EP1474000A1

EP1474000A1 - Method for stabilizing fruit pulp or vegetable flesh, particularly avocado pulp

Info

Publication number: EP1474000A1
Application number: EP02706850A
Authority: EP
Inventors: Antoine Koyazounda
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-13
Filing date: 2002-02-13
Publication date: 2004-11-10
Also published as: WO2003067996A1

Abstract

The invention relates to a method for stabilizing fruit pulp or vegetable flesh with a view to the preservation thereof, comprising a stage in which the fruit pulp or vegetable flesh is transformed into a puree, and a stage in which the fruit or vegetable puree thus obtained is osmotically dehydrated. The osmotic dehydration phase is carried out by placing the puree in the presence of a dehydrating agent in the form of a powder or granules, using a fine-meshed separating film (3). According to one embodiment, a layer (2) of puree to be dehydrated is placed in a basin (1), the layer of puree is covered with said separating film (3) and a layer (4) of dehydrating agent is deposited on the separating film. The invention can be used to stabilize avocado pulp in order to obtain avocado butter.

Description

PROCESS FOR STABILIZING A FRUIT PULP OR A VEGETABLE FLESH, IN PARTICULAR AN AVOCADO PULP

The present invention relates to a method and a device for stabilizing a fruit pulp or a vegetable flesh, with a view to its conservation.

The present invention relates in particular to the stabilization of the avocado pulp.

Avocado fat, the lipid fruit par excellence, is ^' less' used as a fresh food than as a raw material for non-glyceric products, for two major reasons: - oil extraction is laborious and unproductive whatever the method used, in particular because of the high water content of the fruit (about 80% water and 50% on average of pulp in the fruit), - the stabilization of the avocado is very difficult, both for the oil extracted only for the pulp.

The various known stabilization techniques, namely sterilization in a static autoclave, drying on a cylinder, spray drying, actinization (infrared exposure), freezing, etc. have been tested by experts who have led to the next conclusion "... on a pulp of avocado reduced to puree, freezing gives the least bad results. All the thermal techniques proved to be catastrophic for the final product ...""... the only points that are acquired are that the product does not keep in the light, and that it rancid fairly quickly at room temperature ... "(" L 'avocado, its culture, its products ", by Jean Pierre GAILLARD- EDITIONS GP MAISONNEUVE AND LAROSE 75005 PARIS). The other major obstacle to controlling the use of avocado pulp is its tendency to darken very quickly upon exposure to air and light, followed by rancidity of the product. This reaction would be due to an enzyme contained in the pulp and Laurence E. HARRISSON already proposed, in its patent US 2,493,818 of January 10, 1950, to neutralize this enzymatic activity by subjecting the avocado pulp to a fermentation in the presence of lactic acid . However, the addition of ascorbic acid as well as the heat treatment at 95 ° C for 5 minutes does not modify the speed of browning of the lyophilized avocado pulp powder, thus suggesting that the phenomenon is not enzymatic (SIDDAPA et al. in JP GAILLARD, cited above).

It is admitted that in the presence of oxygen from the air, the fatty acids present in the pulp oxidize and give rise to products typical of rancidity which depreciate the lipid fruit. This oxidation is accelerated by ultraviolet radiation and temperature.

However, the composition of the avocado pulp in nutrients, minerals and vitamins cannot leave you indifferent because the avocado is rich:

- in fibers (3.2 g per 100 g), in unsaturated oils in average proportions of 77.3% oleic acids, 10.8% linoleic acid, 6.9% palmitic acids, in percentage of the lipid part which represents approximately 14% of the pulp and has a composition close to that of olive oil,

- in folates (42% of average daily needs) with the advantage, compared to other foods rich in folates, of being consumed fresh and uncooked, in vitamins B, E, C, A in particular, as well as carotenes and carotenoids and mineral salts.

If one of the main difficulties in stabilizing avocado pulp is its richness in water, it would therefore be advisable to dehydrate its pulp without damaging its components, using a means "biophysics" which is the least aggressive possible to get the water out of the pulp.

Among the less aggressive dehydration processes, there is the osmotic treatment, also known as osmotic dehydration, which consists of immersing the product to be dehydrated, trimmed and cut, in concentrated solutions containing one or more solutes (salt, sugar). This process is unfortunately not applicable to the treatment of avocado pulp.

