WO2019048795A1 - Method for preserving raw food items - Google Patents

Abstract

The present invention concerns a method for preserving a raw food item of animal or plant origin, comprising the following steps: a) Incubating the raw food item in an impregnation solution made up of a syrup or an oil, optionally supplemented with plants and/or spices and/or honey; b) Packaging the raw food item under partial vacuum in the impregnation solution of same, the final underpressure obtained being between 5 and 20 millibars; and c) preserving the raw food item in the impregnation solution of same, under partial vacuum, at a temperature of between 0°C and 6°C.

Description

 PROCESS FOR PRESERVING RAW FOODS

FIELD OF THE INVENTION

 The present invention relates to a method of preserving food. This preservation process is based on the vacuum packaging technique.

STATE OF THE ART

 The preservation of food, especially raw food, is a technical problem to which men have never ceased to seek solutions.

 Indeed, it is necessary to be able to build food stocks in anticipation of future periods. It is also necessary to be able to preserve the food during a transport, for example for their marketing and / or consumption in a place different from that of their obtaining.

 During their conservation, the taste and nutritive properties of food diminish. In addition, the edibility of a food may be impaired if pathogenic bacteria and / or fungi develop on that food. Thus, while the fresh food was perfectly edible, it may be toxic if consumed late after bacterial contamination.

 Since antiquity, various food preservation techniques have been developed to help maintain the taste and nutritional properties of foods over time and to ensure their safety after storage.

 Various methods of food preservation are presented below, but not exclusively.

 Many preservation methods are based on the application of high temperatures to the food, in order to destroy the bacteria present on and in the food. These technologies include pasteurization, sterilization, and canning (canning).

Another method of conservation is to place the food cold, low temperatures slowing or even completely stop the development of microorganisms. Alteration of food is thus limited. However, this technique does not destroy the microorganisms present on the fresh food, and they will resume their development upon return to a temperature favorable to their activity. Depending on the temperatures at which the food is exposed, it is called refrigeration (0 ° C - 4 ° C), freezing (-26 ° C) or freezing (-35 ° C to -196 ° C). Frozen or deep-frozen foods are then stored at a temperature of minus -18 ° C.

 Other techniques are related to the partial or total elimination of water from the food: dehydration, drying, lyophilization.

 Other processes are based on the addition to the food of preservatives, such as salt (salting, brining) or spices and / or herbs with antiseptic properties (thyme, garlic, ...). It should be noted that in most cases a preservative also acts as a flavoring agent.

 For example, the preservation solutions presented in the patent application WO 2016/64608 may be mentioned.

 We can also mention the conservation solutions presented in the article by Ariyapitipun et al. (2010), which contain low molecular weight polylactic acid, lactic acid and nisin.

 Another method of food preservation is the vacuum packaging of the food. By reducing the amount of air around the food, and therefore the amount of oxygen, this allows on the one hand to inhibit the growth of aerobic microorganisms, on the other hand to limit the oxidation reactions that can alter the taste and nutritional properties of the food. This process has been known for over 80 years and has been described in numerous patents such as GB 418364, GB 527607, and GB 537171.

 Alternatively, it is also possible to reduce the amount of oxygen around the food to be preserved by replacing the air with a gas mixture containing no or little oxygen.

 Most of these techniques can limit the development of bacteria or fungi on foods. However, it remains difficult to preserve raw foods, such as fruits, vegetables, meat, seafood or fish, over a period of 7 days or more, without altering their taste and nutritional properties.

 Indeed, preservation techniques based on high temperatures alter the qualities of the raw food, the molecular constituents of the food being transformed in contact with heat.

 Freezing and quick freezing alter the structure of the food because the water in the food crystallizes, changing the cell structures. Similarly, dehydration, drying and lyophilization change the structure and appearance of the food.

Vacuum packaging usually results in crushing of the food. This process is most often used for already cooked food products, and therefore less sensitive to changes in cell structure, the molecular constituents having already been modified by heat.

 However, vacuum packaging preservation techniques for raw foods have been proposed.

 The document Vasilatos & Savvaidis, 2013 describes a method of preserving raw food, especially turkey meat, comprising the incubation of said meat in an impregnating solution composed of pure rosemary oil, then its packaging under vacuum part. However, the intensity of the partial vacuum obtained in the container containing the meat and the impregnating solution is not specified.

 JPS62208244 discloses a method of preserving fresh foods comprising:

 Immersion in a seasoning and preserving liquid, consisting of vinegar with added spices and / or herbs such as thyme or rosemary, as well as optionnally oil and liquids;

 - Vacuuming the food immersed in its liquid;

 The preservation of the container evacuated in the cold (0 ° -3 ° C).

 JPS62208244 teaches that raw foods can be kept for a few days, but that beyond two weeks of storage, the food products thus preserved show signs of deterioration.

