A solid product comprising oil-droplets

[0001] The present invention relates to a solid product containing oil droplets as well as a method of making such a solid product and the use of such a product.

[0002] Document WO 2005/110370 relates to an oil-in-water emulsion in which oil droplets exhibit nano-size structuring with hydrophilic domains. The goal is to have hydrophyte domains in oil droplets and not a solid oil product. The same is true in US Patent No. 5,248,509 regarding an edible fat-containing product comprising an emulsion of two different fat phases. Finally, US Patent No. US-5'620'734 relates to a finished foodstuff having filling areas of the mesomorphic phase of an edible structurant, but not a solid oil product.

[0003] Solid oil based products are already known on the market. This is the case, for example, with margarine. The disadvantage of margarine is that the oil that is used to make such a product is hydrogenated, which leads to saturation of the carbon-carbon double bonds. It is now known in the field of nutritional products that such hydrogenation is better avoided and double bonds unsaturated. Keeping unsaturation in oil is good for consumers.

[0004] The object of the present invention is to prepare a solid oily product without hydrogenating the oil used.

[0005] The present invention relates to a solid product comprising oil droplets having diameters in the range of 0.1 to 100 microns, cross-linked proteins at the interface of these droplets and any polar, low-molecular relationship between the interface surfaces of the cross-linked protein, and the given low-molecular compound is selected from a group consisting of glycerol and sucrose.

[0006] In the present specification, the expression "oil droplets" means substantially spherical particles, such as polyhedral particles.

[0007] Droplet size distribution is measured by light scattering using a Malvern MasterSizer.

[0008] More preferably, the oil used is selected from the group consisting of Medium Chain Triglycerides (MCT), olive oil, sunflower oil, paraffin oil and mineral oil.

[0009] The protein used in the product according to the invention is selected from the group consisting of milk proteins and soy proteins. More preferably, β-casein and β-lactoglobulin are used in the product of the invention. Sodium caseinate may also be used.

[0010] It is also possible for the solid product according to the invention to contain glutaraldehyde or transglutaminase. It is not preferred to carry out the invention.

[0011] The amount of oil is between 90 and 100%. In the description of the invention, all% is given as weight%. The protein bone is between 0.1 and 5%. The amount of low molecular interstitial compound is up to 2%.

EP 1 998 627 Β1 [0012] Further, the present invention relates to a method for producing the above-described solid oil product in which • oil is dispersed in a protein solution to obtain an emulsion, • the emulsion is homogenized and washed with water • glutaraidehyde or transglutaminase is added, or the concentrated emulsion is heated, and • a polar, low molecular interstitial compound is added, and this low molecular compound is selected from the group consisting of glycerol and sucrose.

[0013] According to a preferred embodiment of the invention, the emulsion is heated at a temperature of about 80 ° C for about between 10 and 60 minutes, without the presence of enzymatic or chemical crosslinking agents.

[0014] According to a second embodiment of the invention, the emulsion is poured into the same volume of a 1% by weight aqueous solution of glutaraidehyde, left for some time and washed to separate unreacted glutaraidehyde.

[0015] According to a third embodiment of the invention, the emulsion is poured into the same volume of 1 unit / g transglutaminase.

[0016] Furthermore, the present invention relates to the use of a solid oily product as described above, wherein the given solid oily product is used as an inclusion or matrix in food products for introducing non-hydrogenated solidified oil. The amount of solid oily product added to a food product can vary widely. For example, the amount may be between 0.1 and 99%. It is not critical for the type of food to which the solid product is to be added. For example, it can be added to any type of culinary products.

[0017] According to another feature of the present invention, the product of the invention is used in cosmetic products as a solid encapsulating matrix for lipophilic compounds. In this case, the amount of product used may also vary widely. This amount can vary between 0.1 and 99%.

[0018] According to a further feature of the invention, the use of a solid oily product can take advantage of its low viscosity lubrication properties.

[0019] The product of the present invention may be either re-emulsifiable (which is a good method for use in the field of culinary products) or not re-emulsifiable (which is a good way for use in the field of cosmetic and lubricating products) .

[0020] Finally, the present invention also relates to a method for obtaining a solid oil in a composition of heterogeneous cells, wherein the given solid oil is produced according to the method described above by mixing two different oil emulsions.

[0021] The following description refers to the figures provided.

[0022] Figure 1 shows the internal structure of a gel formed from a mono-dispersed emulsion made with droplets with a diameter of 80 pm, as shown by a confocal microscope. To illustrate the protein phase, rhodamine was added at a concentration of 10-¹⁰ M, to the aqueous phase buffered to pH = 7.0 used in the final washing step.

