Impact of Pulsed Electric Field Pretreatment on Extraction Efficiency and Quality Attributes of Sohiong Fruit Juice

Abstract

This study investigates the impact of pulsed electric field (PEF) pretreatment on the extraction and quality of Sohiong juice. A full factorial optimal design was employed to determine the best PEF conditions. Response surface methodology (RSM) was used to evaluate the effects of electric field strength (2–10 kV/cm), treatment time (20–80 s), and solid-water ratios (1:1, 1:1.5, and 1:2) on juice yield (JY), ascorbic acid (AA), color difference (ΔE), cloud stability (CS), total phenolic content (TPC), total anthocyanin content (TAC), and radical scavenging activity (%DPPH). Comparative analysis was performed between PEF and thermal-treated samples, and ANOVA was applied to assess statistical significance. Optimal PEF conditions (10 kV/cm, 60 s, 1:1 solid–liquid ratio) showed a significant (p < 0.05) enhancement of 26, 77, 11, 20 12, and 89% in JY, CS, TAC, TPC, DPPH inhibition, and AA retention, respectively. However, thermally treated samples showed higher shear stress and viscosity than PEF-treated ones. The model demonstrates significant differences (p < 0.05), indicating an excellent fit with higher R² and Adj R² values denoting increased model accuracy. FTIR analysis depicts functional groups like O–H, C=C, and C–O–C indicative of anthocyanins. Further, the absorption range of 1680–1600 cm⁻¹ also suggests the presence of pectin. SEM analysis demonstrated microstructural changes, with a breakdown of the cell membrane in Sohiong pomace, enhancing porosity and aiding improved extraction of valuable compounds. This research highlights that PEF technology can improve the quality of fresh fruit juice while maintaining its nutritional value compared to thermal treatments.