 There is therefore a need for new methods for preserving raw food, which makes it possible to obtain storage times longer than a few days, without the foods thus preserved showing signs of deterioration, these processes being respectful of the nutritional properties and taste of the food. SUMMARY OF THE INVENTION

 The present invention relates to a new method of preserving a raw food, comprising several steps:

 an incubation of the food in an impregnation solution composed of a syrup or an oil,

 followed by a stage of partial vacuum packaging of the raw food in its impregnation solution,

 then a step of conservation of the food thus treated,

characterized in that the conditions of partial vacuum are adapted so as not to deteriorate the structure of the food (in particular, not to crush it) and allow preservation of the food for a period of at least 7 days, or at least 14 days, or at least one month, without altering the taste and nutritional properties of the food.

 The present invention relates in particular to a method for preserving a raw food of animal or vegetable origin, comprising the following steps:

 a) Incubation of the raw food in an impregnating solution composed of a syrup or an oil, optionally supplemented with plants and / or spices and / or honey;

 b) Partial vacuum packaging of the raw food in its impregnating solution, the final under pressure obtained being between 5 and 20 millibars; and

 c) Preservation of raw food in its impregnation solution, under partial vacuum, at a temperature between 0 ° C and 6 ° C.

 More particularly, in the process according to the invention, the step (b) of vacuum conditioning is carried out by applying several successive pressure drops, each pressure drop lasting between 1 and 3 minutes, and preferably for 1 minute 30 seconds. .

 According to a preferred implementation, the storage step (c) is continuous for a period of at least one month. DESCRIPTION OF THE FIGURES

 Figure 1. Characterization of the texture of chicken meat (i) control, (ii) preserved according to the process of the invention in a herbal oil (HH), and (iii) preserved according to the method of the invention in a honey oil (HM).

 A) Maximum firmness at cutting

 B) Average energy required for cutting

 Figure 2. Characterization of the texture of pear (i) control (FT) and (ii) preserved according to the method of the invention in a syrup (F).

 A) Maximum firmness to pierce the fruit

 B) Average energy needed to pierce the fruit

Figure 3. Measurement of the amount of food after storage or control, required to obtain 50% decoloration of oxidized DPPH (blue). The food samples tested are as follows:

V1 HM: Chicken meat preserved in an impregnating solution composed of olive oil with honey; V2HH: Chicken meat preserved in an impregnating solution composed of olive oil with herbs;

 VT: Control chicken meat, not preserved by the process;

 P1 HC: Fish (back of cod) preserved in an impregnation solution composed of lemon olive oil;

 P2HH: Fish (cod back) preserved in impregnation solution composed of olive oil with herbs;

 PT: Control fish, not preserved according to the method.

DETAILED DESCRIPTION OF THE INVENTION

The invention consists in a method for preserving a raw food of animal or vegetable origin, comprising the following steps:

 a) Incubation of the raw food in an impregnating solution composed of a syrup or an oil, optionally supplemented with plants and / or spices and / or honey;

 b) Partial vacuum packaging of the raw food in its impregnating solution, the final under pressure obtained being between 5 and 20 millibars; and

 c) Preservation of raw food in its impregnation solution, under partial vacuum, at a temperature between 0 ° C and 6 ° C.

In other words, this new method of preserving raw and fresh foods (meat, fish, vegetables, fruits) comprises at least three successive steps:

 a) impregnation of the food by immersion in an impregnating solution;

 b) evacuation of the container containing the food and the impregnating liquid, this evacuation being performed so as to remove all the oxygen from the container, and being controlled so as not to crush the food; and

c) the preservation of the food in its impregnation solution, under partial vacuum, at a temperature between 0 ° C and 6 ° C. It should be noted that this process is distinguished from a vacuum impregnation process, such a method being intended to make a flavoring solution enter a food. In a vacuum impregnation process, the following steps are implemented:

 • incubation of a food in an impregnating solution;

 · Partially evacuating the container containing the food and the impregnating liquid; and

 • progressive rise in pressure, up to an atmospheric pressure value, so as to penetrate into the depressurized food an amount of impregnating liquid greater than that which would have penetrated by simple contact between the food and the solution .

 Such a vacuum impregnation process is described in numerous publications, for example in patents FR 2 280 328, FR 2 807 955, US Pat. No. 3,843,810 and US Pat. No. 4,460,610.

 The process of the present invention differs from a vacuum impregnation process in that it is not used for the same purpose since it is a preservation process. Thus, the method of the invention comprises a step (c) of storing the food in its partial vacuum impregnation solution, the vacuum being broken only at the time of consumption or use in the kitchen of the food. In addition, in the process according to the invention, the increase in pressure is not necessarily carried out in a progressive manner, but may be instantaneous since the impregnation of the food with the solution is not the primary goal.

 According to one of its aspects, the present invention relates to a process for enriching antioxidants of a food, this to preserve this food over a prolonged period, without denaturation of its properties and without microbial contamination.

The advantages of the preservation process according to the invention are in particular the following:

 preservation, for a period longer than seven days, of fresh foods, without freezing or sterilization, which deteriorate the taste properties of foods;

 flavoring food with the impregnating solution;

 maintaining taste properties (texture, taste and visual appearance) of raw foods; and

maintaining the nutritional properties of foods, including the antioxidant properties of fruits and vegetables, and where appropriate, the impregnating solution is an oil, transfer of the antioxidant properties of this oil to the raw food (see Example 3).

