Course:FNH200/Lessons/Lesson 08/Page 08.6
8.6 Summary of Lesson 8
- Preservation of food by dehydration involves the removal of water (thus lowering the water activity) from the food to extend the food's shelf life by slowing down microbial growth and chemical/enzymatic reactions.
- Microbial growth and chemical/enzymatic reactions will resume once the food is re-constituted or re-hydrated.
- During dehydration of food, changes such as "cell shrinkage, case hardening, and different chemical changes", can take place.
- During dehydration, several factors (e.g. temperature, air velocity, humidity of the drying air, etc) must be controlled in order to prevent undesirable changes (case hardening, excessive cell shrinkage, etc)
- Packaging materials should not only impart physical protection, but also assist in preserving dehydrated foods by further protecting against moisture absorption, as well as preventing interactions with oxygen and light.
Supplemental Video: Extrusion Drying
FNH 200 Course content on this wiki page and associated lesson pages was originally authored by Drs. Brent Skura, Andrea Liceaga, and Eunice Li-Chan. Ongoing edits and updates are contributed by past and current instructors including Drs. Andrea Liceaga, Azita Madadi-Noei, Nooshin Alizadeh-Pasdar, and Judy Chan.