MXPA05008244A - Biological sensor - Google Patents

Abstract

The invention concerns a portable self-contained biological sensor for detecting the presence of a biological agent such as a bacterium, virus, protozoa or toxins in a sample. Said sensor comprises in one common body (2) means for sampling (8) a sample of the medium, whether solid, liquid or gaseous, means for biological culture or amplification (4) of said sample, detection means (5) inducing a reaction for example on an impregnated reagent strip (12), said reaction being either colorimetric and visible to the naked eye through a transparent eyepiece (9), or detectable by an independent system. The sampling means (8) comprises a plug (3) capable of being screwed or nested on the biological sensor body (2) and a joint (15) providing sealing conditions and the culture medium (11) is comprised in a breakable cartridge (10) so as to enable the sample to be contacted with said culture medium (11). The invention is useful for detecting Bacillus anthracis.

Description

YOGURT WITH BIMODAL STRUCTURE AND PREPARATION PROCEDURE DESCRIPTIVE MEMORY The present invention relates to a yogurt of bimodal structure, in which a flavored preparation, such as a chocolate preparation, can be incorporated. The invention also relates to a method of manufacturing such yogurt. The dairy specialties flavored with the so-called warm aromas are generally very appreciated by consumers. Examples of hot aromas include chocolate, cocoa, caramel, vanilla, coffee, chocolate with pralines, nougat, honey, aromas of oleaginous fruits, such as, especially, walnuts, Hazelnut, almond, pistachio, and spice aromas, such as especially cinnamon, coriander, curry. For example, Danette products, marketed by the Danone group, are dairy specialties with warm aromas that are highly appreciated by consumers. These specialties are non-fermented dairy products, which present pH values generally between 6 and 7. Tests of commercialization of yogurts with such warm aromas, such as chocolate yogurts, have never been fruitful. Indeed, a chocolate yogurt tested before a panel of consumers is attributed a low overall satisfaction rating. This lack of consumer satisfaction can be explained in particular by the organoleptic incompatibility between fermented milk products, such as yoghurts, and warm aromas, especially chocolate aromas. Indeed, at the time of the manufacturing process of a fermented milk product, especially of a yogurt, the fermentation step involves the production, within the milk mass, of lactic acid. The presence of lactic acid in the milk mass decreases the pH values of the latter. In the particular case of a yoghurt, the pH is then lowered to values between 4 and 5. However, in the acidic medium, chocolate and cocoa have a bitter taste and false flavors, such as fermented aromatic notes. Thus, the use of warm aromas to flavor fermented dairy products, such as yoghurts or fresh cheeses, which have pH values between 4 and 5, is limited by the fact of the presence of a past taste and a strong acidity, which denaturalize the true flavor of the aromas used. In the manufacturing processes of fresh cheeses, it is known to incorporate fat, especially cream, into a lean pasta that has already undergone at least one fermentation step. This method of incorporating the cream into the fermented dough allows it to be fortified with fat to a desired value, under a nutritional and sensory plan. In contrast, a procedure, characterized by the incorporation of a sweetened or unsweetened cream, homogenized or not homogenized, in a fermented dough, is not used in the manufacturing processes of a yoghurt, due to the complexity of the process and / or for economic or traditional reasons of the manufacture of a yoghurt. In the classic yogurt manufacturing process, a unique blend is made by mixing all the dairy ingredients of the future yogurt and, finally, the ingredients such as sugar. Then, this unique mixture is homogenized, pasteurized, sown with the specific thermophilic lactic ferments, Streptococcus thermophilus and Lactobacillus delbruekii bulgaricus, and fermented. After cooling, the white dough obtained is packaged directly, alone or after mixing with a fruit or aromatic preparation. In such a method of manufacturing a yoghurt, the fermentation step, in the course of which the entire protein network is formed, constituted by the aggregation of the proteins present in the milk mass, is carried out in the presence of blood globules. fat of reduced size and homogeneous. The latter participate therefore, in an integral and intimate way in the construction of a mixed network of Proteinaceous Matter - Fatty Matter, that is, a dense mixed network with the important intertwining of the fat globules in the protein network. A yoghurt of monomodal structure is observed, that is to say, whose fat globules have diameters distributed around a prevailing average value. Advantageously, if the distribution of the diameters of the fat globules is represented on a graph that represents the volume occupied by the particles, expressed as a percentage with respect to the total volume, as a function of the Neperian logarithm of the diameter of the fat globules, a Gaussian type distribution is observed around a mean value (see Figures 2A-2B). In conclusion, a homogeneity of protein and lipid phases is observed (see Figure 4). Surprisingly, the Applicant has developed a yogurt of bimodal structure, whose acidity perceived in the mouth is considerably reduced. In the same way, the Applicant has discovered an original procedure for manufacturing a yoghurt with a bimodal structure. In a totally surprising way, the Applicant has discovered that yoghurt having a bimodal structure is perceived in the mouth as being less acidic than a product that comes from the fermentation of a single blend. Said yogurt can thus be associated with a preparation containing a warm aroma, especially a chocolate preparation or a vanilla preparation with chocolate chips. The products thus obtained are appreciated and well qualified by consumers. In the sense of the present invention, yoghurt means a coagulated milk product, obtained by lactic fermentation, thanks to the action of thermophilic microorganisms, which come from cultures of Streptococcus thermophilus and Lactobacillus delbruekii bulgaricus, from milk and milk products . It is the presence of these two bacterial strains that characterizes the denomination of yogurt. These microorganisms specific must be viable, in an amount of at least 107 U.F.C./g on the date of consumption, the abbreviations U.F.C mean Colonia Formation Unit. Lactic fermentation involves a reduction in pH and coagulation. Dairy products are selected from the group consisting of pasteurized milk, concentrated milk, partially skimmed milk, pasteurized milk, partially skimmed milk, concentrated milk, skimmed milk, pasteurized milk, concentrated skimmed milk, pasteurized cream, light pasteurized cream, and mixtures thereof. The yoghurt according to the invention can additionally optionally be added with dairy raw materials or other ingredients, such as sugar or sweetening materials, one or more flavors, fruits, cereals, or nutritional substances, especially vitamins, minerals and fibers. The milk raw materials are chosen from the group consisting of milk powder, skimmed milk powder, non-fermented cow's milk whey, partially or fully dehydrated liquid cow's milk whey, concentrated whey, whey powder, lactic acid proteins, concentrated lactic proteins, water-soluble milk proteins, preparations based on milk proteins containing a minimum of 34% of total nitrogenous matter, food casein, caseinates made from pasteurized products. For sugar or sweetening matter, for the purposes of the present invention, any sweetening carbohydrate is understood.

By extension, we can also call as yoghurt, in the sense of the present invention, the products that comprise, in addition to the lactic bacteria, other than the microorganisms Streptococcus thermophilus and Lactobacillus delbruekii bulgaricus, and especially the microorganisms that come from strains of Bifidobacterium and / o of Lactobacillus acidophilus and / or of Lactobacillus casei. These additional lactic strains are intended to confer on the finished product various properties, such as the property of favoring the balance of the flora. In the finished product, the microorganisms must be in a viable state. Such a yoghurt responds thus to the specifications of fermented milks and yoghurts of the standard AFNOR NF 04-600 and of the standard norm StanA-11a-1975. The AFNOR NF 04-600 standard specifies, among other things, that the product should not be heated after fermentation. In addition, in a yoghurt, dairy products and dairy raw materials must represent at least 70% (m / m) of the finished product. A) Yes, the present invention relates to a yogurt, characterized in that it has a bimodal structure, that is to say, where the diameters of the fat globules are distributed around two predominant values. In a totally surprising way, it is observed, in the product according to the invention, on the one hand, the fat globules connected to a mixed network of Protein Matter - Fatty Matter, formed in the fermentation stage, and on the other hand, the aggregates of fat globules free, that is, not connected to the network of Proteic Matter - Fat Matter (see Figure 5). Thus, the yogurt according to the invention is characterized by its bimodal structure comprising, on the one hand, the free fat globules, having a particle diameter comprised between 0.05 and 3 μm, advantageously between 0.31 and 0.42 μm , even more advantageously, between 0.33 and 0.39 μm, and on the other hand, the fat globules connected to the protein network, which have a particle diameter comprised between 10 and 140 μm, advantageously between 41 and 76 μm , even more advantageously, between 48 and 65 μm (see Figures 3A-3B). In comparison, a yogurt of the prior art has a monomodal structure, in which the fat globules are connected to the protein network and have a particle diameter between 10 and 140 μm, advantageously between 41 and 76 μm, even more advantageously between 48 and 65 μm. The Sauter diameter of the yogurt according to the invention is typically two to four times greater than that of a homogenized cream used in the process according to the invention and at least twenty times less than that of a yogurt of monomodal structure, advantageously, to that of the yogurt of monomodal structure used in the process according to the invention. Still more advantageously, the Sauter diameter of the yogurt according to the invention is characteristically at least forty times lower than that of the yogurt of monomodal structure, used in the process according to the invention. The value D (, o.9) of the yoghurt according to the invention is typically at least forty times, advantageously at least sixty times, even more advantageously, at least seventy times higher than that of a homogenized cream, used in the process according to the invention. The D (, o.9) value of the yogurt according to the invention characteristically is 0.9 to 1 time that of the yogurt of monomodal structure used in the process according to the invention. In a particular embodiment of the invention, the yogurt according to the invention is characterized by a diameter of Sauter D (3,2) comprised between 0.70 μm and 1.00 μm, advantageously between 0.78 μm and 0.90 μm, and a value D (V> o.9) between 70.00 μm and 80.00 μm, advantageously between 74.00 μm and 75 μm. In comparison, a yogurt of the prior art, of monomodal structure, is characterized by a diameter of Sauter D (3,2) comprised between 45.00 μm and 46.00 μm, and a D (y, o.9) value comprised between 75.00 μm and 76.50 μm. The diameter of Sauter D (3,2) is the weighted average diameter of the fat globules on the surface. It is defined as the average of the relationship between the equivalent diameter of the volume dv, and the equivalent diameter of the surface, ds: D (3,2) = S Edv3 / Eds2 The equivalent diameter is the diameter that the particle would have if it were spherical, thus, dv is the equivalent diameter of the volume and ds the equivalent diameter of the surface. So dv (6Vp / p), / 2 ds (Ap / p) 1/2 with Vp the volume of the particle and Ap the surface of the particle. The value D (v, o.9) represents the value of the particle size for which the distribution of the particles is such that exactly 90% of the particles in the sample (v / v) have a smaller or equal size. In a particular embodiment of the invention, a diameter of Sauter D (3,2) comprised between 0.78 μm and 0.90 μm and a D value (v, o.9) comprised between 74.00 μm and 75.00 μm, are the advantageous characteristics of yogurt according to the invention. A diameter of Sauter D (3,2) at least three times greater than that of a homogenized cream, used in the process according to the invention, and at least forty times lower than that of yoghurt of monomodal structure, used in the process according to the invention, it is an advantageous feature of the yogurt according to the invention. A D value (v, o.9) at least sixty times