Water activity Laboratory instrument for accurate water activity (aw) measurement For assurance of : Quality Product safety Microbiological stability www.novasina.com „All life needs water!“ Air and water There is no life without water! the important elements on earth for any life „ Water means life! “ Thanks to water, life has developed and new life continues to develop. „ Life needs water“. Water is the „elixir of life“ for animals, humans and plants. But bacteria, fungi and viruses also need water to live. Water is stored in every product. Either in the form of a chemical compound with other molecules or as free water, which is stored between the compounds. What is the optimum amount of both types of water now? The amount of bound water is depending on the chemical reactivity of the substances used. Free water can be affected by production processes as wel as via storage and packing. Alongside the usage of water, too much free water can particularly damage the product. Microorganisms such as fungi or bacteria can optimally grow and thrive on this surface. Their metabolic products are deposited on the product and spoil the quality. Too high water activity means limited durability. Water activity values, which are too low can spoil the taste or appearance. Only an extremely accurate and safe quality measurement of water activity („free water components“) guarantees quality products! Meaning of „water activity“ (a ) w 0...100% RH corresponds to 0.00...1.00 aw Water (H2O) is an important basic element in foods as well as in many pharmaceutical and cosmetic materials and products. For a long time the Free water in products is jointly responsible industry has known how important it is to check free water. The water for the growth of undesirable organisms such activity (aw) measurement forms the basis of this and provides important as bacteria or fungi, which produce toxins or information about the quality of a product. Finally it provides information other harmful substances. But also chemical/ regarding the possibility of microbiological growth on the surface and then biochemical reactions ( e.g. the Maillard conclusions can be made about the stability and durability of a sample. reaction) increasingly take place and possibly change the product’s Water activity is defined as the degree of availability of free water in a sample. Only this component takes an active part in the exchange colour, taste, shape, with the ambient humidity and can possibly form the ideal medium for texture and appearance. microbiological growth on the surface. Above the sample, the humidity is measured immediately after reaching the humidity equilibrium. The relative humidity is measured in % RH and converted in aw electronically. Introduction to aw measuring In the food, pharmaceutical and cosmetic industry, water activity (aw value) is understood as the humidity balance (equilibrium) value of a product, which is ascertained through its partial vapour pressure of water vapour on the surface. This is depending on the following factors: • Chemical compound The optimisation and stabilisation • Temperature of the product properties • Water content require an upper as well as • Storage environment (T / RH) lower aw value limit. Therefore, • Absolute pressure constant supervision of this • Packing quality parameter is essential and necessary for efficient production. Above factors affect also the following properties: There are binding regulations • Microbiological stability (growth) regarding to the aw value to be • Chemical stability (see table) met in foods. The measuring • Content of proteins and vitamins principle applied by Novasina • Colour, taste and nutritional value was checked by the FDA, UNO, • Stability of the compound & WTO, FAO, AOAC and FOS durability (EFSA) and found to be suitable. • Storage and packing • Solubility and texture Novasina, the market-leading provider of accurate water activity measuring instruments Enter the world of water activity! For over 50 years Novasina has been The Lab Touch-aw comes with a semi-temperature controlled measurement developing globally recognised and accurate water activity measuring chamber. Its function premise is that the measurement temperature has instruments for quality and research laboratories. The unique measuring to be always 2°C above room temperature. technology is based on an electrolytic aw value measurement as well as The measurement of the water activity is based on a resistive electrolytic on simple operability and sample conditioning. These are the key factors humidity measurement („Novalyte“ technology) which is one of for correct and repeatable measurements. Thanks to new functions, the Novasina’s core strengths. The advantages are quite simple but essential: effective measuring accuracy and reproducibility could be improved and No hysteresis, high accuracy and repeatability. the scope of applications extended. Most different types of foods, as well as many pharmaceutical, chemical and cosmetic products can be checked Various chemical filters are available to protect the sensor system with the new Lab Touch-aw system from volatiles as alcohol, glycol, glycerine and many more. The use of filters