MXPA99008394A - Fermented milk product production process - Google Patents

Abstract

The present invention is directed to a fermented milk production process in self-rehydrating container comprising a carbohydrate, a fermented milk product forming starter culture, milk powder and eventually other edible solutes, and to a self-rehydrating container adapted thereto. The container contains a semi-permeable membrane which allows the preparation of substantially sterile water solutions using osmotically driven filtration.

Description

PROCEDURE FOR THE PRODUCTION OF FERMENTED DAIRY PRODUCTS Field of the Invention This invention relates to a self-rehydration vessel adapted for the production of fermented milk products, to a process for the production of fermented milk products using a self-rehydration vessel, to a vessel adapted to this process and to the product of fermented milk produced as such.

BACKGROUND OF THE INVENTION The use of yoghurts or fermented milk products in general, as part of the human diet, is considered extremely beneficial for many reasons, including: important bacterial contamination in the upper intestine is prevented by colonization of beneficial organisms; , the problems related to lactose intolerance are reduced, due to the conversion of lactose; antibiotics are produced locally by bacteria of the lactobacillus type; Within the food product, certain minerals are potentially more available for digestion; and fermented milk products have better stability than other equivalent dairy products. However, in many locations around REF .: 31239 world, it is often difficult to prepare yoghurts or fermented milk products in general in the field. This is mainly due to pollution (poor hygiene and sanitation) and the lack of necessary thermostable organisms. In addition, it is essential that the organisms that make fermented milk products grow in the correct medium. A secondary advantage of fermented milk products forming organisms is their antibiotic property. That is, when the growth of potentially pathogenic organisms present in the food product is suppressed or greatly reduced, due to the presence of large quantities of beneficial organisms, due to its rapid growth, which is known as the colonization effect. It has been explained that it is the low pH resulting from the production of lactic acid that prevents the growth of harmful bacteria. The classical process for the production of fermented milk products is known to a person skilled in the art. As it is necessary that the initial culture lack contaminating microorganisms, it is indicated that the containers in which the fermented milk product is produced should be as clean and disinfected as possible. Although the bacteria producing fermented milk products have a colonizing effect, other pathogenic microorganisms could also be developed. This occurs safely when the temperature at which the fermented milk product is prepared is less than 40-45 ° C.

Objects of the Invention Taking into account the beneficial effects of a fermented milk product and the need to provide convenient and uninfected preparation containers for fermented milk products, especially in countries where purified water is not readily available and when the need is very high of healthy foods, the present invention aims to provide a fermented milk product that facilitates the preparation of yogurt in the field, even in a medium with high biological contamination. It is another object of the invention to exploit the colonization property of the beneficial cultures of fermented milk products, when it is necessary to increase the average life of the rehydrated, potentially contaminated food products.

