Powders are the unsung heroes of the food world. Although rarely consumed on their own, they play starring roles in millions of products by enhancing flavor, providing vitamins or minerals, and improving physical stability and shelf-life. Some products, like protein bars, are made up almost entirely of cold-formed powder paste. But powders can be difficult to work with.
Avoid caking and clumping with water activity
One common problem in the processing of powders is caking and clumping. Caking is a time-dependent reaction where the surface of particles that rub together become sticky and stop flowing. Controlling water activity can stop caking and clumping by identifying water activity levels that cause problems. For example, if a manufacturer buys spray-dried lactose with a water activity of 0.470, he’ll have problems trying to make it move through his machinery.
Solve moisture migration issues with water activity
Powders nearly always get mixed with other ingredients to make a finished product. In a powder mixture or spice blend, the various components may have different water activity values. Because powders have such a small particle size, water moves almost immediately from high water activity components to low water activity ones, making spice blends solidify into rock-hard lumps within minutes. Knowing the water activity of discrete ingredients helps avoid this problem.
Finding a critical water activity can tame damaging chemical reactions
All products have a finite shelf-life. Most powders show a distinct point below which they are shelf stable for months or years. Above this point, they succumb to lipid oxidation, vitamin degradation, and other harmful reactions at a much faster rate. This “critical water activity” is easy to find for any product. The most important clue is a product’s isotherm, which identifies a water activity spec that protects ingredients.
Easy accuracy in a water activity meter
If a manufacturer can solve all these problems in powders and spices, the next challenge is making sure they stay solved. Many quality control instruments are only useful in the lab–they’re either too complicated or too delicate to use anywhere else. The AQUALAB 4TE is different. It gives +/-0.003 aw accuracy no matter where it is. The instrument is solid and easy to use, and doesn’t require any special training or sample preparation. Water activity is as easy to measure on the factory floor as it is in the lab.