Method of preserving raw food

 By "raw food" is meant in the sense of the present invention an edible foodstuff for human or animal food, having a solid structure, which has not undergone cooking.

 Baking is a method of preparing a food in which said food is exposed to heat or radiation for a period of time long enough for the molecular constituents of the food to be modified.

 Any raw and solid food may be concerned by the process according to the invention: it may be in particular a plant (herbs, nuts, berries, fruits, vegetables, rhizomes, roots, mushrooms, leaves, flowers, and others) or a product derived from farmed or wild animals (game, meat, offal, fish, crustaceans, and others).

 According to a particular aspect of the invention, the raw food is selected from a fruit, a vegetable, meat, seafood, fish, and combinations thereof.

 The raw food may in particular be selected from a fruit, a vegetable, seafood, fish, and combinations thereof.

 According to another particular aspect of the invention, the raw food has previously been cut into pieces, before the implementation of the method.

 According to another particular aspect of the invention, the raw food has previously been immersed in boiling water for a period of less than or equal to 1 minute. This so-called "bleaching" step is not considered to be a cooking step, since its duration is less than the time required to obtain a physico-chemical modification in depth of the fibers of the food, whatever it may be. A "whitened" food is therefore a raw food in the sense of the invention. This process helps sanitize the food and limit oxidation. However, many sensitive nutrients, such as vitamins, can be altered at the end of this step which is not privileged.

 According to yet another aspect of the invention, the raw food has previously been cut into pieces and / or immersed in boiling water for a period of less than or equal to 1 minute.

 Vacuum packaging can also be performed for liquid foods, such as wine, milk, soy sauce or honey.

Thus, the invention also relates to a method for preserving a liquid food, comprising the following steps: a) Vacuum packaging of the liquid feed, the underpressure applied being between 5 and 20 millibars; and b) Preserving the liquid feed, under partial vacuum, at a temperature between 0 ° C and 6 ° C.

Impregnation solution

 For the purposes of the invention, the term "syrup" means an aqueous solution comprising at least 10% by weight, relative to the total weight, of sugar and / or honey and / or a sweetening agent.

 For the purposes of the present invention, the term "sweetening agent" means one or more sweeteners and / or steviol and / or any substance (s) derived from sugar.

 A syrup may especially be composed of water and sugar; water and honey; water and a sweetening agent, natural or artificial; or be composed of a wine, a liquor, oil or milk comprising at least 10% by weight of sugar, present naturally or added.

 It is understood that the proportion of sugar and / or honey and / or a sweetening agent is at least 10%, but can also be according to certain variants of at least 15%, at least 20%, at least 25%, not less than 30%, not less than 35%, not less than 40%, not less than 45% and not less than 50% by weight, based on the total weight of the impregnating solution.

 The dynamic viscosity of the impregnation solution at 20 ° C. will preferably be between 1 and 100 mPa.s. The viscosity of the solution may especially be of the order of or equal to 1.005 mPa.s (when it is composed of water), or of the order of or equal to 84 (when it is composed olive oil).

 According to an implementation of the method, the impregnating solution is supplemented with plants and / or spices favoring the preservation of food and / or allowing flavoring of the food.

 According to a first aspect, the impregnation solution comprises a preserving agent, in order to optimize the vacuum packaging preservation process.

 Such a preservative will preferably be selected from traditional preservatives such as salt, plants and spices having an antiseptic action and / or an antioxidant action.

Among the plants having an antiseptic action, we may mention the following plants: wormwood, green anise, mugwort, burdock, basil, benoit, eucalyptus, juniper, lavender, mint, oregano, pine, rosemary, sage, thyme, thyme, garlic, and others. Preservatives with anti-oxidant properties include herbs and spices: cloves, oregano, rosemary, thyme, cinnamon, turmeric, sage, parsley, nutmeg, basil, caraway, curry, ginger , pepper, paprika, saffron, sage, tea, vanilla, mint, and others.

 It should be noted that most of the preservatives mentioned above also have flavoring properties.

 In a second aspect, the impregnating solution comprises a natural flavoring agent, such as vanilla or saffron, or an artificial flavoring agent.

 In a third aspect, the impregnating solution contains edible agents beneficial to human and / or animal health, such as vitamins, zeolite, healing agents, probiotics, antioxidants, mineral salts, and others. For example, minerals that are beneficial to health include iron and magnesium.

 According to this aspect of the invention, the impregnating solution is therefore intended not only for the preservation of the immersed food, but also for its transformation in order to give it additional nutritional properties, and thus to obtain a "food health ".

 According to another aspect of the invention, the impregnating solution contains one or more of the agents mentioned below, and in particular contains a preserving agent and an aromatizing agent; or a preservative and an agent beneficial to human and / or animal health; or an aromatizing agent and an agent beneficial to human and / or animal health.

