Infrared Spectroscopy for Non-destructive and Fast Identification of Artificially Ripened Papaya (Carica papaya)

Abstract

Papaya, the second most consumed fruit in Sri Lanka, is well adapted to all agro climatic zones with high annual production. However, the export amount is less than 2% of the total production due to poor post-harvest processing measures including artificial ripening. Therefore, an attempt was made to use the Near Infrared Spectroscopy (NIRS) for the detection of artificially ripened papaya by Calcium Carbide and Ethephon. Calcium Carbide and Ethephon were applied for artificially ripening of papaya fruits including controls with natural ripening. Each treatment was replicated four times consisting four fruits per each replicate. The fruits were arranged in plastic crates padding with polyurethane foam layer in 36 mm of thickness. Five near infrared spectra per fruit per day were acquired from all papaya samples until the fruits were overripe. Spectral data were pretreated to reduce impacts of environmental noise. Soft Independent Modelling of Class Analogy (SIMCA) calibration models (Pirouette Infometrix, Woodinville, WA, USA) were developed to identify the artificially ripened fruits from the controls. The predictions were accurate as 100% , 95.2% and 98.4% in control samples, CaC2and Ethephon treated samples, respectively Partial Least Square models were also developed to predict the Brix and Firmness values of fruits at ripening. Brix and firmness values were accounted 8.3 and 0.86 correlation coefficients for PLS regression Y fit, respectively. The research revealed that the potential possibility of using NIR technology as a nondestructive identification tool for artificially ripened papaya fruits using CaC2 and Ethephon.