Feasibility of jujube peeling using novel infrared radiation heating technology

• Infrared (IR) radiation peeling technique was successfully applied for jujube skin removal.
• Optimizing peeling condition to obtain the maximum peeling performance.
• IR peeled jujube had lower peeling loss and color change compared to lye peeled ones.

Infrared (IR) radiation heating has a promising potential to be used as a sustainable and effective method to eliminate the use of water and chemicals in the jujube-peeling process and enhance the quality of peeled products. The objective of this study was to investigate the feasibility of using IR heating as a dry-peeling method for jujube. The rotating Li jujube fruits were heated using two electric IR emitters. The effects of IR radiation intensity (5.25–6.07 W/cm2), emitter distance (75–85 mm), and heating time (40–60 s) on the peeling performance of jujube were investigated. Lye-peeled jujubes were used as a control. The operating parameters of the IR peeling system were optimized using response surface methodology (RSM). The heating with an IR intensity of 5.25 W/cm2 at the emitter distance of 75 mm for 56 s were found as the optimum operating conditions resulting in the peelability of 96%, peeling easiness of 3.8 and moisture loss of 1.29% at jujube surface temperature of 115 °C. The experimental results agreed well with those predicted by the models. The IR peeled jujube had significantly low peeling loss and color change compared to lye peeled ones.