 The impregnating solution can thus contain one, two, three, four, five or more additional agents, which are added to the impregnating solution composed of a syrup or an oil.

 According to a preferred aspect of the invention, the preservation process is characterized in that the impregnating solution completely covers the raw food. In other words, the raw food is totally immersed in the impregnating solution.

 The skilled person will adjust, depending on the size of the container containing the food and its impregnating solution, the volume of solution necessary to completely cover the food, so that it is not in direct contact with the walls of the container.

It is understood that the nature and the volume of the impregnating solution will be adapted to the nature and volume of the preserved raw food, these adjustments can easily be made by a person skilled in the art. Container adapted to the process

 Those skilled in the art know the containers adapted to vacuum packaging. These containers must especially be gastight and liquid-tight, so that the created under-pressure is maintained stably over time.

 According to a preferred aspect of the invention, the raw food and its impregnation solution are vacuum-packed in a gas-tight and liquid-tight container, for example in a food-grade plastic bag.

Partial vacuum conditioning

 The conditions for implementing the vacuum packaging step (b) are essential to the successful completion of the process according to the invention.

 It is indeed necessary to obtain a partial vacuum, so as to protect the food deteriorations related to the presence of oxygen, without crushing the food.

 The invention is thus characterized in that the final underpressure obtained in the container comprising the raw food and the impregnating solution is between 5 and 20 millibars, more particularly between 5 and 15 millibars, and preferably between 5 and 15 millibars, 10 millibars, the limit values of these ranges being included in the ranges within the meaning of the present invention.

 The term "partial vacuum" also referred to in physics as "approximate vacuum" is used as opposed to "absolute vacuum" which is characterized by a total absence of material, i.e. a pressure equal to zero and an absence total of molecular particles, even if such a physical situation is almost impossible to obtain.

 Naturally, the value of the underpressure will be adjusted according to the nature of the preserved food: the texture-stable foods can be subjected to low underpressures, around 5 millibars, without their structure being altered. On the contrary, soft textured foods will have to be subjected to moderate underpressures, of the order of 20 millibars, so as not to cause their crushing.

 According to a particular aspect of the invention, the step (b) of partial vacuum conditioning lasts between 1 and 15 minutes.

As indicated above, the partial vacuum conditioning step must be carried out so as to obtain an underpressure in the container of between 5 and 20 millibars. It is generally preferable to obtain this underpressure in a progressive manner, so as not to distort the structure of the preserved raw food. According to one particular aspect of the invention, step (b) of vacuum conditioning is carried out by applying several successive pressure drops, each pressure drop lasting between 1 and 3 minutes, and preferably for 1 minute 30 seconds.

 For example, vacuum conditioning will be achieved by sequentially applying two, three, four, five, six or seven pressure drops each for 1 minute and 30 seconds.

 Naturally, the number of pressure drops exerted will be adapted to the nature and the volume of the conditioned food, in order to extract all the residual air while avoiding the crushing of the food.

 To evacuate a container, several devices exist that include a vacuum pump for extracting the air present in a sealed enclosure. Each vacuum pump is characterized by its power ie its ability to suck air contained in a container.

Machines intended for private customers have powers of the order of 60 m ³ / hour. The machines intended for professionals have powers of the order of 150 to 300 m ³ / hour, and up to 600 m ³ / hour for industrial uses.

 It is understood that the process according to the invention, in which a raw food in its impregnation solution is conditioned under partial vacuum, that is to say under a pressure of 5 to 20 millibars, can be achieved both with a vacuum machine "table" for individuals, such as the machine C100 marketed by MULTIVAC®, as with an industrial machine.

 In catering, the most commonly used equipment is the vacuum bell machine.

 According to one particular aspect of the invention, the vacuum packaging step (b) is carried out by means of a vacuum bell machine.

 This vacuum chamber machine is notably marketed by companies such as LAVEZZINI®, MAGIC VAC® or MULTIVAC®.

 According to one particular aspect of the invention, the step (b) of vacuum conditioning is carried out at a temperature of between 2 and 15 ° C.

 More preferably, the temperature of this step will be between 2 ° C. and

10 ° C, or between 2 ° C and 6 ° C, the limit values of these ranges being included in the ranges within the meaning of the present invention.

Such a decrease in temperature, during the vacuuming stage, makes it possible to optimize the preservation of the raw food subjected to the process, while preserving its nutritional qualities. Conservation step and optional steps

 The process according to the invention is characterized by the presence of a step (c) of preservation of the raw food under partial vacuum, this partial vacuum being characterized by a value of between 5 and 20 millibars of pressure, as obtained during step (b) of vacuum packaging.

 The method according to the invention advantageously allows to keep fresh and raw food for a period of at least a week, two weeks, three weeks or four weeks, without the nutritional and taste qualities of food are deteriorated, nor that aerobic bacteria or fungi may develop.

 According to a particular aspect of the invention, the method is characterized in that the step

(c) Conservation is continuous for a period of at least one month.

