EP0984702A1 - A method of producing uht milk with improved flavour qualities - Google Patents
A method of producing uht milk with improved flavour qualitiesInfo
- Publication number
- EP0984702A1 EP0984702A1 EP98909915A EP98909915A EP0984702A1 EP 0984702 A1 EP0984702 A1 EP 0984702A1 EP 98909915 A EP98909915 A EP 98909915A EP 98909915 A EP98909915 A EP 98909915A EP 0984702 A1 EP0984702 A1 EP 0984702A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- milk
- temperature
- heat treatment
- uht
- enzyme deactivation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
- A23C9/00—Milk preparations; Milk powder or milk powder preparations
- A23C9/15—Reconstituted or recombined milk products containing neither non-milk fat nor non-milk proteins
- A23C9/1508—Dissolving or reconstituting milk powder; Reconstitution of milk concentrate with water; Standardisation of fat content of milk
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
- A23C3/00—Preservation of milk or milk preparations
- A23C3/02—Preservation of milk or milk preparations by heating
- A23C3/03—Preservation of milk or milk preparations by heating the materials being loose unpacked
- A23C3/033—Preservation of milk or milk preparations by heating the materials being loose unpacked and progressively transported through the apparatus
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
- A23C3/00—Preservation of milk or milk preparations
- A23C3/02—Preservation of milk or milk preparations by heating
- A23C3/03—Preservation of milk or milk preparations by heating the materials being loose unpacked
- A23C3/033—Preservation of milk or milk preparations by heating the materials being loose unpacked and progressively transported through the apparatus
- A23C3/037—Preservation of milk or milk preparations by heating the materials being loose unpacked and progressively transported through the apparatus in direct contact with the heating medium, e.g. steam
Definitions
- the present invention relates to a method for producing UHT milk which includes pretreatment of the milk by separation and standardisation, and also homogenisation and heat treatment.
- UHT milk Ultra High Temperature
- a commercially sterile product may be defined as a product which is free of micro-organisms which may grow and multiply under prevailing conditions.
- One object of the present invention is to treat the milk as gently as possible in its pretreatment in order not to subject the milk to heat treatment or mechanical action unnecessarily.
- a further object of the present invention is that the heating process take place at an elevated temperature for a short time, with retained destructive effect, which also contributes to a gentler treatment of the milk, with consequentially improved flavour qualities.
- Yet a further object of the present invention is that the method include an enzyme deactivation in one or more stages in order to obtain a stable, aseptic product.
- Fig. 1 is a flow diagram of an installation for reducing the method into practice.
- the raw milk arrives at the dairy, it is normally at a temperature of 4°C.
- the incoming milk may possibly be stored in buffer tanks, this storage taking place at maintained temperature.
- the separator 2 may be conventional type, but, if it is not the intention to heat the milk before separation, a so-called cold separator 2 may likewise be employed.
- the milk is separated according to the invention at a temperature of 4-15°C, for which reason a certain insignificant heating may take place before the milk arrives at the separator 2.
- a cold separator 2 differs in principle from a standard separator in that the distance between the panels is slightly greater, since cold cream is of a higher viscosity than the warmed cream.
- conventional separation at approx. 55°C may be employed.
- Both the cream and the skimmed milk are at a continued low temperature of 4- 15°C, alternatively 55°C if conventional separation is employed.
- the cream is led in its conduit 3 to a standardisation unit 5 in which it is possible to obtain an exact proportion of cream for re-admixing to the skimmed milk, which gives a milk product with the desired fat content.
- the excess cream is led in a conduit 6 out from the standardisation unit 5 for separate treatment.
- the UHT unit 7 normally also incudes a homogeniser which is preferably placed after the heating of the milk, but which may also be placed ahead of the heating.
- the homogenisation is carried out in order to obtain a milk product where the fat globules are corrtminuted to small fat globules of equal size. If the milk is not homogenised, a cream precipitation will occur, i.e. the fat globules (which are lighter) accumulate in the upper region of the finished package. Almost all consumer milk is homogenised today.
