Effects of acclimation prior to storage on marketable attributes for fresh-market blackberries

Since fresh-market blackberries (Rubus L. subgenus Rubus Watson) are a delicate fruit, handling during harvest and storage impacts marketability and profitably. In 2020 and 2021, four blackberry cultivars (‘Natchez’, ‘Osage’, ‘Prime-Ark^® ® Traveler’, and ‘Sweet-Ark^® CaddoRSQUO) grown commercially in Arkansas were harvested and stored after two acclimation treatments (non-acclimated berries placed at 2°C and berries acclimated at 10°C for 4 h then transferred to 2°C). The blackberries at harvest had physical (3-9 g, 18-31 mm long, 18-23 mm wide, and 6-10 N firmness) and composition (8-12% soluble solids, 3.0-3.3 pH, and 1.0-1.4% titratable acidity) attributes within optimal ranges. Marketability attributes evaluated after storage for 21 days at 2°C included percent leakage (berries with juice visible), decay (visible mold or rot), and red drupelet reversion (drupelets change from black to red) of berries in a clamshell. Acclimation and cultivar did not impact decay, but blackberry decay was higher in 2021 (16.56%) than in 2020 (0.31%). The interaction of acclimation × cultivar × year was significant for leakage. Regardless of acclimation, all cultivars in 2020 (0.83-7.50%) had lower leakage than in 2021 (4.80-55.54%). While acclimation did not impact leakage in any cultivar in 2020, in 2021, non-acclimated ‘Natchez’ had higher leakage than acclimated berries but the reverse for ‘Prime-Ark^® Traveler’ and ‘Sweet-Ark^® Caddo’. Cultivar × year and acclimation × year were significant for red drupelet reversion. Acclimation did not impact red drupelet reversion within each year. Non-acclimated blackberries in 2020 (4.79%) had higher red drupelet reversion than non-acclimated berries (0.97%) in 2021. Year did not impact rates of red drupelet reversion for ‘Natchez’, ‘Osage’, or ‘Prime-Ark^® Traveler’. However, rates were higher for ‘Sweet-Ark^® Caddo’ in 2020 (9.58%) than in 2021 (1.91%). Overall, year and cultivar had more of an impact on marketability attributes than acclimation, but red drupelet reversion and decay were low for fresh market acclimated and non-acclimated blackberries stored at 2°C for 21 days.