SE523355C2 - Heat treatment process for milk, has pre treated milk subjected to final heating step immediately after pre treatment - Google Patents

Abstract

Pre-treated milk is immediately subjected to a final heating step via a buffer vessel (8) and capacity-regulating pump (9). A process for heat-treating milk comprises heating untreated milk in one or more steps, then separating and then standardising, after which the pre-treated milk is subjected to a final direct heating where it is held at a given temperature over a given period of time. The treated milk is cooled in one or more steps and homogenised. The pre-treated milk is subjected immediately to the final treatment via a buffer vessel and a capacity-regulating pump.

Description

canon 10 15 20 25 30 35 523 355 2 n .. o z - a | o q u »u. heat treatment of the milk, which adversely affects the nutrient content of the milk and which can also contribute to the deterioration of the taste of the finished product.

The large storage tanks for storing the milk between treatments mean increased piping and that additional valve arrangements are needed, which means that investments for the dairy increase. All these additional components must also be washed after production has ended, which means an increased environmental impact. All washing also involves a certain amount of product loss because in so-called phase change between production and washing, must empty the pipes with, for example, water.

Homogenisation in connection with pasteurisation also entails additional investment costs at the same time as it entails high operating costs in the form of electricity.

An object of the present invention is to provide a method for the milk to be processed into the intended product immediately after the pre-treatment, which means that one avoids overtreating the milk and one obtains an end product with a better nutritional content.

An additional purpose is to achieve a method that involves a reduced cost for the dairy by lowering investment costs and minimizing product losses.

A further object of the present invention is that the environmental impact can be reduced by the method involving fewer components to wash.

According to the invention, these and other objects have been achieved by giving the method of the type initially described, the characteristics that the pretreated milk is finalized via a buffer vessel and a capacity control pump immediately after the pretreatment.

Preferred embodiments of the invention have further been given the features set forth in the subclaims.

A preferred embodiment of the invention will now be described in more detail with reference to the accompanying drawing, which: Fig. 1 shows a fate diagram for the implementation of the method.

As shown in Fig. 1, the colostrum enters for treatment via a balance tank 1 and a conventional feed pump 2. The incoming colostrum usually maintains a temperature of about 5 ° C. The colostrum is preheated in a first step to a temperature of 55-65 ° C, which suitably takes place in a conventional plate heat exchanger 3. The plate heat exchanger 3 may be a separate heat exchanger, but usually forms a section in a larger plate heat exchanger, which is also used in other method steps. The heating takes place 523 355 211.5: '3 with hot water, alternatively the heating takes place regeneratively in the larger plate heat exchanger. Preheating can also take place in a tube heat exchanger.

The preheated milk is then led into a separator 4, where the skimmed milk is purified, at the same time as the separator 4 divides the skimmed milk into a cream phase and a skimmed milk phase. A milk temperature of 55-65 ° C is the temperature at which the separator 4 has its best efficiency. Alternatively, the colostrum can be purified and separated by microfiltration.

The cream phase and the skim milk phase leave the separator 4 by means of various pipelines, which are led into a standardization equipment 5. In the standardization equipment 5, cream is continuously mixed with skim milk to standardized milk with the desired fat content. The excess cream is led away from the plant through a line 6. The standardized milk, which maintains a temperature of 55-65 ° C, continues in a line 7. Alternatively, only skimmed milk can be used in the remaining part of the method, according to the invention. There is a small buffer vessel 8 on the line 7. The purpose of the buffer vessel 8 is to compensate for fluctuations in the fate that may occur when the separator 4 "opens for shots", ie when the separator 4 gives off sludge separated from the colostrum. The buffer vessel 8 is calculated to be so large that a capacity control pump 9, downstream of the buffer vessel 8, has an even supply of product into the pump 9. After the pump 9, which controls pressure and flow through the process, an additional preheating step is placed.This preheating can suitably take place in a plate heat exchanger The plate heat exchanger 10 is either a separate heat exchanger or it forms a section of a larger heat exchanger, alternatively the second preheating can also take place in a tube heat exchanger.The heating takes place either with hot water or regeneratively, as part of a larger heat exchanger. the type of heat treatment that the final product is to undergo, the preheating takes place to 80-120 ° C.

By having a further preheating of the product, it is possible to make better use of the energy consumption in the final heat treatment, as well as to have a gentler treatment of the milk, with a better taste of the final product.

After preheating, the milk is kept at the preheating temperature, 80-120 ° C for a certain predetermined time interval. This takes place in a so-called holder cell __ 11, which in principle consists of a helically twisted pipe section. By allowing the milk q - S to remain at the preheating temperature for a certain time, an efficient enzyme stabilization is obtained in the milk, which results in a more stable end product with a longer shelf life. At the same time, the holding cell 11 provides an opportunity to obtain a stabilization of protein, which has a positive effect on the plant's operating time. 523 355 n ~ u n nu a ~ c v v u a u nu 4 By stabilizing protein, you get a smaller precipitation of milk proteins, so-called fouling and the plant may be in operation for a longer period of time before washing.

The final heat treatment of the product takes place through so-called direct heating. This can be done as shown in Fig. 1, in an injector 12. Steam is injected directly into the product and raises the temperature thereof to the desired level. The final temperature depends on the product in question. For UHT milk a temperature above 140 ° C applies, for ESL milk above 125 ° C and for HRS-treated milk the temperature must reach 146-152 ° C. The final treatment temperature is maintained in a subsequent holding cell 13, for a certain time interval. Alternatively, the final heat treatment can take place in an infuser, where the atomized product passes through a vapor-filled vessel.

It is important that the capacity controlling pump 9 maintains a constant pressure and flow through the plant. If the fate increases through the plant, the correct preheating temperature is not reached and a larger amount of steam must be added in the final heating, which can give a dilution of the final product.

Reduced flow can conversely increase the dry matter in the final product.

Constant pressure and genom fate through the plant are also important for the result of the heat treatment. If the fate increases through the plant, a faster passage of product through the holding cell 13 is obtained and the correct time interval cannot be maintained. There is a risk that the product will not be sterile or adequately treated, depending on the product in question.

After the holding cell 13, the product is led into an expansion vessel 14 where it is "flash-cooled" to the preheating temperature, i.e. 80-120 ° C at the same time as water, supplied in the form of steam, is removed from the product. Via a conventional feed pump 15 the product is passed on to a homogenizer 16. The product maintains a temperature of about 80 ° C, which is an optimal operating temperature for the homogenizer 16. In the homogenizer 16 the larger fat balls in the milk are split, by forcing it to pass a narrow gap. The homogenized milk has no or little "creaming" and the largest part of all consumption milk is homogenized today. The process is also necessary for the product to be able to be handled when filling in disposable packaging.

As the method according to the invention is not preceded by a conventional pasteurization with homogenization before the product is led to large storage tanks, a homogenizer is saved. Since homogenization is an energy-intensive process, this gives a positive result in operating costs, while at the same time reducing the mechanical processing of the product.

After the homogenized product leaves the homogenizer 16, it is further cooled to a temperature of 20-30 ° C. The cooling preferably takes place in a conventional plate heat exchanger 17. The plate heat exchanger 17 can form its own unit, alternatively it can form a section in a larger plate heat exchanger.

The cooling takes place by means of cold water, alternatively by regenerative cooling in a larger heat exchanger. The cooling can also take place in a tube heat exchanger.

Through the pipeline 18, the finished product leaves the plant in order to be led directly to a filling machine for filling in disposable consumer packaging. The filling takes place in aseptic packaging, alternatively packaging for ESL milk, depending on the type of product treated with the method. Alternatively, filling in consumer packaging can take place after intermediate storage in aseptic storage tanks.

A final heat treatment of milk immediately after the pre-treatment and integrated with it, means reduced investments for the dairy because the method according to the invention means that intermediate storage tanks are not needed, no pasteur is necessary and a homogenizer is also superfluous. In addition, there are reduced piping and valve arrangements. The plant for the implementation of the method can be built as a separate and compact unit.

The method according to the invention means that production costs are reduced because the energy consumption for operating the plant is lower than with conventional handling of corresponding dairy products. Product losses are also reduced by integrating the process.

The method also means reduced environmental impact because the plant needed to carry out the method according to the invention includes fewer components to wash.

Another advantage is a gentler product handling, as the pasteurization that normally precedes the final treatment is excluded. In this way, you only get a heat treatment of the product, which gives a better end product both nutritionally and taste-wise.

Because the preheating is divided into two method steps, you get a more efficient and gentler final heating of the product, while after the second preheating step you can place a holder cell to stabilize the enzyme and protein stabilize the product. This provides a stable and sustainable end product and contributes positively to the plant's operating time by reducing the precipitation of proteins in the various parts of the plant.

As can be seen from the above description, the present invention provides a method with a number of advantages over conventional dairy management.

Claims (4)

10 15 20 25 30 523 355 é PATENTKRAV A method of heat-treating milk, comprising the method steps of: -breaking milk by preheating in a first step, separating and standardizing - bringing the pretreated milk to a buffer vessel (8) and a capacity control pump (9) which provides a constant pressure and genom fate through the plant - that the milk is then and in direct connection with the capacity-giving pump (9) preheated in a second step to 80-130 ° C and kept at this temperature for a certain time interval, for enzyme stabilization. - that the milk is finally heated by direct heating and kept at this temperature for a certain time interval, after which it is cooled in one or more steps and homogenized - that all method steps take place in one context. A method according to claim 1, wherein the product is finally heated to a temperature above 140 ° C and maintained at this temperature for a certain time interval, in order to obtain a UHT-treated product. A method according to claim 1, wherein the product is finally heated to a temperature above 125 ° C and maintained at this temperature for a certain time interval, to obtain an ESL-treated product. A method according to claim 1, wherein the product is finally heated to a temperature of 146-152 ° C and maintained at this temperature for a certain time interval, to obtain an HRS-treated product.