NIR technology for grading kiwifruit
12 June 2015
NIR technology for grading kiwifruit

NIR technology can assess the internal quality of a fruit within milliseconds without even touching the fruit. Hume successfully tested NIR for improved grading of GA kiwifruit in the 2015 packing season.

Two NIR devices were installed on a grader, each consisting of a light source and a sensor. The light source beams Near Infra-Red (NIR) light onto the fruit that pass at full speed over the grader. The sensitive sensor picks up the reflected light, which has a slightly different spectrum depending on the fruit’s internal quality. Smart software in the NIR system is able to translate the spectrum into values for Dry Matter (DM), Brix, Colour and Pressure (softness) of each fruit. These quality values are transferred to the grader computer, which steers each fruit to a certain outlet. In this way, the grader can now produce boxes with fruit not only of a particular size, but also of a particular Dry Matter or other pre-determined quality.

In the 2015 tests, the NIR devises were used for DM segregation, e.g. culling fruit with a very low DM and thus raising the average DM. The results proved exciting. This is a joint project between Hume and the NIR manufacturer Taste Technologies Ltd in Auckland ( with support from Zespri.

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