Peeling of kiwifruit using infrared heating technology: A feasibility and optimization study

Infrared (IR) technology has been studied as an alternative to conventional food processing technologies. The IR technology has attractive merits such as uniform heating, high heat transfer rate, reduced water, and energy consumption and improved product quality and safety. This research studied the feasibility of kiwifruit peeling using IR heating. The response surface methodology (RSM) was used to investigate the effects of IR radiation power (250-850 W), the distance between IR emitter and sample (10-70 mm) and heating time (45-125 s) on the peeling performance and physicochemical properties of kiwifruit. Lye-peeling was used as the control treatment to compare the efficiency of IR peeling. Heating with a power of 446 W at the distance of 70 mm for 125 s was found to be the optimum operating conditions for the IR peeling of kiwifruit. Under these conditions, the results were a peelability of 90%, weight loss of 4.5%, peel thickness of 0.4 mm, surface temperature of 64.1 °C, puncture force of 57.7 N, color difference of 2.4 and ascorbic acid content of 140 mg/100 g fresh fruit. Compared to hot lye peeling, the IR radiation heating caused significant reduction in weight loss, surface temperature, and color differences. It also maintained the firmness of fruits.