higher than that of a homogenized cream, used in the procedure according to the invention, and 0.95 to 1 time equal to that of the monomodal structure yoghurt, used in the process according to the invention, is an advantageous feature of the yoghurt according to the invention. The values of the diameter of the fat globules are determined, preferably, with the aid of a laser granulometry method. In the granulometry method, an apparatus is advantageously used, the MASTERSIZER S (MSS) (Malvern), Helium-Neon laser light source, with a 300 mm focal lens. The measured samples are previously homogenized and then diluted in sodium dodecyl sulfate, 1% SDS. When adsorbed on the hydrophobic parts of the casein micelles and the serum proteins, the SDS causes its deagglomeration by electrostatic repulsion. The addition of SDS makes it possible to avoid the agglomeration of proteins, in particular those that stabilize the fat. It provides an accurate image of the size of the droplets of fat, freeing them from their agglomeration. This technique allows to evaluate the diameter of Sauter D (3,2) of the particles and calculate the value D (V? 0.9). Advantageously, the yogurt is characterized in that it is perceived, in the mouth, by the consumers, as being less acidic than a classic yoghurt, of monomodal structure. The sensory profile serves to create an organoleptic identity card of the product according to the invention. It is the description of a product, with a set of standardized descriptors, by a group of people trained to quantify these descriptors on a scale of evaluation. This group of educated people is the sensory jury. The sensory jury is composed of people recruited with the help of recruitment tests, based on sensory aptitudes, verbal expression, behavior. They are trained for 6 months to describe the products with standardized language and to use a rating scale. At the end of the instruction, they must reach a certain performance, they must be repeatable and discriminating and the judgments must be by consensus. The tests that will be carried out will first be "sequential monastics", that is to say, that no comparison is made, after the comparative tests, between a yogurt of the same composition, of monomodal structure and a yogurt according to the invention. The sensory jury is composed of 15 people, who taste the same product twice following a specific experience plan, none will taste the same product first. Each person on the jury will report their choices on a computer. The data will be treated statistically, by means of an Anova test. Since, on the other hand, everything remains the same, namely the protein content, the fat content, the carbohydrate content, the pH and the Dornic acidity, the yogurt according to the invention is perceived in the mouth as which is less acidic than a classic yogurt. We assume that the difference in the organoleptic perception of the yogurt according to the invention is due to the presence of free fat globules of very small diameter, comprised between 0.05 and 3 μm, which they must have a masking effect on the mouth, on the acidity of the yogurt. The free fat globules should have a coating effect on the mouth and may thus mask the acidity of the yogurt according to the invention. We assume that said free fat globules, of small size, thus mechanically reduce the perception of acidity, of the product according to the invention, by the sensory receptors. In conclusion, this very different organoleptic perception is really due to the granulometric profile of the product, different from that of a classic yogurt. According to an advantageous variant of the invention, a flavored preparation is incorporated into the yoghurt. Advantageously, this flavored preparation is a chocolate preparation or a vanilla preparation with chocolate chips. In the sense of the present inventionBy aromatized preparation is meant any preparation that can be used conventionally for perfuming a yoghurt or a product derived from dairy products. Said preparation may contain, especially one or more flavors, such as warm, fruit flavors, especially of fresh and / or preserved fruits and / or frozen and / or powder and / or fruit purée and / or fruit pulp. and / or fruit syrup and / or fruit juice, cereals, or nutritional substances, especially vitamins, minerals and fibers. Examples of hot aromas include chocolate, cocoa, caramel, vanilla, coffee, chocolate with pralines, nougat, honey, aromas of oleaginous fruits, especially like walnuts, hazelnuts, almonds, pistachios, and aromas of spices, especially cinnamon, cilantro, curry. The original granulometric profile of the yogurt according to the invention modifies the organoleptic perception of the latter, which is now perceived as being less acidic. The incorporation of an aroma of the so-called warm in such yogurt, allows to obtain a tasty yogurt, which does not perceive the bitterness and false tastes that usually present warm aromas, especially chocolate and cocoa, in an acid medium. The yogurt according to the invention may further comprise food additives. The use of these additives must be in accordance with the regulations in force. These additives can be sweeteners and / or flavoring agents and / or colorants and / or preservatives, conventionally used by the person skilled in the art, in the context of the manufacture