01.dec.06
Institute of Food Technologists
http://www.ift.org/news_bin/news/newsFrames.php
Scientists with the Agricultural Research Service (ARS) in Albany, Calif., have invented an inexpensive approach that dried plum processors can use to help ensure no large pieces of a plum's pit remain inside the fruit. The new pit detector could be used as an inexpensive addition to processing lines already equipped with other detectors to find hidden pits or pit pieces.
In the new system, dried plums, or prunes, are moved along a conveyor belt to a roller that gently presses them against the belt. Then, a device known as a force transducer, mounted underneath the conveyor belt and in line with the roller, detects the amount of resistance that the roller encounters. The transducer's reading is sent to a signal processor that is linked to a computer.
Using an algorithm that the scientists wrote, the computer determines whether the transducer's reading indicates the possible presence of a pit or pit piece. If the possibility exists, the signal processor instructs a sorter to remove the prune from the processing line, so it can be retested, hand-sorted or simply rejected.
The accuracy rate is impressive: false positives occur less than one percent of the time.
Though so far tested primarily at laboratory speeds, the device could easily be ramped up to processing plant rates. And, it could likely be used to check other dried stone fruits such as apricots, cherries and peaches.
Agricultural engineers Eric S. Jackson, Ronald P. Haff, and Thomas C. Pearson developed and tested the technology for about 1-1/2 years before deciding it was ready for processors to try.
The scientists received a patent for their invention earlier this year. Some dried fruit processors have already shown interest in it.