- the UHT treatment proper takes place according to the present invention in that the milk is heated to a temperature above 135°C for a brief period of time.
- the heating takes place to 135-175°C for the requisite time, depending upon the requirements on destruction or on the food regulations in each respective country.
- the destruction requirement is dependent upon the bacteria and spore content of the incoming milk.
- the heating of the milk may either take place directly by steam injection or steam infusion or indirectly by the milk being heated in some form of heat exchanger, or a combination of these methods.
- a certain instability in respect of enzyme activity may occur.
- This instability as a result of enzyme activity also affects the flavour of the UHT product and the objective is to obtain a stable, aseptic product.
- such instability may be remedied in that the milk, after the UHT treatment, is cooled in one or more stages at temperatures of between 55 and 70°C, in a time interval of between 2 and 10 minutes, for example 63-65°C for 4-8 minutes, whereafter the product is cooled to packaging temperature.
- the enzyme deactivation requires holder cells of tubular type or the like, which may be integrated into the UHT unit 7.
- the enzyme deactivation may be carried out prior to the heat treatment.
- Deactivation prior to heat treatment takes place in a corresponding manner, in one or more stages at temperatures of between 55 and 70°C, in a time interval of between 2 and 10 minutes, for example 63- 65°C for 4-8 minutes.
- the enzyme deactivation takes place holder cells of tubular type or the like.
- a certain advantage by placing the deactivation ahead of the heat treatment is that this method step need not be carried out under aseptic conditions.
- the ready-treated milk is conveyed in a conduit 8 further to one or more filling machines 9.
- the filling machines 9 are aseptic and may, for example, be of the type which packs the milk into parallelepipedic packaging containers of single-use disposable type.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Dairy Products (AREA)
Abstract
The disclosure relates to a method of producing UHT milk with improved flavour qualities. The method includes pretreatment of the milk by separation and standardisation, and also homogenisation and heat treatment. The treatment takes place at a temperature exceeding 135 °C. The method also includes enzyme deactivation, in one or more stages. The milk is then kept in holder cells at a temperature of 55-70 °C for a period of time of 2-10 minutes. Enzyme deactivation is carried out after the heat treatment, or alternatively before the heat treatment.
Description
A METHOD OF PRODUCING UHT MILK WITH IMPROVED FLAVOUR QUALITIES
TECHNICAL FIELD The present invention relates to a method for producing UHT milk which includes pretreatment of the milk by separation and standardisation, and also homogenisation and heat treatment.
BACKGROUND ART The heat treatment of milk with a view to obtaining a commercially sterile product or so-called UHT milk (Ultra High Temperature) is a well- known phenomenon. To UHT treat the milk implies that it is treated at high temperature for a certain given period of time. As a result of the heat treatment, micro-organisms are destroyed and heat-resistant enzymes are deactivated so that a milk is obtained with a long shelf life at room temperature. A commercially sterile product may be defined as a product which is free of micro-organisms which may grow and multiply under prevailing conditions.
Producing a UHT milk and packing it under aseptic conditions in an aseptic package affords a number of advantages, from the points of view of both distribution and storage. In countries lacking a distribution apparatus and network which function under satisfactory refrigeration, a considerable advantage is to be gained in the employment of aseptic milk products which may distributed and stored at room temperature over a lengthy period of time.
However, all treatment of the milk, both mechanical and thermal, implies that the flavour of the milk may be modified. Today, most methods for UHT treating milk are so gentle that extremely slight flavour modifications occur, as compared with pasteurised milk which is treated at considerably lower temperatures. However, the art is still seeking for a further improvement of the flavour of UHT milk, while maintaining the requirement of the destruction of harmful micro-organisms.
