Quick boiling is part of blanching but only part. Quick chilling is an essential part of the process.
What is Blanching?
The correct meaning of blanching is to briefly immerse food in boiling water (or sometimes steam), then rapidly cool it, usually in ice water, to stop cooking and fix color or loosen skins. Without the quick chilling it is not blanching.
Blanching is an essential step when freezing fruits and vegetables, both commercially and at home. It neutralizes enzymes that might cause later degradation and it also reduces bacteria, lessening the chance of future spoilage. It also helps preserve the original color.
Is Blanching the Same as Parboiling?
No. Parboiling means to partially cook a food by boiling with the expectation of finishing it later by another method (roasting, grilling, or stewing). Parboiling can also be used for vegetables you want to use cold but not be fully cooked, such as parboiling green beans for use in a salad. In this latter case, the parboiling might be followed by a cold water bath. But technically speaking, parboiling always involves considerably longer boiling than blanching, which typically involves just a quick dip in boiling water.
