Pulsed electric field treatment of citrus fruits: Improvement of juice and polyphenols extraction

The impact of pulsed electric field (PEF) treatment on orange, pomelo, and lemon in aqueous media was studied. Whole fruits and stack of peels were PEF treated at electric field strength of 3 kV/cm and 10 kV/cm, respectively. The PEF induced damage of the whole fruit was evaluated by different disintegration indexes. The PEF treatment increased the yield of juice obtained after pressing by 25% for orange, 37% for pomelo, and 59% for lemon. The effect of PEF on different parts of each fruit was studied. Flavedo and albedo were separated from the untreated fruit or PEF treated fruit and solvent extraction (1/1 ethanol/water solution) of polyphenols was conducted. The quantification and characterization of polyphenols in each part was compared for untreated and PEF treated fruit. The application of high electric field strength on orange peels enhanced the extraction of polyphenols up to 22 mg GAE/g DM. Industrial relevance: Citrus fruits are valuable sources of bioactive compounds (vitamins, antioxidants, carotenoids and flavonoids) and their processing represents an industrial importance. An application of PEF to whole fruits may be useful for improving the efficiency of juice extraction from different citrus fruits. The concentration of polyphenols in the extracted juice could be significantly enhanced by the treatment of citrus peels with PEF at high electric field strength.