MXPA06006065A - Shelf stable homogeneous suspension - Google Patents

Abstract

Protein-containing suspensions such as milk that are preserved by a UHT treatment, show age gelation. This age gelation can be reduced by inclusion of an emulsifier with an HLB value below 16.

Description

HOMOGENEOUS SUSPENSION WILL NOT PERISH Field of the Invention The invention relates to homogeneous non-perishable suspensions, especially for milk beverages.

Background of the Invention The sterilization of milk and other suspensions containing protein, such as by ultra high temperature treatment, creates a microbially stable product at room temperature for several months. This preservation technique is used especially for drinks such as milk. In general terms, sterilization, such as treatment at ultra high temperature (UHT), el-eva milk temperature to more than 110 ° C and even more than 125 ° C for a few seconds , followed by rapid cooling. UHT-treated milk that is packaged aseptically results in a "non-perishable" product that does not require refrigeration until it is opened. Although these products can be microbiologically stable for a long period of time, they can have certain defects that limit the useful shelf life of these products. One of these defects that has been exhaustively mentioned "in the art is the gelation by UHT - (also Ref.:172604 referred to as thickening by aging). This defect is observed specifically for products treated by UHT or products sterilized in some other way that have heat treatment and is not observed in products that have not experienced these thermal treatments at high temperature. For example, products that are only pasteurized do not show this defect. UHT gelation is a phenomenon of aggregation that affects non-perishable products and that contains sterilized protein such as concentrated milk and UHT dairy products and other dairy products. UHT gelation may be partially linked to aging thickening or aging gelation. After weeks to months of storage of these products, there is an increase in viscosity accompanied by a visible gelation. In the context of this invention, gelation describes the phenomenon of viscosity increase and / or elasticity of the product. Gelation is generally linked to the formation of a spatial extension network and differs there with other phenomena such as sedimentation that has more to do with the spatial redistribution of the ingredients. An example of sedimentation is when the heavier ingredients in a product sink to the bottom of the container. In the previous definition of gelation, we do not exclude the possibility that the spatial extension network is redistributed after having formed the spatial extension network, ie the gel must be subjected to syneresis, thus pushing a part of the liquid-trapped by network. Upon reaching the point of aging within the maximum shelf life of the UHT product (normally 4 months), the net may have shrunk to a fraction of its original size (> 75%), while retaining its elastic properties. Due to severe aging, which only occurs well beyond the maximum shelf life of the UHT product, the net may have shrunk even a smaller fraction of its original size (> 25%). Note that the aging process of a product that suffers from sedimentation is different from the previous definition; Sedimentation is accompanied by the growth of a layer of ingredients at the bottom of the product. The product does not pass the stage of extending throughout the space. Also, the use of gelling ingredients such as kappa-carrageenan in liquid UHT products is well known in the art to protect them from sedimentation (usually as a result of thermal coagulation). Therefore, gelation usually reduces the sedimentation rate. During the process of UHT or gelation, due to aging, the formation of a spatial extension network can be caused by the aggregation of proteins that lead to the formation of a three-dimensional network. The exact mechanism causing UHT gelation and / or aging is still not fully understood, but it was discovered that it may be at least partly due to the proteolytic cleavage of proteins such as casein in dairy products. It has been described in the art that bacterial or natural plasmin enzymes resistant to heat treatment can. induce the formation of a gel. Another factor normally mentioned in relation to UHT gelation and / or aging is the storage temperature of the sterilized suspension. Also the chemical reactions may be responsible for the gelation by UHT / aging. WO-A-00/64267 discloses that the main problem of perishable milk is aging gelation. This document suggests that the use of food-grade polyphosphates having at least 6 phosphate groups, such as sodium hexametaphosphate in milk fortified with calcium and dairy products, prevents gelation by aging of the milk treated by UHT. Although the aforementioned documents can offer some improvement with respect to the stability of the products treated by UHT, better and more alternatives are desired for this. Furthermore, there are documents concerning the reduction of sedimentation suspensions due to stability and precipitation. For example, EP-A-1, 197, 153 and WO-A-02/065859 concern the reduction of precipitation in emulsions or suspensions. These documents do not mention the products sterilized or treated by UHT and the related problems. Neither these documents provide a solution to the problem of gelation by UHT nor does it suggest the use of specific monoglyceride emulsifiers. The stability of homogeneous suspensions is also mentioned in EP-A-IOS9851. This document shows that a stable suspension can be achieved without emulsifiers by the inclusion of a thickening agent. When these products are subjected to treatment by UHT, they will still show gelation by UHT. Therefore, it is an object of the invention to provide a suspension containing protein that is sterile and non-perishable and that uses an alternative means of stabilization. Brief Description of the Invention We surprisingly discovered that the addition of a small amount of monoglyceride emulsifier or emulsifier. specific reduces the gelation of the sterilized protein contained in suspensions. Therefore, the invention relates to an aqueous suspension containing protein and fat or a fat replacement and from 0.01% by weight to 1% by weight of emulsifier with a hydrophilic / lipophilic balance at or below 16, characterized in that the suspension comprises 0.01% by weight to 1% by weight of a monoglyceride emulsifier with a hydrophilic / lipophilic balance at or below 16 and further characterized- in that the suspension has been sterilized. In another aspect, the invention relates to the use of an emulsifier to reduce gelation by aging in suspensions containing sterilized protein, especially milks treated by UHT. In another aspect, the invention relates to a method for preparing an aqueous suspension comprising protein and fat or a fat replacement and from 0.01% by weight to 1% by weight of emulsifier with a hydrophilic / lipophilic balance at or below of 16, wherein the suspension comprises 0.01 to 1% by weight of a monoglyceride emulsifier with a hydrophilic / lipophilic balance at or below 16, characterized in that the method involves sterilization of the suspension. Detailed Description of the Invention In the context of the invention is preferably of lactic origin but the term also covers miscellaneous assortments and non-dairy products, whereby the origin of the protein, fats and other ingredients can be dairy, of vegetable, marine origin or the combination of these.

