The importance of water potential measurements – water activity meter

ELPRO Adhesive from the sales programme of our Swiss partner Rotronic , we present solutions for the efficient measurement of water activity. The importance of water potential measurements – the Water Activity Meter and a description of the issues can be found in the article below.

WATER ACTIVITY HAS A MAJOR IMPACT ON PRODUCTION PROCESSES

The water activity or water potential determines the ratio of the water vapour pressure of a product to the saturation pressure of pure water at the same temperature. It is a measure of the water vapour pressure created by free or non-chemically bound water in foods and other products.

Measuring water activity is a key parameter to ensure quality control of products or materials that are sensitive to moisture.

Water activity affects the following characteristics of raw materials or products: microbiological stability, chemical stability, enzymatic stability, colour, taste and nutritional value, protein and vitamin content, compositional stability, shelf life, storage and packaging, solubility and texture.

Areas of use, applications

Determination of water activity is crucial in the food, tobacco, pharmaceutical and cosmetics industries. It is particularly relevant when dealing with perishable products (such as foodstuffs, cereals and seeds). If products contain too much free water, they spoil, and the same happens if they have too little.

OPTIMAL ON-SITE SOLUTION FOR WATER ACTIVITY MEASUREMENTS

In connection with the above mentioned issues, ELPRO Lepenik presents the HP23-AW-A portable mini laboratory for water activity analysis HP23-AW-A portable laboratory for water activity analysis. The HP23-AW-A is used as a portable laboratory unit for the quantitative analysis of the presence of water vapour in a specific material.

The Water Potential Meter measures water activity in the range 0.00 to 1.00 AW, relative humidity and temperature, allowing the calculation of a wide range of parameters. Each of the two sensor inputs can be configured to accept either digital humidity and temperature sensors or an analogue sensor that measures any signal (air pressure, air velocity, etc.).

The HP23-AW-A portable water activity analyser from HygroPalm includes the AwQuick function, which allows accurate AW (water activity) measurements of most products in about 5 minutes.

The results obtained on water activity provide us with information and control

The use and measurements of HP23-AW provide a better reference for monitoring water activity control than data on total moisture content alone.

The HP23-AW provides information on the following parameters:

• microbiological, chemical and enzymatic stability of perishable products,
• cohesion and flow properties of hygroscopic powders,
• adhesiveness of coatings,
• solubility and structure,
• dimensional stability of materials,
• tensile strength and elasticity recovery,
• compaction pressures.

Benefits of water activity measurements

• direct measurement of free water,
• non-destructiveness,
• fast and easy measurement,
• measuring the difference in sample preparation.

Other specifications

• the instrument can be easily transported to the measurement site
• the possibility to display all psychrometric calculations
• 8 separate databases possible (up to 250 records per database)
• measurement record (stores up to 10,000 data records with %RV, °C, date and time)
• calibration:
  • can be used to calibrate and adjust HC2-A sensors or HC2 probe sensors, transducers and other devices based on AirChip 3000 technology
  • full calibration and adjustment function
  • calibration against a reference sensor or reference environment
  • see the HP23-AW calibration link
• the functions of the analyser:
  • conventional water activity measurement
  • measurement of accelerated water activity
  • automatic switch-off at the end of the measurement

Our partner Rotronic offers a range of solutions for monitoring, monitoring and control of humidity and/or ERH in their sales programme. Read the brochure.

Subscription options

Rotronic HP23-AW-A

• instrument with two sensor inputs

Rotronic HP23-AW-A-Set-14

• Rotronic HP23-AW-A – instrument
• HC2-AW sensor for measuring product samples
• WP-14-S Specimen holder (height 14 mm)
• PS14; 10 disposable sample cups, 14 mm (0.55″) deep
• the selected relative humidity calibration standards:
  • EA10; standard humidity 10% RH (five bottles per carton)
  • EA35; standard humidity 35% RH (five bottles per carton)
  • EA50; standard humidity 50% RH (five bottles per carton)
  • EA80; standard humidity 80% RH (five bottles per carton)
• AC1124; carrying case

Rotronic HP23-AW-A-Set-40

• Rotronic HP23-AW-A – instrument
• HC2-AW sensor
• WP40; sample holder (height 40 mm)
• PS-40 disposable sample container (10 pieces)
• the selected relative humidity calibration standards:
  • EA10; standard humidity 10% RH (five bottles per carton)
  • EA35; standard humidity 35% RH (five bottles per carton)
  • EA50; standard humidity 50% RH (five bottles per carton)
  • EA80; standard humidity 80% RH (five bottles per carton)
• AC1124; carrying case

The importance of water potential measurements – water activity meter

We also recommend you to take a look at the laboratory device for measuring water activity HygroLab and the article ”Measuring water activity”. The HygroLab has the possibility of four sensor inputs. Allows simultaneous or asynchronous AW speed measurement. It is operated via a high-quality touchscreen. The AW meter can also be connected to the internet for remote control via PC or tablet. Measurements can be monitored (real-time) and measurement reports can be uploaded anytime, anywhere.

Author Katarina Žunko, source Rotronic. ”Water Activity”
March 2022

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