Water Activity and its Influence on Product Quality

Markus Bernasconi, Key Account & Product Manager Novasina AG, markus.bernasconi@novasina.ch

Water Activity is defined as the current volume and availability of “free” water in a sample and should not be directly compared with the water content (g water / g substance). The water activity is given as the aw – value and ranges between 0 (absolute dryness) and 1 (100% relative humidity).

Pascal-ST/Z

The new Pascal–ST/Z measurement devices are working by measuring the static differential pressure. This method is based on a silicone membrane, which is deformed when pressure is acting on it and provides a corresponding measurement value. This technology has certain physical limits though. Due to the mechanical stress and meterial fatigue a zero–point drift occurs after a certain time.

PascalMaxx

Available in the measurement ranges 0 to 500 Pa and 0 to 2000 Pa this instrument is used predominantly for filter and V–belt monitoring in Fan Filter Units. Thanks to the integrated automatic zero–point calibration system, measurements are carried out with high reproducibility and stability. This allows ideal conditions for monitoring and controlling purposes. The robust design protects the electronics and sensor. The large display enables a fast and reliable reading of the actual measurement value. Besides the scalable analogue output (V and mA) the device disposes of a 230V relay contact. Therefore high loads can be connected and switched.

Water Activity Measurement, Simple as Never Before!

Let‚s welcome the next generation of high quality water activity meters made by Novasina. Touch a new world, driven by the ease of use and fast menu access by a touch–screen combined with a semi–temperature–stabilised measurement chamber for consistent and reproducible measurement results (aW–Value). The latest sensor and measurement technology coupled with re–useable humidity calibration standards provide a very economical solution to precision water activity measurements. Furthermore, the standards are an easy method for double–checking the instrument and sensor‚s high performance.

LabSwift-aw

The Swiss measurement instrument manufacturer Novasina AG launches the new water activity measurement device LabSwift–aw. The portable instrument is suitable for mobile applications in laboratories of at the production line. If in food stuff, drugs or cosmetics, anywhere high measurement speed and accurate measurement results are required the LabSwift–aw can be used for improving the measurement efficiency and therefore reducing the time needed for the measurement and thus also the costs per measurement.

HygroMaxx HVAC Measurement Instrument for Relative Air Humidity & Temperature

Novasina‚s new cost efficient humidity/temperature measurement instrument HgroMaxx fits ideally in HVAC control systems. The device has scalable analogue outputs (0 to 10V or 4 to @0mA) and allows an ideal adjustment with the requested measurement range. Furthermore it offers the possibility of a 3-point adjustment for humidity and 1–point adjustment for temperature. It achieves a high accuracy (+/– 1.5% RH) and reproducibility. The adjustment is done quite easily by simply pushing a button

HygroGuard 30 RH/T Data Logger System

Developed for the climate and air quality monitoring of buildings and climate sensitive production process the Novasina HygroGuard 30 standard data logger offers versatile precision measurement and monitoring capabilities.

Unique to its design in LAN connectivity and power options: battery, USB and PoE (Power over Ethernet) offering network or standalone capabilities. A compact and intuitive design enables ease of integration giving flexibility, reliablity and accuracy. The big display offers a easy reading at a glance.

Applications include data centers, climate sensitive production, museums and warehousing in the food, pharmaceutical and electronics sectors. But also in the transportation sector and cold chain monitoring such data loggers can be easily used.

As Easy as Never Before: Control and Improve your Product Quality!

Tired to perform never-ending and work-intense stability and shelf-life testing to get an idea about the durability or chemical/physical behavior of your product over time? Or, are you looking for additional measures to improve the quality of your products?

Then it is a perfect moment to talk about a little known, but very powerful parameter which is so easy to measure: Water Activity

As human needs water to survive,bacteria, molds and other pathogens do as well. The difficulty is that water in a product can be present in two different forms: bound and free. Bounded water (i.e. crystal water) can not support the growth of microorganisms but free water does. But how much of this free water is in a product? Unfortunately, there is no analytical method available to determine the amount of free water. Moisture or water content provides the amount of total water - means, bound and free together, without a clue how much is the contribution of the free water. But, no worries, there is a method to measure the activity of the free water, and self-naming it is the Water Activity.