FR2788940A1 - Preserving apples, apple pieces, etc. by dehydration and then frying - Google Patents

Abstract

Fruit is preserved by dehydration and then frying. An Independent claim is included for the apparatus for perfuming the above process. Preferred Features: The fruit may be dehydrated by warm air at 170 deg C, coated in fat and sugar that caramelises when fried and finally deep frozen. The frying is performed in double walled hemispherical vessels with a grill top.

Description

The present invention relates to a method and an installation for the

treatment

  and storing pieces of fruit that are intended to be ready for use.

  The installation comprises a set of means which are intended to implement

said treatment method.

  In the current state of the art, in order to preserve fruits and pieces of fruit, it has already been proposed to dry or dehydrate them, and possibly to

  freeze. As examples, mention may be made of the processes described in the documents FR-

  A-2 474826, FR-A-2 606 976, FR-A-2 627 666 and FR-A-2 656 502, and the documents

  US-A-3,962,355, US-A-4,647,469 and US-A-4,844,931.

  The interest of dehydrating fruits essentially lies in the prolonged conservation of these. It is particularly advantageous to store the fruits or the pieces of fruit so that they are always available to the consumer. The

  fruit dehydration has been known since antiquity.

  Another method of preserving fruit is to freeze or freeze it. But the water contained in the cells of the fruit is transformed into ice which bursts the cells of the fruit and which lets out perfumes. This drawback can be partially avoided by freezing in liquid nitrogen, since the crystallization mode is then different. Fruits still lose

  much of their organoleptic qualities.

  Document FR-A1-2 606 976 describes a process for treating plant foods. The food is dehydrated under vacuum in a hot oven after a heat treatment by frying at 80 C. Thus, this process only concerns a simple dehydration. Document FR-A-2 627 666 describes a process for the preparation of dehydrated fruit, in particular dehydrated apple pieces. The fruits are first cut into pieces whose thickness does not exceed 20 mm and these are subjected to drying in a current of hot air. The air stream has a temperature between 100 and 120 C, then the current is maintained with the pieces until the internal temperature of the pieces is between 50 and 80 C, finally drying continues at decreasing temperatures between 85 and 40 C until dryness is obtained

  fruit between 3 and 10%. The pieces of fruit can be stored in bulk.

  Preferably, they will be put in a sachet and possibly mixed with other fruits or ingredients, and finally may be pasteurized. This process does not yet concern

  than dehydration, even if it is more complex.

  Document FR-A-2 656 502 proposes a series of steps: placing a chamber in a vacuum in which the fruits are placed on trays, heating the wall of the chamber, introduction of water vapor into the enclosure, re-evacuating the latter, heating the trays, returning the enclosure to atmospheric pressure. This

  document proposes rehydration and evacuation.

  Document US-A-4 647 469 describes a dehydration and freezing process for pieces of peeled apples. The apple pieces are blanched in 85-95 C water for one to three minutes. They are then dried with hot air at a maximum temperature of 60 C until the weight is reduced by 50% compared to their initial weight. The pieces are then frozen. Apples thus processed have the same use as fresh apples. In this process,

  suggests blanching, that is, partially cooking the apples.

  Document US-A-4 844 931 describes a continuous process for dehydrating fri-uits or vegetables by the use of heat and vacuum. The products are cut into slices and then introduced onto keys arranged in an oven supporting the vacuum, and whose temperature is maintained between 30 and 80 C. A vacuum level between 1 and 5 Torr (1 to 5 mm of mercury) is created in the oven enclosure. Oil is also brought into contact with the products, until the water content of the products drops to around 2%. The operation lasts between 10 and 20 hours, and the products are blown at the end of the cycle when they reach the last shelf. Products undergo beforehand

  a continuous dehydration treatment which lowers their water content to around 15-

  %. The products are passed through an oil bath at a temperature between 50 and 80 ° C. at atmospheric pressure. After dehydration, put the pieces of fruit in

contact with oil.

  According to other documents, the freezing is preceded by a control of the

  sugar contained in the pieces of fruit.

  Document FR-AI-2 474 826 describes a process for the preparation of dried fruit strips. The fruit strips, whose water soluble sugar content is controlled, by immersing the strips not yet treated in a syrup solution, to be between 6 and 25% by weight, are frozen to reduce their level of humidity by desiccation between 15 and 65%. The fruit strips are then subjected to a microwave vacuum treatment to lower their humidity to% by weight. Document US-A-3,962,355 relates to a dehydration process for fruit or plants. The products are cut into pieces, then fried in a sugar-based syrup for 15 to 20 minutes at 65-90 C. The excess syrup is removed, then the pieces are dehydrated to a water content of 6- 8% by contact with hot air at 70 C and under a pressure of 0-160 mm of mercury, then cooled under vacuum also. Apples can also be fried in oil at 120-165 C

for 3 to 4 minutes.

  An object of the present invention therefore consists in providing a method which overcomes the drawbacks mentioned above, by not altering the qualities of the product.

  of origin (taste, texture, and external appearance).

  Another object of the invention is to improve the dehydration and contact phases of a syrup with the pieces of fruit, which improves the

cost price of the final product.

