Effect of low-temperature storage regimes on the UV-B sensitivity of apple anthocyanin

Low-temperature storage is widely used to extend apple shelf life. However, prolonged storage often diminishes fruit coloration, reducing consumer appeal. This study evaluated light-induced coloration sensitivity in apples after 2 months of storage at 2°C under three different conditions: only 2℃ (Cold), controlled atmosphere (CA), and 1-methylcyclopropene (1-MCP) treatments. Experimental data included postharvest physicochemical properties, phenolic contents, and antioxidant activities in apples exposed to UV-B irradiation, with or without methyl jasmonate (MeJA) treatment, following low-temperature storage. Storage conditions significantly affected sensitivity to UV-B-induced coloration change, as well as anthocyanin, flavonol, total phenolic content, and radical scavenging capacity, presenting the superior response in 1-MCP, secondly ranked in CA, and finally ranked in Cold. MeJA treatment further enhanced red coloration and anthocyanin accumulation in apples stored under both 1-MCP and CA conditions. Specifically, 2 W m⁻² UV-B and MeJA-treated apples under 1-MCP exhibited a 53 % higher anthocyanin levels compared with UV-B-only-treated apples. Antioxidant activities significantly increased in UV-B irradiated apples stored under CA and 1-MCP, whereas no significant changes were observed under Cold, regardless of MeJA application. Overall, this study demonstrates that storage under 1-MCP conditions effectively preserves apple responsiveness to light-induced pigmentation following extended low-temperature storage, promoting red coloration and raising bioactive compound levels during postharvest UV-B exposure, and ultimately improving apple quality.