of foodstuffs, and especially in the context of the production of foodstuffs. yoghurts This list is not limiting, other food additives may be used, but under two conditions: they should not be placed directly on dairy compounds and will only be provided by the added ingredients. The subject of the present invention is also a process for the preparation of a yogurt such as that described above, characterized in that it comprises the following steps: a) production of a yoghurt according to a conventional method of the art; b) manufacture of a homogenized cream; c) mixing the yoghurt dough with the homogenized cream; d) obtaining a yogurt with a bimodal structure. Advantageously, step a) of manufacturing a yoghurt comprises at least one step of lactic fermentation. Advantageously, step a) of manufacturing a yoghurt comprises at least one stirring step. Advantageously, the homogenized cream added in step c) is sweetened. The proportions of homogenized cream to be added depend on the nature and content of the fat of the cream used in the manufacturing process, as well as on the nature and content of the fat of the yoghurt dough used in the manufacturing process . The person skilled in the art, in light of his classical knowledge, is perfectly capable of determining the minimum quantities of homogenized cream to be added, to modify the organoleptic perception of the final product, and the maximum amounts of homogenized cream to be added, in order to preserve the yogurt denomination. In an advantageous embodiment of the invention, the proportions of cream added to the yoghurt dough are comprised between 7 and 14% (m / m) of homogenized cream, with respect to the total weight of the finished product, and advantageously, between 9 and 9. and 12% (m / m) of homogenized cream, with respect to the total weight of the finished product. He final product comprises at least 70% (m / m) of dairy products and dairy raw materials, to be able to benefit especially from the denomination of yogurt, the amount, by weight, of the yogurt dough in the finished product is at least 56% (m / m), with respect to the total weight of the finished product. In the sense of the present invention, a homogenised cream is understood as a cream, which comes from milk, prepatenturized, which has been subjected to a heat treatment and homogenization. Advantageously, this cream can be sweetened. The cream can be sweetened by any sweetening material, namely, any sweetening carbohydrate, conventionally used by the person skilled in the art. As an example of the sweetening matter, sugar beet sugar or white sugar, cane sugar or red sugar and sweeteners such as aspartame, saccharin, cyclamate, acesulfame K and thaumatin can be mentioned. . Homogenization is a process well known to the person skilled in the art, which makes it possible to produce fat globules, whose diameters have, in a narrow spectrum, a low average, of the order of 0.1 to 1.0 μm, and a deviation of the scarce type. The homogenization operation is carried out at a temperature higher than 60 ° C, in a homogenizer, an apparatus that allows to project milk under strong pressure, of the order of 150 to 350 kg / cm2, in a duct, at the end of which a conical valve is applied, especially agate or of steel. The cream, when opening a passage between the latter and its seat, is laminated and the physicochemical structure of the globular membrane is modified. The homogenization is in a single or double stage. Yogurt dough is produced according to a method known in the art. Illustratively, step a) of manufacturing a yoghurt, according to a classical process of the art, comprises the following steps: i) mixing of prepacked or concentrated and standardized milk; ii) heat treatment after homogenization of the mixture obtained after step i); iii) cooling the mixture to the fermentation temperature, then sowing the mixture with the thermophilic lactic ferments specific for Lactobacillus Bulgaricus and Streptococcus Thermophilus; iv) cooling to a temperature between 15 and 25 ° C; v) storage. According to an advantageous embodiment of the invention, the prepasteurized or concentrated and standardized milk is mixed, at the time of step i), with a mixture of proteins, advantageously, caseinates and serum proteins, and optionally with a sweetening material. Advantageously, the protein mixture and the sweetening material are in the form of powders. The prepasteurization corresponds, in the sense of the present invention, to a thermal treatment of raw milk, 7 in order to destroy the pathogens and reduce the total flora. According to a conventional procedure, the prepasteurization is carried out at a temperature comprised between 70 and 80 ° C, advantageously at a temperature of about 72 ° C, for about 30 seconds. The standardization of the fat and protein materials of milk, corresponds to an elaboration of a milk mixture, gathering the dairy raw materials to obtain a precise content of proteins and fat. In a conventional manner, the thermal treatment, at the time of step ii), takes place at a temperature comprised between 80 and 100 ° C. Eventually, step iii) of fermentation further comprises the addition of other lactic acid bacteria, such as strains of Bifidobacterium and / or Lactobacillus acidophilus and / or Lactobacillus casei. The fermentation temperature is