Optimization and Intensification of Bioactive Components and Antioxidant Activity of Extracts from Date Fruit (Phoenix dactylifera L.) Using Pulsed Electric Fields (PEF) Technology and Thermal Processing

Abstract

The objective of this study was to assess the impact of pulsed electric field (PEF) treatment on the extraction of polyphenolics and antioxidant activity from downgraded date palm fruits. The PEF pretreatments (frequency: 30 Hz, time: 50 μs, pulse number: 240, the electric field strengths were found to be 1, 2, and 2.5 kV.cm−1, and methanol (50%) and temperatures (20, 40, 50 °C)) were optimized and applied before extraction to produce an extract of date fruits with a high content of bioactive compounds. The extracts obtained immediately after pretreatments were analyzed for total polyphenolic content, antioxidant activity, and phenolic profiles. The results revealed that the PEF-assisted extracts at 2.5 kV.cm−1 at T50 °C exhibited higher polyphenol content (+27%) and antioxidant activity (+31%) and notably improved phenolic profiles compared to untreated extracts. PEF treatment processing significantly enhanced the bioactive components and antioxidant activities of date fruits over time, regardless of the treatment applied and the extraction’s temperature. Hence, the application of PEF combined with thermal processing can be an appropriate alternative treatment for a better extractability of bioactive compounds from fruit of dates and food byproducts. These biomolecules could be consumed as new food technology, incorporated as food additives, and nutraceuticals products.