Effects of high-intensity ultrasound processing on the physicochemical properties and microbial inactivation of apple juice enriched with gallic acid

Resumo

The aim of this study was to evaluate the influence of high-intensity ultrasound (HIUS) specific energy on the microbial inactivation and physicochemical properties of gallic acid enriched-apple juice. The beverage was enriched with 0.1 g gallic acid per100 g apple juice. The treatments were performed using two HIUS processes, low power and long time (LPLT) and high power and short time (HPST); both operating at the same specific energy levels (1, 3, 5, and 7 kJ/g). The most effective aerobic mesophilic heterotrophic bacteria (AMHB) inactivation was obtained by using the HPST process at the specific energies of 5 and 7 kJ/g, which of them resulted in the same log reduction of 3.14. Physicochemical properties, such as pH, soluble solids content, zeta potential, and color difference (?E) were not influenced by the HIUS processes or specific energy levels. The gallic acid content also was preserved in all HIUS treatments.