Description of the invention According to the invention, a fermented milk product (such as a yogurt or buttermilk) is made inside a self-rehydration vessel comprising, as at least a part of its walls, a semi-permeable membrane. In a preferred embodiment, the self-rehydration vessel has two compartments, as described in British patent application No. 9705455.5 of the present applicant. In this container shared, a compartment has walls impervious to water and optionally to oxygen and contains a material to be rehydrated. Another compartment, which is osmotically active, has at least a part of its semi-permeable walls, allowing obtaining sterile water through an osmotically directed filtration process as described in EP 360,612 or in USP 4,920. 105, and contains osmotically active solutes. These compartments are separated by a non-permanent closure. The container thus used in the production process of fermented milk products of the present invention contains fermenting milk product organisms and milk powder in admixture with a carbohydrate, such as, for example, sugar, which it can function as an osmotically active solute. In the variant using the compartmented container, the fermented milk product forming bodies and the milk powder are retained in the water impermeable compartment and the osmotically active solute in the osmotically active compartment. A "fermented milk product" according to the present invention may contain at least one of the following organisms: Lactococcus lactic (different sub-species), Streptococcus salivarus, Streptococcus cremoris, Streptococcus lactis, Streptococcus diacetilactis or Streptococcus thermophilus (different sub-species). species), Lactobacillus bulgaricus (different sub-species), Leuconostoc cremoris or Leuconostoc lactis, but other organisms forming fermented milk products are known to those skilled in the art. These organisms can be adapted to provide products of different consistency, ie, liquid fermented milk products, thick fermented milk products, yogurt, kefir, whey, cheese-like products, etc. Classes of organisms that have excellent self-stability have been identified if they are kept dry and oxygen-free. The compartmented container allows this requirement to be met, since the water-impermeable compartment can additionally have an excellent oxygen barrier and gas can be applied to remove the oxygen before closing it. This container can itself be contained within a hermetically sealed container. The self-rehydration vessel is a container for producing fermented milk products indicated, because the present applicant has observed that using these organisms together with carbohydrates and dry skimmed milk, it is possible to convert lactose into lactic acid and water within the container . As a result, a reduction in pH is achieved together with a significant growth of said organisms. A combination of these effects helps to suppress the potential growth of pathogenic organisms within the package and generates fermented milk products substantially free of microbiological contaminants. The carbohydrate that is necessary for osmotically directed filtration to occur is favorably any carbohydrate that can maintain the yogurt-producing organisms during the conversion of lactose into lactic acid and that promotes its growth. Preferably, the carbohydrate is lactose, sucrose, dextrose and the like; more preferably, lactose is used. Within the self-rehydration vessel, solid or liquid fermented milk products can be made which are considered to have extreme consumption advantages, using known cultures. The milk powder contained in the container can be any type of dry milk. However, the best results are obtained with skimmed milk powder. Similarly, a powdered milk useful for specific applications, such as High Energy Therapeutic Milk can be used. The process for preparing fermented milk products according to the invention comprises immersing a self-rehydration vessel in water and leaving the vessel submerged until the filtered water has reached a sufficient level. The osmotically active carbohydrate, the starter culture and the milk powder are included together in the container. Once the container has been submerged in water, rehydration of the different solutes is initiated and the starter culture is activated. Using organisms of fermented milk products together with a carbohydrate and dry milk powder, a reduction of the pH and a significant growth of said organisms takes place. Therefore, the combination of these effects helps to suppress the potential growth of contaminating organisms within the bag and generates a fermented milk product. In a variant, the method of making fermented milk products according to the present invention comprises submerging a compartmentalized self-rehydration vessel in water, where the water-impermeable compartment contains the starter culture and milk powder, while the The osmotically active compartment contains an osmotically active carbohydrate, leave the container submerged until the filtered water has reached a sufficient level, break a non-permanent seal separating the two compartments, allow the water-impermeable compartment to be filled with the sterile water of the other compartment. compartment, allow the starter culture and milk powder to dissolve, keep the container at a temperature above 25 ° C, preferably between 30 ° C and 45 ° C, depending on the thermal resistance of the milk product forming organism fermented, and allow the fermented milk product to be formed. When the starter culture is sufficiently resistant to be maintained without particular measures to improve its self-stability and / or when the starter culture has a sufficiently high colonizing potential (thus preventing the growth of polluting organisms), the single-container is particularly suitable. compartment. On the other hand, when it is necessary to keep the starter culture dry and without oxygen so that it has an acceptable average life or when the colonizing potential of the culture is not sufficiently high, it is preferable to use the compartmented container. Normally, 6 to 7 hours are required for a mixture of milk and starter culture to become a fermented milk product. Therefore, it is necessary to foresee an initiating culture that can develop more than the contaminating microorganisms potentially present in the other solutes during the rehydration period, when the milk powder / water / starter culture mixture is not in its full growth capacity . A preferred "single-compartment" self-rehydration vessel comprises a composite i-permeable membrane consisting of a support layer with a relatively high molecular weight cut selected from the group consisting of cellulose, regenerated cellulose (CELLOPHANE ® or cuprophane), benzoylated cellulose and collagen, and a thin layer with a low molecular weight cut, as described in the British patent application of the present applicant No. 9705454.8, in process. Preferably, the thin layer consists of a hydrophilic polyurethane such as those conventionally used to cover fabrics with a protective coating that is impermeable to water but permeable to water vapor. The reduction of the molecular weight cut-off of the overall membrane structure allows keeping more solute compounds inside the milk solutions of the present invention, thereby obtaining a more nutritious yogurt, especially when using, for example, Therapeutic Milk of High energy. It is well within the possibilities of the specialist in the field, the development of more sophisticated fermented milk products through the use of, for example, other beneficial microorganisms (such as bifidus), other powdered solutes (such as fruit juice powder) , thickeners, etc.), coloring agents, etc. Again, the colonizing effect (pH and growth rate) of the fermented milk product organisms will impede the development of contaminating organisms possibly present in such solutes. Preferably, fermented milk product organisms with pH lowering properties are used, which ensure a pH decrease at pH 4-4.5 in 6 hours of rehydration. The examples set forth below illustrate the invention without intending to limit its scope in any way. As a fermented milk product embodiment, a yogurt has been made, but other types of fermented milk products are well within the scope of the invention.