Most dairies today treat the incoming milk in a similar manner, irrespective of whether the milk is to be further treated at high temperature, i.e. UHT treatment , or whether the milk is to be sold as a pasteurised product. This implies that the incoming milk, which is at a temperature of
4°C, is heated to approx. 55°C and separated, standardised and homogenised. Thereafter, the milk is pasteurised at 72°C for 15 seconds, or in similar time/ temperature conditions. The milk which then is to be UHT treated for obtaining an aseptic product is treated further by heating to approx. 140°C for a period of time of approx. 4 seconds.
In connection with UHT treatment of milk, a certain instability in the product may occur, because of enzyme activity. This may also have a negative effect on the flavour of the finished product.
OBJECTS OF THE INVENTION
One object of the present invention is to treat the milk as gently as possible in its pretreatment in order not to subject the milk to heat treatment or mechanical action unnecessarily.
A further object of the present invention is that the heating process take place at an elevated temperature for a short time, with retained destructive effect, which also contributes to a gentler treatment of the milk, with consequentially improved flavour qualities.
Yet a further object of the present invention is that the method include an enzyme deactivation in one or more stages in order to obtain a stable, aseptic product.
SOLUTION
These and other objects have been attained according to the present invention in that the method of the type described by way of introduction has been given the characterizing feature that the heat treatment takes place at a temperature exceeding 135°C, and that the method also includes enzyme deactivation in one or more stages at a temperature of 55-70°C for 2-10 minutes.
Preferred embodiments of the present invention have further been given the characterizing features as set forth in the appended subclaims.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
One preferred embodiment of the present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawing, in which:
Fig. 1 is a flow diagram of an installation for reducing the method into
practice.
DESCRIPTION OF PREFERRED EMBODIMENT
When the raw milk arrives at the dairy, it is normally at a temperature of 4°C. The incoming milk may possibly be stored in buffer tanks, this storage taking place at maintained temperature. When the milk is to be treated, it is conveyed along a conduit 1 to a separator 2. The separator 2 may be conventional type, but, if it is not the intention to heat the milk before separation, a so-called cold separator 2 may likewise be employed. The milk is separated according to the invention at a temperature of 4-15°C, for which reason a certain insignificant heating may take place before the milk arrives at the separator 2. Experiments have demonstrated that a certain, albeit negligible, increased fat content is obtained in the skimmed milk on separation at low temperatures. However, the advantage is that a gentler treatment of the milk will be obtained than is the case in separation at conventional temperature. A cold separator 2 differs in principle from a standard separator in that the distance between the panels is slightly greater, since cold cream is of a higher viscosity than the warmed cream. Alternatively, conventional separation at approx. 55°C may be employed. As a result of the separation, there will be obtained, from the separator 2, cream in one conduit 3 and skimmed milk in one conduit 4. Both the cream and the skimmed milk are at a continued low temperature of 4- 15°C, alternatively 55°C if conventional separation is employed. The cream is led in its conduit 3 to a standardisation unit 5 in which it is possible to obtain an exact proportion of cream for re-admixing to the skimmed milk, which gives a milk product with the desired fat content. The excess cream is led in a conduit 6 out from the standardisation unit 5 for separate treatment.
By separation and standardisation at a relatively low temperature of 4-15°C, there will be obtained a considerably gentler pretreatment of the milk which is to be further treated to UHT milk. Conventional dairy handling and pretreatment of UHT milk involves hot separation at 55°C and most generally pre-pasteurisation at 72°C for 15 seconds, or at similar time / temperature combinations. These heating operations imply an unnecessary temperature action on the milk which, in a later stage, is to be subjected to substantially higher temperatures with a view to obtaining a commercially sterile product.
The conduit 4 with the cream re-admixed into the skimmed milk is led to a UHT unit 7 of conventional type. The UHT unit 7 normally also incudes a homogeniser which is preferably placed after the heating of the milk, but which may also be placed ahead of the heating. The homogenisation is carried out in order to obtain a milk product where the fat globules are corrtminuted to small fat globules of equal size. If the milk is not homogenised, a cream precipitation will occur, i.e. the fat globules (which are lighter) accumulate in the upper region of the finished package. Almost all consumer milk is homogenised today. The UHT treatment proper takes place according to the present invention in that the milk is heated to a temperature above 135°C for a brief period of time. Preferably, the heating takes place to 135-175°C for the requisite time, depending upon the requirements on destruction or on the food regulations in each respective country. The destruction requirement is dependent upon the bacteria and spore content of the incoming milk. Experiments have demonstrated that a heating according to the present invention gives a product which satisfies the requirements of commercial sterility.