advantageously between 30 and 50 ° C, more advantageously between 35 and 45 ° C, and even more advantageously between 37 and 41 ° C. The product put to ferment is cooled, as soon as it reaches the desired acidity, at a temperature comprised between 15 and 25 ° C, advantageously, at a temperature comprised between 18 and 22 ° C. Advantageously, the acidity considered corresponds to pH values between 4 and 5, more advantageously between 4.2 and 4.8. The yogurt thus obtained is then stored in a storage tank, advantageously at a temperature comprised between 15 and 25 ° C, even more advantageously at a temperature between 18 and 22 ° C. The homogenized cream is produced according to a method known in the art. Illustratively, step b) of manufacturing a homogenized sweetened cream, according to a classical process of the art, comprises the following steps: i) mixing a prepatenturized cream; ii) heat treatment after homogenization; Ii) sterilization; iv) cooling, then storage. Advantageously, at the time of step i), a sweetening material is incorporated into the prepatenturized cream. In the sense of the present invention, the term "sweetening matter" is understood to mean any material commonly used by the person skilled in the art to provide a sweet taste to food products. As examples of sweetening substances, sugar beet sugar or white sugar, sugar cane or red sugar, sweeteners such as aspartame, saccharin, cyclamate, acesulfame K and thaumatin can be mentioned. The homogenization stage allows to produce fat globules whose diameters have a low average, of the order of 0.1 to 1.0 μm, and a deviation of the scarce type, that is, a narrow spectrum. The sterilization is advantageously carried out at a temperature above 100 ° C for a fairly short time. By way of advantageous, the sterilization time is between 10 and 30 seconds. The cream is then cooled to a temperature comprised, advantageously, between 5 and 15 ° C, more advantageously at a temperature comprised between 6 and 10 ° C. The cream thus obtained is then stored in a storage tank, advantageously at a temperature comprised between 5 and 15 ° C, even more advantageously at a temperature comprised between 6 and 10 ° C. According to an advantageous variant of the invention, the mixing step c) first comprises a stage of incorporation in line or in vat (in batches) of the homogenized sweetened cream, in the yoghurt dough, after a mixing step of the homogenised sweetened cream and the yogurt dough, online, in a static or dynamic mixer or in a tank. Advantageously, the mixing step of the homogenized sweetened cream and the yogurt dough takes place in a static mixer. According to another advantageous variant of the invention, the preparation process further comprises a step e) of incorporation of a flavored preparation in yoghurt of bimodal structure. The proportions of the flavored preparation to be added depend on the nature of the flavored preparation used, especially on its concentration of the aroma and the aroma used, as well as of nature, particularly taste, of the final product considered. The person skilled in the art, in the light of classical knowledge, is perfectly capable of determining the minimum and maximum quantities of the flavored preparation to be added. In an advantageous embodiment of the invention, the proportions of the flavored preparation added in yoghurt of bimodal structure are comprised between 10 and 18% (m / m) and advantageously between 12 and 16% (m / m), of the flavored preparation, with respect to the total amount of the finished product. For the purposes of the present invention, the term aromatized preparation means any preparation which can be used conventionally for perfuming a yoghurt or a derivative product of dairy products. Said preparation can therefore contain, in particular, one or more flavors, such as warm aromas, fruit, cereals or nutritional substances, especially vitamins, minerals and fibers. Examples of hot aromas include chocolate, cocoa, caramel, vanilla, coffee, chocolate with pralines, nougat, honey, aromas of oleaginous fruits, especially nut, hazelnut. , the almond, the pistache, and aromas of spices, especially like cinnamon, cilantro, curry. Advantageously, in the preparation process according to the present invention, the flavored preparation is incorporated in line or in vat (in batches) in the yoghurt of bimodal structure, after mixing in tank or in line by means of a static or dynamic mixer, even more advantageously, by means of a dynamic mixer. In a particularly advantageous manner, the flavored preparation incorporated is a chocolate preparation or a vanilla preparation with chocolate chips. According to another advantageous variant of the invention, the preparation process further comprises a stage f) of packaging, after cooling, and finally of storage. Advantageously, the yogurt according to the invention is cooled after packaging at a temperature between 2 and 6 ° C. The yogurt according to the invention thus obtained can also be stored in a storage tank, advantageously, at a temperature comprised between 5 and 22 ° C, before being packaged after cooling at a temperature comprised between 2 and 6 ° C. The subject of the present invention is also a yogurt which can be obtained by the process such as that described above, characterized in that it has a bimodal structure.

