CH715875B1 - Process for the preparation of a dehydrated food product based on fruits and/or vegetables. - Google Patents

Abstract

The invention relates to a process for the preparation of a dehydrated food product based on ingredients of vegetable origin, in particular fruits and/or vegetables comprising: the production of a gelled central part composed of fruits and/or vegetables comprising : the production of a mixture based on fruit and/or vegetable pulp, not yet gelled but containing at least one gelling agent, the cooking of the mixture, the molding of the mixture, the refrigeration to obtain a gelled preparation in a three-dimensional form , then dehydration of the preparation until a water activity „aw“ lower than 0.91; the production of an envelope made up of fruits and/or vegetables comprising mixing the fruit and/or vegetable pulp, pouring the mixture obtained onto a surface so as to form a layer, dehydrating the layer to a water activity „aw“ less than 0.65, then peeling off the at least partially dehydrated layer and possibly cutting it; assembly by envelopment or at least partial covering of the central part gelled by the envelope and the bonding by pressure of the envelope against the central part.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for preparing a dehydrated natural food product based on ingredients of plant origin, in particular fruit (s) and / or vegetable (s) and such a product rich in nutrients and fiber.

STATE OF THE PRIOR ART

[0002] Snacks have become an important part of many people's diets. Unfortunately, many popular, inexpensive, between-meal foods are high in added sugars, fats, salt, and unwanted additives like artificial colors, emulsifiers, and/or preservatives. The food industry is therefore looking for snack food products which are based on essentially natural products.

[0003] Fruits and vegetables are a source of fibre, antioxidants, vitamins, mineral salts and other essential nutrients. Their consumption is recommended daily in a balanced diet. However, these foodstuffs are perishable, often wasted and misused. This is due to the very demanding specifications of production and distribution players. Some of these foodstuffs are recycled in the form of juices, jams, purées, pieces, in dehydrated or frozen form. However, a good part is not valued and the part that is valued lacks attractiveness and diversity for the consumer.

[0004] The object of the invention is therefore to produce a food product based on fruits and/or vegetables which can be kept at room temperature, which uses recoverable products from fruit and/or vegetable farming, which is without health risk, easy to store, transport and consume. Another object is to offer a product with a natural taste and appearance, with a pleasant texture in the mouth and therefore attractive to consumers.

[0005] Patent application CN104336551 relates to a method for producing dried fruits and vegetables comprising a step of extracting the pulp and grinding the fruits/vegetables, mixing and homogenizing the pulp obtained, concentrating under vacuum at low temperature, molding and freezing and drying of fruits and vegetables to obtain a dried finished product rich in nutrients and maintain the original taste of fresh fruits.

[0006] Patent application WO2005023016 relates to a method for preparing a food product in which a first freeze-dried component of fruit or vegetable is mixed with a second component comprising a complementary food such as a binding agent (for example particles of cereals) so the water activity is between 0.15 and 0.3 to obtain a water balance of less than 0.35.

[0007] Patent application WO2016202830 relates to a dried food product consisting of fruits and/or vegetables produced at low temperature and substantially without the presence of oxygen. The method consists in forming a mixture of fruits or vegetables, optionally adding herbs or spices, pre-dehydrating the mixture and optionally aeration it using an inert gas, then drying the mass again by microwave under reduced pressure conditions and optionally continuing dehydration under reduced pressure conditions.

[0008] The state of the art thus focuses on the conditions for producing a dehydrated homogeneous product based on fruit or vegetables while attempting to preserve the nutritional characteristics and the color of the starting ingredients. However, the attractiveness, the texture in the mouth and the diversity of the products of the state of the art can be improved.

DISCLOSURE OF THE INVENTION

The object of the present invention is therefore to overcome these drawbacks.

Thus, the invention relates to a method for preparing a food product based on ingredients of plant origin, in particular fruits and / or vegetables comprising: the production of a gelled central part composed of fruits and/or vegetables comprising the production of a mixture based on fruit and/or vegetable pulp, not yet gelled but containing at least one gelling agent, the cooking of the mixture, the molding the mixture, refrigerating to obtain a gelled preparation in a three-dimensional form, then dehydrating the preparation to a water activity (aw) of less than 0.91; the production of an envelope made up of fruits and/or vegetables comprising: the production of a mixture of the fruit and/or vegetable pulp, the pouring of the mixture obtained onto a surface so as to form a layer, the dehydration of the layer up to a water activity (aw) of less than 0.65, peeling off the at least partially dehydrated layer and possibly cutting it; assembly by enveloping or at least partial covering of the central part gelled by the envelope and the bonding by pressure of the envelope against the central part.

