Antioxidant Potential of Sodium Alginate Coffee Husk Coating on Cherry Tomatoes

Sodium alginate is a biopolymer widely used in the formulation of edible coatings due to its biocompatibility and its ability to form a matrix for the incorporation of compounds with antioxidant activity, such as coffee husk extract. Its application to cherry tomatoes is particularly relevant, given the high postharvest perishability of this vegetable. Thus, the present study aimed to evaluate the antioxidant potential of sodium alginate-based edible coatings incorporating coffee husk extract in the preservation of cherry tomatoes during refrigerated storage. The fruits were divided into three treatments: no coating (NR), sodium alginate coating (ALG), and alginate coating containing coffee husk extract (EXT). During the storage period, the activity of the enzymes polyphenol oxidase (PPO) and peroxidase (POD), the total phenolic compound content, and the antioxidant capacity were determined using the ABTS method. The ALG treatment maintained the highest total phenolic content on day 5 (5.39 ± 0.07 µg gallic acid/mL), with no significant reduction compared to day 0. The EXT treatment exhibited the highest antioxidant capacity on day 5 (0.87 ± 0.00 µmol Trolox eq./100 mL), differing significantly from the other treatments. Furthermore, the ALG and EXT treatments limited enzymatic activity during storage, with lower (p < 0.05) PPO activity than the NR treatment on days 3 and 5. For POD, EXT showed the lowest values on days 3 and 5, followed by ALG. The findings indicate that the coffee-husk coating preserved bioactive compounds, reduced enzymatic browning, and showed potential for extending the postharvest shelf life of cherry tomatoes.