Innovative Non-Destructive Device for Fruit Quality Assessment and Early Disease Diagnosis

The stage of maturity reached at harvest influence the quality at consumption as well as the storage life, the post-harvest fruit management and disease susceptibility. Often, when the harvest is performed too early, fruits might undergo a precocious softening during storage, and do not reach full flavor and aroma when ripe. Although the definition of the proper harvest time is recognized as very important, its determination is based on parameters performed with simple instruments. In Actinidia deliciosa, soluble solids content and dry matter has been proposed as maturity indexes. In Actinidia chinensis, the optimal harvest time is determined on the basis of flesh color. From the end of last century, non-destructive techniques, such as NIRs (Near Infrared Spectroscopy) and electronic nose have been realized and used for assessing the quality of kiwifruit. However, these devices require time consuming calibrations and are used to measure the standard parameters (SSC, DM, degrees H) determined by traditional devices. Recently, the University of Bologna patented innovative and simplified NIRs equipment (DA-Meter and Kiwi-Meter) allowing the definition of fruit maturity stage by means of an index based on the difference in absorbance between specific wavelengths (I-AD). This index correlates with the main traditional parameters as well as with changes in flesh color. In addition the availability of these portable instruments allow their use on the fruit attached to the trees to monitor the ripening evolution and the fruit ripening heterogeneity. Other non-destructive devices such as the electronic nose can be used to analyze the volatile compounds for fruit ripening stage determination, but more interestingly for early diagnosis of the main fruit diseases affecting kiwifruit in asymptomatic fruits and vines. Are here reported the results obtained with a the use of the Index of Absorbance Difference to follow the fruit ripening along the supply chain, from the field condition up to the cold storage level and the results obtained with the analysis of volatile compounds performed with an e-nose allowing early diagnosis of important fruit disease affecting the fruits such as Grey mould and Sclerotinia rot and the vine such as PSA.