Development and optimization of dry-peeling method for plums (Prunus domestica) using infrared radiation heating technology

This study explores the feasibility and optimization of infrared (IR) dry-peeling for plums (Prunus domestica) as a sustainable alternative to conventional lye peeling, aiming to enhance product quality and minimize environmental impact. A laboratory-scale system equipped with a ceramic IR emitter and rotating fruit rollers for loosening peels and a novel rubber-tube peel removal device was designed. The effects of IR emitter power (350-1000 W), heating time (90-150 s), and emitter distance (20-70 mm) on physicochemical properties and peeling performance were evaluated using Response Surface Methodology (RSM). The results showed that optimal conditions (797.48 W, 70 mm, 107 s) achieved 90% peelability, 4.5 peeling easiness (1–5 scale), 0.30% moisture loss, 0.12 mm peel thickness, 40°C surface temperature, 13.5 ΔE color change, and 14 mg/100 g ascorbic acid retention. Hot lye peeling (10% NaOH, 85°C, 100 s) was used as a control treatment, and the findings indicated that IR has the potential for significantly reduced moisture loss (0.30% vs. 9.56%), preserved bright yellow hue (Hue angle 82 vs. 55°), and enhanced ascorbic acid retention (14 vs. 10.5 mg/100 g), while eliminating chemical wastewater. The rubber-tube device, with 76.67% peelability under optimal IR conditions, performed comparably to lye pretreatment and showed potential for replacing manual peeling and enhancing process hygiene. • The infrared heating technology is suggested as a dry-peeling method for plum. • Higher IR power, longer time boost peelability; closer distance raises temperature. • IR dry-peeling retained physicochemical characteristics of the plum to lye peeling. • The new skin-separating mechanism effectively removed the peel of IR-treated plum.