Blanching process is a brief heat treatment in hot water or steam applied to vegetables and some fruits before freezing to inactivate enzymes that would otherwise degrade colour, flavour and vitamins during frozen storage.
In trade practice
Processors set time and temperature parameters for each vegetable type and verify enzyme inactivation using the peroxidase test; a positive result means blanching was insufficient. Rapid cooling immediately follows to prevent carry-over cooking and to ensure the product enters the freezer at a low temperature. Buyers routinely request blanching validation records, including time-temperature logs and peroxidase test results, as part of supplier qualification.
In a specification
A product specification typically states the blanching method (water or steam), the target enzyme inactivation standard and the requirement for supporting validation records from the processor.