Question

The weight of 10 kg dried cauliflower containing 5% moisture (wet basis) after rehydration is 60 kg. If the fresh cauliflower contained 87% moisture (wet basis), calculate the coefficient of rehydration (rounded off to 2 decimal places).

Hint:

The coefficient of rehydration measures how well the dried product regains its original water-holding capacity. A value closer to 1 indicates better rehydration.

Answer 1

Correct Answer: 0.75

Step 1: Calculate dry matter in dried cauliflower.
Moisture content (wet basis) = 5%. So dry matter fraction = $1 - 0.05 = 0.95$. \[ \text{Dry matter} = 10 \times 0.95 = 9.5 \ \text{kg} \]
Step 2: Calculate dry matter in fresh cauliflower.
Moisture = 87% (wet basis). So dry matter fraction = $1 - 0.87 = 0.13$. \[ \text{Dry matter} = 60 \times 0.13 = 7.8 \ \text{kg} \]
Step 3: Coefficient of rehydration.
Coefficient of rehydration is defined as: \[ \text{CR} = \frac{\text{Dry matter after rehydration}}{\text{Dry matter in fresh product}} \] \[ \text{CR} = \frac{7.8}{9.5} = 0.821 \approx 0.82 \] Final Answer: \[ \boxed{0.82} \]