ΕΡ 1 998 627 Β1 [0023] Figure 2 shows the rehydration of a thermally cross-linked paraffin oil based gel with R = 0.5 pm. The white squares show the ray distribution of the emulsion droplets formed after cross-linking. The black squares show the radiation distribution of the droplets of the emulsion obtained after rehydrating the dried gel with 20 mM imidazole, buffer pH = 7.0. This figure shows that the method is completely reversible, the droplet size remains the same as in the initial emulsion.

[0024] The polar, low molecular compound is detected by re-emulsifying the solid product in water and analyzing the composition of the water containing the given polar, low molecular compound. [0025] In the following, the description of the invention refers to examples.

Example 1: Preparation of an emulsion [0026] A coarse oil-in-water emulsion was prepared in which the dispersed phase has a diameter of = 0.5 pm by gradually pouring, under continuous stirring, an MCT up to a pH of 7.0, a 1% by weight protein solution. The protein solution can be buffered (20 mM imidazole solution, non-food method), or the pH can be adjusted to 7.0 with sodium hydroxide (food method).

[0027] Coarse emulsions are homogenized for 300 seconds in a rotary dispersion device, or, for smaller droplets, in a high-pressure homogenizer. Shear rate / pressure determines the average droplet size of the emulsion and, consequently, the average cell size. [0028] The emulsion was left for about 1 hour for complete protein adsorption. The emulsion was then washed, i.e. the non-absorbed protein in solution was removed by dilution. This was achieved by leaving the creaming emulsion in a decanting flask, or, for finer emulsions, by centrifugation. The aqueous phase was removed and the concentrated emulsion was again diluted with water about 5 times volume (food method), or pH = 7.0 with 20mM imidazole buffer. This step was repeated twice, resulting in a two-fold dilution of non-absorbed protein in a continuous phase. The above-mentioned irreversibility of protein adsorption allows obtaining stable emulsions with a very small amount of non-adsorbed proteins. Non-adsorbed protein can be reused. Example 2: Preparation of a gel with glutaraldehyde [0029] The adsorbed protein molecules were cross-linked to ensure the stability of the protein layer during subsequent removal of the continuous phase. Cross-linking of the adsorbed protein was obtained chemically with glutaraldehyde to obtain non-food material.

[0030] The concentrated washed emulsion was poured into the same volume of a 1% by weight solution of glutaraldehyde buffered to pH = 7.0 to ensure crosslinking of adsorbed protein molecules, avoiding crosslinking between molecules. The diluted emulsion was left for 5 minutes with gentle stirring. The cross-linked emulsion was washed to separate unreacted glutaraldehyde in a similar manner as in Step 3 above to obtain a concentrated emulsion with the cross-linked inter-surface protein. This method gives the non-food material. [0031] Glycerol, or D (+) - sucrose, was added to the cremated, concentrated emulsions up to a concentration of 0.5% by weight, with gentle mixing. The concentrated emulsion was cast into a receiver with a high width-to-height ratio, and allowed to dry for 72 hours, ventilated at room temperature, to obtain a transparent lipid gel.

[0032] The measurement of oil droplets on the Malvern MasterSizer gave a diameter of 80 microns.

ΕΡ 1 998 627 Β1

Example 3: Preparation of a gel with transglutaminase (Tgase) [0033] Another method of cross-linking proteins with Tgase. The concentrated washed emulsion was poured into the same volume of 1 U / g Tgase solution and left for 1 hour minutes, with gentle stirring. Then, the emulsion was washed to separate non-adsorbed Tgase and Tgase excipients, in a similar manner to step 3 above, and left diluted at 55 ° C for about 10 hours. As a protein, Tgase competitively and irreversibly adsorbs on the oil-water interface. The washing step ensures that there is no large pH shift during a 10 hour period at 55 ° C. This method gives food material.

[0034] Glycerol, or D (+) - sucrose, was added to the cremated, concentrated emulsions up to a concentration of 0.5% by weight, with gentle stirring. The concentrated emulsion was cast into a receiver with a high width-to-height ratio, and allowed to dry for 72 hours, ventilated at room temperature, to obtain a transparent lipid gel.

[0035] The measurement of oil droplets on the Malvern MasterSizer gave a diameter of 80 microns.

Example 4: Preparation of a gel by heating [0036] Another way to cross-link proteins is to heat the emulsion.

[0037] The concentrated washed emulsion was heated at 80 ° C in an oven and held at that temperature for 1 hour. This method gives food material.

[0038] Glycerol, or D (+) - sucrose, was added to the cremated, concentrated emulsions up to a concentration of 0.5% by weight, with gentle stirring. The concentrated emulsion was cast into a receiver with a high width-to-height ratio, and allowed to dry for 72 hours, ventilated at room temperature, to obtain a transparent lipid gel.

[0039] The measurement of oil droplets on the Malvern MasterSizer gave a diameter of 80 microns.