content of 5 to 20 % and -then frying it again under reduced pressure at a temperature not higner than 100C, and Japanese Patent Laid-Open No. 22652/1982 has disclosed another process for preparing dry food by frying slices or strips of various food materials under reduced pressure.
However these processes have been employed only for preventing undesirable phenomena such as browning which may be inhibited by frying at a low temperature and -nsufficient drying which may be avoided by slicing.
As a resul-t of our researches to determine ap-propriate conditions for preparing excellent dry food ,~
47~
in a laboratory, we have found that the aimed excellent dry food may be prepared by frying a food material at a temperature of 80 to 130C depending on the material under pressure of 20 to 100 mmHg.
However, a dry food product prepared under the abovementioned conditions in an industrial scale would not be crisp but somewhat moist. This product does not exhibit crispness nor sufficient expansion. Ad-ditional frying under reduced pressure would dehydrate the product without any expansion. The product thus obtained has a hard surface which hits against teeth and contains a large amount of oil, which means that the preparation is completely unsuccessful.
As a result of detailed examination on the frying of food, we have found that the initial contact of pre-fried food with a heated oil would result in rapid evaporation of moisture accompanied by expansion within the food to thereby form a porous tissue. It is nec-essary to maintain the oil around the food at a tem-perature appropriate for expansion until the completion of the evaporation. The evaporated moisture would generally cause a rapid fall of the temperature of the oil around the food. Therefore the delayed or stopped evaporation of moisture from the food would result in an insufficiently porous tissue to thereby form a - 3 - ~ 7~t7 partially hard or shrinked product, so long as it is allowed to stand as such. Additional frying might contxibute to the completion of dehydration. However the product would be impregnated with the oil and become hard, oily and shrinking.
In order to avoid these undesirable phenomena, the frying oil may be circulated or stirred. However the initial evaporation of molsture under reduced pres-sure is much vigorous than that under atmospheric pressure, which might prolong the lowering o the tem-perature of the oil around the food. Consequently the food product thus obtained might become 'nard and oily.
Our subsequent researches have revealed that a 1~ complete dehydration and frying may be achieved by supplying a large amount of heat while keeping the temperature as it is, i.e. without raising it.
Nothing but steam can supply a large amount of heat at once. Furthermore a conventional heater equipped with steam pipes only at the bottom is unable to supply a sufficient amount of heat. Therefore we have found it necessary to employ a frying tank equipped with many pipes at the bottom and sides and if possible, at the center.
~ 7 Summary of the Invention It is an objec-t of the present invention to provide a process for preparing dry food which comprises frying one or more food material(s) such as vegetables, root-crops, fruits, edible fungi, fishery products, seaweeds, beans, cereals, nuts, livestock meats or processed goods -thereof as it is or in a sliced form(s) under reduced pressure in a frying tank equipped with many steam pipes to which a sufficient amount of pressurlzed steam for providing appropriate amount of heat is supplied to prevent or restore a rapid fall of the temperature o:E the frying oil.
Brief Description of the Drawings Fig. 1 is a vertical section of a frying apparatus l~ used in the present invention wherein 1 is a frying apparatus, 2 is a frying tank, 3 are steam pipes and 10 is a vegetable oil.
Detailed_Description of the Preferred Embodiments According to the process of the present invention, it is possible to fry a food material at any cons-tant temperature from 80 to 130C by supplying a large amount of pressurized steam to many pipes equipped at least at the bottom and on the walls of a frying tank without inhibiting the frying operation to thereby supply a _ 5 _ ~ 2 ~
sufficient arnount of heat to prevent or restore a rapid fall in the temperature of the frying oil. For example, a fried potato which exhibits a complete ex-pansion without undergoing browning and contains 1.8 %
of water may be obtained by frying a potato material at a constant temperature of 120C, although the time required for frying may be somewhat prolonged.
In the process of the present invention, a stirrer may be equipped in the Erying tank in order to circulate the frying oil rapidly to thereby achieve uniform dis~
tribution of the supplied heat. Alternately a basket containing the food material to be fried may be immersed and subjected to a vertical or rotary motion in the oil to stir the oil.
More particularly, the process of the present invention may be carried out by connecting a steam supply apparatus to the steam pipes equipped in the frying tank, setting the apparatus to a desired tem-perature from 80 to 130C and supplying a lar~e amount of steam at the temperature as set above constantly.
The optimum temperature for frying may vary depend~
ing on the food material to be fried. Table 1 shows examples of the food materials used in the process of the present invention and the optimum temperatures thereof for frying.
