Impact of ultrasound, pasteurization, and their combination on quality parameters, bioactive compounds and health-promoting properties of juices from various Citrus aurantium cultivars

This study aimed to evaluate the effects of ultrasound treatment (UA), pasteurization (P), and their combination on juices from seven Citrus aurantium cultivars: Consolei, Fasciata, Listata, Crispifolia, Foetifera, Bizzarria, and Canaliculata. Both untreated and processed juices were analysed using high-performance liquid chromatography (HPLC) and physicochemical methods. The health-promoting properties were assessed by testing the inhibition of carbohydrate hydrolysing enzymes, and pancreatic lipase. Antioxidant activity was also measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and Ferric Reducing Antioxidant Power (FRAP) assays. The combined use of ultrasound followed by pasteurization proved effective in enhancing the extraction and stabilization of bioactive compounds, thus improving the antioxidant and nutritional profiles of the juices. Hesperidin was identified as the predominant compound, with concentrations ranging from 176.4 to 1804.6 mg/L in untreated C. aurantium cv Foetifera and Consolei, respectively, followed by naringenin. Although the impact of pasteurization alone differed among cultivars, it generally led to a decrease in antioxidant activity and the ability to inhibit α-amylase, α-glucosidase and pancreatic lipase. Across all cultivars, combined ultrasound and pasteurization significantly increased (p < 0.01) phenolic and flavonoid levels compared to untreated juice, demonstrating a consistent treatment effect. The application of pasteurization alone reduced the antioxidant activity as well as the enzyme inhibitory activity but combining it with ultrasound assisted extraction led to significant recovery, with an increase of + 100.0 % in α-amylase inhibition and + 74.5 % in pancreatic lipase inhibition. Overall, the obtained results showed that ultrasound pre-treatment of juice is an effective method to improve the extraction of bioactive compounds and led to maintain high levels of these molecules even after the pasteurization process.