Develop e-Nose tool for rapid interception of infested fruit

Abstract

The aim of this task is to develop a novel system that reliably identifies FF-infested from uninfested fruits by recognition of infestation-specific volatiles organic compounds (VOCs) and to use these for the “training” and validation of an e-Nose system that can be deployed as a useful FF detection tool. This is done for the target FF on a variety of selected fruit types (peaches, pears, apples, oranges).
Infestation, sample preparation and volatile collection
Depending on the season and the availability of fruits, samples of peaches, pears and apples are obtained from the market. Volatile organic compounds (VOCs) are collected by dynamic headspace analysis technique using Porapak Q (80/100 mesh) as absorbent with non-infested fruits as control. VOCs are analyzed by Gas Chromatography-Mass spectrometry (GC-MS) and identified by using appropriate spectral libraries and authentic standards.
The specific volatile profiles were further used as a training and validation set for the e-Nose system that can be deployed as a commercially available tool that could be used to discriminate between FF-infested from un-infested fruits.
Results showed that specific esters are FF species specific for peaches. In case of pome fruits, esters increase along with the procession of fruit ripening and quantitative differences are observed between healthy and infested fruits. In citrus, the monoterpene, D-limonene and the sesquiterpene, valencene were the main VOCs detected in healthy and infested fruits. E-(β)-ocimene and homoterpene E-4,8-dimethylnona-1,3,7-triene (DMNT) were also found insignificant quantities in infested fruits. The preliminary results of e-nose on detection of infestation by FF on peaches are quite promising.