  According to one characteristic of the invention, the process for treating and preserving fruit, in particular apples or pieces of apple, comprises the following steps: dehydration, and

- frying.

  According to another characteristic, the treatment method also comprises the following step:

- freezing.

  According to another characteristic, dehydration is carried out at a

  maximum temperature of 170 C by circulation of hot air over the pieces of fruit.

  According to another characteristic, the frying is carried out so that the dehydrated pieces of fruit are browned in fat and sugar in order

  to form a caramelization which will be absorbed by the pieces of fruit.

  An installation is advantageously provided for the implementation of said method. It includes means for dehydrating at high temperature and

means for frying.

  According to another characteristic, the means for dehydrating are discontinuous.

  According to another characteristic, the means for dehydrating are continuous.

  According to another characteristic, the means for frying are pots

  semi-hemispherical double wall with a mesh cover.

  The above mentioned features of the present invention, as well as

  others will appear more clearly on the following reading of the description of a

  exemplary embodiment of a set of means making it possible to implement the

  process for treating apples or apple pieces which has been described above

  above, said description being made in relation to the accompanying drawings, among which:

  Fig. 1 is a diagram of the path followed by the pieces of apple, FIGS. 2A and 2B show views in vertical section of a dehydrator with discontinuous operation and a dehydrator with continuous operation, FIG. 3 is a cross-sectional view of the stove means, and

  Fig. 4 is a schematic perspective view of a plate freezer.

  We have shown in FIG. I a diagram of the path followed by the pieces of apple to

  treat and keep according to the invention.

  A conveyor I transports said apples 32 already peeled, without core and cut. Said apples 32 are immersed in a bath of citric acid 2 in a conventional manner and then the apples cutting phase is carried out 3. Said apples 32 are then transported on a conveyor 4 to be placed in a dehydrator 5 and to then be brought to the frying phase 6. After having completed this treatment, it is then proceeded to deep-freezing 7, then to packaging.

8 and finally storage 9.

  According to the process of the invention, the apple pieces therefore undergo

  first dehydration, then frying and, finally, possibly deep-freezing.

  The initial water content of the apple is, for example, 90%, but is in fact more or less variable depending on the season. Dehydration prepares the apple for frying. The reduction in the free water of the apple makes it possible to improve or modify properties of the apple, such as the texture, the aptitude for rehydration.

and possibly the color.

  In terms of texture, the dehydrated apple is less fragile, more resistant to handling and temperature increases. So we avoid

  crushing, the formation of compote, mash.

  As far as rehydrating ability is concerned, the dried apple acts like a sponge. As soon as it is in contact with a liquid or semi-liquid, it will impregnate it. Thus, we can formulate, by absorption, the apple as desired. Regarding color; the apples are more or less browned depending on the time and temperature used. When the product is dark, you can reduce the pan-frying time that follows. As shown in Fig. 2A, a dehydrator with discontinuous operation (10), each thin layer of apple (32) is placed on a wire rack 11. The racks 11 are superimposed and spaced enough to allow the circulation of hot air therebetween, this circulation being , for example, caused by one or more simple fans 12 which are placed above the stack of racks and / or laterally near the stack. The set is completed by an extractor, not

shown, like a range hood.

  Thus the hot air / apple contact is increased. The smaller the pieces, the faster the dehydration. The air circulation speed is, for example, 2.5 m / s. Under the effect of the high temperature of 170 ° C maximum, the water contained in the apples turns into water vapor and is evacuated from the dehydrator by suction. The circulation of hot air by means of fans 12 must be distributed throughout the dehydrator over all of the racks 11. For example, the dehydration time has been set at 1 h for 300 kg. However, the time / temperature couple can be varied according to the coloring and the dehydration

as desired.

  As shown in Fig. 2B, a continuously operating dehydrator 19, the apple pieces (32) can be placed between a double mesh conveyor belt 13 which passes successively on trays 14 also with mesh which are placed one below the other, the double carpet folding in accordion, each fold being supported by a plate 14. A number of fans 15 ensures circulation

  air. We can adopt the same parameters as above.

  At the outlet of the dehydrator of FIG. 2A or of FIG. 2B, you should know that the initial water content of the apple is around 90%. The weight of the apple will be for example 300 kg, there will be a reduction in the total weight of 20% to 30%, i.e.

  remaining quantity between 240 Kg and 210 Kg.

  As the initial thickness of the apple pieces, we can have them 5 cm to

  1/4, 1/8, 1/16, cubes, pieces and a row for whole and a half apples

  apples. It is observed that the pieces of apple which come out of the dehydrator are firm with good resistance to finger pressure; they are not dry and are not cracked; they do not secrete exudate under finger pressure. The

  browning of the pieces is more or less marked depending on the desired product.

  Pan-fried apple is, by definition, a dehydrated apple that is browned in fat and sugar to form, by Maillard reaction,

  a caramelization which will be absorbed in the fruit.

