How Ripe is “Ripe”?

The force gauge exerts a specified force on the specimen, while the torque sensor and fixture rotate at a consistent rate of speed.


An agricultural testing laboratory required an accurate way to quantify fruit and vegetable ripeness. The customer’s specification called for twisting a rubber-tipped probe onto the skin of the fruit or vegetable, while pressing down at a specified force, until the skin breaks. This test was previously done by hand with a mechanical device.

How Mark-10 Helped:

In order to achieve more consistent results less prone to human error, the laboratory turned to Mark-10. A customized torque tester was developed, consisting of a torque test stand, force gauge, torque sensor with indicator, and custom fixtures.

Instead of a torque sensor mounted to the linear positioning adapter, a force gauge was mounted. This allowed for axial force to be applied and maintained for the duration of the test. A torque sensor was adapted to the rotating base of the test stand, supplied with custom length rubberized posts to secure the sample.

As the test stand rotates at a specified speed, and as the force gauge applies a specified force, the torque indicator captures the peak torque value at which the skin broke away from the fruit or vegetable. The lower the torque value, the more ripe the sample.

With this data in hand, the laboratory was able to better assess the ripeness of fruits and vegetables, and research correlations between ripeness and environmental and agricultural factors.

Products used: