CH684985A5 - Method for preparing and preserving cooked dishes under vacuum with controlled temperatures and cooking and cooling times - Google Patents

Abstract

Method for preparing and preserving cooked dishes based on any edible product, characterised in that the foods are introduced raw into a hermetic sachet (sealed bag), which is placed under vacuum, are cooked in a steam (vapour) oven at a temperature and for a period which are specific for each preparation, and are then cooled, without an intermediate stage, down to the temperature of 10 DEG C over a period of from 1 h 30 to 2 h. The preparations thus obtained do not contain additives, colouring agents or emulsifying agents, retain their succulence, are easy to use and have a long shelf life.

Description

1

CH 684 985 A5

2

Description

The present invention relates to a process for the preparation and preservation of dishes and cooked dishes based on all edible products.

One of the best known techniques for ensuring such preparations is the cooking of food products under vacuum, which however has the drawback of its limited shelf life. Certain heat treatments of food products (patents JP 71 019 573 B and FR 2 658 894 A1) recommend cooking in an atmosphere loaded with carbon dioxide in order to improve this shelf life. In general, it is established that the increase in the shelf life comes at the expense of the taste quality of the products; and vice versa. All of these techniques use coloring agents, preservatives or additives.

According to the present invention, it becomes possible to combine the taste quality of the products and cooked dishes with an optimized shelf life.

In the usual technique of vacuum cooking at low temperature, the possibly braised and seasoned foodstuffs are placed in plastic envelopes which are sealed after aspiration of the air to be heated for several hours at temperatures varying around 60 ° C. .

At these relatively low temperatures the proteins do not coagulate and lose little of their water of hydration so that the tenderness of the food and its aromas are preserved; but this comes at the expense of pasteurizing value.

Conversely, an increase in the pasteurizing value considerably increases the expiry date for conservation, and therefore sale, of the products, but to the detriment of the "succulence" of the products whose organoleptic value is then low.

The present invention initially consists of using dishes in the natural state (subject to peeling and washing or debiting) without additives, coloring or preservatives which will be cooked in an oven steam vacuum; secondly, after cooking, the temperature of these dishes will be lowered quickly.

The dishes are introduced raw in a sachet formed using synthetic food films with high hygienic and thermal performance. It is essential that two films of different thicknesses be put in place to compose the sachet; the thinner film will form the upper part of the sachet and the thicker film will form the lower part. It will be formatted to the desired depth by thermal stretching, the thermo-forming temperature being 109 ° C. This device is necessary to ensure a better distribution of the products inside the sachet.

The bag is then closed by 4 thermo-shaped welds at identical temperature over the same width. It is essential that the bag is closed by 4 welds carried out simultaneously under the same temperature and on the same width so that the seal of the bag is perfect.

The previous data (film thicknesses, weld temperature, weld width) are generally displayed by the machine or film manufacturers. As an illustration for a Multivac R 5100 machine, the welding temperature will be 155 ° C for welds 3 mm wide (for example: NOD 116 and NFD 165 films according to GRACE and CRYOVAC references).

Once the bag is closed, the vacuum drawing force displayed (7.5), the vacuum will be made at 950 mbar over a period of 4 to 10 seconds. This data of 950 mbar is decisive. It should not be exceeded because the dishes would start to "cook" inside the sachet. It should not go below this value in which case the excessive volume of air in the sachet would shorten the duration of consumption by oxidation.

The sachet thus placed under vacuum is then cooked in a steam oven. The steam cooking mode is to be used in preference to the other cooking modes, insofar as it provides a uniform temperature without "acouples", "linear".

The cooking temperature and cooking time are specific to each type of product so that it retains its organoleptic qualities under the best conditions of shelf life.

Applied to the cooking of the following products: beef (minced, stew, tongue), pork (sauteed, minced), ham on the bone, coq au vin, couscous, lamb stew, stew, sauerkraut, duck leg, stew of veal, the cooking chamber is maintained at a temperature of 80 ° C for 45 min.

Applied to the cooking of the following products: beef paupiettes, minced steak, paupiette of pork, chicken leg, the cooking chamber is maintained at a temperature of 70 ° C for 60 min.

Applied to the cooking of the following products: pork sausage, minced poultry, sautéed turkey, meatballs, skewer, the cooking chamber is maintained at a temperature of 70 ° C for 45 minutes.

Applied to the cooking of the following products: turkey cutlet, lamb fillet, rabbit fillet, duck breast, the cooking chamber is kept at a temperature of 70 ° C for 10 minutes.

