Blanched vegetables are those that have been boiled or steamed prior to freezing to prevent the enzymes from breaking down the vegetables. Blanching stops enzyme degeneration of the vegetable while it is in the freezer. This improves the flavor, color, nutrient content and texture of the vegetable when it is frozen. Failure to blanch vegetables prior to freezing them can result in a loss of flavor and toughening of the vegetable.
When a vegetable develops on a plant, enzymes work to make it grow and mature. These enzymes continue to work even after the vegetable has been picked. Simply freezing a vegetable does not retard this process. Blanching vegetables is the only method to stop these enzymes from aging the vegetable further. Unblanched frozen vegetables often don't taste right and can be tougher and dull in color.
The main methods of blanching vegetables are boiling, steaming or microwaving. The time it takes to blanch a vegetable depends on the specific type of vegetable. There are many guides online that list the blanching times for vegetables.
To blanch vegetables, a large kettle pot of water is needed. One gallon (3.78 L) of water should be used per 1 pound (0.45 kg) of vegetables. While the vegetables boil or steam, a separate pot should be prepared with the same amount of water. Ice should then be added to this water.
After the vegetables have been boiled or steamed for the indicated amount of time, they should be plunged into the pot of ice water. The vegetables should be left in the ice water for the same duration they were in the heat. The blanched vegetables should be drained or removed from the ice water and then packaged and placed in a freezer as normal.
Blanched vegetables are cleaned of dirt and microorganisms. The process also stops the enzymes that age vegetables in the freezer. Blanched vegetables sport a vibrant color and maintain their vitamins and minerals.
Failing to blanch vegetables prior to freezing them typically results in a loss of flavor, color, vitamins and minerals. The benefits gained from blanching a vegetable make the time put into this process worth it for many people. Not blanching vegetables can waste food and the time spent growing the vegetables.
Blanching vegetables is a relatively precise science. Over- or under-blanching vegetables is not much different from not doing it at all. Under-blanching vegetables results in an increase in enzyme activity, which prematurely ages the vegetables in the freezer. Over-blanching vegetables can cause a loss of flavor, colors and minerals. Anyone who wants to blanch vegetables should be sure to to find out the exact amount of time needed to blanch the specific vegetables.