Freeze-drying and amber glass: a superior synergy for preserving the vitamin C and bioactive wealth of green chilli powder

Problem and aim Green chillies are rich in bioactive compounds but suffer significant nutrient loss during conventional drying and storage. This study aimed to systematically evaluate the effects of four drying methods—sun drying (SD), tray drying (TD), microwave-assisted vacuum drying (MaVD), and freeze-drying (FD)—on the physicochemical properties of green chilli powder, and to assess the impact of three packaging materials (low-density polyethylene [LDPE], clear glass, and amber glass) during six months of storage. Remarkable results Freeze-drying (FD) significantly outperformed other methods, retaining the highest levels of capsaicin (73.50 ± 0.22 mg/100 g), total chlorophyll (142.48 ± 0.18 mg/100 g), total phenolics (39.76 ± 0.38 mg GAE/100 g), and vitamin C (113.40 ± 0.28 mg/100 g). Scanning electron microscopy (SEM) revealed that FD preserved a porous, intact microstructure, while other methods caused structural collapse. During storage, amber glass jars provided superior protection against light and oxygen, preserving chlorophyll and vitamin C significantly better than LDPE and clear glass ( p < 0.05). Significance of study This study establishes an integrated “process-package” strategy combining FD with amber glass packaging. This approach effectively bridges the gap between processing and long-term storage, offering a commercially viable method for producing high-quality, shelf-stable green chilli powder with maximized bioactive retention for the nutraceutical and functional food industries.