When percentages are used in weight, these are based on the total weight of the product unless otherwise indicated. In the context of the invention, sterilization can be achieved by any suitable method such as treatment at ultra high temperature (UHT), or treatment at elevated temperature over a long period of time such as for 30 minutes at a temperature of approximately 110 ° C. In the context of the invention, the term sterilization also encompasses regulated shelf life treatments using temperatures greater than 110 ° C. The preferred method of sterilization is the UHT treatment. In the context of the invention, sterilization is defined as a heat treatment which aims to eliminate microorganisms, including bacterial spores. Preferred sterilization treatments are, for example, 30 to 130 ° C or one second at 145 ° C. To estimate the minimum heat treatment necessary to achieve sterilization, an fO factor is normally used, which is a measure of the total thermal load the product has undergone. It is generally accepted that an oF of 3 is the minimum thermal load necessary to remove most heat-labile bacteria. As an example: at 121 ° C, an oF of 3 means a warm-up time of 3 minutes. In the context of the invention, the UHT treatment is defined as the treatment at a temperature greater than 120 ° C.

The products according to the invention are suspensions comprising a protein. Without wishing to be bound by any theory, it is thought that the protein is at least responsible for the phenomenon of gelation in suspensions treated by UHT. Preferably the aqueous suspension comprises 0.5 to 10% by weight, more preferably 1 to 5% by weight and even more preferably 2 to 4% by weight of protein. It can be seen that the level of protein is determined, among other things, by the physical characteristics of the product in which they are applied. The more viscous products generally comprise a higher level of protein. The products according to the invention preferably have a viscosity of 2 to 100 mPa.s at a temperature between 5 and 25 ° C and a shear rate of 100 Hz. More preferably the products have a viscosity less than 50 mPa.s at a speed of shear stress of 100 Hz at a temperature of approximately 20 ° C. The gelation effect is usually determined visually. It can be observed that a thick appearance of the composition is especially noticeable when pouring the product. The stirring removes most of the excess gelation and therefore the gelation is determined before shaking the product. It can be generally observed that gelation leads to an increase in viscosity by about 8 mPa.s or alternatively a greater than 50% increase in the viscosity of the product under the same conditions of temperature and shear stress. For example, gelation is described in Schwart-zel et al., 1980, Rheumatic behavior of UHT steam injected dairy products on aging, Journal of Food Process Engineering 3, p. 143-159. A method for determining gelation is also described in alstra et al., "Dairy Technology, principies of milk properties and processess". Marcel Dekker Inc., New York, Basel ISBN 0-8247-0288-X, 1999 (first edition). The protein can be of any origin or it can be of plant origin, for example soy protein or protein of dairy origin. Preferably, the protein is protein of dairy origin because it is the protein that confers the desired flavor, texture and aroma to the milk. The suspensions are stabilized by the addition of an emulsifier. The emulsifier has a hydrophilic-lipophilic balance value. { HLB value) of or less than 16. The HLB value is a parameter that describes the solubility of the surfactant. The HLB value is a concept introduced by Griffin in 1950 as a measure of hydrophilicity or lipophilicity of nonionic surfers. It can be determined experimentally by the phenol titration method developed by Marszall; see "Parfumerie, Kos etik", Vol. 60, 1979, pp. 444-448 and Rompp, Chemistry Lexicon, 8th edition, 1983, p. 1750. According to the invention, emulsifiers with an HLB value at or less than 16 are hydrophobic emulsifiers. It has been found that emulsifiers with an HLB greater than 16 will not change to the desired stabilization against aging gelation. Optionally, these emulsifiers with HLB values greater than 16 may be present in addition to the emulsifiers with HLB values at or below 16. Preferably, the emulsifier has an HLB value of