Examples Example 1 A container is prepared with a composite membrane consisting of a membrane support membrane of regenerated cellulose with a molecular weight cut-off of 1800 and a thin layer of hydrophilic polyurethane applied by direct gravure coating at 10 g / m (wet weight) . The hydrophilic polyurethane is prepared as follows: In a round bottom flask, with four nozzles, of 2 liters, equipped with a mechanical stirrer, a thermometer, an air condenser, a nitrogen inlet and a dropping funnel, a solution of 133.02 g of polyethylene glycol (PEG 600 (HOECHST)) having a molecular weight of about 600 and 79.00 g of 1,1 '-methylenebis (4-isocyanatocyclohexane) in 342.00 g toluene. The mixture is heated to 90 ° C with stirring and 25 mg of dibutyltin laurate (DABCO T12 (AIR PRODUCTS)) is introduced as a catalyst. The reaction mixture is maintained at 90 ° C for 6 hours and then cooled. A solution of 13.68 g of isophorone is introduced into a second 2-liter round-bottomed flask equipped with a mechanical stirrer, a thermometer, an air condenser, a nitrogen inlet and a dropping funnel. diamine in 350.00 g of isopropyl alcohol. The contents of the first flask are cooled to room temperature and then added slowly to the alcohol / amine mixture (second flask). The extension of the chain is completed after approximately 3 hours. To the mixture, 44.2 grams of non-volatile silica (TS100 DEGUSA) and 50 g of toluene are added.

