Storage life extension of raspberry using chitosan composite coating functionalized with Bidens pilosa extract

Reducing postharvest losses in raspberries is mandatory to increase their marketability. Due to health concerns, excessive use of postharvest fungicides to reduce postharvest losses has become a global concern. This study investigated the potential of chitosan composite coating functionalized with Bidens pilosa extract in maintaining the quality and extending the shelf life of raspberry fruit (‘Microprop’). Treatments included 2% chitosan (Ch) enriched with 0.1 mg L^‑1 B. pilosa (BP) at 1, 3, and 5% to form Ch-1%BP, Ch-3%BP and Ch-5%BP, respectively, as well as Ch, distilled water, and control (unwashed). Treated fruit were stored in cold storage at 4±1°C and 90±5% relative humidity for 9 d, and measurements were at 3-day intervals. The rate of respiration and ethylene production continued to increase for coated fruit as the uncoated fruit respiration and ethylene began to decline after 6 d of storage. Control fruit reached the highest peak of respiration rate (49.98 mL CO₂ kg^‑1 h^‑1) and ethylene production (56.87 µL C₂H₄ kg^‑1 h^‑1), while fruit coated with Ch-1%BP exhibited the lowest respiration rate (19.1 mL CO₂ kg^‑1 h^‑1) and ethylene production (37.93 µL C₂H₄ kg^‑1 h^‑1). After 9 d of storage, fruit coated with Ch-1%BP had the lowest weight loss (16.74%), decay incidence (17.3%), and a higher juice content (61.13%). Control fruit had the highest weight loss (48.33%), decay incidence (83.2%), and low juice content (19.43%). This resulted in the extension of shelf life by 3 d in chitosan composite coating. Results indicated that Ch-1%BP composite coating could be used for postharvest preservation of the investigated raspberry cultivar.