Thus the method according to the invention proposes to produce a product, in particular allowing the upgrading of downgraded fruits and / or vegetables, made essentially in two assembled parts, including a gelled heart improving the texture in the mouth and an envelope which at least partially coats and which protects the core and gives the whole a good hold for easy and practical consumption.

[0012] For the production of the central part of the product, the rapid cooling of the mixture after cooking and before dehydration is carried out so that the core temperature does not remain at values between +10° C. and + 63° C. for more than two hours. Thus, this makes it possible to guarantee the wholesomeness and the gelation of the mixture. The refrigeration can be done in a cooling cell, or any other means allowing rapid refrigeration. The preparation is thoroughly chilled after cooking and before dehydration, preferably below +10°C, preferably between 0°C and +5°C, more preferably +4°C.

[0013] The term “pulp” is not limiting and can include any edible part of these fruits and/or vegetables, in particular the flesh but also the skin and part of the ground pips or stones. Some of these parts can also be used in the mixture as natural gelling agents.

[0014] The preparation of the mixture comprises mechanical agitation or by other means. The mixing can be done for example by grinding, mixing, homogenization, aeration, pressing, centrifugation and any combination. It can be done under vacuum or without vacuum.

[0015] Washing operations with drinking water, trimming (pitting, stemming and peeling), cutting may precede mixing. Similarly, a pretreatment operation can be carried out before mixing. Similarly, a weighing operation can be provided before and/or after cutting and making the mixture.

[0016] Preferably, the acidity and the fraction of soluble dry matter(s), including sucrose, of the mixture are controlled so as to ensure the quality of the final product. This control is carried out respectively by measuring the pH with a pH meter and by measuring the Brix degree with a refractometer, at room temperature. Thus, the mixture of pulp for the production of the central part and/or the envelope is made with fruits and/or vegetables, and optionally the addition of soluble solute(s), preferably sugar, so as to achieve a Brix degree greater than 6°B, preferably greater than 10°B, more preferably between 10°B and 40°B.

[0017] The structure of the gelled central part and of the envelope and more particularly the action of the texture agents is generally dependent on the pH. For example, most pectins act very well in an acid medium below 3.8. In the respective parts of the product, acidic fruits and/or vegetables are preferred so as to be able to reach a pH of less than 7, preferably less than 5.2 and particularly less than 4.5, in particular between 3.0 and 4.5, and thus allow the microbiological stability of the mixture or of the preparation during the various stages of the process.

[0018] When the sugar content of the fruits used is sufficient, as for certain varieties of apples, it is not necessary to add soluble solute(s), in particular sugar, to the mixture. However, if the main ingredient is a fruit or vegetable with a low sugar content, adding sugar to the mixture may be necessary until a Brix level measurement above 6°B is reached, preferably above 10°B, more preferably between 10°B and 40°B. The addition of soluble solute(s) in the preparation leads to a limited reduction in the water content of the product during dehydration with a limited effect on the consistency of the product. Thus this addition makes it possible to maintain a tender and slightly elastic texture. According to one aspect, sugar is added to the mixture for producing the central part and/or the envelope. Sugar here refers to sucrose, fructose, starch hydrolysates and other isolated sugar preparations. This term also includes the part of the monosaccharides and disaccharides present in certain foodstuffs, for example, honey, syrups, juices, pulp, puree and concentrates of plants such as fruits, agave and elderberries.

Similarly for the structure conferring the holding of the central part, the production of the mixture comprises the addition of at least one gelling agent. This gelling agent can have thickening, stabilizing and/or emulsifying properties. Preferably, the gelling agent is selected from: agar agar, pectins, carrageenans, gums (gellan, xanthan, carob, guar, cellulose, etc.), alginates, konjac, starches, gelatins, potassium chloride and combinations.

[0020] Preferably, the mixture for the central part comprises the mixture of fruit and/or vegetable pulp and other ingredients chosen from: vegetable juice, water, broth, dairy products, spices, aromatic herbs, seeds, plants, alcohol, cereals, sweeteners, cocoa, chocolate, natural flavorings and colorings and combinations.

These additional ingredients make it possible to adjust the consistency of the mixture and to vary the tastes and/or the textures of the final product.

[0022] The shaping of the central part can be done by casting in molds, preferably in silicone, blisters or molds with starch powder imprint.