~2~ 7 Table 1 Optimum temperature for frying (C) Food 80 - 90 Welsh onion ~white part), spinach, okra, cucumber, strawberry 90 - 95 Welsh onion (green part), eggplant, broccoli, lettuce, melon pimento, kidney bean, green pea, asparagus, raw mushroom, burdock, 95 - 100 garlic, apple, banana, kiwi, raisin, boiled fish pastes (kamaboko and chikuwa), raw oyster onion, cabbage, Japanese radish, lotus root, pineapple, persimmon, 100 - 105 lean pork, white meat of chicken, beef, beef liver, tangle, wakame seaweed 105 - 110 carrot, pumpkin, pork skin, chicken skin, potato chip 110 - 130 frozen pineapple, potato stick The pressure of the whole apparatus containing the frying tank may be reduced. In order to remove the moisture of a food material rapidly, it may be fried under reduced pressure of approximately 20 to 100 mmHg, preferably at approximately 20 to 60 mmHg. In order 7 ~2~ Q7 to prevent a rapid decrease in the degree of the reduced pressure caused by the rapid evaporation of moisture at the initial contact of the food with the frying oil, some means such as switching over to a powerful vacuum pump, stirring the frying oil or subjecting a basket containing the food to a vertical or rotary motion may be employed.
Various food materials such as those as such, those cut into various forms or those soaked into liquors optionally containing sugar, table salt or fruit juices may be used in the process of the present invention.
In the process of the present invention, it is particularly preferable to soak a food material into an aqueous solution of thick malt syrup in a concentra-tion of 10 to 60 % for 0.5 to 24 hours. By this opera-tion, the moisture within the food would be thoroughly removed ~y the osmotic pressure. Therefore expansion may be completed rapidly at frying to thereby obtain a crisp food product having an excellent texture.
Frying may be continued for 10 to 30 min at an appropriate temperature. It may be somewhat shorter at a higher temperature while it may De somewhat longer at a lower temperature.
After the completion of the frying, the basket containing the food material may be drawn up from the - 8- ~244707 oil and moved vertically to swish the oil off or al-ternately rotated above the oil to swish the oil off by centrifugation, thereby taking out the fried food from the apparatus which has been brought under ordinary pressure.
An example of an apparatus which can be used in the process of the present invention will now be il-lustrated wi-th reference to Figure 1, which is a vertical section of a ~rying appara-tus wherein 1 is a cyllndrical frying apparatus as a whole, 2 is a frying tank, 3 are steam pipes wound around the sides and the bottom of the frying tank three turns densely, 4 is a wire net basket comprising four steps each containing potato chips 5 which would fall into the central space of the frying tank 2 to fry the potato sticks 5, 6 is a shaft for hanging the basket 4 while 7 is a door.
After pulling up the shaft 6, potato sticks 5 are in-troduced into the basket 4 successively from the door 7. 8 and 8 are inlets of steam while 8' and 8' are outlets thereof through which a large amount of pres-surized steam at 150C would be passed. The steam pipes 3 are filled with pressurized steam to thereby heat added vegetable oil 10 to 125C continuously. 9 is a deaerating pipe connected to a condenser and a large vacuum pump ~not shown in the figure~ to maintain ~ 9 ~ 1 2 4 ~ ~ 0 7 a reduced pressure oE approximately 20 to 100 mmHg during the frying period. 11 and 12 are a vertical and a rotary motor, respectively. The vertical motor 11 is used for pulling up the basket 4 above the oil to set the potato sticks 5 and for moving the basket 4 vertically in the vegetable oil during the frying period. The rotary motor 12 is used for rotating the basket 4 clockwise or counterclockwise in the vegetable oil during the frying period and for rotating the basket 4 after pulling up to remove the oil by centrifu-gation.
Although frying of potato sticks has been illustrated above as an example, other food materials may be fried in the same manner. When the material to be fried is amall, a wire net basket of fine meshes-should be employed in order to prevent the escape of the material through the net. In addition, the temperature of steam should be adjusted to the optimum temperature for each food.
In the process of the present invention, food materials can be fried at a low temperature of 80 to 130C continuously by supplying a large amount of pres-surized steam sufficient for providing an appropriate amount of hea-t to prevent or restore the rapid fall of the temperature at the initial stage of frying in - lo - ~4~7 a short period through many steam pipes equipped on the walls and at the bottom of a Erying tank. A large amount of heat supplied in the process of the present invention exhibits many excellent effects such as con-tinuous rapid evaporation of the moisture in a food material at the initial stage of frying which may result in the formation of an excellent porous tissue and the inhibition of intrusion of oil.