Thus, the present invention aims to provide a method for stabilizing a fruit pulp or a vegetable flesh which does not have the drawbacks of the known methods, in particular for the stabilization of fresh avocado pulp and l '' obtaining a functional food, naturally rich in mono and polyunsaturated fatty acids, fiber, phytosterols and fructose.

To this end, the idea of the present invention is to carry out an osmotic dehydration of a fruit pulp or of a vegetable flesh previously reduced to a puree, in the presence of a dehydrating agent in powder or granules, for example sugar or salt, by means of a fine mesh separating film allowing the exchange of water between the puree and the dehydrating agent.

More particularly, the present invention provides a method for stabilizing a fruit pulp or a vegetable flesh with a view to its conservation, comprising a step of transforming the fruit pulp or vegetable flesh into a puree and a osmotic dehydration step of the fruit or vegetable purée thus obtained, the osmotic dehydration step being carried out by placing the purée in the presence of a dehydrating agent in powder or granules by means of a separating film to fine mesh. According to one embodiment, the method comprises the following steps: depositing a layer of mash to be dehydrated in a bowl, covering the layer of mash with the separating film, and depositing a layer of the dehydrating agent on the separating film.

According to one embodiment, the mash is placed in a shallow bowl having a large surface relatively to its depth, provided with a removable cover in canvas or other fine mesh material, which protects the contents of the bowl while allowing the ambient air circulation.

According to one embodiment, the separating film is made of woven cotton.

According to one embodiment, the separating film is of dimensions substantially greater than those of the bowl in order to rise substantially on the walls of the bowl when it is arranged on the puree to be dehydrated.

According to one embodiment, the dehydrating agent comprises sugar or a mixture of sugars.

According to one embodiment, the dehydrating agent is sucrose.

According to one embodiment, the puree to be dehydrated is avocado puree. According to one embodiment, the method comprises the addition of an antioxidant agent during the preparation of the avocado puree.

According to one embodiment, the antioxidant agent is kiwi pulp or any other fruit or vegetable reducing the natural oxidation of avocado in the presence of air.

According to one embodiment, the purée to be dehydrated and the dehydrating agent are each deposited in a layer with a thickness of a few millimeters to a few centimeters. According to one embodiment, the osmotic dehydration process is carried out at a temperature between 13 and 40 ° C.

According to one embodiment, the osmotic dehydration process is carried out at room temperature without the addition of heat.

According to one embodiment, the osmotic dehydration process is carried out at a controlled temperature of the order of 28 ° C. According to one embodiment, the osmotic dehydration process is carried out without forced air movement.

According to one embodiment, the puree to be dehydrated is left in the presence of one dehydrating agent for a few tens of hours.

According to one embodiment, the method comprises the addition to the puree, before or after its osmotic dehydration, of at least one n-3 polyunsaturated fatty acid, in a proportion of a few percent by weight. According to one embodiment, the method comprises the addition to the puree, before or after its osmotic dehydration, of docosahaxaenoic acid and / or of eicosapentaenoic acid.

According to one embodiment, the method comprises the addition to the puree, before or after its osmotic dehydration, of natural fruit essences to obtain a product ensuring protection of the myocardium and having an anti-atherogenic action.

The present invention also relates to a device for stabilizing a pulp of fruit or vegetable flesh reduced to a puree, comprising at least one shallow bowl and of large surface area relatively to its depth, for receiving a layer of puree fruit or vegetable, a fine mesh separating film to cover the mash layer, and a dehydrating agent in powder or granules, to be deposited as a layer on the separating film to obtain a Osmotic dehydration of fruit or vegetable puree.

According to one embodiment, the device comprises a removable bowl cover made of canvas or other fine mesh material, to protect the contents of the bowl while allowing the circulation of ambient air.

According to one embodiment, the separating film is made of woven cotton. According to one embodiment, the separating film is of dimensions substantially greater than those of the bowl in order to rise substantially on the walls of the bowl when it is arranged on the fruit or vegetable puree. According to one embodiment, the dehydrating agent comprises sugar or a mixture of sugars. According to one embodiment, the dehydrating agent is sucrose.