[0023] Once cooled rapidly, in the case of a mold without imprint, the gelled preparation is unmolded and can be cut into portions or sections according to the desired length corresponding to that of the envelopes. The cutting can be done with a knife, a guitar or a roller with a stainless steel or ceramic blade or any other appropriate means. In the case of a mold with an imprint, the gelled preparation forming the central part is not necessarily cut out, in particular when the part is molded to the final dimensions and shapes.

According to one aspect of the invention, the refrigerated preparation is gelled for the dehydrated central part at a temperature below 65°C, preferably between 20°C and 60°C. The temperature is that measured in the enclosure. Preferably, the relative humidity (RH) of the dehydration enclosure, for example an oven, is also controlled during the dehydration so as to reach a value below 50% RH at the end of the dehydration. The dehydration is continued until a water activity of the gelled preparation is less than 0.91, more preferably between 0.5 and 0.7. The lowering of water activity allows inhibition of microbial growth phenomena and stabilization of the final product.

For the realization of the envelope, the casting of the mixture can be done on a non-stick surface such as a silicone sheet. The sheet is preferably sanitized with a fast-acting food sanitizer. Preferably, a sufficient surface layer is made to be able to be cut to form one or more envelopes. However, it is possible to make the layer to the precise size of the envelope on a surface with an imprint. According to another aspect of the invention, the dehydration of the layer for the envelope and/or of the gelled preparation for the central part is carried out at low temperature, that is to say at a temperature below 65° C., from preferably at a temperature between 20°C and 60°C. The temperature is that measured in the enclosure. Dehydration can be done under vacuum or without vacuum. Dehydration can be done in open or closed circuit. According to a preferred example, it takes place in an oven but can be carried out by any other suitable means. Preferably, the relative humidity (RH) of the dehydration enclosure is also controlled during the dehydration so as to reach a value below 50% RH at the end of the dehydration. Dehydration can use other techniques such as for example cryodesiccation.

The dehydration of the layer for the envelope is continued until a water activity (aw) of the central part is preferably less than 0.65, more preferably a water activity of between 0.35 and 0.5. The lowering of water activity allows inhibition of microbial growth phenomena and stabilization of the final product.

Preferably, the dehydration can be done in the presence of bactericidal radiation, preferably by means of ultraviolet radiation. Bactericidal radiation is useful when dehydration is not done under vacuum. Such a procedure makes it possible to reduce the bacterial load and confers a final product without health risk.

According to one aspect, the mixture for the casing comprises the mixture of fruits and/or vegetables and at least one ingredient chosen from: vegetable juice, water, broth, dairy products, spices, aromatic herbs, seeds, plants , cereals, sweeteners, cocoa, chocolate, flavors, natural colors, alcohol and combinations.

[0029] In order to limit the oxidation and enzymatic browning reactions as well as to reduce the surface microbial load which could remain despite the prior washing, the fruits and/or vegetables can undergo a pretreatment before mixing. Preferably, a soaking operation in a solution of antioxidants such as ascorbic acid, citric acid, sodium bisulphite, or in fruit juice or any other sweetening solution and combinations and/or a heat treatment of Whitening in hot water and/or steam can be done before mixing.

[0030] Once the water activity of the two parts has been sufficiently lowered, the assembly of the two parts can take place. A step of checking the water activity values for each part may precede assembly.

[0031] Thus, according to one aspect, the envelope is wrapped around the central part, preferably in the manner of a roll, preferably with an overlap of the envelope allowing the envelope to be glued on itself. . The envelope could also cover at least one face of the central part, for example to form successive layers: envelope/central part/envelope.

[0032] The central part can be made in the form of an elongated bar or else of a mass in the form of a ball, pâté, cube or other shapes.

The invention also relates to a dehydrated food product based on ingredients of plant origin, in particular fruits and / or vegetables obtained by the process of the invention and comprising: a gelled central part composed of fruits and/or vegetables having a water activity (aw) of less than 0.91, preferably between 0.5 and 0.7; a casing composed of fruits and/or vegetables having a water activity (aw) of less than 0.65, preferably between 0.35 and 0.5; the envelope being glued to the central part and surrounding it or covering it at least partially.

The water activity is measured using a digital Aw-meter under ambient temperature conditions (20° C.).

Other characteristics and advantages of the invention will become apparent on reading the following description, with reference to the appended figures, for which: FIG. 1 shows the essential steps of an example of the method according to the invention; Figure 2 is a photo of a final product obtained according to the process.

