In a world of globalization and big food consumption, there is an increasing demand for food processing technologies that leave food nutritionally unchanged; one of them is pulsed electric field technology. In this paper, we analyze the effects of high-intensity pulsed electric field treatment on the content of selected bioactive substances (phenolic compounds and anthocyanins), which are most present in red fruits. For this purpose, strawberry juices obtained from strawberries (Fragaria × ananassa Duch. cv. 'Albion') at two different stages of ripeness were treated with HIPEF at 40 and 50 kV cm^-1 and frequencies of 100 and 200 Hzh for 3 and 6 minutes. The content of polyphenols (4-Hydroxy-3-methoxycinnamic acid, 4-Hydroxybenzoic acid, caffeic acid, trans-p-Coumaric acid, myricetin, catechin, ellagic acid, kaempferol and chlorogenic acid, quercetin) and anthocyanins in juice samples (pelargonidin-3-glucoside, cyanidin-3-glucoside, pelargonidin-3-rutinoside) was identified and quantified by the HPLC-DAD technique. Chromatographic separation was performed using a C18 column with 1 ml/min column flow and a gradient elution program. Juices from strawberries with a higher degree of ripeness have a higher content of polyphenolic compounds (ellagic acid, caffeic acid, myricetin, kaempferol, pelargonidin-3-rutinoside, pelargonidin-3-glucoside). The PEF treatment positively affects the composition of these analytes and increases their concentration in the juices, but only under ideal conditions (50 Hz /100 kV/cm/3 s). If the ideal conditions found are violated, their concentration decreases.

Acknowledgements: This research was funded by the Croatian Science Foundation through the funding of the Hurdle Technology and 3D Printing for Sustainable Fruit Juice Processing and Preservation project, IP-2019-04-2105. This work was carried out within the project "Food Safety and Quality Center" (KK.01.1.1.02.0004). This project is co-financed by the European Union from the European Regional Development Fund.