Researchers laser in on the perfect apple

Researchers have developed a method to help farmers harvest climacteric fruits - like apples, bananas, pears and tomatoes - at their precise peak in ripeness, using laser biospeckle technology.

Climacteric fruits continue their maturation off the tree or vine, so these fruits emit ethylene and are characterised by a climacteric peak - indicating a maximum ethylene release.

By tapping biospeckle activity, generated by illuminating a biological medium with coherent light, the researchers studied the evolution of two batches of Golden apples’ speckle patterns as they underwent the ripening process in both low- and room-temperature environments. The results were published in The Optical Society’s journal Applied Optics.

The team was aiming to produce a technique that was both simple and low cost. They used coherent light, a laser beam, polarisers and quarter-wave plates to generate different incident polarisations, and a digital camera to record the speckle pattern.

One of their ultimate goals is to develop a portable tool to enable farmers to non-invasively assess their fruits’ maturity in orchards or fields to detect the optimal time to harvest their crops.