Applied to the cooking of duck foie gras, the cooking chamber is kept at a temperature of 70 ° C for 20 minutes.

Applied to the cooking of osso bucco, the cooking chamber is maintained at a temperature of 70 ° C for 120 min.

Applied when cooking whole roasts, the oven is kept at a temperature of 70 ° C for 5 h for beef, for 3 h 30 for pork for 3 h for veal and for 2 h 30 for turkey .

Applied to the cooking of the following products: salmon, hake, saint-pierre, trout, the cooking chamber is maintained at a temperature of 80 ° C for 8 min.

Applied to the cooking of the shrimps with dill and the gratin of seafood, the cooking chamber is kept at a temperature of 80 ° C for 15/20 minutes.

5

10

15

20

25

30

35

40

45

50

55

60

65

2

3

CH 684 985 A5

4

Applied to the cooking of fish soup and all sauces, the cooking chamber is maintained at a temperature of 80 ° C for 45 minutes.

Applied to the cooking of all vegetables, the cooking chamber is maintained at a temperature of 100 ° C for 25/30 min.

Applied to the cooking of all fruits, the cooking chamber is kept at a temperature of 100 ° C for 20/30 min.

Applied to rice cooking, the process requires the following operating mode: the rice must be prior to its introduction into the sachet, heated in peanut oil in the following proportion: 3 di peanut oil per kilo raw rice. This rice should be heated until it becomes translucent. Once cooled to a temperature of around 10 ° C, this rice is mixed in the sachet with a broth previously prepared and the temperature of which has also been brought down to 10 ° C. The rice-broth mixture is in proportion (by volume) of 1/3 of rice to 2/3 of broth.

The sachet is hermetically sealed and placed in a cooking chamber at a temperature of 100 ° C for 25/30 min.

According to a variant of the preceding operating method, the process allows the preparation of a Risotto base: the rice (of the Vialone, Arborio or similar type) must be prior to its introduction into the sachet, heated in peanut oil according to the following proportion: 2 dl of oil per kilo of raw rice. This rice should be heated until it becomes translucent. Once cooled to the temperature of about 10 ° C, this rice is mixed in the sachet with a strong broth previously prepared and whose temperature has been brought down to 10 ° C. The rice-broth mixture is in proportion of 100 g of rice for 250 g of broth. 10 g of butter should be added for the same proportions. The sachet is hermetically closed, drawn under vacuum at 950 mbar and placed in a cooking chamber at a temperature of 100 ° C for 14 min. It is treated as indicated for the whole process. The implementation of this basic preparation can be done as follows: after opening the sachet, the content is heated in a container to which the desired accompanying product is incorporated (for example: boletus, parmesan, tomatoes, saffron, sea food...)

Applied to the cooking of semolina the process requires the following operating mode: the semolina is cooked in the traditional way for 3 to 4 minutes. Excess water must be evaporated. 20 g of butter are added per kilo of semolina. It is cooled to 10 ° C. The semolina thus prepared is introduced into the sachet which is placed in a cooking chamber at a temperature of 80 ° C for 20 min.

Applied to the cooking of pasta, the process requires the following operating mode: the pasta is traditionally cooked with water. They are cooled to 10 ° C. They are seasoned once cooled. Add 1 dl of oil and 10 g of butter per kilo of cooked pasta. The pasta is put in the bag. The bag is placed under vacuum

at 950 mbar (vacuuming time from 4 to 6 seconds).

Certain cooked dishes based on side sauces in particular, may require pre-cooked or marked products. In this case it is necessary that these products have reached a temperature of 10 ° C maximum when they are placed in the cooking bag with the main dishes. This maximum temperature is essential in order to avoid the release of vapor inside the bag during the heat sealing operations.

Similarly, in order to promote uniformity in the cooking of products, is it necessary not to place the dishes to be cooked in superimposed layers, but to arrange them as thin as possible (2 to 5 cm) at the inside the bag.

The sachet which has finished cooking is taken out of its cooking enclosure and immediately placed in a refrigerated cabinet so that the temperature of the sachet is lowered to 10 ° C and this as soon as possible, between 1 h 30 and 2 h. More than the cooling speed of the temperature of the sachet, it is the need for a “linear” lowering, without intermediate bearing, which is a determining condition of the process.

The principle which guided the research which led to the present invention is based on a preliminary observation: the apparent incompatibility of the "taste" with the shelf life, and on a conclusion: only two data must be taken into account to overcome this incompatibility: temperature and time.