  To fry the apple pieces (32) in a pot, they are passed through a mixture of sugar, fat and possibly additives. We proceed to a slow and sequential mixing which allows to turn the pieces of fruit without crushing them. The contact between the apple and the hot wall of the pot must be long enough to allow caramelization on the surface and penetration into the heart of the product. The water vapor released by the apple is evacuated by evaporation and suction using an extractor hood so as not to rehydrate the pieces of

Apple.

  During the development and study of the stove equipment, several criteria were set. To have the maximum contact between the hot wall of the pot, a

  part, and the apple pieces and the juices, on the other hand, we chose a semi-pot

  hemispherical which will only be partially filled, for example to a fifth of its total volume. To avoid crusting or crusting, use a double walled pot fed under an internal pressure of 7 bars, which will allow

to have a homogeneous temperature.

  To be able to turn a half-apple on the other side and not to crush it, we chose, for the pot, a horizontal axis which allows to take the apple (32) from below and not on side if it had a vertical axis. The lid of the pot is

  screened to allow water vapor to escape.

  An exemplary embodiment of such a pan is shown in FIG. 3, which shows in cross section a pot 21, according to the invention. The pot 21 has the shape of a double wall hemisphere which is surmounted by a mesh cover 22. An agitator 23 is installed in the pot 21 and is actuated by means of a horizontal shaft 24 which passes through the double wall 25 and which is set in rotary motion by a motor, not shown. A burner 26 is also provided under the pot 21. By way of example, the characteristics of such a pot 21 in operation are as follows:? Temperature: 190 C under a pressure of 7 bars Yield: 300 Kg / h Passage time: 50 Kg every 10-15 minutes Brewing. 5 rpm sequentially The apple (32) is caramelized on all sides and has an organoleptic flavor of caramel to the core. It was not crushed, it stayed in

  its initial form as at the beginning of introduction into the dehydrator.

  When frying different ingredients can be added to apples (, nuts, grapes, alcohol, prunes, cinnamon, caramel ...). The product will be presented in its form

  or embellished according to the customer's request.

  The pan-fried apples are put to drain and cool on wire racks at 4 C for at least 30 minutes in order to have a freezer entry of 10 C to C. Then, the apples are slowly poured onto the conveyor to distribute them evenly and form a thin layer of fruit. In addition, as the products are drained, they stick less to each other. The more the pieces are separated,

the better the freezing.

  The apples are conveyed to the freezer using a HDPE film

  a speed of 5 to 45 rpm. The freezing time can vary from 5 to 45 minutes.

  Freezing is done, Fig. 4, by contact with a refrigerated plate 31 at -40 C. The phenomenon of crusting on the surface to freeze the interior of the fruit with cold air is sent over. The hot air released by the apples is evacuated by evaporators, not shown. The product comes out at -18 C to the core. The pieces are separated from each other, there are no blocks or block formations during the

storage.

  The packaging is done in cardboard of 10 or 20 Kg or in metal box of 300 Kg, The shelf life can be 12 months. But the seared apples

  can also be non-frozen and packaged fresh with a duration of 40 days.

  Apples or apple pieces can also be used as vegetables or fruits. They can be found in different areas, for example: Catering. apple pudding, game accompaniment Pastry chef: a tarte Tatin, apple turnover, four-four filled, dairy pie: tracer in yogurt, bilayer Glacier: sorbet or ice cream with pieces of fruit Dessert: dessert, cream with pieces of fruits

  The pan-fried apple thus prepared can be used directly by the manufacturer.

  It is a time saver in the context of its use compared to a raw apple

  that you have to peel, peel, cut and brown.

  But the product can also be consumed as it is for dessert or as an accompaniment. As the apple can be impregnated with different ingredients, it stands out from the fruits that are just coated or candied that can be found today

on the market.

  Freezing type IQF (Individually Quick Freczing) used in the case

  this allows easier dosing and is adaptable to existing materials to date.

  The advantage of this deep-freezing system is that it does not require thawing before the product is introduced. Having a quick freeze prevents the formation of crystals which could burst the cells of the product and lead to the oozing of exudate when thawed. The product is thus always

  food standards and perfectly fit for consumption.

Claims (7)

  1) Process for processing and preserving fruit, in particular apples or apple pieces, characterized in that it comprises the following steps: - dehydration, and - frying.   2) Treatment method according to claim 1, characterized in that it also comprises the following step: - freezing.   3) Treatment method according to claim 2, characterized in that the dehydration is carried out at a temperature of about 170 C by circulation   hot air on the pieces of fruit.   4) Treatment method according to one of the preceding claims,   characterized in that the frying is carried out so that the dehydrated pieces of fruit are browned in fat and sugar in order to form a   caramelization which will be absorbed by the pieces of fruit.   ) Installation for the implementation of said method according to one of   previous claims characterized in that it comprises means for   dehydrating at high temperature (10, 19) and means for frying (21).   6) Installation according to claim 5, characterized in that the means for   dehydrate are discontinuous (10).   7) Installation according to claim 5, characterized in that the means for dehydrate are continuous (19).   8) Installation according to one of claims 5 to 7, characterized in that the   means for frying are semi-hemispherical double-walled pots (25)   having a mesh cover (22).