In a UHT unit 7 of conventional type, the heating of the milk may either take place directly by steam injection or steam infusion or indirectly by the milk being heated in some form of heat exchanger, or a combination of these methods.
In some UHT treatments of milk, a certain instability in respect of enzyme activity may occur. This instability as a result of enzyme activity also affects the flavour of the UHT product and the objective is to obtain a stable, aseptic product. According to the present invention, such instability may be remedied in that the milk, after the UHT treatment, is cooled in one or more stages at temperatures of between 55 and 70°C, in a time interval of between 2 and 10 minutes, for example 63-65°C for 4-8 minutes, whereafter the product is cooled to packaging temperature. The enzyme deactivation requires holder cells of tubular type or the like, which may be integrated into the UHT unit 7.
Alternatively, the enzyme deactivation may be carried out prior to the heat treatment. Deactivation prior to heat treatment takes place in a corresponding manner, in one or more stages at temperatures of between 55 and 70°C, in a time interval of between 2 and 10 minutes, for example 63-
65°C for 4-8 minutes. The enzyme deactivation takes place holder cells of tubular type or the like. A certain advantage by placing the deactivation ahead of the heat treatment is that this method step need not be carried out under aseptic conditions. The ready-treated milk is conveyed in a conduit 8 further to one or more filling machines 9. The filling machines 9 are aseptic and may, for example, be of the type which packs the milk into parallelepipedic packaging containers of single-use disposable type.
The heating of the milk modifies the milk chemically, with the result that the flavour of the milk undergoes a change. Thus, the art is striving to achieve as slight a chemical action as possible on UHT treatment of the milk. Flavour is a subjective factor, but by measurements of lactulose in the milk, it is possible to gain an indirect measurement of the effects on flavour. The higher the temperature loading to which the milk is subjected, the higher will be the level of lactulose content in the milk. Experiments in pretreatment and UHT treatment of milk according to the present invention have demonstrated that lower levels of lactulose content, and thereby indirectly an improved flavour of the finished UHT will be obtained.
As will have been apparent from the foregoing method of treating the milk, there will be obtained an aseptic product which, as a result of the gentle treatment, gives considerably improved flavour qualities.
Claims
1. A method for producing UHT milk which includes pretreatment of the milk by separation and standardisation, and also homogenisation and heat treatment, characterized in that the heat treatment takes place at a temperature exceeding 135┬░C; and that the method also includes enzyme deactivation in one or more stages, at a temperature of 55-70┬░C for 2-10 minutes.
2. The method as claimed in Claim 1, characterized in that the enzyme deactivation takes place after the heat treatment.
3. The method as claimed in Claim 1, characterized in that the enzyme deactivation takes place before the heat treatment.
