Question

Which of the following statements is true regarding drying and dehydration of fruits and vegetables?
(A). Freeze drying is not covered under the methods of preservation of fruits and vegetables by drying or dehydration.
(B). Microorganisms and enzymes need water in order to be active.
(C). Dried, dessicated or low moisture foods are the traditional dried foods
(D). Intermediate moisture or IM foods contain between 15% to 50% moisture.
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (B) and (C) only.
• C. (A), (C) and (D) only.
• D. (B), (C) and (D) only.

Hint:

The key to preservation by drying isn't just removing moisture, but reducing 'water activity' (a_w), which is the available water for biological reactions. This is the scientific principle that makes drying effective.

Answer 1

The Correct Option is D

 

Step 1: Understanding the Concept: 
The question asks to identify the correct statements about food preservation through drying and dehydration. The underlying principle is the removal of water to inhibit spoilage. 
 

Step 2: Detailed Explanation: 
Let's analyze each statement: 
\[\begin{array}{rl} \bullet & \text{(A): This statement is false. Freeze drying (lyophilization) is a specialized method of dehydration where water is removed from a frozen product through sublimation (solid to gas phase). It is a form of drying. } \\ \bullet & \text{(B): This statement is true. The fundamental principle of preservation by drying is to reduce the water activity (aw) of the food. Below a certain water activity level, most microorganisms cannot grow, and enzymatic reactions are significantly slowed down. } \\ \bullet & \text{(C): This statement is true. Traditional methods like sun drying produce low moisture foods (e.g., raisins, dried fish) which are often referred to as dried or desiccated foods. } \\ \bullet & \text{(D): This statement is true. Intermediate Moisture (IM) foods, such as jams, jellies, and some dried fruits like dates, have moisture content in the range of 15-50\%. They are shelf-stable due to a combination of reduced water activity and other factors like high sugar content. } \\ \end{array}\] 

Therefore, statements (B), (C), and (D) are true. 
 

Step 3: Final Answer: 
The correct option includes statements (B), (C), and (D).