Effects of non-thermal techniques on polyphenols in table olives (cv. Nocellara del Belice).

Processing technologies strongly affect the nutritional and phytochemical quality of table olives. This study investigated the effects of thermal treatment (TT), high-pressure processing (HPP), pulsed electric fields (PEF), and cold plasma (CP) on the polyphenol composition of table olives (Olea europaea L., cv. Nocellara del Belice) using UHPLC-PDA, NMR profiling, and LC-HR-MS/MS. Processing technology influenced polyphenol profiles more strongly than parameter variation. TT, HPP, and PEF promoted the conversion of glycosylated polyphenols into non-glycosylated aglycones, with oleuropein decreasing by up to 80%. TT increased tyrosol up to three-fold, while HPP and PEF increased hydroxytyrosol and tyrosol up to 2.5-fold compared with non-treated olives. In contrast, CP induced only moderate changes under low-moisture conditions, with quantified polyphenols increasing by around 20% on average. These findings demonstrate technology-specific polyphenol modification pathways and support tailored processing strategies to modulate olive polyphenol composition while maintaining nutritional quality.