A Note on Potential Applications of Physical Properties of Bruised Tissue of Apples for Automated Sorting
B in fruits and vegetables is becoming an increasing problem due to the increased use of mechanization in harvesting and handling. In apples, bruising is especially a problem with the current methods of production. When harvested from tall, dense trees by mechanized methods, apples are subjected to high drops and increased contact with limbs and other apples. This problem has brought about a need for faster and better sorting methods for removing bruised fruit from apples, either packaged for fresh market or intended for processing. Apple processors are as much concerned about bruised apples as the buyers for fresh market. Much work has been done in recent years to learn more about bruising in apples and techniques for detection. Several techniques have been tried using reflectance or transmittance of waves of the electromagnetic spectrum. No techniques, however, have been developed to sort the fruit successfully and automatically. The purpose of this paper was to review all the physical characteristics and properties of apples which appear to be affected by bruising. Behavior of apple tissue to various parts of the electromagnetic spectrum not previously reported was investigated to determine potential applications in automatic bruise detection. Previously reported electronic detection techniques are also discussed.