Optimization of Pectin Extraction from Lemon Peel Powder by Ohmic Heating Using Full Factorial Design

Ohmic heating-assisted extraction has emerged as an effective method preferred in recent years. This extraction method is affected by experimental factors such as temperature, process time, and voltage gradient. The present study aimed to optimize the pectin extraction process from lemon peel powder samples by the ohmic heating-assisted extraction method. In this study, the effects of 3 different voltage gradients (7, 9, and 11 V/cm), 3 different solid to liquid ratios (1:20 g/mL, 1:40 g/mL, and 1:60 g/mL), and 3 different holding times (0, 60, and 120 min) and their interactions were investigated to determine the optimum extraction condition at constant temperature (80 °C) and pH = 1 sulfuric acid solution. The factors examined in the optimization procedure were pectin yield, power consumption, and energy efficiency. The optimum conditions were found to be 11 V/cm voltage gradient, 1:60 g/mL solid to liquid ratio, and 120-min holding time with a desirability value of 0.778. The results of this study could give important information about the design of industrial scale ohmic heating units, especially from different food wastes in industrial pectin production.