Process of heating food rapidly to predetermined temperature, holding it at this temperature for a predetermined time, and then either rapidly cooling the food or passing it to subsequent processing without delay.Importance if blanching:
1. Preparation of fruits and vegetables before canning, freezing or dehydration.
2. To inactivate or destroy enzyme substrates such as peroxidase.
3. Cleaning raw material and reducing bacterial load.
4. Expelling cellular gases.
5. Softening foods so that filling foods to the containers is facilitated.
6. Improving textures especially for dehydrated foods.
Methods of blanching:
Food immersed in water and then heated to blanching temperature - cause a high loss of soluble in some food.
Utilizes saturated steam at atmospheric pressure - food is conveyed through the steam chamber for a pre-set time, then discharged to a washer or cooler.
Heat-resistance enzymes found in most vegetables:
Peroxidase
- Play a role in oxidative deterioration of vegetables during storage. Used as an index of the effectiveness of blanching treatments.