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Freezing Fruits and Vegetables


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Susan Shockey, PhD, of the OSU Extension-Franklin County, discusses the basics of freezing various fruits and vegetables.

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Freezing Fruits and Vegetables

  1. 1. Simple, Safe, Easy to Learn Freezing Fruits and Vegetables
  2. 2. Today’s Topics <ul><li>Basics of freezing fruits and vegetables </li></ul><ul><li>Preventing fruits from discoloring </li></ul><ul><li>Blanching vegetables </li></ul><ul><li>Packaging frozen fruits and vegetables </li></ul><ul><li>Thawing methods for fruits and vegetables </li></ul>
  3. 3. Before preserving any food, consider the types of foods your family enjoys and the usefulness of the preserved product in your lifestyle .
  4. 4. Basics for Handling Food Safely <ul><li>Prevent bacteria from spreading through your kitchen </li></ul><ul><ul><li>Wash hands : </li></ul></ul><ul><ul><ul><li>Warm water and soap for 20 seconds before and after handling food </li></ul></ul></ul><ul><ul><li>Sanitize : Cutting boards, utensils, and countertops </li></ul></ul><ul><ul><ul><li>Use a solution of 1 tablespoon of unscented, liquid chlorine bleach in 1 gallon of water </li></ul></ul></ul>
  5. 5. Freezing — Overview <ul><li>Easy, convenient and the least time-consuming </li></ul><ul><li>Slows growth of microorganisms and chemical changes </li></ul><ul><li>Preserves the greatest quantity of nutrients </li></ul>
  6. 6. Selection <ul><li>Vegetables: </li></ul><ul><ul><li>Choose young and tender </li></ul></ul><ul><ul><li>Over-mature may be hard, tough or flavorless </li></ul></ul><ul><li>Fruit: </li></ul><ul><ul><li>Fully ripe, but firm </li></ul></ul><ul><ul><li>Under ripe may be bitter </li></ul></ul><ul><ul><li>Freeze soft, very ripe fruits as purées </li></ul></ul>
  7. 7. Preparing Food for Freezing <ul><li>Thoroughly wash all fruits and vegetables in cold water- DO NOT SOAK! </li></ul><ul><li>Enzymes: </li></ul><ul><ul><li>Vegetables: </li></ul></ul><ul><ul><ul><li>Destroyed by heat, blanching, before packaging and freezing </li></ul></ul></ul><ul><ul><li>Fruits: </li></ul></ul><ul><ul><ul><li>Enzymatic browning </li></ul></ul></ul><ul><ul><ul><li>Controlled by ascorbic acid (vitamin C) or other additives </li></ul></ul></ul><ul><ul><ul><li>Usually not blanched </li></ul></ul></ul>
  8. 8. What is the Freezing Effect? <ul><li>Textural Changes: </li></ul><ul><ul><li>Water freezes and expands foods </li></ul></ul><ul><ul><li>Ice crystals cause the cell walls of fruits and vegetables to rupture, making them softer when thawed </li></ul></ul><ul><ul><li>Vegetables with very high water content do not freeze well </li></ul></ul><ul><ul><ul><li>Ex. Celery, lettuce and tomatoes </li></ul></ul></ul><ul><ul><li>Vegetables with lower water content become more compact </li></ul></ul><ul><ul><ul><li>Ex. Spinach and broccoli </li></ul></ul></ul>
  9. 9. Freezing Pointers <ul><li>Check freezer temperature </li></ul><ul><ul><li>0 o F for best quality </li></ul></ul><ul><li>Freeze foods quickly </li></ul><ul><li>Don’t stack food packages until they are solidly frozen </li></ul>
  10. 10. Fruit: Freezing Overview <ul><li>Frozen in many forms </li></ul><ul><ul><li>Whole, sliced, crushed, juiced etc. </li></ul></ul><ul><li>Best quality- choose fully ripe, but firm, fruit </li></ul><ul><ul><li>Immature or overripe produce lower quality when frozen </li></ul></ul>
  11. 11. Fruit: Preventing Darkening and Discoloration <ul><li>Best for peaches, apples, pears and apricots </li></ul><ul><li>Treat washed and sorted fruit with ascorbic acid (Vitamin C) </li></ul><ul><ul><li>1 tsp of ascorbic acid to one gallon of cool water </li></ul></ul><ul><ul><li>Use commercial ascorbic acid mixtures </li></ul></ul><ul><ul><ul><li>i.e. Fruit Fresh ™ (follow manufacturers directions) </li></ul></ul></ul><ul><li>Lemon juice or citric acid solutions </li></ul>
  12. 12. Fruit: Types of Packs <ul><li>Syrup pack (see fact sheet) </li></ul><ul><li>Sugar pack </li></ul><ul><ul><li>Best for slices of soft fruits like strawberries and peaches </li></ul></ul><ul><li>Dry (Tray) pack </li></ul><ul><ul><li>Good for small whole fruits such as berries </li></ul></ul><ul><li>Unsweetened and water packs </li></ul><ul><li>Artificial sweeteners </li></ul>
  13. 13. Fruit: Dry “Tray” Pack <ul><li>Fruit pieces may be frozen individually, in single layer, on a tray </li></ul><ul><li>Freeze until firm then package in rigid container or bag </li></ul><ul><li>Will pour out of container easily when frozen </li></ul><ul><li>Fruit pieces do not “clump” as when packed directly into containers or with sugar syrup </li></ul>
  14. 14. Fruit: Thawing for Serving <ul><li>Timing: </li></ul><ul><ul><li>Dry sugar packs thaw faster than syrup packs </li></ul></ul><ul><ul><li>Unsweetened packs thaw the slowest </li></ul></ul><ul><li>Pointers: </li></ul><ul><ul><li>When used in recipes, allow for added sugar and more juice </li></ul></ul><ul><ul><li>Not all fruits need to be thawed before using </li></ul></ul>
