CH287207A - Process for obtaining a milk product and product obtained by this process. - Google Patents

Description

Process for obtaining a milk product and product obtained by this process. The present invention relates to a process for obtaining a milk product by concentrating and sterilizing milk and during which the milk is subjected to temperatures high enough to have harmful effects on the viscosity and product stability; it also relates to the product obtained by this process.

In the treatment of milks with a view to obtaining products having a relatively high total solid mauers content, the milk (whole or ereme) is frequently subjected to high temperatures. certain stages of the treatment, either to carry out evaporation, or for sterilization, or for your other purpose. In many operations of this kind, the milk is subjected to temperatures exceeding 65 C and, when it is a question of sterilizing it, to temperatures which can rise to 132 C, or during significant periods before or after evaporation or concentration during which the solids content of milk products is increased. The high temperatures to which the milk is subjected during operations of this kind cause an increase in the viscosity of the final fluid product, an increase which, in many cases, is excessive and tends to cause coagulation or curdling of the product. This increase in viscosity may to some extent and in some cases be desirable, as for example in the manufacture of evaporated (unsweetened) milk. Coagulation and the formation of curdled milk are always undesirable. However, the degree of viscosity increase and whether or not curdling appears to depend on many factors beyond the control of the manufacturer: e.g. the composition of the soil of the pfiltures, ete.

The process according to the invention is characterized by the fact that, in order to avoid the harmful effects of high temperatures on the viscosity and the stability of the product, it is incorporated into the milk, before the treatment at high temperature. of which we want to avoid the adverse effects, of the solid constituents of a milk which has been treated with bar exchange materials of the RTI type ID="0001.0272" WI="13" HE="4" LX=" 1291" LY="1677"> mineral, so as to lower the ratio of calcium to phosphorus.

Milk production. evaporates, for example, includes four main operations which involve heat, ä. i.e. preheating, actual evaporation, homogenization and final sterilization.

During preheating the milk is heated before entering Jans 1'ev aporatetti-. The temperatures usually used are between 84 and 100 C, although higher temperatures can be used if working under pressure. As will be seen below, this operation can have other effects besides preheating. Evaporation is generally carried out at temperatures in the range of 49 to 84°C, under reduced pressure, so that it boils. The time required for evaporation depends on the initial content of the milk subjected to the treatment. total solids content as well as the desired total solids content in the final product, which may be between 26 and 34%, depending on local requirements. water, fresh milk or fresh milk added to the milk to adjust the solids and fat content to the required standards.

After evaporation and possibly after adjustment of the milk to the desired standards, the evaporated milk is homogenized. In general, for this operation, the temperature can be of the order of 49 to 65 C and the pressure of order of 140 to 210 kg per cm2. A typical set of operating conditions is 210 kg per cm2 at 57 C.

The evaporated and softened milk is then sterilized at a temperature varying between 104 and 132 C, either before or after canning. The time required varies according to the temperature used, the time being shorter at higher temperatures. The temperature and time required for Sterilization as well as the time required to reach the Sterilization temperature and for subsequent cooling sollt. factors affecting product viscosity.

The final product must have a viscosity which favors the uniform distribution of fats and prevents their segregation. This viscosity must be high enough for the product to be stiff without being too strong. It can vary between 75 and 450 seconds ä. 16 C, determined by means of the standard type viscometer used in this bat, known as the Borden flow meter; it is preferably close to 250 to 350 seconds.

However, it is very delicate to achieve the desired viscosity as well as the desired sterility and flavor while maintaining the 1a. stability of the milk, that is to say by preventing the formation

massive formation of eaillots year of lumps or say less the formation of such eaillotcs which do not dissipate by had menies by simple agit.a tion of the final product.

To maintain its stability, until now various salts, such as solium bicarbonate, have been added. sodium aeetate and sodium dipliosphate, preferably already reheated before the preheating operation. However, it is diffieile by this mod@-eii to obtain regularity, the entirety of bolls result, it has been observed that it is possible to control the viscosity of the final product and to stabilize the starting milk vis-à-vis the treats termic ingredients with neust effects to which it is treated (concentration and in particular sterilization) thanks to A. the use of solid constituents of a milk, whole or i-6m6, which has been processed by dehydrated materials from bares of the n-linear type. This treatment can be carried out by putting the alt, preferably in a light state, in contact with silicates of bares such as they have been used in the nailing procedures. water, such as zeolites, laneonite, artificial zeolites and nominally adsorbent compounds not suitable for bar exchange, such as silica gel, but activated by treatment with water alealis and alealine salts, such as sodium chloride (see patent patent N 2045097). Such c1'eeban `@e bare materials reduce the teneuh en. caleium as well as eleium in phosphorus of ]alt is in effect killing - a proportionately greater reduction of aleium than of phosphorus. In a treatment of this kind, there is a noticeable alteration, both in the calcium content and in the phosphorus content of the non-fat solid constituents of the milk, as well as a certain reduction in the calcium-lipliosphorus ratio. , ee, s changes resulting in a reduction of the milk coagulation tension.

In such processing of whole milk or skimmed milk, the ratio of alkium to phosphorus in the solid non-fat constituents of milk, which ratio in normal, whole or skimmed milk is. of the order of <B>1.175</B> to 7.240, can be reduced to 1.155 or even less, thanks to the fact that the reduction of the calcium content is proportionally somewhat higher than that of the phos content. - phore. By increasing the relative proportions of base-exchange materials used, it has been possible for the patentee to obtain in the total non-fatty solids constituents of the traue product a ratio of calcium to phosphorus to ranium of about 0.815, which corresponds to a CaO/P205 ratio of about 0.500. The preferred range for the calcium phosphorus ratio is 0.815 Å. 1,000. It is appropriate to designate the products produced by the expression products treated by bare exchangers of the mineral type in order to distinguish them from the milk products obtained by subjecting the fluids to a treatment by means of selective ion exchange materials, a treatment which ensures a proportionally higher elimination of calcium than of phosphorus.

The solid milk constituents iodified by bar exchange and resulting from the treatment defined above are mixed with the milk (whole or skimmed) to be concentrated in the proportions necessary to provide, for example, 5 Å. 60% and preferably 20 to 50% of the total solids contained in the final evaporated product. These solid milk constituents modified by bar exchange can be added in the form of fluid milk (whole or skimmed); Alternatively, the treated milk may be evaporated to a total solids content suitably approximating the desired solids content in the final product, for example 25.9 to 34%, or to at any intermediate concentration, and add as is; it is further possible to bring the treated milk to a solid state, preferably by evaporation followed by spray drying, and to add the resulting dry solids. The addition of treated solids can be effected at any convenient point in the treatment. For example, in the case of the preparation of evaporated milk, this addition can take place in the preheater before or during the preheating operation, or even between the evaporator and the homogenizer. The addition can also take place between the homogenizer and the sterilizer, but as it clearly appears, it is preferable to carry it out before the homogenizer, since the latter contributes to the mixture of the constituents. milk solids treated with the main mass of milk.

When added prior to concentration or evaporation, the solid constituents of bar-exchanged milk may be added either below. form of the treated milk fluid, either under gel of the evaporated treated milk fluid, or finally in the form of dry solids extracted from the treated fluid, the addition being preferably made in the preheater or before it. When added after evaporation or 1a. Concentration, the solid constituents of the treated milk are usually introduced in the form of the treated fluid milk, evaporated to a concentration close to Gelle sought in the final product an higher than this or below 1a. form of the dry solid extract of this fluid. The conventional adjustment of the total solids and fat content of the evaporated product is then carried out before proceeding to the final sterilization.

The bare-exchanged milk solids can, if desired, be substantially fat-free. It is possible in this Gas to adjust the grassy maueres content of the final product before the sterilization operation as in the conventional technique.

As an example of implementation of the process according to the invention, year a. prepares a bar-exchange-treated milk, using a synthetic bar-exchange zeolite (1st product brand crystallite), which had previously been prepared for treatment by an appropriate regeneration process, using solutions alkalis, such as sodium hydroxide, and salts, such as sodium chloride (method described in U.S. Patent No. 2,102,642). , the final ratio of calcium to phosphorus being in the order of 1.1:5-1. This treated milk was then converted into a dry powder by the usual process of evaporation and spray-drying. evaporated whole milk having a content of 30% total solids, the powder obtained was added to the milk, after evaporation and before the sterilization of the milk.This whole milk, tested alone, required the addition of about <B>373)</B> g of disodium phosphate per tonne of evaporated milk to ensure its stability; with the addition of the powder obtained from the milk treated by base exchange, in the quantity necessary to provide 8 to 10% of the solids content of the product and without any addition of salt, stabilized products are obtained satisfactory without clots and of good consistency. As another example, in preparing evaporated milk at about 25% total solids, milk was added. skimmed milk treated by base exchange, containing 18% total solids, prepared by contact of skimmed milk with regenerated crystallite as described above. This product was incorporated into milk subjected to the evaporation treatment before the actual evaporation operation, in sufficient proportions to provide 25 and 50% of the total solids of the final product. Sterilization was carried out at 116°C for 19 minutes. In both cases, the products proved to be stable with respect to coagulation, the consistency of the final product being a little less thick in the case of the. high phis content in base-exchanged milk. Milk to. focus was forming. clots when it was subjected to the evaporation and sterilization treatment without addition of the solid constituents of the milk treated by base exchange.

It has been found that when the propor tion of the solid constituents of milk. treated in relation to the total solids of the milk being treated, exceeds about 601/o, an inversion most often occurs and irreversible clot formation reappears following the heat treatment. The calcium:1phosphorus ratio was used to characterize the effects of the treatment of milk with the base exchange material; of the mineral type; it must be clearly understood (it does not mean that this is the only result obtained, nor that it is the only effective result to ensure the stabilizing effect described; it does indeed seem that this treatment leads to certain other effects to which the stabilizing action referred to may be due in part at least, This seems to be confirmed, to some degree at least, by the fact The final stable is frequently found within the normal range in untreated milk, which is unstable when subjected to the heat treatment of concentration or sterilization.

Claims (2)

CLAIMS: I. Process for obtaining a milk product by concentration and sterilization of a milk and during which the milk is subjected to temperatures high enough to have harmful effects on the viscosity and the stability of the product, characterized by the fact that, in order to avoid such an action, it is incorporated into the milk, before the treatment. high temperature, the harmful effects of which it is desired to avoid, of the solid constituents of a milk. which has been treated with base exchange materials of the mineral type, so as to lower the calcium/phosphorus ratio. II. Milk product obtained by the process according to claim I. SUB-CLAIMS: 1. Process according to claim I, characterized in that the proportion of the solid constituents of the milk treated by base sample is between 5 and 60% compared with. to all the solid constituents present in the product. 2. Process according to claim I, characterized in that the calcium/phosphorus ratio in the solid constituents of the milk treated by base exchange is between <B>0</B>.815 and 1.155 .