Example 2 Self-rehydration containers containing 30.7 g of Infant Formula Milk (IFM) or 36.5 g of Therapeutic Milk (TM) and different yogurt forming organisms are placed in water. When the internal volume has reached 200 ml, 7.5 hours in the case of Infant Formula Milk and 8.5 hours in the case of Therapeutic Milk, the bags are gently removed from the water. Next, the bags are stored at different temperatures: in the refrigerator (at approximately + 4 ° C) at room temperature (at 25 ° C, with a relative humidity of 75%); in a tropical stove (at 38 ° C, with a relative humidity of 90%). Every hour (for 24 hours) a bag is opened and the pH of its contents is measured. TABLE 1 shows the measured pH values. The White samples do not contain any yoghurt-forming organism, the samples from strain 1 contain 6 mg of RA024 (from TEXEL) as a yoghurt-forming organism; samples of strain 2 contain 6 mg of MY087 (from TEXEL) as a yogurt-forming organism; the samples of strain 3 contain a mixture of 3 mg of RA024 (from TEXEL) and 3 mg of MY087 (from TEXEL) as a yoghurt-forming organism; and the samples of strain 4 contain 6 mg of MA.016 (from TEXEL) as a yoghurt-forming organism; TABLE 1 pH change for 24 hours Milk Condition Sample 0 1 2 3 4 5 6 7 IFM White Fridge 6.68 6.68 6.73 6.85 6.55 6.67 6.89 Strain 1 6.68 6.67 6.69 6.74 6.44 6.53 6.77 Strain 2 6 , 50 6.50 6.57 6.65 6.43 6.54 6.69 Strain 3 6.50 6.49 6.54 6.46 6.32 6.64 6.80 Strain 4 6.46 6, 44 6.40 6.34 6.26 6.24 6, 14 6.03 Environment White 6,65 6,64 6,62 6,44 6,40 6,47 6,54 Strain 1 6,64 6,60 6,57 6,40 6,27 6,09 5,95 Strain 2 6, 65 6.64 6.68 6.40 6.60 6.62 6.72 Strain 3 6.63 6.60 6.60 6.35 6.22 6, 16 6.10 Strain 4 6.50 6.39 6, 19 6.01 5.73 5.38 5.12 4.76 Tropical White 6.47 6.44 6.49 6.49 6.46 6.43 6.30 Strain 1 6.37 6.05 6.63 4.71 4.26 4.26 4.20 Strain 2 6.44 6 , 39 6,35 6,21 5,36 4,78 4,40 Strain 3 6,42 6,23 5,93 5.53 4,50 4.36 4,30 Strain 4 6,55 6,15 5.64 5,16 4, 77 4.41 4.30 4.23 M Refrigerator White 6.53 6.49 6.55 6.66 6.39 6.54 6.73 Strain 1 6.68 6.47 6.53 6.61 6.33 6 , 42 6.58 Strain 2 6.50 6.50 6.57 6.65 6.43 6.54 6.69 Strain 3 6.50 6.49 6.54 6.46 6.57 6.64 6.80 Strain 4 6.51 6.54 6.51 6.44 6.44 6.47 6.5-1 6.55 Environment White 6.48 6.46 6.51 6.53 6.56 6.64 6.75 Strain 1 6.47 6.45 6.46 6.30 6.25 6.21 6.17 Strain 2 6.45 6 , 46 6.51 6.35 6.30 6.43 6.53 'Strain 3 6.47 6,44 6,46 6,20 6, 18 6, 13 5,98 Strain 4 6,44 6,40 6,36 6,30 6,25 6,21 6, 17 5,91 Tropical White 6.26 6.21 6.24 6, 15 6, 10 5.90 5.40 Strain 1 6, 19 6.04 5.84 5.08 4.85 4.64 4.52 Strain 2 6, 26 6.19 6, 14 5.55 4.89 4.63 4.43 Strain 3 6.23 6.11 5.96 5.49 4.88 4.64 4.48 Strain 4 6.47 6.22 6, 18 6.09 5.97 5.84 5.68 5.27 TABLE I (Continuation - 1) Milk Condition Sample 8 9 10 11 12 13 14 15 IFM White Fridge 6.89 Strain 1 6.75 Strain 2 6.89 Strain 3 6.66 Strain 4.78 5.80 5.72 5.40 5.49 5.38 5.27 5.13 Environment White 6.59 6.59 6.58 6.58 Strain 1 5.63 5.30 4.94 4.61 Strain 2 6.76 6.63 6.50 6.33 Strain 3 5.86 5.55 5.24 4.93 Strain 4 4.47 4.30 4.32 4.24 4.24 4.22 4.21 4.18 Tropical White 5.83 5.32 4.81 4.30 Strain 1 4, 15 4.12 4.08 4.03 Strain 2 4.25 4.18 4.11 '3.99 Strain 3 4.22 4.17 4 , 12 4.06 Strain 4 4, 10 4.08 4.07 4.04 4.04 4.05 • 4.02 4.02 TM Fridge White 6,99 Strain i 6,75 Strain 2 6,99 Strain 3 6.66 Strain 4 6,46 6,70 6,62 6,55 6,54 6,57 6,65 6,42 Environment White 6.76 6.70 6.63 6.56 Strain 1 5.98 5.68 5.36 5.07 Strain 2 6.56 6.43 6.30 6, 18 Strain 3 5.66 5.30 4.94 4.57. Strain 4 5.81 5.66 5.48 5.24 5.05 4.89 4.77 4.66 Tropical White 4.88 4.65 4.42 4.19 Strain 1 4.42 4.34 4.26 4.17 Strain 2 4.28 4.20 4.12 4.02 Strain 3. 4.35 4.27 4.19 4 , 1 1 Strain 4 5,08 4,86 4,73 4,60 4,51 4,49 4,46 4,43 TABLE I (Continued - 2) Milk Condition Sample 16 17 18 19 20 23 24 IFM White Refrigerator 6 , 72 Strain 1 5,19 Strain 2 6,82 Strain 3 6,15 Strain 4 5,02 4,94 4,81 4,73 4,69 Environment White 4,35 Strain 1 4,24 Strain 2 4,24 Strain 3 4,23 Strain 4 4, 19 4, 19 4,21 4,21 4, 19 Tropical White 3,80 Strain 1 3,79 Strain 2 3,64 Strain 3 3,64 Strain 4 4,02 3,98 3 , 99 4.00 3.99 TM White Fridge 6,62 Strain i 5,95 Strain 2 6,63 Strain 3 6,24 Strain 4 6,40 6,50 6,55 6,45 Environment White 4, 17 Strain 1 4,24 Strain 2 4,33 Strain 3 4, 13 Strain 4 4,60 4,62 4,58 4, 19 Tropical White 3,82 Strain 1 4,07 Strain 2 3,68 Strain 3 3,78 Strain 4 4 , 38 4.38 4.36 4.21 From the data in TABLE 1, it seems that both infant formula and therapeutic milk show a similar trend under refrigeration conditions, which is that there is no reduction in pH for any sample. In addition, in the milk of infant formula and in therapeutic milk a general tendency is observed, which consists in that only samples containing RA024 show any reduction of pH at room temperature. This reduction is detected initially after 8 hours of storage and, in both cases, the pH decreases to a value of 4.5 after 11 hours. In tropical conditions: Infant formula: The pH shows an initial reduction after 3 hours in all samples, except the blank. After 5 hours, the two samples containing R2.024 have reached a pH of 4. After 7 hours, the sample containing MY087 has only reached a pH of 4. After 11 hours, the blank itself has shown a reduction at a pH of 4.5. Therapeutic milk: All samples containing the probiotic show a reduction in pH after 2 hours. All the samples seem to act in a similar way. All reached a pH of 4.5 after 5 hours, except for the white, which reached a pH of 4.5 after 11 hours. In this TABLE, it seems that tropical conditions are the optimal conditions to induce the reduction of pH, that is, the growth of the crop that produces yogurt. The best crop is probably MA016 or RA024. Both induce a rapid reduction of pH in the two milks tested.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (6)

