Changes in the polyphenol profile of tomato juices processed by pulsed electric fields

Abstract

The effect of pulsed electric fields on the polyphenol profile of tomato juices was studied. First, tomatoes were subjected to moderate-intensity pulsed electric fields (MIPEFs) and then were immediately refrigerated at 4 °C for 24 h. Treated and untreated juices were then subjected to high-intensity pulsed electric fields (HIPEFs) or thermal treatment (90 °C for 60 s). In comparison to references, tomatoes subjected to MIPEF treatments led to juices with a higher content of polyphenol compounds. A slight decrease in polyphenol compounds was observed over time in thermal- and HIPEF-treated juices, with the exception of caffeic acid. However, HIPEF-processed tomato juices had a higher content of polyphenol compounds (ferulic acid, caffeic-O-glucoside acid, p-coumaric acid, chlorogenic acid, rutin, and naringenin) just after processing and through storage than those thermally treated. Therefore, the combination of MIPEFs and HIPEFs could be proposed as a strategy for producing tomato juices with a higher content of phenolic compounds.

The authors express their 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. The authors 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 Olga Martin-Belloso. Anna ́ Vallverdu-Queralt received support from MEC for the training ́ of researchers