4. The method as claimed in any of the preceding Claims, characterized in that the enzyme deactivation takes place at a temperature of 63-65┬░C for 4-8 minutes.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9700928 | 1997-03-14 | ||
SE9700928A SE508869C2 (en) | 1997-03-14 | 1997-03-14 | Method for producing UHT milk with improved taste properties |
PCT/SE1998/000413 WO1998041102A1 (en) | 1997-03-14 | 1998-03-09 | A method of producing uht milk with improved flavour qualities |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0984702A1 true EP0984702A1 (en) | 2000-03-15 |
Family
ID=20406157
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98909915A Withdrawn EP0984702A1 (en) | 1997-03-14 | 1998-03-09 | A method of producing uht milk with improved flavour qualities |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0984702A1 (en) |
CN (1) | CN1255832A (en) |
AU (1) | AU6428198A (en) |
BR (1) | BR9808264A (en) |
EA (1) | EA001568B1 (en) |
SE (1) | SE508869C2 (en) |
WO (1) | WO1998041102A1 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6372276B1 (en) | 1997-03-14 | 2002-04-16 | Tetra Laval Holdings & Finance S.A. | Method for producing sterile, stable milk |
US6652900B2 (en) | 1997-03-14 | 2003-11-25 | Tetra Laval Holdings & Finance S.A. | Method and plant for producing a sterile milk product |
US6326044B1 (en) | 1997-06-19 | 2001-12-04 | Tetra Laval Holdings & Finance S.A. | Filter apparatus and method for the production of sterile skimmed milk |
US6737096B2 (en) | 2000-03-29 | 2004-05-18 | Tetra Laval Holdings & Finance S.A. | Method and apparatus for producing a sterile milk product |
SE521186C2 (en) | 2001-11-30 | 2003-10-07 | Tetra Laval Holdings & Finance | Method and apparatus for testing the cleaning efficiency of a filter in a filter system |
ES2528761T3 (en) * | 2010-03-25 | 2015-02-12 | Molkerei Alois Müller GmbH & Co. KG | Procedure for the manufacture of milk for the manufacture of cheeses from raw milk |
CN105142414A (en) * | 2013-04-25 | 2015-12-09 | 阿尔拉食品公司 | Improved milk and milk-related products |
CN103454301B (en) * | 2013-09-18 | 2015-12-23 | 宜兰食品工业股份有限公司 | The detection method of heat stability of protein in a kind of milk powder |
CN104670578A (en) * | 2013-11-30 | 2015-06-03 | 山东工大机械有限公司 | Instantaneous sterilizing type constant temperature device for beer |
DE102016200571B4 (en) * | 2016-01-18 | 2019-12-05 | Universität Hohenheim | Process for the production of long-life milk and stable milk produced by the process |
PL237308B1 (en) * | 2018-02-23 | 2021-04-06 | Okregowa Spoldzielnia Mleczarska W Lowiczu | Method for producing milk with extended shelf life and with increased content of vitamin D3 |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8606524D0 (en) * | 1986-03-17 | 1986-04-23 | Mini Of Agricultural Fisheries | Deactivating heat stable enzymes |
SU1676569A1 (en) * | 1988-11-04 | 1991-09-15 | Всесоюзный Научно-Исследовательский И Экспериментально-Конструкторский Институт Продовольственного Машиностроения | Sterilized milk production method |
RU2048155C1 (en) * | 1992-01-27 | 1995-11-20 | Прокопенко Борис Евгеньевич | Continuous-action distiller |
-
1997
- 1997-03-14 SE SE9700928A patent/SE508869C2/en not_active IP Right Cessation
-
1998
- 1998-03-09 EP EP98909915A patent/EP0984702A1/en not_active Withdrawn
- 1998-03-09 CN CN98805117A patent/CN1255832A/en active Pending
- 1998-03-09 AU AU64281/98A patent/AU6428198A/en not_active Abandoned
- 1998-03-09 EA EA199900831A patent/EA001568B1/en not_active IP Right Cessation
- 1998-03-09 WO PCT/SE1998/000413 patent/WO1998041102A1/en not_active Application Discontinuation
- 1998-03-09 BR BR9808264-7A patent/BR9808264A/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO9841102A1 * |
Also Published As
Publication number | Publication date |
---|---|
EA001568B1 (en) | 2001-04-23 |
SE9700928D0 (en) | 1997-03-14 |
AU6428198A (en) | 1998-10-12 |
SE508869C2 (en) | 1998-11-09 |
WO1998041102A1 (en) | 1998-09-24 |
CN1255832A (en) | 2000-06-07 |
SE9700928L (en) | 1998-09-15 |
BR9808264A (en) | 2000-05-16 |
EA199900831A1 (en) | 2000-04-24 |
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