To illustrate the present invention, the following examples will be given.
Example 1 A frying apparatus as shown in Fig. 1 was employed.
A vegetable oil was poured into a frying tank.
Steam was supplied from a large pressurized steam genera-tor to steam pipes. The frying temperature was set at 120C and pressurized steam at 150C was continuously supplied to maintain this temperature during the frying period.
Potato sticks (10 mm x 5 mm x 100 mm) were introduced into a basket, the frying apparatus was closed and a vacuum pump was started. When the pressure reached 40 mmHg, the basket containing the potato sticks were immersed in the frying tank.
During the immersion, a slight lowering of the oil temperature was observed. However no significant
2'~7~
change in the -temperature (i.e. 120C) was observed as a whole.
After the immersion, the basket was moved vertically c~ a,~L~s -~ ~ at a distance of 10 ~ in every 30-min without taking the sticks out of the oil, thereby uniformalizin~ the oil temperature and evaporating the moisture rapidly.
Frying was completed within 15 min. ~he basket was pulled up and rotated above the oil under reduced pressure to swish the oil off. The apparatus was brought under ordinary pressure and the sticks were taken out.
The dry fried potato thus obtained was crisp and exhibited an excellent texture and free from browning.
Example 2 The same frying apparatus as shown in Fig. 1 was employed.
Salad oil was poured into a frying tank. Steam was supplied from a large pressurized steam generator to steam pipes. The frying temperature was set at 117C and pressurized steam at 150C was continuously supplied to maintain this temperature during the frying period.
Onion slices of 8 mm in width were soaked in a 3n ~ aqueous solution of thick malt syrup for 10 hours 2~ at room temperature.
- 12 _ ~2~7~7 After soaking and swishing water off, the onion slices were introduced into a basket comprising four steps and the apparatus was closed. Subsequently a vacuum pump was started and the basket containing the onion slices was immersed into the frying tank under a pressure of 40 mmHg.
During the immersion, a slight lowering of the oil -temperature was observed. However, no significant change in the -temperature (i.e. 117C) was observed as a whole.
After the immersion, the basket was moved vertically ~ecvn~/s at a distance of 10 cm in every 30 ~ without taking the slices out of the oil, thereby uniformalizing the oil temperature and evaporating the moisture rapidly.
1~7 Frying was completed within 12 min. The basket was pulled up and rotated above the oil under reduced pressure to swish the oil off. Then the apparatus was brought under ordinary pressure and the slices were taken out.
The dry onion thus obtained showed no browning and an excellent reversion in hot water. In addition, it exhibited an excellent texture.
change in the -temperature (i.e. 120C) was observed as a whole.
After the immersion, the basket was moved vertically c~ a,~L~s -~ ~ at a distance of 10 ~ in every 30-min without taking the sticks out of the oil, thereby uniformalizin~ the oil temperature and evaporating the moisture rapidly.
Frying was completed within 15 min. ~he basket was pulled up and rotated above the oil under reduced pressure to swish the oil off. The apparatus was brought under ordinary pressure and the sticks were taken out.
The dry fried potato thus obtained was crisp and exhibited an excellent texture and free from browning.
Example 2 The same frying apparatus as shown in Fig. 1 was employed.
Salad oil was poured into a frying tank. Steam was supplied from a large pressurized steam generator to steam pipes. The frying temperature was set at 117C and pressurized steam at 150C was continuously supplied to maintain this temperature during the frying period.
Onion slices of 8 mm in width were soaked in a 3n ~ aqueous solution of thick malt syrup for 10 hours 2~ at room temperature.
- 12 _ ~2~7~7 After soaking and swishing water off, the onion slices were introduced into a basket comprising four steps and the apparatus was closed. Subsequently a vacuum pump was started and the basket containing the onion slices was immersed into the frying tank under a pressure of 40 mmHg.
During the immersion, a slight lowering of the oil -temperature was observed. However, no significant change in the -temperature (i.e. 117C) was observed as a whole.
After the immersion, the basket was moved vertically ~ecvn~/s at a distance of 10 cm in every 30 ~ without taking the slices out of the oil, thereby uniformalizing the oil temperature and evaporating the moisture rapidly.
1~7 Frying was completed within 12 min. The basket was pulled up and rotated above the oil under reduced pressure to swish the oil off. Then the apparatus was brought under ordinary pressure and the slices were taken out.
