Question

Consider the following unit operations; arrange them in sequence as performed during wet milling of pulses
A. Conditioning
B. Mixing with red earth
C. Soaking
D. Dehusking
E. Grading
Choose the correct answer from the options given below:

• A. C, B, D, E, A
• B. C, B, A, D, E
• C. B, C, A, D, E
• D. C, A, B, D, E

Hint:

To find the sequence quickly in exams:
- Milling begins with Soaking (C).
- Milling ends with Dehusking (D) and then final Sorting/Grading (E).
This helps you identify the correct sequence starting with C and ending with E.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Pulse milling involves removing the outer husk (dehusking) and splitting the cotyledons to produce dhal.
The wet milling method is a traditional process commonly used in India to loosen the tightly bound husk from the cotyledons.

Step 2: Detailed Explanation:
Let us trace the correct sequence of unit operations in the wet milling of pulses:
1. Soaking (C): The clean, graded pulses are first soaked in water for several hours to allow the cotyledons and husk to absorb moisture.
2. Mixing with red earth (B): After draining the excess water, the wet pulses are mixed with about 4% to 5% red earth slurry. The red earth helps absorb surface moisture, prevents mold growth during drying, and helps loosen the husk.
3. Conditioning (A): The mixture of pulses and red earth is sun-dried or conditioned in hot air for 2 to 4 days to reduce the moisture content to about 10% to 12%. This alternate wetting and drying makes the husk brittle.
4. Dehusking (D): The dried, conditioned pulses are passed through a dehusker (typically an abrasive roller mill) to remove the brittle husk.
5. Grading (E): The milled output is graded to separate the dehusked split dhal, whole dehusked dhal, broken pieces, and undehusked grains.
The correct sequence is C \(\rightarrow\) B \(\rightarrow\) A \(\rightarrow\) D \(\rightarrow\) E.

Step 3: Final Answer:
The correct option is (B).