The reliable and low-cost quantitative detection of ethylene for food/fruit applications remains an unsolved problem.
Existing commercial systems are able to quantify ethylene (at sub ppm levels) but either they are off-line: require
periodic sample collection and use of reagents or high-cost. We will report on the development of an RFID reader with
onboard micro-machined metal oxide gas sensors aimed at monitoring climacteric fruit during transport and vending.
The developed platform integrates a commercial off the shelf inductive coupling RF transceiver in the 13.56MHz band,
fully compliant with the ISO15693 standard, micro-hotplate gas sensors, driving and readout electronics. If the sensors
are operated at a fixed temperature, the reader could work as an alarm level monitor able to assess the conservation stage
of apples. On the other hand, when the sensors are operated under an optimised temperature-modulation mode, accurate
calibration models for the species that are relevant to assess the conservation stage of apples (i.e., ethylene, acetaldehyde
and ethanol) can be built. Finally, different feature extraction techniques such as the FFT and the Energy Vector will be
used in combination with pattern recognition tools like PLS and PLS-DA to show that our system is able to identify and
quantify the species that are relevant for the application considered.