Figure 1 shows a preferred example of the product manufacturing process according to the invention. The method can be carried out according to two branches of implementation; one relating to the production of the gelled central part; the other concerning the realization of the envelope. These two branches can be made in parallel or separately and then the product is assembled from these two parts. Certain process steps can also be carried out jointly in order to save on preparation time and cost. The steps that may be common are: the selection of fruits and/or vegetables, washing, trimming, cutting, possible pre-treatment, weighing and mixing.

The choice of species and varieties of fruit is not limited. Preferred examples are however: apples, pears, prunes, peaches, apricots, grapes, red fruits, exotic fruits, citrus fruits, tomatoes, etc. Fruits with a high content of simple carbohydrates, complex carbohydrates and polyols are however particularly interesting since their use reduces the need to add these ingredients. Similarly, many species and varieties of vegetables can be used with a preference for those with a high value in simple carbohydrates, complex carbohydrates and polyols such as: carrots, potatoes, beets, peas, parsnips, beans, onions, peppers, etc. The two parts are made from fruit and/or vegetable pulp after washing and trimming, possible pre-treatment and cutting into pieces, then mixed with at least one ingredient (preferably several) chosen from among: vegetable juice , water, broth, dairy products, spices, aromatic herbs, seeds, plants, cereals, alcohol, sweeteners, cocoa, chocolate, natural flavorings and colorings. In some cases, the addition of liquid makes it easier to prepare the mixture.

[0038] Most fruits and vegetables have tastes, flavors, colors as well as oxidative stability which differ according to the species and the varieties. Slight natural variations may also be present for the same varieties depending on the environment. Consequently, the acidity characteristics and the fraction of soluble solids are measured because they are functions of the fruits and/or vegetables used.

[0039] The fruits and/or vegetables for the central part and/or the envelope part may require pretreatment before the mixture is produced. This pretreatment can be a bleaching heat treatment with hot or boiling water and/or steam in order to stabilize the color of the natural ingredients and at least partially destroy the microorganisms. Alternatively or cumulatively, the pretreatment may comprise an operation of soaking in a sweetening solution, fruit juice or a solution of antioxidant agents. The antioxidant agents can be chosen from: ascorbic acid, citric acid, sodium bisulphite as well as any combination.

[0040] After weighing, the fruits and/or vegetables are mixed. This step can be carried out separately or jointly.

The proportion of fruits and/or vegetables relative to the other ingredients added to the mixture is at least 60% (by weight) at the time of their implementation, preferably at least 75%, even more preferably between 80% and 99.9%.

For the central part, a gelling agent can be added to the mixture. This gelling agent can have thickening, stabilizing and/or emulsifying properties. This operation may be optional when the mixture already contains a sufficient quantity of gelling agent contained in the fruits and/or vegetables used. Any type of gelling agent can be used such as pectin, agar agar or others. A pH adjustment step may be provided. Acidification can be obtained by adding, for example, citric acid or, on the contrary, be attenuated with, for example, sodium bicarbonate. In the next step, the mixture is cooked. Preferably, the cooking is carried out with continuous stirring. Cooking is a rise in temperature to disperse and dissolve the constituents of the mixture and possibly destroy the microorganisms potentially present. The cooking conditions (temperature and time) are chosen according to the solubility characteristics of the gelling agent(s) contained in the mixture. The cooking temperature is above 30°C, preferably between 60°C and 100°C. The cooking time is greater than 30 seconds, preferably between 1 minute to 1 hour.

[0043] After cooking, the mixture can be flavored and/or colored, preferably using ingredients of natural origin.

[0044] After cooking, the mixture should preferably be homogeneous and sufficiently liquid to be able to be poured easily. The mixture is poured into a mold with a non-stick surface such as silicone or any other food-grade non-stick material. The surface is first disinfected with a fast-acting food-grade disinfectant. The mold can have any cavity of suitable shape such as elongated to make bars or sausages. The mold can also be a deformable molding sheet or plate making it possible to mold the mass at least in part to give it a three-dimensional shape.

After casting, the cast mixture is subjected to core cooling at low positive temperature, of the order of +1°C to +8°C. The cooling is carried out as quickly as possible and preferably in less than 2 hours following the end of the cooking. Cooling can be done in a cooling cell or by any other means.

