Biodegradable blend films containing thermoplastic starch (TPS), polylactic acid (PLA), and poly(butylene adipate-co-terephthalate) (PBAT) were assessed for red chili storage under modified atmosphere packaging (MAP) at 10 C. Performances of biodegradable blend films were compared to polypropylene (PP) film and the control (unpacked). Gas permeabilities and permeability ratios were determined to measure the ability of the films to create an optimal atmosphere for red chili storage. PP film attained values close to the recommended MAP gas concentrations and maintained desirable chili quality parameters up to the 15th day. Biodegradable films did not achieve the recommended MAP gas concentrations, but high water vapor permeability prevented moisture loss and maintained firmness and overall quality. No discoloration was recorded in all MAP treatments, while biochemical parameters showed a decreasing trend, with measured levels significantly higher in MAP samples than unpacked samples. MAP for red chili was achieved using a packaging system, with similar gas permeabilities to PP film but with significantly higher water vapor permeability.biodegradable blend film, modified atmosphere packaging, permeability, permeability ratio, red chili | INTRODUCTIONChili pepper is one of the most consumed global spices, eaten fresh or dried and processed as paste, sauce, pickled, and canned products. Chili pepper contains vitamin A (140.8 RE of β-carotene), vitamin C (87-90 mg/100 g), and capsaicin as the active component present in chili that has proven pharmaceutical/medicinal properties. 1 Thailand contributes 5.44% market share of chili worldwide as exported green and red chili, dried and ground, chili dips, and chili paste. 2 Chili peppers are widely grown in Thailand, with consumption at 5 g/person/ day. 3 Annual fresh and dried chili production increased from 165 and 460 MT in 2009 to 348 and 100 MT in 2019, respectively, based on FAO code 0689. However, chili crops are susceptible to various detrimental physiological, microbial, and mechanical factors. Dehydration, blossom end rot, and chilling injury are common physiological deteriorations, usually attributed to storage conditions, through decay-causing organisms such as Botrytis and Alternaria and soft rots of fungal and bacterial origin. 4 Mechanical damage such as crushing, stem punctures, and scrapes affects the appearance and acceptability of chili, while also contributing to faster weight loss and decay.To minimize crop losses, proper postharvest intervention such as low-temperature storage and modified atmosphere packaging (MAP) should be implemented. MAP alters the normal air conditions in a package from 21% oxygen (O 2 ) and 0.03% carbon dioxide (CO 2 ) to a level that decelerates the enzymatic degradation of complex substrates and plant respiration rate to achieve a certain level of microbial control. 5 MAP applied to small quantities of produce to modify the atmosphere 6 can be active or passive. Active MAP involves displacement of the in-package atmosphere by f...