These objects, characteristics and advantages as well as others of the present invention will be explained in more detail in the following description of the method of

1 invention, made without implied limitation in relation to the attached figures among which:

- Figure 1 is a sectional view of a dehydration device according to the invention, and illustrates the dehydration process according to the invention, Figure 2 is an exploded view of the dehydration device of Figure 1.

The osmotic dehydration process according to the present invention relies on a mechanism for diffusing water through a solid but flexible exchange surface, acting like a membrane. It can be carried out at room temperature and allows the subtraction of water without physical change or modification of the qualitative composition of the product to be dehydrated, and makes it possible to extend the duration of use of the puree. fruit or vegetable subjected to this process, especially avocado pulp.

Simple diffusion corresponds to the net displacement of material from one region to another as a function of the concentration gradient. This displacement is governed by Fick's law according to which the quantity of solute (DN) which migrates in a time (Dt) over a distance (Dx) is inversely proportional to this distance and is proportional to the surface of the migration plane (A ) as well as the difference in concentration (DC) existing on either side of this plane.

Thus, the larger the exchange surface and the difference in concentration, and the shorter the distance between the two media, the greater the water flow and the faster the osmotic dehydration. In other words, the osmotic dehydration time decreases when the exchange surface between the two media increases and / or when the concentration difference between the two media increases and / or when the distance between the two media decreases, because in in each case the flow of water between the two media is greater.

FIG. 1 represents an exemplary embodiment of an osmotic dehydration device according to the invention. The device 10 comprises a shallow bowl 1 but with a large surface. The puree to be dehydrated is deposited at the bottom of the bowl in a thin layer 2. A thinner exchanger film 3 (which may also be called separator film) is then deposited on the mash layer. Next, a layer 4 of a dehydrating agent is deposited on the exchanger film 3. Such an arrangement minimizes the risk of contact between the mash and the oxygen in the air, and the large surface of the bowl 1 makes it possible to treat and collect an appreciable volume of mash. The bowl is made of a material compatible with fresh food, non-deformable walls in the presence of the mash to be dehydrated.

The bowl has for example a length of 100 cm, a width of 80 cm, a depth 4cm, a flat and smooth bottom, and is provided with lateral gripping notches. The exchange surface obtained is large and is, in the example cited above, of the order of 800 cm ² .

Large-scale production can be obtained by providing a battery of cuvettes, side by side or possibly stacked one on top of the other, preferably providing a space between the modular units in order to allow the circulation of ambient air. As illustrated by the exploded view of FIG. 2, a removable cover 5 is preferably arranged on top of the bowl 1. The cover 5 is essentially made of canvas or of a braided material with fine mesh. The canvas or the mesh material is fixed to a frame of the cover which cooperates with the walls of the bowl to maintain the cover. Such a cover protects the contents of the bowl while allowing the circulation of ambient air.

The exchanger film 3 is for example formed by means of woven cotton cloths, for example the cloths sold by the PAREDES laboratories under the reference 7 443 000. Such cloths are not very adherent and are easily peeled from the layer of avocado puree. once it is dehydrated. Their thickness is less than 2 millimeters.

As another example, the exchanger film can also be a butter cloth. Much cheaper, woven more finely, such a canvas is reusable subject to sterilization. According to the tests carried out, the ideal treatment temperature is around 28 ° C, and can be natural or controlled. Such a temperature allows dehydration to 35% in 48 hours, and less than 35% if one prolongs the duration of treatment without exceeding five days. However, the osmotic dehydration process can also be carried out at a lower temperature, for example up to 15 ° or even 13 ° C, at a slower rate.

Forced ventilation can also be provided without the addition of heat, although this is not essential. On the other hand, at 35 ° C or more, the treatment is faster and lasts less than 24 hours. It may thus be advantageous to implement the method according to the invention in tropical countries, at room temperature. Above 38 ° C, it is desirable to increase the amount of sucrose. Various embodiments of the final product can be provided, as described below. First embodiment

First, a step of maturing the avocado pulp is planned. Fruit ripening is carried out as if to bring the fruit to table maturity, that is to say soft and depressible after five to seven days of storage at a temperature of about 20 to 25 ° C, in a ventilated atmosphere. The entire stock must be inspected case by case. During a trimming and stoning step, the fruits are then cut manually as well as the remains of peduncles. This manipulation allows a visual inspection of the pulp to remove fruit with spots. The mash to be dehydrated is then prepared using a mixing tank ensuring the mixing of the avocado pulp, until a fresh paste is obtained which should preferably be smooth and not have residual fragments capable of resist the osmotic diffusion process.

