Vegetables frozen without blanching are safe to eat, but the quality will not be good. Blanching (scalding vegetables in boiling water or steam for a short time) is a must for almost all vegetables. Blanching stops the action of enzymes. If enzymes remain active during freezer storage, they can cause undesirable changes in flavor, texture and color, as well as loss of vitamin A and vitamin C.
Blanching time is crucial and varies with vegetables. Under-blanching stimulates the activity of the enzymes and is worse than no blanching. Over-blanching causes loss of flavor, color, vitamins and minerals. See this guide for recommended blanching times for specific vegetables.
If you spend all the time growing vegetables and tending your garden, blanching may seem like one extra step. But it is a necessary step to maintain that fresh garden flavor.
For information on different methods for blanching and preserving foods, refer to Quality for Keeps: Freezing Vegetables (pdf). For more information about nutrition and food preservation, visit MissouriFamilies.org.
Contributor: Karen Sherbondy, MEd, RD, LD, Extension Associate, Nutrition and Exercise Physiology, University of Missouri Extension, 816-655-6227