Cold storage duration affects the levels of physiochemicals in blackberry cultivars

Blackberry fruits contain generous amounts of bioactive compounds with strong antioxidant properties, yet their postharvest quality rapidly deteriorates under suboptimal storage conditions. This study assessed the phytochemical and biochemical responses of three blackberry cultivars (‘Jumbo’, ‘Chester’, and ‘Prime-Jim’) during cold storage at +4 °C over 21 days. Cold storage significantly altered total phenolic content (TPC), flavonoid levels, antioxidant activity, and organic acid profiles across all cultivars. The highest TPC on day 21 was observed in ‘Chester’ (4027.0 mg GAE/L), which also showed the best retention of ascorbic acid (1241.5 mg/kg). The retention value is better shown as percentage retention from initial value at harvest. ‘Jumbo’ exhibited the most stable antioxidant activity, with DPPH inhibition rates maintained above 67 % by day 21. In terms of organic acids, ‘Jumbo’ preserved citric acid (35.20 mg/kg) and tartaric acid (456.76 mg/kg) better than the other cultivars. ‘Prime-Jim’ retained higher levels of individual phenolics such as quercetin (2.61 mg/100 g) and chlorogenic acid (3.36 mg/100 g) at the end of storage. These cultivar-specific variations reflected up to 30 % differences in bioactive compound retention. Principal Component Analysis (PCA) clearly separated the cultivars based on their phytochemical profiles, with ‘Chester’ positioned strongly due to high TPC, ascorbic acid, and antioxidant activity. Strong correlations were found between organic acids and antioxidant metrics, highlighting their interdependence. Overall, the results demonstrate that selecting the appropriate cultivar and managing storage duration are critical to preserving blackberry quality and functional potential in the fresh fruit supply chain.