html5-img
1 / 13

Food Preservation by Freezing and Canning

Food Preservation by Freezing and Canning. Chapter 30. Freezing. Clarence Birdseye began frozen food industry in 1920s Research and Developments “Antifreeze” proteins - control size of ice crystals Air impingement – fast cooling Pressure shift – small crystals

isi
Download Presentation

Food Preservation by Freezing and Canning

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Food Preservation by Freezing and Canning Chapter 30

  2. Freezing • Clarence Birdseye began frozen food industry in 1920s • Research and Developments • “Antifreeze” proteins - control size of ice crystals • Air impingement – fast cooling • Pressure shift – small crystals • Time-temperature indicators – monitor temperatures

  3. Freezing Process • Three stages • Product lowered to freezing • Ice crystals form • Temperature lowered to storage temperature • Microorganism activity is minimal • Will grow after thawing • Enzyme processes may continue • Blanching

  4. Changes in Frozen Foods • Formation of crystals • Fruits and vegetables cells may be damaged • Rapid freezing favors small ice crystals • Enzyme Action • Blanching • Sugar or sugar syrups

  5. Changes in Frozen Food • Nonenzymatic Oxidation • Usually associated with fat • Fat of pork particularly susceptible • Desiccation • Moisture loss by sublimation • Freezer burn • Activity of Microorganisms • Inactive or minimally active at low temperatures • Growth and activity resume after thawing

  6. Freezing Techniques • Fruits • Vegetables • Meat, Fish, Poultry • Eggs • Prepared Foods

  7. Other Issues • Container selection • Use and management of freezer

  8. Canning • Application of heat to destroy essentially all microorganisms • Vegetative Cells and spores • Sealing product in sterilized containers

  9. Canning History • French prize • Nicolas Appert – 1809 preserved foods • Development of tin canister • Early 1800’s canned foods for British Navy • Commercial canning • Batch and continuous retorts • Aseptic canning • Retort pouch

  10. Home Canning • Containers – Glass jars • Pack methods • Raw • Hot

  11. Home Canning (Processing) • Boiling water bath (212°F / 100°C) • Must be high pH or ACIDIC foods • Tomatoes may or may not have adequate acid levels • Follow recommended time and temperatures • Pressure canning (240°F / 116°C) • LOW ACID foods must be processed with pressure • pH higher than 4.6 • Use pressure canner with accurate gauge • Adjustments necessary at high altitudes • Use recommended pressure and time • Allow pressure cooker to cool and depressurize

  12. Containers • Commercial canning • Tin-plated steel • Aluminum • Glass • Retort flexible packages • Home canning • Glass jars with self-sealing lids • No larger than quart size is recommended

  13. Additional Issues • Heat penetration • Obtaining a partial vacuum • Obtaining an effective seal • Handling after processing

More Related