Description of the Figures Figures 1A-1B illustrate the granulometric distribution of the fat globules in a homogenized sweetened cream (experiments 1 and 2). A monomodal distribution is observed.

Figures 2A-2B illustrate the granulometric distribution of the fat globules in a classic yoghurt (experiments 1 and 2). A monomodal distribution is observed. Figures 3A-3B illustrate the granulometric distribution of the fat globules in a yoghurt according to the invention (experiments 1 and 2). A bimodal distribution is observed. Figure 4 represents a microscopic observation of a yoghurt of monomodal structure, obtained by a classical procedure, with 6% fat. Figure 5 represents a microscopic observation of a yogurt obtained by the method of the invention, from a yoghurt dough with 3.7% fat and a sweetened cream homogenized with 20% fat. The following examples illustrate the invention, however, without limiting it.

EXAMPLE 1 Formula of a chocolate yogurt according to the invention Formula of a chocolate yogurt according to the invention: Yogurt dough 75.5% m / m Homogenised sweetened cream 10.5% m / m Chocolate preparation 14% m / m The yogurt mass is composed of 3.7% m / m of fat, a total protein content of 4.23% m / m and comprises 7.2% m / m of sucrose, mixed with the homogenized sweetened cream composed of 20% m / m of fat and 15% m / m of sucrose. This product is composed of 6.4% m / m of fat, 3.6% m / m in total of proteins and 15.5% m / m of carbohydrates, with 7% m / m of sucrose. The sum of the non-dairy and non-fermented dairy ingredients in the finished product is less than 30% by mass. This product respects the legal restrictions of the denomination of yogurt.

