Display omitted ► Alginate as edible coating maintains plum quality during postharvest storage. ► Ethylene production was inhibited by alginate coating in 4 climacteric plum cultivars. ► Softening, weight and acidity losses were delayed by alginate treatment. ► Colour changes, due to anthocyanin and carotenoid accumulation, were retarded in alginate-coated plums. Four plum (Prunus salicina Lindl.) cultivars (“Blackamber”, “Larry Ann”, “Golden Globe” and “Songold”), were treated with 1 or 3% alginate as an edible coating before storage. Analytical determinations were made after 7, 14, 21, 28 and 35 days at 2°C and after a 3 day period at 20°C (shelf-life). Both treatments were effective in inhibiting ethylene production for all cultivars, especially when 3% alginate was used. The changes in fruit quality parameters related to plum postharvest ripening, such as weight and acidity losses, softening and colour changes, were significantly delayed by the use of both edible coatings. The delay of the ripening process was also related to lower anthocyanin and carotenoid accumulation. Overall results suggest that these treatments could increase the plum storage period with optimum quality, 2 weeks for “Larry Ann” and “Songold” and 3 weeks for “Blackamber” and “Golden Globe” more than controls.