UNLABELLED: This study delves into the exploration of waste extracts, especially derived from onion components such as peel, stalk, flower, and petiole, for their potential use in edible coatings aimed to extend the shelf life of strawberries. The research investigates the antioxidant and antimicrobial properties of these onion waste extracts (OWEs), identifying key phytochemicals through GC-MS analysis. The identified key phytochemicals such as β-sitosterol, phytol, 1-butanol, 3-methyl-, formate, and 5-hydroxymethylfurfural were responsible for the biological activity of OWEs. The findings demonstrate that the OWEs containing coating materials, particularly from flower, stalk, and petiole, effectively safeguarded strawberry quality for 14 days at 4 °C, countering microbial deterioration. The findings not only shed light on the efficacy of these extracts in preserving the quality of strawberries but also emphasize their role in reducing environmental impact through sustainable waste utilization. By offering a natural alternative to synthetic chemicals, this study provides insights into enhancing the sustainability, safety, and economic viability of fresh fruit preservation in the post-harvest phase. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-024-06053-6.