The dry onion thus obtained showed no browning and an excellent reversion in hot water. In addition, it exhibited an excellent texture.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for preparing dry food which comprises frying one or more food material(s) under reduced pres-sure in a frying tank, having a plurality of steam pipes on the side walls and the bottom, in such a way that these pipes surround the food material(s) to be fried, and the pipes being supplied with sufficient pressurized steam for providing an appropriate amount of heat to prevent rapid fall of the temperature at frying.
2. A process for preparing dry food as set forth in Claim 1, wherein one or more food material(s) are soaked in a 10 to 60% aqueous solution of thick malt syrup for 0.5 to 24 hours at 5 to 80°C and are then fried under reduced pressure.
3. A process for preparing dry food as set forth in Claim 1, wherein frying is carried out at approximately 80 to 130°C under a reduced pressure of approximately 20 to 100 mmHg.
4. A process for preparing dry food as set forth in Claim 1, wherein a basket containing one or more food material(s) is moved in oil during frying.
5. A process for preparing dry food as set forth in Claim 2 wherein a basket containing one or more food material(s) is moved in oil during frying.
6. A process for preparing dry food as set forth in Claim 2, wherein frying is carried out at approximately 80 to 130°C under a reduced pressure of approximately 20 to 100 mmHg.
7. A process for preparing dry food as set forth in Claim 3, wherein a basket containing one or more food material(s) is moved in oil during frying.
8. A process for preparing dry food as set forth in Claim 6, wherein a basket containing one or more food material(s) is moved in oil during frying.
9. A process as set forth in any one of Claims 1, 2 and 4 in which the food material is selected from the group of vegetables, rootcrops, fruits, edible fungi, fishery products, seaweeds, beans, cereals, nuts, livestock meats or processed goods thereof.
10. A process as set forth in Claim 7, in which the food material is selected from the group of vegetables, rootcrops, fruits, edible fungi, fishery products, seaweeds, beans, cereals, nuts, livestock meats or processed goods thereof.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58-154133 | 1983-08-25 | ||
| JP58154133A JPS6047653A (en) | 1983-08-25 | 1983-08-25 | Preparation of dried food |
| JP58-169215 | 1983-09-16 | ||
| JP58169215A JPS6062950A (en) | 1983-09-16 | 1983-09-16 | Preparation of dried food |
| JP58-189992 | 1983-10-13 | ||
| JP58189992A JPS6083547A (en) | 1983-10-13 | 1983-10-13 | Preparation of dried food |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1244707A true CA1244707A (en) | 1988-11-15 |
Family
ID=27320607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000460845A Expired CA1244707A (en) | 1983-08-25 | 1984-08-13 | Process for preparing dry food |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1244707A (en) |
| DE (1) | DE3429900A1 (en) |
| FR (1) | FR2555415A1 (en) |
| GB (1) | GB2146225A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1001573A3 (en) * | 1988-04-01 | 1989-12-05 | Eclat Participations Sa | Method for manufacturing of vegetable or fruit chips. |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3044880A (en) * | 1959-01-09 | 1962-07-17 | Gen Foods Corp | Method of making a cooked potato product |
| FR1541859A (en) * | 1966-10-28 | 1968-10-11 | Inst Voor Bewaring | Process for preparing a fried potato product and oven for frying under reduced pressure a pre-fried potato product |
| US3635722A (en) * | 1967-01-09 | 1972-01-18 | George A Moore | Method of pressure cooking foods |
| US3501316A (en) * | 1967-07-27 | 1970-03-17 | Golden Skillet Corp | Method of frying chicken |
| SE391275B (en) * | 1975-04-07 | 1977-02-14 | Concordia Dev Ab | FLOAT TYPE |
| US4148729A (en) * | 1976-08-25 | 1979-04-10 | Howard George A | System for storing and handling used cooking oils |
| DE2746728A1 (en) * | 1977-10-18 | 1979-04-19 | Fanenbruck | FRYER |
| FR2514474B1 (en) * | 1981-10-13 | 1988-07-15 | Utilisation Ration Gaz | DEVICE FOR HEATING AN OIL BATH |
-
1984
- 1984-08-10 GB GB08420344A patent/GB2146225A/en not_active Withdrawn
- 1984-08-13 CA CA000460845A patent/CA1244707A/en not_active Expired
- 1984-08-14 DE DE19843429900 patent/DE3429900A1/en not_active Withdrawn
- 1984-08-21 FR FR8413008A patent/FR2555415A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB8420344D0 (en) | 1984-09-12 |
| GB2146225A (en) | 1985-04-17 |
| DE3429900A1 (en) | 1985-03-07 |
| FR2555415A1 (en) | 1985-05-31 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |