Method for continuous sterilization of liquid product based on milk and installation for its implementation

 

(57) Abstract:

Use: sterilization of liquid product based on milk. The essence of the invention: method of sterilization of liquid product based on milk includes indirect preheating of the product and final heating to sterilization temperature of 140-150oC by direct steam injection. The product is cooled by the so-called instant cooling, which evaporates the amount of steam corresponding to the number of added steam. The product is cooled by indirect cooling. Before instant cooling, the product is cooled from the temperature sterilization 140-150oC to a temperature in the range of 90-120oC in the first stage of the indirect cooling, after which the product is cooled by instant cooling to a temperature of 70-85oC. Installation for sterilizing contains the capacity to weigh 1, connected with the first heat exchanger 4 indirect acting to heat the product based on milk. Nozzle for injection of steam 6 is located in the output pipe of the heat exchanger 4. For the nozzle for injection of steam 6 are section 8 exposure and accuminata tank 10, in which the product is cooled by instant cooling. which of conduct 9 for cooling the product. 2 S. and 6 C.p. f-crystals, 1 Il.

The present invention relates to a method for continuous sterilization of liquid product based on milk and installation for implementing this method.

Usually the product is pre-heated by indirect heating and then heated to sterilization temperature is 140 150oC by injection of steam directly into the product flow. After sterilization, the product is cooled by the so-called instant cooling, which evaporates water vapor corresponding to the number of added steam, and then the product is finally cooled by indirect cooling.

Due to the injection of steam directly into the product provides very rapid heating to a temperature of sterilization. Continuous process of direct injection of steam in milk, known as INT-processing, was introduced in the early 60-ies and are described, for example, in the patent Sweden N 218503 (or the United Kingdom patent N 937782/. INT means "ultra high temperature" (ultrahigh temperature).

Indirect processes for online processing has emerged as a consequence of the energy crisis in the 70-ies. Indirect processes can be returned to a huge amount of additional thermal energy, Toya instant cooling.

Direct heating of milk to a temperature sterilization, following an instant evaporation may be carried out so quickly that the dwell time at the temperature sterilization may be only a few seconds, although bacteriological effect is still sufficient. Indirect sterilization is necessarily slower, and the time at which the milk is maintained at a temperature above 120oC, significantly more than longer than milk support at such high temperatures, the more prone to destruction of the various components of milk. Hard thermal treatment leads to high values of lactulose, which is considered the criterion spoilage of milk and testifies to its low quality.

Interest in direct online processes now again increasing, partly due to the fact that milk supplied to the dairy periodically find some very resistant bacterial spores, and the fact that it is desirable to obtain a higher quality, i.e., sterilized and high quality products.

According to the present invention offers a new way of performing sterilization treatment, which provides more videomay during sterilization.

The method according to the invention is mainly characterized in that the milk products before instant cooling is cooled from a temperature of 140-150oC using the indirect cooling to a temperature in the range of 90-120oC, and then from this temperature the product by instant cooling cooled to a temperature of 70-85oC. Liquid milk products, not to mention milk with different fat content in cream, can be component to restore milk, ice cream mixes, or condensed, or evaporated (dried) milk.

The milk products sensitive to mechanical impact at temperatures above 110oC. According to the proposed method the product gently mechanically cooled to a temperature in the range of 90-120oC, and instant cooling, i.e., the evaporation of steam, start again at this lower level. When this lower operating temperature get less number of products on the basis of milk on the walls of the vacuum vessel. The various components of milk are less subject to degradation, and therefore according to the invention receive more high-quality dairy product. Not to mention less damage to the product shall be up to sterilization temperature is 140oC, need 25-30 kg of steam/ 1000 kg of product when working with heat exchanger for indirect heating. In order to heat the product to the same temperature by the injection of steam and flash evaporation, it is necessary to 135 kg of steam per 1000 kg of product. According to the present invention using only 70-75 kg of steam per 1000 kg of product.

When using indirect processes the flow of water is quite small. Heating and cooling water can circulate in closed loops. In the system of direct heating and cooling, the water flow is large enough, because the cooling of the vessel, which provide instant cooling, you need a large amount of water, about 1000 litres of cooling water per 1000 litres of product.

When using the method according to the invention need only half that amount of water, because the instantaneous cooling is carried out at a lower temperature.

According to the method according to the invention preheating of the product on the basis of milk is carried out by indirect heating to a temperature of 90-125oC, preferably to a temperature of 115-120oC, after which the final heating by injection of steam into the product. Earlier preliminary magiceye temperature during steam injection box, reduced.

The method according to the invention typically includes a reception stabilization of proteins during pre-heating. The product is maintained at the required temperature for 0.5-5 min after heating to 80-100oC. According to the method of the present invention sterilized product appropriately homogenized on stage, followed by immediate cooling. Usually the injection of steam is performed using the nozzles for the injection of steam through which the steam and the product is administered in the form of concentric threads.

The advantage of the proposed method is that the cooling of the product from the sterilization temperature is first carried out by indirect cooling with a cooling rate higher than 5oC/s, i.e. the temperature of the product is reduced, at least at the 5oC in C. If your hardware supports it, the cooling rate can be increased up to 7-11oC.

Installation for the continuous sterilization of liquid products on the basis of milk according to the method according to the invention contains the capacity for weighing product. The first heat exchanger indirect actions connected with weighing capacity. This heat exchanger has one or more steps prior NCLI pair is section extracts. The installation also contains vacuumers capacity in which the product is cooled through instant cooling, and the second heat exchanger indirect acting to cool the product. The installation is mainly characterized in that between the section extracts and vacuumized capacity installed additional heat exchanger indirect acting to cool the product after injection of steam. Mostly this additional heat exchanger (cooler) comprises a tubular heat exchanger, in which there is a high temperature difference between the cooling medium, usually water, and the product.

The present invention is described below with reference to the accompanying drawing, which shows a variant of the invention, shown only as an example. Temperatures indicated in the drawing, should be regarded as approximate.

Capacity 1 for weighing product that must be processed in accordance with the method according to the invention, is connected by a pipe 2 to a pump 3 connected to the heat exchanger 4 indirect actions, which in this case has two steps of pre-heating.

When the product was heated to the appropriate temperature, 90ooC. the product is Then passed through a nozzle 6 for injection of steam, in which the product is mixed with steam 7 and is heated to a temperature of 145oC. After the origin through a short section of the shutter 9, the product is cooled by water in a heat exchanger direct action to a temperature of 111oC. From the heat exchanger 9 product consistently goes into the vacuumized container 10, in which the product is immediately cooled by the evaporation of the fluid that was added to steam. The product comes out of the vacuum vessel 10 at a temperature of 80oC and then cooled in the second heat exchanger indirect steps 11 to a temperature of 25oC.

If necessary between the two steps of pre-heating can be installed pump to increase pressure. After the vacuum vessel or, perhaps, after the first stage of pre-heating can be installed homogenizer for homogenization product.

1. Method for continuous sterilization of liquid product based on milk, including pre-heating by indirect heating, heated to sterilization temperature by direct injection of steam into the product and cooling by so ablanovo pair, and the final cooling by indirect cooling, characterized in that instant before cooling, the product is cooled from the temperature sterilization 140 150oWith up to a temperature in the range of 90 120oWith the first stage of the indirect cooling, after which the product is cooled by instant cooling to 70 85oC.

2. The method according to p. 1, characterized in that the preheating is carried out until 90 125oWith, preferably 115 120oS, followed by injection of steam.

3. The method according to p. 2, characterized in that the preheating stage includes stabilization of the protein at which the product after heating up to 80 - 100oC is maintained at this temperature for 0.5 to 5 minutes

4. The method according to p. 1, wherein the sterilized product passes through a stage of homogenization after instant cooling.

5. The method according to any of paragraphs.1 to 3, characterized in that the injection of steam is carried out in a nozzle for injection of steam flow concentric flows of steam and product.

6. The method according to p. 1, characterized in that the cooling of the product from the sterilization temperature in the first stage of cooling is carried out with a cooling rate higher than 5oWith/s

8. Installation according to p. 7, characterized in that said additional heat exchanger consists of a tubular heat exchanger.

 

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FIELD: milk industry.

SUBSTANCE: method involves normalizing, bactofuging, homogenizing, pasteurizing and bottling milk. After bactofuging procedure, milk is cooled to temperature not in the excess of 6°C, with following bottling of milk. Pasteurizing procedure is carried out in capped bottles at temperature of 65-74°C for 5-10 min. Heating procedure for following pasteurizing procedure is carried at heating rate of 2-10°C/min, and cooling after pasteurizing procedure is carried out at cooling rate of 0.10-0.15°C/s. Method allows milk shelf time to be increased up to 25 days.

EFFECT: prolonged shelf life, high gustatory qualities, improved biological and nutritive value of milk, and reduced power consumption.

4 cl, 1 tbl, 1 ex

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