SPECTRAL IMAGING VIS-NIR SYSTEM TO FORECAST THE CHILLING INJURY ONSET ON CITRUS FRUITS

Cold storage is one of the most important and useful opportunities to preserve citrus fruit quality and to extend the sales period.
Citrus fruits, however, are susceptible to chilling injury (CI) depending on species, cultivar, and the length of exposure to low temperatures.
Symptoms of chilling injury include pitting, brown staining, increased decay and quality deterioration.
Aim of the work was to forecast the chilling injury development by non-contact hyperspectral VIS-NIR imaging on the fruit rind at least 10 days in advance before its visual appearance.
The analysis was made on 130 fruits of ‘Femminello siracusano’ lemons (Citrus limon [L.] Burm.) stored at 5°C and high relative humidity.
Spectral images were made 14 times.
The opto-electronic system for the images acquisition was made by a VIS-NIR spectral scanner (DV Padova), which can acquire bidimensional spectral images with a very good optical (250 Kpixels) and spectral (115 l) resolution.
After 104 days, 79% of the fruits showed damaged areas.
Partial least squares (PLS) regression analysis was applied for constructing a predictive model based on the spectral normalized response, constructing the model on a sub sample and verifying the model (test) on independent ones.
Hyperspectral PLS model allows to predict chilling injury onset on lemons 14 days before the visual appearance with a percentage of 95% of correct classification and only 21% of false (both sound and CI).

V International Postharvest Symposium

P. Menesatti, G. Urbani, G. Lanza

spectral imaging, visible, near infrared, chilling injury, citrus

https://doi.org/10.17660/ActaHortic.2005.682.181