guarantees an unaffected aw measurement and avoids a sensor contamination and thus extends its shelf-life. LabTouch-aw with touch screen interface Due to the use of filter systems to protect the measuring sensor, today Your advantages: even samples with non-aqueous additives such as alcohol, acids/bases or • Easy accessible menus by chlorine etc. can be measured efficiently and accurately. Such filter systems large touch-screen do not generally affect the measuring of the water activity. The LabTouch- • Semi-temperature-stabilised measurement chamber aw system ideally uses the highest physically possible measuring speed. • Re-usable SAL-T humidity standards and long-life sensor for Thanks to modular expandability and pre-conditioning, a higher number economy of samples can also be measured quickly and accurately. • Fast and precise aw-measurement thanks to the unique The new Lab Touch-aw with its simple and clear operation by touchscreen „Novalyte“ measurement technology sets a new standard for aw laboratory measuring devices. Thanks to • Specific chemical sensor protection filters available modular construction, the system can be expanded by up to 2 additional • Calibration data are stored on the sensor (no calibration required measuring chambers. Its unique hardware and software architecture after sensor replacement)) enables highly accurate, reproducible measuring results over a wide measuring range. As a result, all recommendations and regulations of • Data logging function with SD card authorities/control boards such as HACCP, AOAC, FDA etc. can be met. • Factory calibration at 7 aW-value points Each Lab Touch-aw is equipped with a SD-card which can be used for data • Checking, testing and adjusting possibilities with reusable transfer to Windows-based PC systems. For data and sample visualisation, SAL-T humidity standards analysis and archiving, Novasina offers a tested PC software. • Visualisation and analysis software „Novalog MC“ www.novasina.com The LabTouch / Click-aw product range Lab Click-aw No.1 Lab Touch-aw With the LabTouch-aw measuring instrument you acquire a long-lasting laboratory device, which is upgradeable at all times thanks to its advanced technology. Extra LabClick-aw’s can simply and easily be attached to a Lab Click-aw No.2 LabTouch-aw advanced as additional measuring units. A LabTouch-aw manages and operates up to 2 LabClick-aw using just one cable If necessary, the sensing unit can be replaced quickly and easily by the per chamber. As a result, it is possible to measure up to 3 samples user. Every factory-delivered sensor comes with a factory calibration at simultaneously. The intelligent network independently recognises a new all points which are stored on a small memory on the sensor-board itself. chamber and correspondingly lintegrates it in the network. This allows the user to mount the sensor and start measuring without An SD-card is used for long-term storage and management of all measuring performing a calibration. data which can be read-out by using a standard PC and Novasina‘s Verification and calibration of the meter is done by re-useable Novasina Novalog MC software. humidity standards. These are easy to handle, offer great long-term The software of each LabTouch/Click-aw can be updated using the SD-stability and generate reproducible aw values. A set of 4 aw standards card on which you can put the downloaded update files. This way, the is included in each LabTouch-aw delivery. The SAL-T standards do not instrument can be kept up to date at any time. contain a due date as shelf-life mostly depends on their handling and storage. Field data have proven a shelf-life of 3-5 years Specifications LabTouch / LabClick-aw system LabTouch-aw LabClick-aw Measuring Principle aw Resistive electrolytic air humidity measurement Measuring Principle temperature Surface infrared measurement + NTC element Measuring Range aw (full) 0.03 ...... 1.00 aw Measuring Range temperature 5....45 °C ( 41......113°F ) Accuracy aw (Range) +/- 0.005 aw (0.10 ... 0.97 aw) +/- 0.010 aw (0.10 .... 0.95 aw) Accuracy temperature (Range) +/- 0.15 °K (5 ... +45°C) +/- 0.15 °K (5 ... +45°C) Resolution aw / temperature 0.001 aw / 0.1°C 0.001 aw / 0.1°C Accuracy of temperature control +/- 0.05°C No temperature control Semi-temperature control, programmed temperature must be always +2°C above environmental temperature! Mains supply (instrument) 5 VDC +/- 6%, max. power requirement : 10 W Power supplied by Lab Touch-aw Power supply (external) 90....264 VAC 50 / 60 Hz, output -> +5 VDC Power supplied by Lab Touch-aw Display 4.3“ resistive touch-screen (color LC display) Reflective LC-display with adjustable contrast Communication SD card /type: SD / SD data system: FAT-16 / FAT-32 N/A Housing Two-part PC/ABS design housing measurement chamber aluminium anodised Weight 2.8 kgs 1.2 kgs Protection Class / Dimensions IP 22 / Dimensions approx. : 300 x 200 x 105 mm IP 30 / Dimensions approx. 