Performance evaluation of pectin extraction from grapefruit peel powder by ohmic heating

This study is to investigate the performance properties during the extraction of pectin from grapefruit peel powder using ohmic heating. Pectin extraction was carried out under different voltage gradients (7–11 V/cm), different solid: liquid ratios (1:20–1:60), and different holding times (0–180 min) at constant pH and temperature (80°C). The voltage gradient and solid: liquid ratio affected the time to reach the target temperature. The highest energy efficiency value for all voltage gradients and solid: liquid ratios were obtained in the 0 min holding time, and the efficiency value, which changed between 89.47% and 56.02%, was negatively affected by the increase in the holding time. The exergy efficiency was lower than the energy efficiency and decreased due to the increasing holding time and decreasing voltage gradient. Also, the exergy efficiency was found to be between 73.69% and 18.09%. Determining the performance characteristics of the system will make a significant contribution to pilot and industrial-scale system/process applications for the future. Practical application: In this study, pectin was successfully obtained from grapefruit powder using an ohmic heating system. The operating conditions for the obtained pectin include constant pH (pH:1) and temperature (80°C) but various voltage gradients, solid: liquid ratios, and extraction times. It has been observed that voltage gradient and extraction time were effective on energy efficiency. When looking at exergy efficiency, voltage gradient, solid: liquid ratio, and extraction time were effective. It has been observed that the improvement potential (IP) value calculated for the system decreases depending on the increasing voltage gradient. The results obtained in this study are thought to be an important data source for literature, pilot, and industrial-scale production systems. It has been realized that ohmic heating, which is increasingly used, is an alternative technique for pectin production.