Quality attributes optimization of orange juice subjected to multi-frequency thermosonication: Alicyclobacillus acidoterrestris spore inactivation and applied spectroscopy ROS characterization.

• BBD-RSM optimized AAT inactivation spores and quality attributes of orange juice. • Best treatment inactivating AAT vegetative cells (4 logs) is TS-20/40. • Cells reduction by US and TS treatments correlated with O 2 •- and H 2 O 2 production. • FT-IR and UV–Vis spectroscopy can be used to detect ROS of TS treated orange juice. • LF-NMR confirmed dehumidification stimulated by sucrose explained AAT reduction. This is the first time to investigate the synergistic inactivation effect and mechanism of multifrequency ultrasound (MTUS) on A. acidoterrestris (AAT) vegetative cells and spores, nutrients and enzymes of orange juice. The optimized results of MTUS (using Box Behnken design- surface response methodology) and further comparison with different mode of ultrasound (mono-and multi-frequency) revealed that 20/40 kHz, 24 min and 64 °C were the best optimum results. The AAT spores and vegetative cells were inactivated by 2 and 4 logs, respectively, without deteriorating orange juice contents. In addition, AAT inactivation indicated an inversely proportional relationship with ROS production. FT-IR and UV–Vis spectroscopy characterization confirmed the existence of ROS in treated orange juice and LF-NMR analysis confirmed the inactivation of AAT spores. The findings illustrated the successfully used dual-frequency ultrasound technology for fruit beverages, promoting beneficial changes in physical properties without any significant effects on the quality of ascorbic acid. [ABSTRACT FROM AUTHOR]