225 x 140 x 85 mm Volume Measurement Head 21.1 mL, standardised sample dishes Dimension Measuring Chamber 40 x 12 mm Sealing Measurement Chamber Spring loaded measurement head plus lip seal a value measurement method w The test sample is placed in a completely sealed and temperature-Intramolecular effects as van der Waals forces slow down the diffusion stabilised measuring chamber. After closing the chamber, the sample or inhibit the free water to move towards the surface and interact with humidifies or dehumidifies the surrounding air volume inside the chamber the air in the chamber. As a consequence, special attention is given once by exchanging free water from the sample and humidity from the air. high carbohydrate or protein content is available in the sample. At a certain point, the mass flow of water in each direction is constant, Fat is another story. Once a sample is covered with a fat layer, no free means, equilibrium is reached. At this point, the air humidity is linked water can pass through, thus the displayed aw value might be wrong. to water activity, thus an air humidity measurement can be used to The solution here is the sample preparation by breaking through the fat determine the water acitvity of the sample. State-of-the-art instruments layer (mainly cutting or mixing of sample) are monitoring the status of this equilibrium and are notifying the user once it is reached. The following factors play an important role in the To exclude external influences, mainly temperature, a temperature measuring accuracy and speed: controlled chamber is a prerequisite, otherwise, nobody knows if the shift in aw value comes from the sample or the temperature. • Temperature of the sample and measuring chamber is measured • Equilibrium detection mode • Sealing of the measuring chamber • Sample preparation • Measurement accuracy of the air humidity sensor The measuring speed largely depends on the sample properties and stability of environmental conditions, mainly temperature. Food industry Typical measuring samples Testing of products and raw materials to optimise • Meat, fish, poultry durability, colour, taste, nutritional value and • Fruit, berries, fruit additives, processing. Final inspection, quality assurance as • Bread, cakes and pastries, jam, biscuits well as packing optimisation regarding durability. • Dried sausage, nuts Optimising process and energy costs during • Butter, yoghurt, quark, cheese production. • Chocolate, cocoa, chocolate bars, sweets Quality controls in accordance with • Pasta products, rice, cereals HCCP WHO, FDA, AOAC • Spices, dried soups • Stock cubes, yeast Pharmaceutical industry Typical measuring samples Tests of basic materials, semi-finished and finished products for process properties and possible • Different powders reactivities. Checking further process abilities in • Granules the subsequent process levels. Checking product • Tablets, coated tablets properties regarding the intake and release of free • Gels, creams water into the environment. • Various liquid materials • Specific drugs Quality controls in accordance with HCCP, SOP, FDA, SOP Cosmetic industry Typical measuring samples Quality assurance of basic materials, semi-finished and finished products. Optimising • Powders durability, colour, fragrance as well as taste and • Creams and gels processing. Optimising packing regarding durability • Cosmetics and presentation. • Colours • Conditioning creams Quality controls in accordance with HCCP, WHO, FDA, SOP Some well known companies who associate quality with Novasina: Novasina – Swiss quality, flexibility and competence Since its establishment almost 50 years ago, the Novasina company has specialised in the accurate measuring of air and material humidity. The basis of this was the world’s first, self-developed electronic measuring sensor for measuring humidity. This technology is based on the resistive electrolytic measurement principle. This was further developed and optimised over decades. This measuring principle is generally the most demanding and most accurate. Modern substances and materials allow continuous optimisation and expansion of the area of application of this measuring sensor. Today the highly accurate humidity measurement is among our core competences and forms an important pillar of our success. Intensive research and development further ensures a decisive advantage for us. Novasina sensors and measuring instruments are mainly applied to the area of air and material humidity. This is almost exclusively used in industrial applications as well as in research and development. We fully develop and produce Novasina precision measuring instruments in which our Know-how of many years is always included. We are proud of the „SWISS MADE“ label, which guarantees the highest quality, innovation and longevity. The diversity of our customers, business partners and applications as well as our international orientation makes Novasina the competent partner for demanding humidity measurements in the industrial sphere! Customer uses and innovation always come first with Novasina! For further technical information, see the technical data sheets: Consultation, sales and services: Manufacturer : Novasina AG Neuheimstrasse 12 CH - 8853 Lachen SZ Switzerland . 004321.00 Phone : +41/ (0)55-642-67-67 Fax : +41/ (0)55-642-67-70 Dok. Nr E- Mail : info@novasina.ch Internet : www.novasina.com Subject to technical changes An ISO 9001 : P 2008 certified company since 1996