Coffee silverskin extract coating: bioactive profile and enzymatic activity of fresh melon

Minimal processing of fruits accelerates physiological and biochemical changes that compromise their quality and shelf life. In this context, edible coatings enriched with bioactive natural extracts represent a promising strategy for reducing these changes and adding value to agroindustrial byproducts. Accordingly, the present study aimed to evaluate the effects of an edible sodium alginate coating incorporated with coffee silver skin extract (Coffea arabica) on bioactive compounds and enzymatic activity in minimally processed melon during refrigerated storage. Melon cubes were divided into three treatments: uncoated (NR), coated with alginate (ALG), and coated with alginate plus extract (EXT). The samples were stored at 4 ± 1 °C for five days and analyzed on days 0, 3 and 5 for total phenolic compounds, antioxidant capacity using the ABTS method, and the activities of the enzymes polyphenol oxidase (PPO) and peroxidase (POD). The NR treatment had the highest phenolic compound content on day 3 (2.43 ± 0.46 μg EAG/mL), while the ALG treatment had the lowest value (0.97 ± 0.21 μg EAG/mL). The EXT treatment maintained its antioxidant capacity throughout storage, unlike the ALG treatment, which showed a significant reduction on the third day (0.04 ± 0.00 μmol Trolox/100 mL). In addition, treatments with EXT showed lower (p < 0.05) PPO activity on day 5 and reduced POD activity on days 3 and 5 of storage. The results indicate that an edible coating containing coffee silver skin extract can preserve bioactive compounds, slow enzymatic browning, and promote the postharvest preservation of minimally processed melons.