Hyperspectral Imaging Combined with Chemometrics Technique for Monitoring the Quality of Strawberries Under Various Pre-Cooling Treatments

Hyperspectral imaging (HSI) combined with chemometrics has emerged as a rapid and non-destructive technique for fruit quality evaluation, enabling efficient monitoring of biochemical changes during postharvest storage. Among quality indicators, antioxidant activity is closely associated with nutritional value and physiological stability. This study aimed to develop an HSI-based approach for assessing the antioxidant capacity of strawberries subjected to different pre-cooling treatments during storage. Strawberries were treated with five pre-cooling methods and stored for up to 41 days. Antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. Hyperspectral data were collected and preprocessed using multiplicative scatter correction (MSC), followed by partial least squares regression (PLSR) to construct predictive models. Among the treatments, immersion vacuum cooling combined with one-cycle pulsing (IVCWP1) exhibited significantly higher DPPH scavenging activity (61.17 ± 12.31%) than immersion vacuum cooling with water (IVCW, 52.89 ± 18.30%) (p < 0.05). The PLSR model developed using MSC-corrected average reflectance spectra showed superior predictive performance and a higher coefficient of determination (R2) than models based on raw spectra. The results demonstrate that HSI coupled with chemometrics is an effective and practical tool for non-destructive evaluation of antioxidant activity and comparison of pre-cooling strategies in strawberries.