  15. 15. Vegetables: Freezing Overview <ul><li>Select young, tender, high-quality vegetables </li></ul><ul><li>Sort for size and ripeness </li></ul><ul><li>Wash small lots at a time, lifting out of water- DO NOT SOAK! </li></ul>
  16. 16. Vegetables: Water Blanching <ul><li>Primary method of destroying enzymes in vegetables </li></ul><ul><li>Directions: </li></ul><ul><ul><li>Boil water in a kettle with lid </li></ul></ul><ul><ul><li>1 gallon water per 1 lb. of vegetables </li></ul></ul><ul><ul><li>Lower vegetables into vigorously boiling water . Put lid on. Water should hardly stop boiling or return to a boil within a minute. Start timing the blanching as soon as water returns to a boil. </li></ul></ul><ul><ul><li>At end of blanching time, quickly remove vegetables from boiling water and place in cold or ice water bath to stop cooking process. </li></ul></ul>
  17. 17. Vegetables: Steam Blanching <ul><li>Directions: </li></ul><ul><ul><li>Use kettle with tight lid and basket </li></ul></ul><ul><ul><li>1 to 2 inches of boiling water in bottom of pan </li></ul></ul><ul><ul><li>Vegetable should be in a single layer in basket </li></ul></ul><ul><ul><li>Start timing as soon as the lid is on </li></ul></ul><ul><ul><li>Remove from kettle and place in cold or ice water bath </li></ul></ul><ul><ul><li>Takes 1 to 1 ½ times longer than water blanching- check times for each food </li></ul></ul>
  18. 18. Vegetables: Cooling After Blanching <ul><li>After blanching in water or steam, cool immediately in cold water </li></ul><ul><li>Change water frequently or use running water or iced water (1 lb. ice per 1 lb. vegetable) </li></ul><ul><li>Cooling time should be the same as the blanching time </li></ul><ul><li>Drain thoroughly </li></ul>
  19. 19. Vegetables: Types of Packing <ul><li>Dry Packing </li></ul><ul><ul><li>Pack after the vegetables are blanched, cooled, and drained </li></ul></ul><ul><ul><li>Pack quickly, pushing air out of package as you work towards top </li></ul></ul><ul><li>Tray Packing </li></ul><ul><ul><li>After draining, spread pieces in a single layer on a shallow pan </li></ul></ul><ul><ul><li>Freeze firm </li></ul></ul><ul><ul><li>Package quickly, pushing air out as you work </li></ul></ul>
  20. 20. Vegetables: Packaging <ul><li>Use freezer bags or rigid freezer-safe containers </li></ul><ul><ul><li>Squeeze air from bags before sealing </li></ul></ul><ul><ul><li>Leave ½ to I inch headspace for expansion in rigid containers </li></ul></ul><ul><li>Use only moisture–proof, vapor-proof packaging designed for freezing </li></ul><ul><li>Do not reuse cardboard containers or plastic containers from commercially prepared food products </li></ul><ul><li>Label and date product </li></ul>
  21. 21. Vegetables: Thawing for Serving <ul><li>Most vegetables can be cooked without thawing </li></ul><ul><li>Corn-on-the-cob should be partially thawed before cooking so that it will heat all the way through </li></ul><ul><li>Leafy greens cook more evenly if partially thawed </li></ul>
  22. 22. Recommended Storage Times <ul><li>Fruits </li></ul><ul><ul><li>Most frozen fruits maintain high quality for 8 to 12 months </li></ul></ul><ul><ul><li>Unsweetened fruits lose quality faster than fruits packed in sugar or sugar syrups </li></ul></ul><ul><li>Vegetables </li></ul><ul><ul><li>Most vegetables will maintain high quality for 12 to 18 months at 0°F or lower </li></ul></ul><ul><ul><li>Use your home-frozen vegetables before the next year’s crop is ready for freezing </li></ul></ul>
  23. 23. What to do if the freezer stops working: <ul><li>Keep the freezer closed </li></ul><ul><li>If the freezer will be stopped for more than 24 hours use dry ice (if obtainable) or move the food to another freezer </li></ul><ul><li>Thawed fruits that still have ice crystals can be refrozen or used in cooking, baking and making jams and jellies </li></ul><ul><li>Vegetables containing ice crystals or at 40 ° F or below can be refrozen </li></ul><ul><ul><li>Thawed vegetables should be thrown out </li></ul></ul>
  24. 24. Summary <ul><li>Freezing fruits and vegetables is a safe, easy way to preserve foods </li></ul><ul><li>Wash all fruits and vegetables thoroughly </li></ul><ul><li>Follow blanching charts for vegetables </li></ul><ul><li>Use proper procedures and equipment, including freezer-safe materials </li></ul><ul><li>Use the freezing process that works best for your family meal needs </li></ul>
  25. 25. Questions? <ul><li>“ This material has not been peer-reviewed for statewide distribution -- blind peer review pending.” </li></ul>
  26. 26. References: <ul><li>Angell, D., & Shertzer, J.(2009) Freezing Fruits. Cooperative Extension, The Ohio State University. </li></ul><ul><li>Angell, D., & Shertzer.J.(2009) Freezing Basics . Cooperative Extension, The Ohio State University. </li></ul><ul><li>Angell, D., & Shertzer, J. (2009) Freezing Vegetables. Cooperative Extension, The Ohio State University. </li></ul><ul><li>Andress, E., & Harrison, J. (2006) S o Easy to Preserve (5 th ed.). Cooperative Extension, The University of Georgia. </li></ul>