Effects of pulsed electric fields on the bioactive compound content and antioxidant capacity of tomato fruit

Abstract

The effect of moderate intensity pulsed electric fields (MIPEF) on the bioactive compounds (total polyphenol, lycopene, and vitamin C content) as well as on the antioxidant capacity of tomato fruit was studied. The MIPEF treatment conditions were optimized to obtain tomato fruit with a high content of bioactive compounds. Tomato fruits were subjected to different electric field strengths (from 0.4 to 2.0 kV/cm) and number of pulses (from 5 to 30) and then immediately refrigerated at 4 °C for 24 h. A concentration of bioactive compounds higher than that of untreated tomatoes was obtained in MIPEF-treated tomatoes. A 44% increase in total polyphenol content was achieved under 30 pulses at 1.2 kV/cm. The hydrophilic antioxidant capacity was also enhanced by 44% applying 18 pulses at 1.2 kV/cm, and the lipophilic antioxidant capacity was increased by 37% under 5 pulses at 1.2 kV/cm. The maximum overall level of bioactive compounds and antioxidant capacity in the treated tomatoes was obtained under 16 pulses at 1 kV/cm. Therefore, MIPEF treatments could be considered an effective method to enhance the bioactive compound content and antioxidant potential of tomatoes.

We express our gratitude to CICYT’s (AGL2010-22319-C03), RETICS RD06/0045/0003 from the Spanish Ministry of Science and Innovation (MICINN) for financial support. The CIBERobn CB06/03 is an initiative from the Instituto de Salud Carlos III, Spain. We also acknowledge the financial support of the Spanish Institute of Agricultural and Food Research and Technology (INIA) through the project RTA2010-00079-C02- 02. ICREA Academia Award is also acknowledged by O. M-B. A.V-Q received support from MEC for the training of researchers.