The fresh or mashed paste thus obtained is then poured into a thin layer, for example of the order of 2 centimeters, in the bottom of the bowl (Figure 1). The exchanger film is immediately extended to the surface of the thin layer of avocado, taking care to raise the edges of the film on the vertical walls of the bowl. The dehydrating agent, preferably powdered sucrose, is then immediately poured into a uniform layer 1 to 2 cm thick above the exchanger film, and reinforces the pressure exerted on the edges of the exchanger film which go up against the walls of the bowl. The assembly is installed in an environment without other ventilated cover the aforesaid lid, preferably at a ^'temperature of 28 ° C. The amount of sucrose to spread is around 500 g per 100 g of puree to be treated. This sugar can be reused later provided that it is collected under strict hygienic conditions, allowed to dry, and then sprayed.

The avocado "butter" is collected after 48 hours in the event of exposure to an ambient temperature of 28 ° C, in the open air, by folding the edges of the exchanger film towards the center of the bowl to form a sort of purse that peels off the layer of avocado butter. This avocado butter is then collected by means of a flexible squeegee, and is immediately packaged in opaque boxes or jars, with controlled sterility, sealed after closing. A plastic food film can be placed on the avocado butter before the containers are closed.

Preferably, the avocado butter thus conditioned is stored in a controlled atmosphere, with a humidity level of less than 60%, a fairly low temperature of the order of 4 ° C., however, being able to have an average of around 15 ° C. . Freezing is also possible. Storage is carried out protected from light, so that the product retains its color and flavor. A recommended marketing method is to provide packaging and distribution in the form of doses of 20 grams.

Second embodiment

The protection against oxidation, in addition to that provided by the sucrose cover, can be advantageously reinforced by adding Kiwi pulp. In this case, the Kiwi pulp is added to the avocado pulp in the mixing tank, during the preparation of the puree, after extracting the Kiwi seeds through a potato masher. As before, the whole is stirred and then poured into a thin layer in the bowl, then covered with the exchanger film and the sucrose layer.

With proportions of 30 to 50% of Kiwi pulp, this embodiment allows the addition of fibers and nutrients specific to the final product, and makes it very nutritionally balanced. Third embodiment It has been established that western populations consume too many n-6 polyunsaturated fatty acids compared to n-3 unsaturated fatty acids. Docosahexaenoic acid or DHA (or 22: 6 n-3) is anti-atherogenic just like eicosapentaenoic acid or EPA (or 20: 5 n-3). The EPA has the added benefit of exercising protective properties ¹ vis-à-vis myocardial ischemia, which is not the case of DHA. It is therefore interesting to enrich the product, either in the first formulation or in the second (with Kiwi), with fatty acids not deodorized by heating, polyunsaturated n-3, in variable proportions from 2 to 10 grams per 100 grams of mash to dehydrate (with or without kiwi pulp). The mixing can also be done after osmotic dehydration, by increasing the percentage of n-3 fatty acids from 4 to 20 grams per hundred grams of dehydrated product. Flavoring with natural essences of fruits or vegetables or any other natural product makes it possible to perfect the palatability of the final product.

Thus, the addition of omega fatty acids with or without fresh kiwi pulp provides a fresh product that can be used in dietetics.

It will be clear to those skilled in the art that the method according to the invention is capable of various other alternative embodiments. In particular, although it has been proposed above to spread the puree to be dehydrated at the bottom of a bowl, it is possible to spread the puree between two layers of the dehydrating agent, with the interposition of two exchanger films.

The method according to the invention is also susceptible of various applications. Although this process was initially designed for the stabilization of avocado pulp, it goes without saying that it remains applicable to any type of fruit or vegetable (for example mango, guava, eggplant ...) whose pulp or the flesh reduced to a puree has a sufficiently dense texture to be arranged in a layer in the presence of a dehydrating agent such as sugar or salt.

