Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 2nd International Congress on Bioactive Compounds

Dairy desserts are appreciated worldwide, with different flavors for consumers. Thermosonication (TS) is one of the studied emerging technologies. It consists of treating the products using high-intensity ultrasound combined with heating, aiming to preserve bioactive compounds and provide microbiological safety besides decreasing the processing time compared to conventional heating. This study aimed to assess the effect of TS (90 °C, 200, 400, and 600 W) on the bioactive compounds values (DPPH, ACE, total phenolic count, TPC, and α-amylase and α-glucosidase values), microbiological shelf life (lactic acid bacteria, total aerobic mesophilic bacteria, molds and yeasts counts, LAB, AMB, MY) and volatile compounds of Jamun fruit dairy dessert [UHT milk (52.8%), milk cream (10%), Jamun fruit (25%), guar gum (0.1%), xanthan gum (0.1%), powdered milk (5%) and sucrose (7% w/w)]. Products submitted to conventional pasteurization (HTST, 90 °C) or untreated (control, no HSTS or TS) were processed for comparisons. In all the microbial groups evaluated, there was a lower log reduction (γ) in the sample treated with HTST than in the TS treatments. However, there was no significant difference between the different applied ultrasound powers (200, 400, or 600 W, p > 0.05). In this way, considering LAB and molds and yeasts, higher microbial reductions (1 log CFU mL−1) were observed in TS treatments than in HTST. LAB was the microbial group most influenced by the TS treatment, with γ values from 2.37 to 2.49. At the same time, AMB presented γ values from 0.59 to 0.68, and the reduction in molds and yeasts was in the order of 1.12 to 1.14. Overall, TS treatments maintained lower microbial counts at the end of the storage period, regardless of the microbial group. The joint application of temperature with ultrasound accentuates the cavitation effect, generating a more significant impact on the collapse of the generated microbubbles and consequently affecting the membranes and cell walls of the microorganisms. Regarding the bioactive compounds, TS samples showed higher values for DPPH, ACE, α-glucosidase, and α-amylase inhibitory activities and TPC content compared with the HTST and with even more satisfactory results when compared with the control sample (p < 0.05). Among the TS samples, the use of the highest ultrasound powers (400 and 600 W) generated significantly better results in DPPH, ACE, α-glucosidase, and α-amylase inhibitory activities compared with the lowest power (200 W) (p < 0.05), but without differences in the TPC content (p > 0.05). Regarding volatile profiling, 17 to 23 volatile compounds were identified, depending on the treatment applied. The most identified organic groups were hydrocarbons (10) and terpenes (8), and all formulations presented caryophyllene as a terpene. At the same time, the application of HTST and TS contributed to the appearance of terpenes compounds, such as β-phellandrene and α-cubene, regardless of the TS power used. Sonication and increased temperatures may have caused jamum fruit cells to rupture, resulting in terpenes' extraction. In conclusion, TS proved to be an efficient emerging technology for dairy desserts processing.