Postharvest chlorine dioxide spray as a strategy to maintain quality in ‘Monterrey’ strawberry fruits

Commercial strawberry (Fragaria × ananassa) is valued for its quality attributes and its antioxidant content; however, its rapid softening and microbial susceptibility limit their postharvest quality. This study evaluated chlorine dioxide (ClO2) spray at 3 and 5 ppm on the postharvest physiology and biochemical properties of ‘Monterrey’ strawberries over 9 days. The 3 ppm treatment effectively mitigated weight loss, maintaining fruit mass between 35 and 40 g on days 3–7, whereas control fruit decreased to 25–30 g. Soluble solid content remained stable across treatments (7–10 °Brix). Fruit dimensions exhibited a positive response, with increases of 10–15% in width and 8–12% in height under 3 ppm ClO2. Significant biochemical changes were also observed in ClO2 treatments: total phenolics rose to approximately 600 mg GAE/100 g FW at 5 ppm, with concomitant increases in flavonoids, anthocyanins, and antioxidant capacity (FRAP), which improved by 20–30%. Furthermore, ClO2 treatment modulated α-mannosidase and β-acetylhexosaminidase activities in a concentration- and time-dependent manner during postharvest storage. Collectively, these findings demonstrate that ClO2 spray – particularly at 3–5 ppm – enhances fruit retention, preserves antioxidant potential, and downregulates cell wall-degrading enzymes, offering a cost-effective strategy for improving postharvest quality in commercial strawberries.