Changes in Optical Absorption and Scattering in 1-MCP-Treated and Untreated Pears After Short-Term Storage: Relationships with Quality, Sensory Traits, and Ethylene Production

Non-destructive techniques, such as time-resolved reflectance spectroscopy (TRS), can support pear producers in delivering high-quality fruit, promoting consumption and attracting new consumers. In this study, optical properties (absorption coefficient, µa; reduced scattering coefficient, µ’s), measured by TRS in “Conference” and “Abate Fetel” pears during simulated post-storage shelf life, were related to quality characteristics, sensory attributes and ethylene production. Nine batches of 60 pears each per cv—corresponding to harvest, untreated and 1-MCP-treated fruit, evaluated after 1, 3, 6, and 7 days of shelf life at 20 °C following 2 months at −1 °C—were measured by TRS at 650 nm (“Conference”), 670 nm (“Abate Fetel”), 780 nm and 940 nm, analyzed for skin color (h°), firmness, soluble solids content (SSC), titratable acidity (TA), ethylene production, and sensory properties. Both µa and µ’s showed clear changes during a simulated shelf life period, reflecting biochemical and structural modifications associated with ripening. The µa650/670, linked to chlorophyll content, decreased over time and was closely linked to firmness loss, peel yellowing, and to increases in ethylene production, SSC, juiciness, sweetness, and aroma. µ’s decreased due to structural changes in the flesh during fruit softening. Predictive models based on µa and µ’s enabled the non-destructive assessment of several quality and sensory attributes. Good performance was obtained for SSC in “Conference”, for instrumental firmness in “Abate Fetel” and for sensory firmness in both cultivars, while moderate accuracy was achieved for juiciness. The inclusion of both µa and µ’s in the models highlighted their complementary role in capturing compositional and structural changes during pear ripening. Overall, TRS is a valuable tool for the non-destructive assessment of pear quality, though variability between cultivars suggests that further validation is needed to improve robustness and applicability.