Claims

1. A method of stabilizing a fruit pulp or a vegetable flesh with a view to its conservation, characterized in that it comprises a stage of transformation into puree of the fruit pulp or of the vegetable flesh and a osmotic dehydration step of the fruit or vegetable puree thus obtained, and in that the osmotic dehydration step is carried out by bringing the puree in the presence of a dehydrating agent in powder or granule form via a fine mesh separator film (3).

2. Method according to claim 1, comprising the following steps:

- deposit a layer (2) of mash to be dehydrated in a bowl (1),

- cover the mash layer with the separating film (3), and

- deposit a layer (4) of the dehydrating agent on the separating film (3).

3. Method according to claim 2, wherein the mash is deposited in a shallow bowl (1) having a large surface relative to its depth, provided with a removable cover of canvas or other fine mesh material, which protects the content of the bowl while allowing the circulation of ambient air.

4. Method according to one of claims 1 to 3, wherein the separator film (3) is woven cotton.

5. Method according to one of claims 2 to 4, wherein the separator film (3) is of dimensions substantially greater than those of the bowl in order to go up appreciably on the walls of the bowl when it is arranged on the mash to be dehydrated.

6. Method according to one of claims 1 to 5, wherein one dehydrating agent comprises sugar or a mixture of sugars.

7. The method of claim 6, wherein the dehydrating agent is sucrose.

8. Method according to one of claims 1 to 7, characterized in that the purée to be dehydrated is avocado puree.

9. The method of claim 8, comprising adding an antioxidant during the preparation of the avocado puree.

10. The method of claim 9, wherein the antioxidant agent is kiwi pulp or any other fruit or vegetable reducing the natural oxidation of avocado in the presence of air.

11. Method according to one of claims 1 to 10, in which the purée to be dehydrated and the dehydrating agent are each deposited in a layer with a thickness of a few millimeters to a few centimeters.

12. Method according to one of the preceding claims, wherein the osmotic dehydration process is carried out at a temperature between 13 and 40 ° C.

13. Method according to one of the preceding claims, in which the osmotic dehydration process is carried out at ambient temperature without the addition of heat.

14. Method according to one of claims 1 to 12, wherein the osmotic dehydration process is carried out at a controlled temperature of the order of 28 ° C.

15. Method according to one of the preceding claims, wherein the osmotic dehydration process is carried out without forced air movement.

16. Method according to one of the preceding claims, in which the purée to be dehydrated is left in the presence of the dehydrating agent for a few tens of hours.

17. Method according to one of the preceding claims, comprising the addition to the puree, before or after its osmotic dehydration, of at least one n-3 polyunsaturated fatty acid, in a proportion of a few percent by weight.

18. Method according to one of the preceding claims, comprising adding to the puree, before or after its osmotic dehydration, docosahaxaenoic acid and / or eicosapentaenoic acid.

19. Method according to one of the preceding claims, comprising adding to the puree, before or after its osmotic dehydration, natural fruit essences to obtain a product ensuring protection of the myocardium and having an anti-atherogenic action .

20. Device (10) for stabilizing a fruit pulp or a mashed vegetable flesh, characterized in that it comprises: - at least one shallow bowl (1) with a large surface area relatively to its depth, to receive a layer (2) of fruit or vegetable puree,

- a fine mesh separator film (3) to cover the mash layer, and

- a dehydrating agent in powder or granules, to be deposited in a layer (4) on the separating film to obtain osmotic dehydration of the fruit or vegetable puree.

21. Device according to claim 20, comprising a cover (5) of removable bowl in canvas or other fine mesh material, to protect the contents of the bowl while allowing circulation of one ambient air.

22. Device according to one of claims 20 and

21, in which the separating film (3) is made of woven cotton.

23. Device according to one of claims 20 to

22, in which the separating film (3) is of dimensions substantially greater than those of the bowl in order to rise substantially on the walls of the bowl when it is arranged on the fruit or vegetable puree.

24. Device according to one of claims 20 to

23, wherein the dehydrating agent comprises sugar or a mixture of sugars.

25. Device according to one of claims 20 to 24, wherein the dehydrating agent is sucrose.