In the first phase of the process, the organoleptic qualities of the products could be preserved and even amplified by the adaptation of a system of vacuum cooking with steam of the raw products without any chemical agent or coloring or preservative, and at a temperature and a strictly supervised duration.

In fact, the products being cooked at "low" temperatures and for periods much shorter than those usually accepted for analogous methods, the elimination of salmonella and the destruction of the vegetative cells of the bacterium Clostridium perfringens could not be carried out.

We know that at temperatures above 55 ° C heat kills the vegetative cells from these spores, but the remaining spores can germinate during cooling.

From this observation, the shorter the cooling time, the less the possibility of anaerobic spores germinating again.

According to the present invention, in the second phase of the process, the previous consideration is applied. The bag leaving its cooking chamber is immediately subjected to a thermal shock causing the products to cool until reaching the temperature of 10 ° C in a time varying from 1 h 30 to 2 h. This lowering of temperature can usefully be implemented from commercial cold cabinets fitted with extractors (in order to accelerate the speed of a5

10

15

20

25

30

35

40

45

50

55

60

65

3

5

CH 684 985 A5

6

temperature drop by evacuation of steam).

It is however fundamental that this lowering of the temperature takes place in a linear fashion, that is to say without intermediate stage, without interruption of the process and this in order to avoid a re-germination of the spores.

The products thus treated can validly be stored for several weeks at a temperature of 0 ° C to 5 ° C.

The previous considerations and the merit of this process were tested by the Cantonal Laboratory of Valais in a report dated October 17, 1991. This Laboratory proceeded to the analysis of 5 samples of products prepared according to the present invention. These samples were analyzed 3 times: the first on receipt of the samples (08/26/91); ia second after 8 days of storage at a temperature above + 5 ° C and 16h at + 17 ° C; the third after the samples have been placed in the fridge for 8 days, then for 8 days at + 10 ° C.

The analyzes were carried out according to the prescriptions of the Swiss Manual of Foodstuffs Chapter 56.

The organoleptic examination revealed no anomalies.

The bacteriological examination is also positive since the samples are declared to be of good bacteriological quality and as being suitable for storage under refrigeration. No growth of bacteria having taken place, it appears that the heat treatment according to the present invention is sufficient to completely inactivate them. Furthermore, the detection limit (10 / g) of anaerobic spores is very low, which is all the more remarkable since these spores are only inactivated by sterilization and not by a heat treatment as carried out during cooking under empty.

The advantages of such an invention are numerous:

- the products used are necessarily extremely fresh and do not contain any additives, colorants or preservatives;

- the products are cooked under vacuum in their sachet and fully retain their nutritional value (no loss by evaporation, cooking water, etc.) as well as the trace elements and vitamins, so that a smaller quantity of food ensures superior nutritional intake;

- the products are kept in a refrigerated atmosphere for several weeks without any organoleptic or bacteriological alteration;

- the products are easily "usable" without any other preparation than to immerse them in water below the boiling point for about 10 minutes or to introduce them into a microwave oven, taking care to puncture the sachet beforehand ;

- products heated in a bain-marie can withstand an extended wait of approximately 2 hours without altering the product or overcooking; the unopened sachet can be cooled quickly and then easily stored again in a refrigerated atmosphere.

Claims (22)

