This portable instrument enables accurate determination of water activity (aw value) in food products, helping ensure product stability and shelf life.
Equipped with data logging functions, it is ideal for use in quality control and production settings.
Suitable for measuring a wide range of materials including butter, fruit mixes, spices, mushrooms, flour, biscuits, sausages, and more. Unit only.
Water activity is a key factor affecting the stability of powders and dehydrated products during storage. By controlling water activity, manufacturers can maintain product structure, texture, stability, density, and rehydration properties.
Water activity also indicates how the water in food interacts with microorganisms. Higher aw values promote faster growth of bacteria, yeast, and mould. Below a certain threshold, only non-harmful microorganisms can grow. Lower the aw even further, and few - if any - microorganisms can grow and spoil the food.
Water activity influences the following characteristics:
- Microbiological stability
- Chemical stability
- Enzymatic stability
- Colour, taste, and nutritional value
- Content of proteins and vitamins
- Stability of composition
- Shelf life
- Storage and packaging
Water Activity and Micro-organisms
Water activity reveals the amount of water available to microorganisms. Each type of microorganism requires a minimum water activity value in order to grow. Below are some examples of typical values taken from literature:
| Measuring range | 0.03 to 0.98 aw | Resolution | 0.001 aw |
|---|---|---|---|
| Calibration | 0.10 to 0.80 +/- 0.01 aw, 0.00 to 0.10 and 0.80 to 0.98 +/- 0.04 aw (at 25°C) | Temperature range | 0 to + 50°C, calibration +/- 0.5°C (at 25°C) |
| Measuring range of relative humidity | 0 to 100% rh, resolution: 0.1% rh | Temperature | Can be set to °C or °F as required |
| Dew point | -55°C to + 60°C, resolution 0.1°C, -67°F to 140°F | Absolute humidity | 0 to 130 g/m³, resolution 0.1 g/m³ |
| Equilibrium moisture content | 2% to 30%, resolution 0.1% |