Non-destructive detection of chilling injury in sweet peppers using UV fluorescence imaging

Accurate and early detection of chilling injury (CI) in sweet peppers is essential to preserve post-harvest quality and minimize economic losses during storage and distribution. This study developed and validated a novel UV-induced fluorescence imaging method for non-destructive, real-time detection of CI in sweet peppers immediately after cold storage. The fluorescence spectral analysis with both microscopic and macroscopic imaging were combined to identify chlorophyll fluorescence changes as a sensitive early indicator of CI. Using an optimized decision-tree classifier (based on the a∗ color channel of fluorescence images), the method achieved 91.7 % classification accuracy in distinguishing chilling-injured from healthy peppers. The results also revealed that red peppers had greater chilling tolerance than green or purple cultivars, which were more susceptible to CI under the same conditions. Unlike previous methods that typically require longer room temperature incubation after cold storage, our method uses only a one-day room temperature treatment, significantly reducing detection time. The results demonstrate that the fluorescence-based approach is highly accurate, cost-effective, and practical for detecting CI in sweet peppers, addressing a key challenge in post-harvest quality assessment. • UV fluorescence imaging method detects chilling injury in sweet peppers. • Achieved 91.7 % accuracy using optimized a∗ channel classification. • Chlorophyll fluorescence reliably indicates early chilling injury. • Detects CI rapidly with just 1-day room temperature treatment.