Lactose-free milk is on trend: Aseptically dose small quantities, safely and accurately
4 March 2015
Lactose-free milk is on trend: Aseptically dose small quantities, safely and accurately
The VARI-DOS-ASEPT aseptic dosing station from GEA TDS is an innovation that enables users to dose aseptic liquids in very small quantities of 0.2 and 0.3 g/litre directly into the main aseptic product flow – with total accuracy and at favourable cost. This offers significant added value for the beverage industry – in the manufacture of lactose-free milk, for instance. The stimulus to develop this innovative dosing station came directly from the everyday experience of SIG Combibloc’s dairy customers.
Customers needed a method that would enable them to produce beverages containing special ingredients such as enzymes, functional additives, vitamins, flavours or extracts more safely and accurately, and thus more cost-effectively, than existing systems were able to do. GEA TDS engineers set to work on this request, and developed a technological masterpiece that is now proving its value in practice.
The production of lactose-free milk is a good example of how the new aseptic dosing station is bringing clear added value to the beverage industry in practical terms. In theory, it is easy to make lactose-free milk. Simply add a bit of the enzyme lactase to normal milk, and after a certain amount of time you have lactose-free milk. The challenge is to keep the quantity of the required enzyme as small as possible, and to make sure that the enzyme is added in conditions of the utmost aseptic safety, because the lactase enzyme is a comparatively high-cost item in the cost accounting. The dosing must be absolutely safe in aseptic terms, highly accurate, as far as possible automated, and rapid, so that no contaminants are introduced into the production process. Only then is high product quality guaranteed.
Optimal quality, favourable costs
The VARI-DOS-ASEPT presents an alternative method for aseptic dosing which differs in key aspects from existing systems, and offers optimal product quality at favourable costs. Ludger Tacke, Head of the Aseptics Division at GEA TDS: "Basically, there are two ways of making lactose-free milk. In both methods, the aim is to break down the milk sugar, lactose, in the milk, which causes intolerance reactions in many people. The enzyme lactase is used to break down the lactose into glucose and galactose, so that most consumers will then no longer have any problem. The lactase enzyme can be added to the milk prior to heat-treatment; everything is then heat-treated together and subsequently packaged for long life."
This batch technology is a reliable method, but a more costly one, requiring comparatively large quantities of the enzyme, because the heat treatment alters the lactase enzyme; to some extent, the enzyme is even marginally decomposed by the effects of the heat. In addition, the storage temperature for microbiological reasons is very low, which greatly delays the degradation Therefore a high quantity of enzymes must be added in advance to achieve the desired effect.
At around five to six cents in enzyme costs per litre, the method is very expensive and consequently is suitable only for small quantities. In this method, 0.8 to 0.85 g/litre of lactase (activity 5,000 units) is added to the pasteurised milk, which has a temperature of 8 to 10°C. The hydrolysis time is about 24 hours. A shortcoming of this method is, that the milk has to stay in the tanks during hydrolysis and thus the tanks cannot be used for production. Furthermore, the milk turns brown faster (the Maillard reaction).
Considerably more efficient is the method of adding the enzyme after the heat treatment by aseptic dosing. If the milk has already cooled, no more of the enzyme will be destroyed by heat. Tacke: "0.2 to 0.3 g of enzyme is enough for one litre – that’s only about 10 to 15 per cent of the quantity you previously needed when adding the enzyme prior to the heating process."
Existing dosing stations – which are used to add very small quantities of additional aseptic liquids to the main product after the heat-treatment has taken place – have the disadvantage that at key points, such as when sterilising and when placing the needles in the product flow, the operator has to perform some actions by hand. And that always represents a risk for aseptic product safety. Another critical point is that with existing systems, the enzyme is delivered to the dairy processing plant in a bag, which in turn is inside a container. In this position, these bags cannot be emptied fully, which means a loss of enzymes.
A plus for safety
VARI-DOS-ASEPT differs in key aspects from existing systems, and offers optimal product quality at favourable costs. During sterile dosing with VARI-DOS-ASEPT, approximately 0.3 g of sterile lactase per litre is added to the milk after the UHT process has taken place. Hydrolysis occurs in the carton pack, and takes about 5 days at room temperature. With this method, while a dosing station is required and the hydrolysis time is longer, the enzyme costs are up to 85 per cent lower than with the batch method.
Furthermore, the method offers a high level of flexibility in production. Milk does not have to stay in the tanks and so the tanks are available for production. Product quality is improved as well, as the Maillard effect is significantly delayed.
With existing systems, the enzyme is delivered to the dairy processing plant in a bag, which in turn is inside a container. With the new VARI-DOS-ASEPT dosing station, the product to be dosed is delivered in specially developed bags similar to those used in the pharmaceutical industry – comparable to a hanging infusion bag, which can be emptied down to the last drops. There is no danger of the bag being crushed in the container, and residues then being left in the bag. This also saves costs. The container consists of this bag and a hose that is firmly connected to the bag. A dosing needle is fitted to the tip of the hose. All components are already sterilised when they reach the beverage manufacturer. That means the individual components no longer need to be touched by hand – a huge plus for aseptic safety. These bags are delivered by the company optiferm. The company filters ingredients from a wide range of international suppliers and fills them in the above-mentioned special bags for the VARI-DOS-ASEPT.
Tacke: „To ensure the needle enters the main product flow in flawlessly aseptic conditions, we have developed a special multifunction port valve to which the empty hose, inside which is the aseptic filling feed system, is connected upstream of the aseptic filling machine. The port valve, of which two are provided so that production can run continuously, has an automatic sterilisation function, where the needle is sterilised with steam. This takes place when the operator will be having no further contact with the components. In its mini sterile zone in the aseptic vacuum, the needle is then automatically moved to the production position. Then the filling feed system and the needle are filled with the aseptic liquid via the valve. The aseptic liquid is measured out using a high-precision balance and dosed into the product flow in exactly the required amount. In the event of a production stoppage, the port valve is simply closed and the needle remains in the production position within its sterile zone, until it’s put into operation again. A sterile air overpressure ensures consistently reliable sterility. Manual withdrawal and re-sterilisation is not necessary. This is another plus point for aseptic safety."
Precise dosing – many areas of application
Apart from the lactase enzyme, a wide range of other aseptic additives can also be accurately delivered into the aseptic product flow, using the new dosing station. Norman Gierow, Head of Global Product Management Market at SIG Combibloc: "Numerous areas of application can be imagined here, particularly if we think about added value products. Ingredients such as lactoferrin, vitamins, various flavours and extracts or colourants – with extras such as these, our customers need to ensure that their routine production operation works with the utmost precision, and is absolutely clean and aseptically safe, in order to maintain outstanding product quality at favourable costs. And in this process, the VARI-DOS-ASEPT is a real improvement. We’re very proud to have had a hand in initiating this project, and with VARI-DOS-ASEPT GEA TDS has developed an innovative dosing station that really is one-of-a-kind. We’re certain that with this solution, beverage customers all over the world will benefit considerably when it comes to product quality and cost-effectiveness. In fact, that’s already being demonstrated in practice."
Heike Thevis – Press Officer
SIG International Services GmbH
Rurstraße 58, D-52441 Linnich, Germany
Tel.: +49 2462 79 2608
Fax: +49 2462 79 17 2608