What is a food preservative?
Have you ever noticed the packet included when you buy snacks at a shop?
This packet is a “food preservative.”
You can enjoy snacks, bread, and other foods, with peace of mind because of this packet packaged together.
There are many causes for food deterioration, and the use of food preservatives prevents deterioration.
Causes for food deterioration
-
Temperature -
Humidity -
Light -
Microorganisms
Relationship between influential factors and shelf life
| Factor | Long shelf life | Short shelf life | |
|---|---|---|---|
| Environment | Temperature | Low | High |
| Humidity | Low | High | |
| Light | Weak | Strong | |
| Oxygen concentration | Low | High | |
| Ingredient | Water Activity | Low | High |
| pH | Low (High) | Neutral | |
| Microorganisms | Initial bacterial count | Small | Large |
| Packaging | Packaging film | Highly gas barrier | Low gas barrier |
| Gas displacement | Present | Absent | |
| Ethanol gas | High concentration | Low concentration | |
What is water activity (Aw)?
There are two main types of water contained in foods: “free water” and “bound water.”
“Free water,” easily evaporates and migrates, and can be used to propagate microorganisms.
“Bound water” binds to proteins and carbohydrates in foods.
Water activity is expressed as a numerical value showing the amount of “free water” and is an indicator of preservability of foods.
* The water activity value is defined as the relative humidity on the surface of foods.
As an example, jam is a food containing a high moisture content, but its water activity is not so high because much of the water is bound to sugar.
On the other hand, white bread is fairly high in water activity because it contains little sugar and salt.
The EZ-200, which enables high-precision and short-time measurements and includes a color touch panel, is the only made-in-Japan water activity meter.
FREUND’s food preservatives
FREUND’s food preservatives that prevent the deterioration of foods are broadly divided into three types.
-
Ethanol evaporation agent
Ethanol gas is subject to evaporation in sealed packaging to prevent the growth of mold and also retain “softness” and “moistness” of foods.
-
Ethanol evaporation agent + Oxygen absorber
The strongest bacteriostatic effect is exerted by combining the two functions.
-
Oxygen absorber
Oxygen in sealed packaging is absorbed to prevent the growth of mold and also prevent deterioration by oxidation.
Food preservatives should be used in accordance with the foods used and the purpose.
| Ethanol evaporation agent | Ethanol evaporation agent + Oxygen absorber | Oxygen absorber | |
|---|---|---|---|
| Inhibitory effects on fungi and bacteria | Mold ✓✓ Yeast Fair Bacteria Fair |
Mold ✓✓ Yeast ✓ Bacteria ✓ |
Mold ✓✓ Yeast Fair Bacteria Fair |
| Softness/moistness | ✓✓ | ✓ | -（Poor） |
| Antioxidant effect | -（Poor） | ✓✓ | ✓✓ |