EXAMPLE 2 Method of preparing a yoghurt with chocolate according to the invention a) manufacture of the yoghurt dough A preparation based on milk and milk products is preheated to 81 ° C, degassed, then cooled to 89 ° C. It is then homogenized under hot conditions and under a pressure of 250 bars. At the exit of the homogenizer, the preparation must be at a temperature of 95 ° C. Following the homogenization step, the preparation is pasteurized for 8 minutes at 95 ° C, then placed at room temperature. The preparation is then cooled to a temperature of 4 ° C.

Then, the preparation is sown with the thermophilic lactic ferments, at least with the lactic ferments that come from strains of Streptococcus thermophilus and Lactobacillus delbruekii bulgaricus, and heated up to 39 ° C. The preparation is left to ferment. When the yogurt dough has been sufficiently fermented, that is, when it reaches an acidity corresponding to a pH value of about 4.65, it is passed over a 0.5 mm filter, then cooled to a temperature of 20 ° C. Depending on the desired characteristics of the final product, the person skilled in the art knows the parameters of the procedure to be modified. b) manufacture of the homogenized cream The skim milk is sweetened and mixed with a cream with 400 g / l of fat. This preparation is filtered on a 0.5 mm filter. Subsequently, it is preheated to 95 ° C, then it is placed at room temperature for 6 minutes before being homogenized under a total pressure of 205 bars. After the homogenization step, the preparation is pasteurized at a temperature of 118 ° C, then cooled to 6 ° C. Depending on the desired characteristics of the final product, the person skilled in the art knows the parameters of the procedure to be modified. c) mixing the yoghurt dough with the sweetened homogenised cream and incorporating the preparation with chocolate. 10.5% homogenized cream sweetened in 75.5% yogurt dough is incorporated in a static mixer. Then, in a dynamic mixer, 14% by mass of a vanilla preparation with chocolate chips is incorporated. The percentages are expressed in mass, with respect to the total mass of the finished product. The yogurt is packaged and stored in a cold room.

EXAMPLE 3 Measurement of the granulometric distribution of fat globules a) Products tested The particle size distribution of the fat globules in the following products is measured: - a homogenised sweetened cream; - a yogurt obtained by the classical process (classical yogurt) - a yogurt obtained by the process of the invention, in which the fat was added after the fermentation step. b) Measurement method In order to determine the structure of the products, laser granulometry methods were used. In the method of granulometry, an apparatus was used, the MASTERSIZER S (MSS) (Malvern), Helium-Neon laser source, with a 300 mm focal lens. The measured samples were previously homogenized and then diluted in 1% SDS. When adsorbed on the hydrophobic parts of the casein micelles and the serum proteins, the SDS causes its deagglomeration by electrostatic repulsion. The addition of SDS makes it possible to avoid the agglomeration of proteins, in particular those that stabilize the fat. It provides an accurate picture of the size of the fat droplets, freeing them from their agglomeration. This technique allows to evaluate the diameter of Sauter D (3,2) of the particles and calculate the value D (V, o.9) - The measurement protocol of the granulometric method is as follows: 1. Start the laser 30 minutes at least, before doing the measurement (warm-up time of the device) 2. Configuration of the material: - 300 mm focal lens; - polydispersity analysis; - refractive index: water 1.33; fat 1.46; - laser alignment; - measurement of background noise. 3. Sample preparation (dilution in the presence of SDS at 1%) 4. Placement of the sample in the measurement cell, to obtain a turbidity level of 15% to 30% . Launching of the measurement: - evaluation of the size distribution of the fat globules; - diameter calculation of Sauter D (3,2) and D (v, o.9). 6. Cleaning with distilled water between each sample To ensure the reproducibility of the measurements and to get rid of the uncertainties related to handling, two measurements were made per sample. c) Results: The values obtained for the main parameters are summarized in table 1 below: TABLE 1 D (3.2) corresponds to the Sauter diameter that illustrates the average size of the fat globules. The value D (v, o.9) represents the value of the size of the particles for which a particle distribution is observed, such that Exactly 90% of the particles in the sample (v / v) have an inferior or equal size. Figures 1A-1 B illustrate the granulometric distribution of the fat globules in the homogenized sweetened cream (experiments 1 and 2). A monomodal distribution and a particle diameter of fat globules between 0.05 μm and 2.28 μm are observed. Figures 2A-2B illustrate the granulometric distribution of fat globules in classical yogurt (experiments 1 and 2). A monomodal distribution and a diameter of the particles of fat globules between 12.21 μm and 120.67 μm are observed. Figures 3A-3B illustrate the granulometric distribution of the fat globules in the yoghurt according to the invention (experiments 1 and 2). A bimodal distribution and particle diameter of the fat globules between 0.05 μm and 2.65 μm, on the one hand, and between 14.22 μm and 120.67 μm on the other hand, are observed. d) Conclusions The yoghurt according to the invention has a bimodai structure, due to the presence of small size fat globules and the presence of fat globules, of an important size, connected to the protein network.

