Question

Hand refractometer: "Brix" value at physiological maturity in sugarcane is

• A. 4 to 8%
• B. 10 to 12%
• C. 18 to 20%
• D. 28 to 30%

Hint:

To confirm maturity in the field, check that the ratio of Brix readings between the top and bottom of the sugarcane stalk is close to 1.0 (indicating uniform ripeness).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Sugarcane maturity is determined by measuring the concentration of dissolved solids (primarily sucrose) in the stem juice.
A hand refractometer is a field instrument used to measure this concentration, which is expressed in degrees Brix ($^{\circ}\text{Brix}$).

Step 2: Detailed Explanation:
- A Brix reading represents the weight percentage of sucrose in a pure water solution.
- During the ripening phase of sugarcane, sucrose accumulates in the stalk internodes, moving from the base upward.
- When sugarcane reaches physiological maturity and is ready for harvest, the juice from the middle portion of the stalk typically shows a Brix reading of 18% to 20%.
- At this stage, the sucrose content is at its peak, and glucose levels are low, which maximizes sugar recovery during industrial processing.
- A Brix value below 16% indicates the crop is immature, while values above 22% suggest it is over-mature or drying out.

Step 3: Final Answer:
The hand refractometer Brix value at physiological maturity in sugarcane is 18 to 20%.