In the following operation, the cooled mixture is dehydrated, preferably after demolding and cutting into sections or portions. The dehydration is preferably carried out at low temperature, that is to say at a temperature below 65° C., preferably between 20° C. and 60° C., in a dehydration oven for a sufficient time to obtain a water activity (aw) of the central part of less than 0.91, preferably between 0.5 and 0.7. The relative humidity of the oven is controlled so as to decrease during the operation to reach a value lower than 50% RH. In these values, bacterial growth is inhibited and the product is stable after assembly with the envelope and in packaging which maintains this balance. The cutting can be carried out to form sections or portions of at least 1 cm in length, for example between 5 and 25 cm.

[0047] The casing part is, for its part, cast on a surface, preferably flat, to form a layer. The surface can be formed in a non-stick plate or sheet, for example silicone or parchment paper. Once the layer of fruit and/or vegetable mixture has been formed, it is subjected to dehydration at low temperature, that is to say at a temperature below 65° C., preferably between 20° C. and 60° C. , preferably in an oven. The dehydration operation is carried out until a layer is obtained whose water activity (aw) drops below 0.65, preferably becomes between 0.35 and 0.5. Once the layer is dehydrated, the layer is peeled off from the surface, for example from the release sheet. The layer is cut to form the envelopes in a shape and size allowing the envelopment, rolling up or at least partial covering of the gelled central parts. Note that the cutting of the layer can be done before peeling off the surface. Note that the layer can also be peeled off and cut before reaching the final water activity value. In this case, the dehydration of the layer or of the envelope continues after detachment or cutting up to the final water activity (aw) value.

The envelopes, composed mainly of fruits and/or vegetables, have a dry texture which can be handled but which is slightly sticky, thus enabling them to stick on themselves and on the sections or portions of gelled fruits and/or vegetables. The central part has a tender and slightly elastic texture composed mainly of fruits and/or vegetables.

For example, the envelopes are cut according to a length equal to or greater than the length of the sections or portions and according to a width greater than the perimeter of the sections, so as to be able to be rolled up on the sections with a circumferential covering part of the envelope. Preferably, the covering forms several times around the perimeter of the section or of the portion.

[0050] The wrapping operation can be carried out manually or mechanically.

[0051] The section of the sections or portions can be of different three-dimensional shapes such as a circle, a square, a diamond, a trapezium, a semicircle, a triangle, etc. The sections or portions can be wrapped in a straight or curved configuration or even be deformed into a spiral shape before or after wrapping. Several envelopes can be used to wrap the central part. Likewise, several central parts can be enveloped by one or more envelopes. The central parts and/or envelopes can consist of different ingredients, in particular different (or a mixture of) fruits and/or vegetables.

[0052] The final product can be packaged in any packaging, preferably making it possible to preserve the characteristics of the product over time.

EXAMPLE :

[0053] Two varieties of local apples were selected for the development of this recipe example, the Gala and the Boskoop. The choice of local and seasonal ingredients thus makes it possible to limit natural variations linked to the environment and nutritional losses thanks to a reduction in storage time. In addition, the use of the Boskoop variety with a sour flavor with the rather sweet Gala allows a complementarity of flavors and aromas which gives the present invention a unique taste.

[0054] After the steps of washing, trimming, cutting, weighing, mixing/grinding, the liquid obtained is too thick for homogeneous pouring, therefore it is mixed with a less viscous liquid, in this case, a juice of apple obtained by extraction.

Step 1: Elaboration of the external part (envelope) of the product:

A quantity of 500 g to 2000 g of apple juice resulting from the extraction of the flesh is mixed with a quantity of 500 g to 2000 g of apple pieces. The ratio between flesh and juice is preferably 1:0.75. These ingredients are mixed until a homogeneous result is obtained. These two ingredients are homogenized by grinding. A few drops of lemon can also be added. The acidity of the mixture is measured with a pH meter of the PCE-PH 22 type. The pH measurement is between 3 and 4 on average. The measurement in degrees Brix is carried out by a digital refractometer of the PCE-DRB 1 type. It is between 10°B and 20°B. The sufficiently thick and homogeneous liquid is then poured onto a non-stick sheet placed in a dehydration oven at less than 65° C. until the water activity (aw) of between 0.35 and 0.5 is reached. Water activity is measured with a digital Aw-meter of the Humimeter RH2 type (RH2-AW Wert). The dehydrated preparation is then peeled off and cut.

