Ultrasound-assisted lye peeling of peach and comparison with conventional methods

Abstract

Abstract In the present study, ultrasound-assisted lye peeling (ULP) was applied in peaches (Prunus persica L. Batsch) and compared with other methods. Different lye concentrations, ultrasonic power density, peeling time and temperature were investigated during ULP process. To evaluate peeling effectiveness, peeled thickness, peeling loss, peach color and peeling performance score were determined. The effects of ULP on quality of peaches were also considered to determine the optimum peeling process. As a result, Lye concentration of 0.50 mol/L combined with a power density of 270 W/L for 90 s at 90 °C demonstrated the optimal peeling effectiveness. Compared with manual peeling, hot water peeling (90 °C, no lye), ultrasound-assisted hot water peeling (90 °C, no lye, 270 W/L) and lye peeling (90 °C, alkali concentration of 0.50 mol/L), ULP showed the highest peeling performance score accompanied with appropriated peeling loss and peeled thickness. The color, soluble solids and titratable acidity for ULP peaches showed slight difference from peaches peeled by other methods. Industrial relevance Traditional peeling methods especially LP not only led to excessive loss of pulp but also damaged the environment to a great extent. Ultrasound as a green technology enhanced mass transfer and heat transfer, further promoting the efficiency of peeling process. In this study, ULP showed higher peeling performance with reduced peeling time, and the peaches quality was guaranteed, demonstrating the potential of ULP as an alternative to conventional peach peeling methods.