Effect of thermosonication and probiotic fermentation on bioactive compounds and microbial activity of <i>Elaeocarpus floribundus</i> (jalpai) juice

Abstract This study investigated the impact of pasteurization (PS) and thermosonication (TS) on the quality of Jalpai ( Elaeocarpus floribundus ) juice. TS was applied at 30 °C, 40 °C, and 50 °C for 30–60 min using 40 % and 50 % amplitude. Compared to raw juice, TS enhanced total phenolic content (34.07 mg GAE/mL), flavonoids (17.99 mg QE/mL), vitamin C (15.28 mg/100 mL), and antioxidant activity (1.22 mg Trolox/mL), while reducing microbial loads. Complete inactivation of TVC and YMC was achieved at 50 % amplitude under optimum conditions. A probiotic beverage was developed using Lactobacillus plantarum and Lactobacillus paracasei . Fermentation led to reduced pH, TSS, and TPC, with increased titratable acidity, flavonoids, and antioxidant activity. TS retained heat-sensitive nutrients and supported probiotic growth. During storage at 4 °C, vitamin C declined slightly, but other nutrients remained stable. The synergistic effect of TS and fermentation improved juice quality, suggesting a commercially viable method for probiotic beverage production.