 This storage step will be carried out at a temperature between 0 ° C. and 6 ° C., preferably between 2 ° C. and 6 ° C., the limit values of these ranges being included in the ranges within the meaning of the present invention.

 Naturally, this conservation stage can be much longer, with a duration of at least two, three months, four months, five months or even six months, depending on the nature of the preserved food, and consumption which will be made later, food products intended to be cooked can be of a lower taste quality than food products consumed without cooking as soon as the vacuum breaks.

 The examples presented in the experimental part relate in particular to raw foods subjected to the preservation process according to the invention, preserved during the following periods: 31 days, 38 days, 70 days, 84 days and 106 days.

 All the foods thus preserved have a satisfactory sanitary quality, in terms of microbial contamination, at the end of their conservation period.

 It is understood that the method according to the invention does not include any step of heating, sterilization or pasteurization of raw food, or raw food incubated in its impregnating solution.

 According to a particular implementation of the method, said method further comprises a step d) of increasing the pressure in the container containing the raw food and its impregnating solution, in other words a vacuum breaking step, this step being performed either before the use or consumption of the food, or after cooking the raw food in its impregnating solution.

The cooking of the food while it is vacuum-packed is a technique known to those skilled in the art, referred to as "vacuum cooking". Such a cooking method maintains the integrity of the food and its taste properties. The kitchen under vacuum is thus characterized by cooking food previously vacuum conditioned for a prolonged period at relatively low temperatures. The advantages of this type of cooking are numerous: the nutrients are preserved because of the gentle cooking, and the food has a better taste and visual quality.

 Thus, according to one particular embodiment of the invention, the method of preserving the raw food comprises an additional step of vacuum cooking said food, which consists in applying a source of heat to the container containing the raw food and its food. impregnation solution, the under-pressure inside this container being between 5 and 20 millibars.

EXAMPLES

Example 1. Analysis of the taste properties of foods preserved according to the process of the invention

 A) Characterization of the texture of preserved foods

The raw foods tested are: chicken fillet and pear.

 The chicken fillet was incubated in two different impregnation solutions: Herb Oil (HH) and Honey Oil (HM). A sample of "control chicken", not treated by the process, is tested in parallel.

 The chicken was cooked in a water bath at 65 ° C for 30 minutes in the impregnating liquid, then after breaking the vacuum, marked in a hot pan 30 seconds on each side.

 The pear was incubated in a flavored syrup. A sample designated "Control Fruit" (FT), not processed by the method, is tested in parallel.

 Vacuum conditions were as follows: a MULTIVAC® bell vacuum machine was used to obtain 10 millibars under pressure in the aluminum containers containing the food and the impregnating solution.

 The characterization of the texture of the food was carried out using a texturometer according to conventional methods. The chicken was evaluated for the total cutting of the product on 100% of the height. The pear was evaluated by measuring the penetrometer and piercing it completely.

 The results are shown in Figures 1 (chicken) and 2 (pear).

These results highlight the fact that the preservation process has a minor textural softening effect on both chicken and pear. We lose between 13% and 25% firmness of the food, depending on the food and the impregnating solution used.

 This loss of firmness, however, does not affect the taste properties, as was found during the consumer test presented below.

B) Consumer test

 The tested foods are: chicken fillet, cherry tomato, fennel, pear and clementine.

 The method used for the consumer test is based on NF V09-500 (2012): Sensory analysis - Methodology - General guidelines for the production of hedonic tests with consumers in a controlled space.

 A panel of 100 naive consumers, representing the French population, was used for this consumer test.

 A questionnaire containing six questions relating to the visual and taste experience of the product was submitted to them.

 The results obtained are as follows: a) Chicken preserved in an impregnation solution composed of oil and honey; the chicken is, before tasting, cooked in the same way as described above.

Table 1. Appreciation of the chicken after conservation

Visual Rating Rating Rating Appreciation Rating Perception Perception (average / 9) (average / 9) overall texture appetite tastes chicken taste

 (average / 9) (average / 9) (% of consumers responding "just right")

6.66 (+/- 1, 36) 6.77 (+/- 1, 67) 6.89 (+ / 6 1, 63) 6.77 (+/- 1, 66) Sweet taste 68%

 collected by 10%

respondents b) Cherry tomato preserved in an impregnating solution composed of herbal oil

 Table 2. Appreciation of cherry tomato after conservation

Visual Note Rating Rating Appreciation Rating Perception Perception (average / 9) (average / 9) overall texture appetite tastes tomato taste

 (average / 9) (average / 9) (% of consumers responding "just fine", 61 (+/- 1, 23) 6.94 (+/- 1, 08) 6.73 (+/- 1, 08 ) 6.92 (+ / 6 1, 25) Thyme taste 73%

 was perceived

 by 10% of

 probed

c) Fennel preserved in a solution of impregnation composed of lemon oil Table 3. Appreciation of fennel after conservation

Visual rating Note of taste Appreciation rating Perception perception of (average / 9) (average / 9) overall texture tastes appeals taste fennel

 (average / 9) (average / 9) (% of consumers responding "just fine", 89 (+/- 1, 32) 6.21 (+/- 1, 28) 6.62 (+/- 1, 25 ) 6.1 (+/- 1 .43) A lemon taste 63%

 was perceived

 by 20% of

probed d) Clementine preserved in an impregnating solution composed of a syrup flavored with vanilla and saffron

Table 4. Appraisal of clementine after storage

Visual rating Note of taste Rating Appreciation Perception of Perception of (average / 9) (average / 9) overall texture appetite tastes clementine taste

 (average / 9) (average / 9) (% of consumers responding "just fine", 73 (+/- 1, 52) 6.16 (+/- 1, 55) 6.22 (+/- 1, 44 ) 6.22 (+/- 1, 49) No taste 43%

 Appendix 48% of respondents rated perception of taste as "not enough"

e) Pear preserved in an impregnating solution composed of a syrup with vanilla and saffron

 Table 5. Pear appreciation after conservation

Visual Note Rating Rating Appreciation Rating Perception Perception (average / 9) (average / 9) overall texture appetites taste pear

 (average / 9) (average / 9) (% of consumers responding "just fine", 58 (+/- 1, 33) 6.38 (+/- 1, 40) 5.99 (+/- 1, 55 ) 6.1 1 (+/- 1, 63) No taste 52%

Annex On the whole of the tasting, all the products obtain notes well above the average, which shows the satisfaction of the consumers and thus the maintenance of the taste qualities of the food during their conservation. EXAMPLE 2 Physicochemical Characterization of Foods Preserved According to the Process of the Invention

Some oils such as olive oil have antioxidant activity. Experiments were conducted to determine whether this antioxidant activity could be transferred to the food product stored under vacuum, in an impregnating solution composed of olive oil, flavored or not.

 The "DPPH" method was used: typically, the measurement of the antioxidant power is carried out by observing the reaction between the free radical DPPH (2,2-diphenyl-1-β-picrylhydrazyl) and the compound likely to have an antioxidant action. The oxidation of DPPH transforms it into a blue-colored compound, measurable by spectrophotometry at 515-518 nm. The decrease in the color signal is correlated with an antioxidant action of the test compound.

 In Figure 3, the measured parameter is NC50 of the DPPH, i.e., the amount of potentially antioxidant compound required to achieve the 50% decrease in blue color. Indeed, NC50 is equal to the concentration of the active substance which corresponds to a 50% inhibition of the DPPH target.

 The following foods have been tested for antioxidant capacity:

 • Control chicken meat (not preserved by the method, VT), or preserved in an impregnating solution composed of honey olive oil (V1 HM) or herbal olive oil (V2HH);

 • Fish (back of cod) control (PT), or preserved in solution of impregnation composed of olive oil with lemon (P1 HC) or olive oil with herbs (P2HH).

 Each sample of raw food was placed in a plastic bag with the impregnating solution. The assembly was subjected to a 10 millibars underpressure, with a MULTIVAC® vacuum bell machine.

 For the chicken, a medium-weight fillet of 18g was incubated with 20g of honey or herbal oil.

For the fish, a medium weight fillet of 84g was incubated with 15g of lemon or herb oil. Before breaking the vacuum, the chicken and fish were cooked in a water bath for 20 minutes for the fish and 30 minutes for the chicken.

 As is clear from FIG. 3, the meat and fish preserved according to the process of the invention have antioxidant capacities greater than those observed for the control meat (VT) and the control fish (PT), which are not incubated in the solutions. impregnation. Indeed, smaller amounts of food are needed to achieve a 50% decrease in the blue color due to oxidation of DPPH.

 Moreover, it should be noted that the different impregnating solutions do not all confer the same antioxidant activity to food.

 These results demonstrate that the antioxidant capacities of olive oil and herbs, honey and lemon, are transferred to the raw food stored in these solutions after vacuum packaging according to the method of the invention.

Example 3. Preservation of nuts in an impregnation solution composed of oil

Nuts are foods that can be kept as is, but that out of their shells tend to go rancid quickly.

 In order to avoid this phenomenon, the shelled nuts may advantageously be preserved according to the process of the invention, in an impregnation solution composed of oil.

EXAMPLE 4. Preservation of fruits and vegetables having been subjected to the process according to the invention, kept for a period of at least 30 days. Tests to detect any bacteriological contaminations have been carried out by a microbiology laboratory accredited by COFRAC (N ° accreditation: 1-0889). Tables 6 to 12 below summarize the results as of August 17, 2017, 31 days or 38 days after food manufacturing, as applicable. Table 6. Mango incubated in lime and vanilla syrup