Step 2: Development of the central part of the product:

A quantity of 100 g to 1500 g of apple juice resulting from the extraction of the flesh is mixed with 100 g to 1500 g of apple pieces. The meat to juice ratio is preferably 1:0.29. These ingredients are mixed until a homogeneous result is obtained. These two ingredients are homogenized by grinding. The acidity of the mixture is measured with a pH meter of the PCE-PH 22 type. The pH measurement is between 3 and 4 on average. The measurement in degrees Brix is carried out by a digital refractometer of the PCE-DRB 1 type. It is between 10°B and 20°B. A gelling agent such as 0.2 to 30 g of agar agar (ie less than 10 g/l or g/kg) is added to the preparation which is brought to high temperature with continuous stirring.

The preparation is then poured into a silicone mold which is then placed in a cooling cell to reach 4° C. in about 1 hour 30 minutes. Once cooled, the gelled preparation is removed from the mold and then cut into portions in the form of bars using a roller with stainless steel blades.

These gelled sticks are placed in a dehydration oven at less than +65° C. until the desired water activity of the product is reached.

Step 3: Assembly.

The dehydrated gelled stick is placed on a strip constituting the outer part of the present invention and then rolled up with manual pressure over several centimeters to form a roll. This step can be carried out with any technique allowing winding.

The product obtained is a stick as shown in Figure 2 comprising a gelled heart and a fruit envelope holding the heart in place.

Claims (10)

1. Process for preparing a food product based on ingredients of plant origin, in particular fruits and / or vegetables comprising: – the production of a gelled central part composed of fruits and/or vegetables comprising: the production of a mixture based on fruit and/or vegetable pulp, not yet gelled but containing at least one gelling agent, the cooking of the mixture , molding the mixture, refrigerating to obtain a gelled preparation in a three-dimensional form, then dehydrating the preparation to a water activity “aw” of less than 0.91; – the production of an envelope made up of fruits and/or vegetables comprising: the production of a mixture of the fruit and/or vegetable pulp, the pouring of the mixture obtained onto a surface so as to form a layer, the dehydration of the layer until a water activity "aw" less than 0.65, the detachment of the layer at least partially dehydrated and the possible cutting of this one; – assembly by wrapping or at least partial covering of the gelled central part by the envelope and bonding by pressure of the envelope against the central part. 2. Method according to claim 1 or 2, characterized in that the production of the mixture for the production of the central part comprises the addition of at least one gelling agent selected from: agar agar, pectins, carrageenans, gums, alginates, konjac , starches, gelatins, potassium chloride and combinations. 3. Method according to any one of the preceding claims, characterized in that the preparation of the mixture for the central part comprises the addition of at least one ingredient chosen from: vegetable juice, water, broths, spices, aromatic herbs, seeds , plants, cereals, alcohol, sweeteners, cocoa, chocolate, natural flavors and colors and combinations. 4. Process according to any one of the preceding claims, characterized in that the gelled, refrigerated preparation for the central part is dehydrated at a temperature below 65°C under vacuum or without vacuum. 5. Process according to any one of the preceding claims, characterized in that the dehydration of the said layer for the casing takes place at a temperature below 65° C., under vacuum or without vacuum, preferably in an oven. 6. Method according to any one of the preceding claims, characterized in that the gelled preparation for the central part is dehydrated to a water activity "aw" of between 0.5 and 0.7 and/or the envelope is dehydrated up to a water activity "aw" between 0.35 and 0.5. 7. Method according to claim 6 or 7, characterized in that the dehydration of the gelled preparation for the central part or of the layer for the envelope is carried out in the presence of bactericidal radiation, preferably with ultraviolet radiation. 8. Method according to any one of the preceding claims, characterized in that the production of the mixture for the envelope comprises the addition of at least one ingredient chosen from: vegetable juice, water, broth, spices, aromatic herbs, seeds , cereal, sweeteners, cocoa, chocolate, flavorings, colorings, alcohol and combinations. 9. Method according to any one of the preceding claims, characterized in that the envelope is wound around the central part, preferably in the manner of a roll, preferably with an overlap of the envelope allowing a bonding of the envelope on itself or the envelope covers at least one face of the central part. 10. Dehydrated food product based on ingredients of plant origin, in particular fruit and/or vegetables comprising: – a gelled central part composed of fruits and/or vegetables having a water activity “aw” of less than 0.91, preferably between 0.5 and 0.7; – an envelope made up of fruits and/or vegetables having a water activity “aw” of less than 0.65, preferably between 0.35 and 0.5; the envelope being glued to the central part and surrounding it or covering it at least partially; the product being obtained by the process according to any one of the preceding claims.