I love summertime and the abundance of fresh fruit and vegetables. It’s always about this time of year that the old joke starts circulating about not leaving your car windows down when you’re at church on Sunday because someone may leave a bag of squash or other veggies for you. Gardens are overflowing with fresh produce right now! If you’re wondering what to do with the abundance, try preserving it!
Home food preservation has been around for years and years as a way to keep fruits and vegetables for future use. Freezing is a quick and easy method to preserve foods at home, and it helps for quick dinner preparation in the future because most of the preparation work is already done. Freezing also preserves nutritive quality, so frozen foods resemble fresh foods.
When you freeze produce, consider five factors that are responsible for most of the quality losses: enzymes, air, microorganisms, large ice crystals, and evaporation.
Enzymes are naturally occurring substances that control ripening in produce. Freezing slows down enzyme activity, but most frozen vegetables will lose quality in the freezer unless they are blanched first. Blanching improves flavor, color, texture, and nutrient retention, and it slows or stops the action of enzymes in the ripening process.
The exclusion of air from frozen foods helps prevent enzyme reactions and oxidation, which causes surface browning. This problem is common in fruits, but some vegetables, such as potatoes, are also affected by air.
Microorganisms such as bacteria, molds, and yeast are present on all fresh foods and multiply quickly when the temperature is between 40° to 140°F. Freezing does not kill microorganisms, but it will slow the growth if the food is held at 0°F or lower. When thawed, the surviving microorganisms will grow again, so proper handing and preparation is important.
Large ice crystals form in food when the food is not frozen quickly or kept at a constant storage temperature of 0°F or lower. The large ice crystals rupture food cells and cause a soft, mushy texture. Freeze foods quickly and keep them at a constant storage temperature to form small ice crystals for best quality.
Evaporation of moisture may happen if poor packaging materials are used allowing foods to lose moisture. Moisture evaporation causes a loss of color, flavor, and texture. Long term exposure to air causes plant fibers to dry, a process known as freezer burn. Proper packaging materials help to retain moisture.
For more information about freezing specific fruits and vegetables, visit the website for the National Center for Home Food Preservation at http://nchfp.uga.edu/ or contact Kate Whitney at the Bosque County Extension Office at 254-435-2331.