less than 14, more preferably from 1 to 10, more preferably of 2 to 9 and with superlative preference of 3 to 6. We have discovered that emulsifiers with HLB at or below 14 are more effective in reducing gelation by UHT and / or aging. This effect can be reinforced by the presence of another effective agent with the polyphosphate. Therefore, in an alternative embodiment, the product comprises an emulsifier with an HLB greater than 14 but less than 16 combined with a polyphosphate. Preferably the emulsifier is selected from the group comprising monoglycerides, lecithins, diglycerides, diacetyl tartaric acid monoglycerides and diglycerides, sucrose esters of fatty acids, sodium stearyl lactylate (* SSL), mono citric acid esters and diglycerides or combinations of these. Preferred emulsifiers are monoglycerides, lecithins, diglycerides and combinations thereof. The most preferred emulsifier is monoglyceride, especially saturated monoglyceride. Examples of these emulsifiers are Hymono ™ 8903 and Dimodan ™ hp. In the context of the invention, proteins are not included in the term emulsifier. The amount of emulsifier is dependent on the type of emulsifier selected and the relative amount of the protein present but generally the level of the emulsifier ranges from 0.01% to 1% by weight, more preferably from 0.05 to 0.5% by weight, more preferably from 0.05 to 0.2% by weight. It can be seen that for each emulsifier there is an optimum quantity for its operation. In one embodiment, the preferred amount of monoglycerides, diglycerides and SSL is from 0.05 to 0.5% by weight. In another embodiment, the preferred amount of fatty acid sucrose ester is from 0.01 to 0.3% by weight. In a preferred embodiment, the total level of emulsifier, including the emulsifier that may be, naturally present in the products, such as milk, is 0.05 to 1% by weight. In an alternative embodiment, the emulsifier is lecithin, wherein the total amount of lecithin, including the phospholipids naturally present in the product is 0.05 to 1% by weight, more preferably 0.07 to 0.5% by weight. In a more preferred embodiment, the emulsifier is a monoglyceride which is present in an amount of 0.01 to 0.08% by weight of the total weight of the product. This level includes the amount of monoglyceride that can be naturally present in the product as milk when the average level of the natural monoglyceride is present is about 0.004% by weight. The aqueous suspension comprises fat or fat replacement. The fat can have any origin. It is preferred that the fat be milk fat or vegetable fat or a combination of these. In those embodiments where the fat is vegetable fat, it is selected from the group comprising sunflower oil, safflower oil, soybean oil, olive oil, linseed oil or combinations of these. Most preferred fats have a polyunsaturated fatty acid (PUFA) content of at least 30% by weight PUFA in the total triglyceride composition. The amount of fat is preferably from 0.1 to 8% by weight, more preferably from 1 to 5% by weight. Optionally, the products comprise a fat replacement. The fat replacement is preferably selected from the group comprising sucrose polyesters, phytosterols or esters thereof, including their saturated stanol equivalents or a combination thereof. It has surprisingly been discovered that the addition of an emulsifier, especially monoglyceride in the amount described to the suspension comprising fat and a phytosterol ester increases the stability against UHT gelation and / or aging of these products at a surprisingly high level. It is more preferred that the aqueous suspensions comprise a fat and a phytosterol or ester thereof. The phytosterols, also known as vegetable or plant sterols, can be classified into three groups, 4-desmethylsterols, 4-monotethylsterols and 4,4'-dimethylsterols. In oils, they exist mainly as free sterols and sterol esters of fatty acids although sterol glycosides and acetylated sterol glycosides are also present. There are three main phytosterols, namely, beta-sitosterol, stigmasterol and ca pesterol. Schematic drawings of the mentioned components are as provided in "Influence of Processing on Steroids of Edible Vegetable -Oils", S.P. Kbchhar; Prog. Lipid Res. 22: pp. 161-188. The respective 5α-saturated derivatives such as sitostanol, campestanol and ergostanol are also encompassed in the term phytosterol.

Preferably, the phytosterol is selected from the group comprising β-sitosterol, β-sitostanol, campesterol, campestanol, stigmasterol, brassicasterol, brassicastanol or a mixture thereof. The phytosterols in this preferred embodiment are esterified with a fatty acid. Preferably, the sterols are esterified with one or more C-22 fatty acids. For purposes of the invention, the term C2-22 fatty acid refers to any molecule that comprises a C2-22 backbone and at least one group acid. Although not preferred within the context of the present invention, the C2-22 backbone can be partially replaced by secondary chains that are present. Preferably, the C2-22 fatty acids are linear molecules comprising one or more acid groups as terminal groups. It is more preferred that they be C8-22 fatty acids as they occur in natural oils. Suitable examples of these fatty acids are acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid and capric acid. Other suitable acids are, for example, citric acid, lactic acid, oxalic acid and maleic acid. The most preferred are myristic acid, lauric acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, ketoleic acid, erucic acid, elaidic acid, linoleic acid and linolenic acid.

When desired, a mixture of fatty acids can be used for esterification of the sterols. For example, it is possible to use an oil or natural fat as a source of the fatty acid and carry out the esterification by means of an interesterification reaction. Preferably, the suspensions comprise a thickening agent. This thickening agent contributes to the physical stability of the suspension. In a preferred embodiment, the thickening agent can be selected from the group comprising carrageenan, locust bean gum, xanthan gum, pectin, gum arabic, gelatin, guar gum or combination of any of these. Suitable amounts of thickening agent are in the range of 0.005 to 0.5% by weight, preferably 0.01 to 0.1% by weight. In a preferred embodiment, the suspensions additionally comprise a multivalent metal ion such as calcium. Optionally, the suspension comprises other ingredients. Examples of these ingredients are beneficial agents such as live lactobacillus bacteria or vitamins; a stabilizing agent such as polyphosphate, coloring agents, flavoring agents, herbs, pieces of fruit, fruit pulp, vegetable or fruit concentrate, fruit juice, antioxidants, sequestering agents and salts.

The suspension can be prepared from these ingredients as for example reconstituted milk but it is preferred that the suspension be a natural product such as milk to which the emulsifier is added. In a preferred embodiment, the invention relates to a milk comprising about 0.1 to 5% by weight of fat, 0.01 to 0.2% by weight of monoglyceride and 0.2 to 4% by weight of phytosterol ester. The suspension can be used as such or can be part of another composition as a food product. It is preferred that the suspension be used as such. Even more preferred than the suspension is milk or juice, more preferably milk. In another aspect, the invention relates to the use of an emulsifier with an HLB value of or less than 16 to reduce gelation by aging in the suspensions containing sterilized protein, especially milk treated by UHT. The invention is illustrated by the following non-limiting examples. E n g e Generation Determination of stability - gelation - by UHT / aging The gelation. by aging is determined by observation by a panel of at least 5 people. Milk becomes liquid (pourable without visual clumps) in a soft gel, in some cases developing small lumps of protein. The gelation by aging is identified based on the following questions: 1. Is there a liquid layer on the surface greenish or less cloudy than milk? (yes / no) 2. Is there homogeneity when pouring milk? (yes / no) 3. Are there visible lumps? (yes / no) 4. Can you hear lumps that fall while the milk is being poured? (yes / no) 5. Is there a structure similar to the tofu / crust on the bottom? . { yes / no) It is very important that these observations are made before shaking the product because the agitation can eliminate the gelation.

