Effect of technological processes and storage on flavonoids content and total, cumulative fast-kinetics and cumulative slow-kinetics antiradical activities of citrus juices

Juices from the mandarin Clemenules (Citrus clementina Hort. ex Tan.), the tangor Ortanique (Citrus reticulata Blanco x Citrus sinensis Osb.) and the sweet orange Valencia Late (Citrus sinensis) have been industrially squeezed, pasteurized, concentrated and stored under refrigeration (4 degrees C) and at room temperature (20 degrees C). After each process, the flavanone-7-O-glycosides (FGs) and fully methoxylated flavones (FMFs) contents as well as total, cumulative fast-kinetics and cumulative slow-kinetics antiradical activities were determined and compared with those from the corresponding fresh hand-squeezed juices. Neither industrial-squeezing, nor pasteurization or concentration significantly affected FGs and FMFs contents and antiradical activities of assayed juices. Storage caused a slight decrease of the FMFs contents but a significant reduction of both soluble hesperidin contents and cumulative fast-kinetics antiradical activities in all assayed juices. These decreases were dependent on storage temperature. Characteristic values of the varietal characterization parameters, which are derived from the FMFs contents and antiradical activities of fresh hand-squeezed juices, held valid for industrially squeezed, pasteurized and concentrated juices. After storage, however, only the FMFs-derived varietal characterization parameters and cumulative slow-kinetics antiradical activity remained valid for the resulting juices.