EXAMPLE 4 Observation with the optical microscope a) Tested products The particle size distribution of the fat globules was measured in the following two products: - a yoghurt obtained by a classic procedure with 6% fat, that is, a classic yogurt of monomodal structure; - a yogurt obtained by the process of the invention, from a yoghurt dough with 3.7% fat and a sweetened cream homogenized with 20% fat. b) Measurement method The optical microscope method is based on the principle of fluorescence, and this tool allows us to observe the structure in terms of the size and distribution of the aggregates. The fat is colored by the Blue Nile dye marker. This tool allows us to observe the structure, in terms of size and distribution, of the protein aggregates in which the fat phase is included, and of the pores that contain the phase soluble, that of soluble proteins. It is observed in the microscope a yogurt of monomodal structure, obtained by a classic procedure, with 6% fat (Figure 4) and a yogurt obtained by the method of the invention, from a yoghurt dough with 3.7% fat and a sweetened cream homogenized with 20% fat (Figure 5). c) Conclusions For the samples corresponding to the yogurt of monomodal structure, we noticed a homogeneity of the protein and lipid phases. The fat globules, obtained after homogenization, of reduced size and homogeneous size, are well connected to the protein network at the time of the fermentation stage, which results in the formation of a dense mixed network, with an important interlacing of the fat globules in the protein network. The structure of the samples corresponding to the yoghurt according to the invention can be considered as very different insofar as the aggregates, a dominant fatty matter, are clearly present, with the simultaneous presence of a relatively dense protein network. In addition, the presence of isolated particles, not connected to the protein network, is clearly observed. Therefore, these observations show a difference between the structure of the samples.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. - A yogurt, which has a bimodal structure comprising fat globules connected to a mixed network of Protein - Fat Matter and free fat globules.

2. The yoghurt according to claim 1, further characterized in that the bimodal structure comprises free fat globules not connected to the mixed network of Proteinaceous Matter - Fatty Matter, with a particle diameter comprised between 0.05 and 3 μm, and fat globules connected to the mixed network Proteinaceous Matter - Fatty Matter, with a particle diameter between 10 and 140 μm.

3. The yoghurt according to claim 1 or 2, further characterized in that it comprises a flavored preparation.

4. The yoghurt according to claim 3, further characterized in that the flavored preparation is a chocolate preparation.

5. The yoghurt according to claim 4, further characterized in that the flavored preparation is a vanilla preparation with chocolate chips.

6. A process for preparing a yoghurt as claimed in any of the preceding claims, from a mass of yoghurt and a homogenized cream, said process is characterized in that it comprises a mixing step of at least 56% by weight of the yoghurt dough with 7 to 14% by weight of homogenized cream, with respect to the total weight of the finished product.

7. The preparation process according to claim 6, further characterized in that the yoghurt dough is stirred.

8. The preparation process according to claim 6, further characterized in that in the mixing step, the homogenized cream is incorporated in line or in vat in the yogurt dough, after mixing with the yogurt dough in vat or online in a static or dynamic agitator.

9. The preparation process according to any of claims 6 to 8, further characterized in that it also comprises a stage of incorporation of a flavored preparation in the bimodal structure yogurt, after the mixing step.

10. The preparation process according to claim 9, further characterized in that the flavored preparation is incorporated in line or in tub in the bimodal structure yogurt, after mixing in tank or in line by means of a static or dynamic stirrer .

11. The preparation process according to claim 9 or 10, further characterized in that the incorporated flavored preparation is a chocolate preparation or a vanilla preparation with chocolate chips.

12. - A yoghurt, which can be obtained by the process described in any of claims 6 to 11, said yoghurt characterized in that it has a bimodal structure.