Effects of polysaccharide-based edible coatings on the shelf life of fresh-cut carrots with different pigmentations

Abstract

Promoting the consumption of purple carrots, particularly in ready-to-eat products, is justified due to their peculiar composition and health benefits for consumers. However, there is limited literature on the shelf life of ready-to-eat purple carrots and the potential role of edible coatings in mitigating their quality decay. This study examined the postharvest behavior of sliced carrots ‘Dordogne’ (orange) and ‘Purple Sun’ (purple), both uncoated and coated with chitosan (CH) or locust bean gum (LBG), stored for 0 (S₀), 4 (S₄), and 8 (S₈) days at 4.0 °C. ‘Purple Sun’ proved a high fresh weight loss (up to 7.57 g 100 g⁻¹ FW) and respiration metabolism. Compared to controls, CH reduced total color difference in ‘Dordogne’ (−70 %) but increased it in ‘Purple Sun’ (+68 %) due to the occurrence of tissue browning. Compared to uncoated controls, at the end of storage, total phenolic and ascorbic acid contents were lower in CH-coated ‘Purple Sun’ (−14 % and −20 %, respectively), while CH preserved total carotenoid content in ‘Dordogne’ (up to 1000 mg kg⁻¹ DW). Moreover, compared to controls, LBG promoted Pseudomonas spp. (+23 % and +22 % in ‘Dordogne’ and ‘Purple Sun’, respectively) and yeasts and molds (+26 % and +24 %, respectively). Overall, these results indicate that issues of ready-to-eat carrots are significantly affected by carrot type, with the gas-barrier effect (in the case of CH for ‘Purple Sun’) and the antimicrobial properties of LBG (for both cultivars) seeming the most critical aspects to enhance the shelf life of the tested carrots.