1. Having described the invention as above, property is claimed as contained in the following claims: • Raapiispte of a? Tp-re.rr? _d? _ata --- C-,? Ara_t? Jgdü-_a_fo tpc_qje a_? T. { ta? a semi-permeable membrane that allows the preparation of substantially sterile aqueous solutions using an osmotically directed filtration, containing a carbohydrate, a starter culture forming fermented milk products, milk powder and, occasionally, other edible solutes,
2. 2. Self-rehydrating container according to claim 1, characterized in that the carbohydrate is selected from the group consisting of lactose, sucrose and dextrose and, preferably, is lactose.
3. 3. Self-rehydration container according to claim 1 or 2, characterized in that the container is divided into two compartments separated by a non-permanent closure, a water-impermeable compartment containing a starter culture forming fermented milk products, milk powder and , occasionally, other edible materials, and containing a second osmotically active compartment a carbohydrate and, occasionally, other osmotically active solutes.
4. 4. Self-rehydration vessel according to claim 3, characterized in that the water-impermeable compartment is also substantially impermeable to oxygen.
5. 5. Yogurt production method, characterized in that it comprises the steps of: a) submerging in water a self-rehydration vessel comprising a semi-permeable membrane and containing a carbohydrate, a yogurt-forming starter culture, milk powder and, occasionally, , other solutes; b) leave the container submerged until the filtered water has reached a sufficient level; and c) optionally, maintaining the bag at a temperature above 25 ° C for a sufficient additional period to allow the fermented milk product to be formed.
6. 6. Process for the production of yogurt using a self-rehydration container according to one of claims 3 or 4, characterized in that it comprises; a) immerse the container in water, b) leave the container submerged until the filtered water has reached a sufficient level, c) break the non-permanent seal separating the two compartments, d) let the waterproof compartment fill with the sterile water of the other compartment, e) allow the starter culture and milk powder to dissolve, f) keep the container at a temperature higher than 25 ° C and allow the fermented milk product to be formed. Fermented milk product obtained using a process according to one of claims 5 or 6.