Why blanch vegetables before freezing? Blanching vegetables before freezing them is critical to their quality, but not their safety. Blanching is scalding vegetables in boiling water or steam for a short time. It is typically followed by quick, thorough cooling in very cold or ice water. Blanching stops enzyme actions which otherwise cause loss of flavor, color and texture. In addition, blanching removes some surface dirt and microorganisms, brightens color and helps slow vitamin losses.
For more information, visit Carolina Canning's webpage about blanching.