Nature of Tests Results Units Values of Conclusion sample reference

 ½ Mango MicroPresence Ufc / g 1,000,000 Satisfactory incubated in organisms with less

an aerobic syrup 30 ° C of 4 x 1 / d:

lime and NF EN ISO 4833-1 30 000

Vanilla Staphylococci <100 # Ufc / g 100 Satisfactory

Made on coagulase

17/07/2017 positive 37 ° C

 Escherichia coli <10 # Ufc / g 10 Satisfactory beta

 glucuronidase

 positive

Table 7. Pineapple incubated in lime and vanilla syrup

Nature of Tests Results Units Values of Conclusion sample reference

 Pineapple Micro <10,000 Ufc / g 1,000,000 Satisfactory incubated in organisms

an aerobic syrup 30 ° C

lime and NF EN ISO 4833-1

Vanilla Staphylococci <100 # Ufc / g 100 Satisfactory

Made on coagulase

10/07/2017 positive 37 ° C

 Escherichia coli <10 # Ufc / g 10 Satisfactory beta

 glucuronidase

positive Table 8. Avocado incubated in olive oil

Nature of Tests Results Units Values of Conclusion sample reference

 Avocado in Micro <10,000 Ufc / g 10,000,000 Satisfactory slices organizations

in aerobic oil 30 ° C

olive NF EN ISO 4833-1

 Made Bacteria <1000 Ufc / g Satisfactory 17/07/2017 Lactics at

 30 ° C

 Ratio flora <100 Satisfactory total / flora

 lactic

 Staphylococci <100 # Ufc / g 100 Satisfactory to coagulase

 positive 37 ° C

 Salmonella spp Absence / 25g Absence Satisfactory [mobile]

 Escherichia coli <10 # Ufc / g 100 Satisfactory beta

 glucuronidase

 positive

Table 9. Green zucchini incubated in olive oil

 Nature of Tests Results Units Values of Conclusion sample reference

 Micro Zucchini <10,000 CFU / g 10,000,000 Satisfactory green in organisms

aerobic olive oil 30 ° C

Made the NF EN ISO 4833-1

 17/07/2017 Bacteria Presence Ufc / g Satisfactory lactics with less

 30 ° C of 4 x 1 / d:

1000 Nature of Tests Results Units Values of Conclusion sample reference

 Ratio flora <100 Satisfactory total / flora

 lactic

 Staphylococci <100 # Ufc / g 100 Satisfactory to coagulase

 positive 37 ° C

 Salmonella spp Absence / 25g Absence Satisfactory [mobile]

 Escherichia coli <10 # Ufc / g 100 Satisfactory beta

 glucuronidase

 positive

Table 10. Potato incubated in grape seed oil

Nature of Tests Results Units Values of Conclusion sample reference

 Apple of Micro1 400 000 Ufc / g 1 000 000 Satisfactory earth, organisms considering aerobically cut 30 ° C of fries, NF EN ISO 4833-1 presence of incubated in bacteria 1 200 000 Ufc / g lactic flora of oil from lactics to

pips of 30 ° C

grape Ratio flora ≤ 100 - Satisfactory

Made the total / flora

 Lactic acid

 Staphylococci <100 # Ufc / g 100 Satisfactory to coagulase

positive 37 ° C Nature of Tests Results Units Values of Conclusion sample reference

 Escherichia coli <10 # Ufc / g 10 Satisfactory beta

 glucuronidase

 positive

 Bacillus cereus <100 # Ufc / g 500 Satisfactory presumptive

 30 ° C

 Salmonella spp Absence / 25g Absence Satisfactory [mobile]

Table 1 1. New potato incubated in olive oil

Nature of Tests Results Units Values of Conclusion sample reference

 Apple of Micro450 000 Ufc / g 1,000,000 Satisfactory new earth, organisms

previously aerobic 30 ° C

bleached, NF EN ISO 4833-1

incubated in Bacteria 9 100 Ufc / g Satisfactory lactic acid oil to

olive 30 ° C

 Made flora Ratio <100 Satisfactory 17/07/2017 total / flora

 lactic

 Staphylococci <100 # Ufc / g 100 Satisfactory to coagulase

 positive 37 ° C

 Escherichia coli <10 # Ufc / g 10 Satisfactory beta

 glucuronidase

positive Nature of Tests Results Units Values of Conclusion sample reference

 Bacillus cereus <100 # Ufc / g 500 Satisfactory presumptive

 30 ° C

 Salmonella spp Absence / 25g Absence Satisfactory [mobile]

Table 12. Cherry tomatoes incubated in basil olive oil

Nature of Tests Results Units Values of Conclusion sample reference

 Micro Tomatoes <10,000 CFU / g 10,000,000 Satisfactory cherry organisms

aerobic incubated 30 ° C

in from NF EN ISO 4833-1

Olive oil Bacteria <1,000 cfu / g Satisfactory added lactic acid to

basil 30 ° C

 Made flora Ratio <100 Satisfactory 10/07/2017 total / flora

 lactic

 Staphylococci <100 # Ufc / g 100 Satisfactory to coagulase

 positive 37 ° C

 Escherichia coli <10 # Ufc / g 100 Satisfactory beta

 glucuronidase

 positive

Salmonella spp Absence / 25g Absence Satisfactory [mobile] Example 5. Preservation of fruits and vegetables having been subjected to the process according to the invention, kept for a period of at least 70 days Analyzes to detect any bacteriological contaminations were carried out by a microbiology laboratory accredited by COFRAC (Accreditation number: 1-0889). Tables 13 to 18 below summarize the results obtained as of July 10, 2017, 70 days, 84 days or 106 days after food manufacturing, as applicable.