Example 1 Carrageenan and monoglyceride (E471, Hymono ™) are added to the skimmed milk (fat content 1.5% by weight of milk fat, protein content 3.2% by weight), stirred and mixed for 10 minutes. The amount of carrageenan is 0.01% by weight and the amount of monoglyceride is 0.01% by weight and O.O5% by weight of sitosterol ester of sunflower oil is added.

The mixture is preheated to 70 ° C and subjected to ultra-high temperature treatment at 143 ° C for 6 seconds by steam injection, then cooled to 70 ° C and homogenized at this temperature at approximately 200 bar. Milk is cooled to 15 to 20 ° C and aseptically filled in aseptic Tetrapaks ™ at room temperature (20 to 25 ° C). After 8 weeks at room temperature, the milks are compared with milks with the same composition except that the monoglyceride was left out or included at a level of only 0.001% by weight. These comparative milks were prepared by the same processes. It was observed by a panel of expert observers composed of 5 people, that the milks with monoglycerides in an amount of 0.1% by weight did not show any gelation or aging after a period of 8 weeks. After the lumps were visible after a period of 8 months, the comparative products showed no lumps or a creamy layer on the surface after a storage period of 4 weeks. For comparative products, especially for question (1). { Is there a liquid layer on the surface greenish or less turbid than milk?) Could be answered as affirmative when the less desired product was indicated.

Example 2 The products were prepared according to the processes and the composition of Example 1. In addition to the addition of carrageenan and 0.05% by weight of monoglyceride, 0.7% by weight of sunsterol oil sterol-ester was added. A panel composed of 5 people found that the resulting products were stable after storage for 8 weeks at a temperature of 20 to 25 ° C. E j emp lo 3 Products were prepared according to the processes of the product composition of example .1 with the following modifications. Instead of the monoglyceride, the emulsion comprises 0.2% by weight DATEM (diacetyltartaric acid monoglycerides and diglycerides, approximate HLB of 9). The amount of carrageenan. it is 0.015% by weight. The resulting compositions were stable and showed no gelation when stored for 16 weeks at 5 ° C. Example 4 The products were prepared according to the processes and composition of Example 1 with the following modifications. Instead of the monoglyceride, the emulsion comprises 0.05% by weight of fatty acid sucrose ester (Ryoto sugar ester A-1170 ™, HLB of approximately 11). The amount of carrageenan is 0.015% by weight. The amount of fatty acid ester of sitosterol in these products was 0.7% by weight. The resulting compositions were stable and did not show gelation when stored for 16 weeks at 5 ° C. 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 (9)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. An aqueous suspension comprising proteins and fats or a fat replacement and from 0.01% by weight to 1% by weight of emulsifier with a balance hydrophilic / lipophilic of less than 16, characterized in that the suspension comprises from 0.01 to 1% by weight of a monoglyceride emulsifier with a hydrophilic / lipophilic balance of or less than 16 and which is further distinguished because the suspension has been sterilized.
2. 2. The aqueous suspension according to claim 1, characterized in that it comprises from 0.5 to 10% by weight of protein.
3. 3. The aqueous suspension according to any of claims 1-2, characterized in that the protein is a protein of dairy origin.
4. 4. The aqueous suspension according to any of claims 1-3, characterized in that the emulsifier is selected from the group comprising monoglycerides, lecithins, diglycerides, mono esters and diacetyltartaric acid diglycerides, sucrose esters of fatty acids, Sodoroil lactylate sodium (SSL), citric acid esters of mono and diglycerides or combination of these.
5. 5. The aqueous suspension according to any of claims 1-4, characterized in that the amount of emulsifier is 0.05 to 0.2% by weight.
6. 6. The aqueous suspension according to any of claims 1-5, characterized in that it comprises from 0.1 to 8% by weight of fat.
7. 7. The aqueous suspension according to any of claims 1-6, characterized in that it comprises a phytosterol.
8. 8. A method for preparing, an aqueous suspension comprising protein and fat or a fat replacement and from 0.01% by weight to 1% by weight of emulsifier with a hydrophilic / lipophilic balance of or below 16, the suspension comprises 0.01% to 1% by weight of monoglyceride emulsifier with a hydrophilic / lipophilic balance of or less than 16, characterized in that the method involves sterilization of the suspension.
9. 9. The method according to claim 8, characterized in that the sterilization involves a UHT treatment.