Claims 1. Process for preparing and preserving ready meals, characterized in that the food product is taken in its natural state without additive, color or preservative, it is placed under vacuum at a pressure of 950 mbar in 4 to 10 seconds , it is cooked in a steam oven at variable temperatures depending on the preparations and finally its temperature is rapidly lowered without overcoming intermediate to reach 10 ° C in 1.30 h to 2 h. 2. Method according to claim 1 characterized in that the food is introduced raw in a sachet. 3. Method according to claims 1 to 2 characterized in that the sachet placed under vacuum is cooked in a steam oven at uniform temperature. 4. Method according to claims 1 to 3 characterized in that the sachet, as soon as its cooking is completed, is immediately placed in a refrigerated cabinet equipped with extractor for a lowering of its temperature until reaching 10 ° C. . 5. Method according to claims 1 to 4 intended for cooking beef (minced, stew, tongue), pork (sauteed, minced), ham on the bone, coq au vin, couscous, lamb stew, stew, sauerkraut , duck leg, veal stew, characterized in that the cooking chamber is kept at a temperature of 80 ° C for 45 min. 6. Method according to claims 1 to 4 for ia cooking beef paupiettes, minced steaks, paupiettes of pork, chicken thighs, characterized in that the cooking chamber is maintained at a temperature of 70 ° C for 60 min. 7. Method according to claims 1 to 4 intended for cooking pork sausages, minced poultry, stir-fried turkey, meatballs, skewers, characterized in that the cooking chamber is maintained at a temperature of 70 °. C for 45 min. 8. Method according to claims 1 to 4 intended for cooking turkey cutlets, lamb fillets, rabbit fillets, duck breasts, characterized in that the cooking enclosure is maintained at a temperature of 70 ° C for 10 min. 9. Method according to claims 1 to 4 intended for cooking duck foie gras, characterized in that the cooking enclosure is maintained at a temperature of 70 ° C for 20 min. 10. Method according to claims 1 to 4 intended for cooking osso bucco, characterized in that the cooking chamber is maintained at a temperature of 70 ° C for 120 min. 11. Method according to claims 1 to 4 intended for cooking whole roasts, characterized in that the cooking chamber is maintained at a temperature of 70 ° C for 5 h for beef, for 3 h 30 for pork for 3 h for the calf and 2 h 30 for the turkey. 12. Method according to claims 1 to 4 intended for cooking the following products: salmon, hake, saint-pierre, trout, characterized in that the cooking enclosure is maintained at a temperature of 80 ° C for 8 min. 13. Method according to claims 1 to 4 desti5 10 15 20 25 30 35 40 45 50 55 60 65 4 7 CH 684 985 A5 8 born from the cooking of shrimps with dill and gratin of seafood characterized in that the cooking chamber is kept at a temperature of 80 ° C for 15 to 20 min. 14. Method according to claims 1 to 4 intended for cooking fish soup and all sauces, characterized in that the cooking chamber is kept at a temperature of 80 ° C for 45 min. 15. The method of claims 1 to 4 intended for cooking all vegetables in that the cooking chamber is maintained at a temperature of 100 ° C for 25 to 30 min. 16. Method according to claims 1 to 4 intended for cooking all the fruits, characterized in that the cooking enclosure is kept at a temperature of 100 ° C for 20 to 30 min. 17. Method according to claims 1 to 4 intended for cooking rice, characterized in that the rice, prior to its introduction into the sachet, is heated in peanut oil in the following proportion: 3 dl of oil peanut per kilo of raw rice until it becomes translucent; once cooled to a temperature of around 10 ° C, this rice is mixed in the sachet with a broth previously prepared and the temperature of which has also been brought back to 10 ° C, the rice-broth mixture being in proportion (by volume) 1/3 rice for 2/3 broth; the bag is hermetically closed and placed in a cooking chamber at a temperature of 100 ° C for 25 to 30 min. 18. Method according to claims 1 to 4 intended for the preparation of a risotto base characterized in that the rice is heated prior to its introduction into the sachet, in peanut oil in the following proportion: 2 dl of oil per kilo of raw rice until it becomes translucent; once cooled to the temperature of about 10 ° C, the rice is mixed in the sachet with a strong broth previously prepared and whose temperature has been brought down to 10 ° C, the rice-broth mixture being in proportion to 100 g of rice for 250 g of broth to which 10 g of butter are added for the same proportions, the sachet is hermetically sealed, vacuum-drawn at 950 mbar and placed in a cooking chamber at a temperature of 100 ° C for 14 min. 19. The method of claims 1 to 4 intended for cooking semolina characterized in that the semolina is cooked in the traditional way for 3 to 4 min, the excess water having to be evaporated; 20 g of butter are added per kilo of semolina; the semolina temperature is lowered to 10 ° C and the semolina thus prepared is introduced into the sachet which is placed in a cooking chamber at a temperature of 80 ° C for 20 min. 20. The method of claims 1 to 4 for cooking pasta characterized in that the pasta is cooked in the traditional way with water, then is cooled to 10 ° C and seasoned once cooled; add 1 dl of oil and 10 g of butter per kilo of cooked pasta; the pasta is put in the sachet and the sachet is placed under vacuum at 950 mbar for 4 to 6 seconds. 21. The method of claims 1 to 20 intended for ready meals based on side sauces which may consist of precooked products characterized in that these products are brought to a temperature of 10 ° C maximum when they are placed in the cooking bag with main food. 22. Method according to claims 1 to 21 characterized in that in order to promote the uniformity of cooking of the products, they are arranged in the smallest possible thickness of 2 to 5 cm inside the cooking bag. 5 10 15 20 25 30 35 40 45 50 55 60 65 5