Table 13. Mango incubated in a syrup

Table 14. Potato cut into fries

Nature of Tests Results Units Values of Conclusion sample reference

 Apple of Micro19,000,000 Ufc / g 1,000,000 Satisfactory land organisms considering

Made the aerobic 30 ° C of the

01/05/2017 Bacteria> 3,000,000 Ufc / g presence of

(lactic-lactic lactic conservation for 70-30 ° C

 days) Ratio flora <100 Satisfactory total / flora

lactic Nature of Tests Results Units Values of Conclusion sample reference

 Staphylococci <100 # 100 Satisfactory to coagulase

 positive 37 ° C

 Escherichia coli <10 # Ufc / g 10 Satisfactory beta

 glucuronidase

 positive

 Bacillus cereus <100 # Ufc / g 500 Satisfactory presumptive

 30 ° C

 Salmonella spp Absence / 25g Absence Satisfactory [mobile]

Table 15. Garlic incubated in oil

Nature of Tests Results Units Values of Conclusion sample reference

 Garlic incubated Staphylococci <100 # Ufc / g 100 Satisfactory in from to coagulase

positive oil 37 ° C

 Made Salmonella spp Absence / 25g Absence Satisfactory 01/05/2017 [mobile]

(Escherichia coli conservation <10 # Ufc / g 100 Satisfactory during 70 beta

days) glucuronidase

positive Table 16. Radishes incubated in olive oil

Nature of Tests Results Units Values of Conclusion sample reference

 Radish incubated Staphylococci <100 # Ufc / g 100 Satisfactory in from to coagulase

positive olive oil 37 ° C

Made Salmonella spp Absence / 25g Absence Satisfactory 17/04/2017 [mobile]

(Escherichia coli conservation <10 # Ufc / g 100 Satisfactory during 84 beta

days) glucuronidase

 positive

Table 17. Green asparagus incubated in olive oil

Nature of Tests Results Units Values of Conclusion sample reference

 Asparagus Staphylococci <100 # Ufc / g 100 Satisfactory green incubated with coagulase

in positive 37 ° C

olive oil Salmonella spp Absence / 25g Absence Satisfactory Made on [mobile]

17/04/2017 Escherichia coli <10 # Ufc / g 100 Satisfactory (conservation beta

during 84 glucuronidase

days) positive Table 18. Tomato incubated in olive oil with basil

REFERENCES

WO 2016/64608

 GB 418364

 GB 527607

 GB 537171

 J PS 62208244

 FR 2,280,328

 FR 2,807,955

 US 3,843,810

 US 4,460,610

Vasilayos, G. C, & Sa Vaidis, I. N. (2013). Chitosan or rosemary oii treatments, singly or combsned to increase turkey meat shelf-life. International Journal of Food Microbiology, 166 (1), 54-58. Ariyapitipun, T., Mustapha, A., & Clarke, A. D. (2000). Survival of Listeria monocytogenes A vacuum-packed raw beef with polylactic acid, lacic acid, and nisin. Journal of Food Protection, 63 (1), 131-136.

Claims

A method of preserving a raw food of animal or vegetable origin, comprising the following steps:  a) Incubation of the raw food in an impregnating solution composed of a syrup or an oil, optionally supplemented with plants and / or spices and / or honey;  b) Partial vacuum packaging of the raw food in its impregnating solution, the final under pressure obtained being between 5 and 20 millibars; and  c) Preservation of raw food in its impregnation solution, under partial vacuum, at a temperature between 0 ° C and 6 ° C. Process according to claim 1, characterized in that the raw food is selected from a fruit, a vegetable, meat, seafood, fish and their combinations. Method according to one of claims 1 or 2, characterized in that the raw food has previously been cut into pieces.  Process according to one of Claims 1 to 3, characterized in that the impregnating solution completely covers the raw food.  Process according to one of Claims 1 to 4, characterized in that the raw food and its impregnating solution are vacuum-packed in a gas-tight and liquid-tight container, for example in a food-grade plastic bag.  Method according to one of claims 1 to 5, characterized in that the step (b) of partial vacuum conditioning lasts between 1 and 15 minutes.  Process according to one of Claims 1 to 6, characterized in that the vacuum conditioning step (b) is carried out by applying several successive pressure drops, each pressure drop lasting between 1 and 3 minutes, and preferably during 1 minute 30 seconds. Process according to one of Claims 1 to 7, characterized in that the vacuum conditioning step (b) is carried out by means of a vacuum bell machine. Process according to one of Claims 1 to 8, characterized in that the vacuum conditioning step (b) is carried out at a temperature of between 2 and 15 ° C. Process according to one of Claims 1 to 9, characterized in that the storage step (c) is continuous for a period of at least one month.