Ultrasound pasteurization of Brazil nut beverage enriched with Opuntia stricta var. dillenii Extract: Effects on quality and bioactives

This study explores ultrasound technology to non-thermal pasteurization of a Brazil nut beverage enriched with Opuntia stricta var. dillenii extract. US technology was validated using Escherichia coli CECT 434 as target microorganism. Combinations of ultrasound parameters (power level, amplitude, duration of the treatment and pulses) were applied through a fractional design 3^k–p. All US treatments were conducted at 30 °C. Thermal pasteurization (63 °C for 20min) was also applied to compare with ultrasound process in terms of E. coli inactivation and technological and quality characteristics of the processed beverages. Ultrasound processing conducted at 80 % amplitude for 12 min achieved a ≥5 log reduction in E. coli, outperforming thermal pasteurization at 63 °C for 20 min. Physicochemical and structural properties (particle size, Z potential, polydispersity index and microstructure) and bioactive composition of the BN beverages were studied during cold storage at 5 °C. Ultrasound processing reduced the particle size when they were applied at low power but caused some agglomeration and emulsion instability at high power. Ultrasounds effectively inactivated microbes while preserving bioactive compounds, resulting a viable alternative to thermal pasteurization to preserve Brazil nut beverages. Further research must be carried out to improve the beverage emulsion stability through cold storage, but a good encapsuLation efficiency of bioctives from the ODP added extract was obtained by the use of ultrasounds.