Abstract

Hot-air drying is widely applied for onion (Allium cepa) preservation, but processing conditions strongly influence the quality of the final powder. This study evaluated the effects of blanching time (0, 3, and 5 min), antibrowning treatments (sodium metabisulfite (Na₂S₂O₅) or sodium sulfite (Na₂SO₃); 0.05 – 0.2% w/v), and drying temperature (60 – 80 °C) on physicochemical, biochemical and sensory properties of onion powder. Optimal conditions (3 min blanching, 0.1% antibrowning agent, and 70 °C drying) minimized browning and maximized phenolic retention, achieving total phenolic content (TPC) of 25.42 ± 0.39 milligrams of gallic acid equivalents per gram (mg GAE/g) dry weight (DW). Gallic acid, caffeic acid, p-coumaric acid, and quercetin were identified as the major phenolic compounds. Sensory evaluation confirmed the desirable color, aroma, and overall acceptability of the optimized product. These findings support the production of high-quality onion powder while contributing to sustainable development goal (SDG) 2 (zero hunger) and SDG 12 (responsible for consumption and production) through improved food preservation, reduced postharvest losses and more efficient use of resources.

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