Food Engineering Practice Test: Principles of Food Preservation by Canning and Drying and Principles of Food Concentrates — Flashcards

Canning and drying are two methods of food preservation. Canning involves processing and sealing food in an airtight container, typically a jar or can. Drying involves removing water from food, which prevents microorganisms from growing and controls enzyme activity. 
Canning involves placing food in jars or cans and heating it to a specific temperature. The heat destroys microorganisms and inactivates enzymes, which preserves the food's safety and quality. The heating and subsequent cooling create a vacuum seal that prevents microorganisms from entering the jar and contaminating the food. 
Drying can be accomplished through a number of methods, including sun drying, mechanical drying, and freeze drying.

Here are some differences between canning and drying:
Shelf life: Canning can provide a shelf life of one to five years, or longer in some cases. Drying has a shorter shelf life than canning.
Nutrient loss: Canning can cause some nutrient loss. Drying preserves the nutrient content of food better than canning.
Spoilage protection: Canning provides better protection against spoilage than drying.
Complexity: Drying is a simpler method than canning.
Equipment: Canning requires more specialized equipment than drying. 

Food concentrates are foods that have had water or other diluting agents removed, resulting in a higher concentration of nutrients or flavors. 
Concentrates are often used in food and drink that only needs the scent and flavor of the fruit, such as sodas, cocktails, drink mixes, pies, jelly, etc.. 
The concentration process is usually employed as a pre-treatment to reduce the initial moisture content of different foods like, milk, tea or coffee prior to their final dehydration in a spray or freeze dryer. 

Examples of concentrated foods include:
Dried fruits
Fruit juices
Nut butters
Canned or dried beans
Powdered forms of foods such as milk powder or protein powder 

Topics include: Food preservation by canning, food storage principles, food concentrates and food storage using the principles of drying and canning.
 

Related: Food Engineering Practice Test: Food Preservation, Principles of Fresh Food Storage,  Principles of Refrigerated Gas Storage of Foods and Principles of Food Freezing