Thermosonication: A Veritable Technique to Improve the Quality Attribute of Black Velvet Tamarind (Dialium guineense Wild) Beverage

The use of emerging processing techniques as an alternative to conventional pasteurisation of fruit beverage has attracted increased attention in recent times. In this study, black velvet tamarind beverage (BVTB) subjected to thermosonication (TS) treatment (45 kHz, 200 W at 40°C, 50°C, and 60°C each for 10, 20, and 30 min) was compared with raw and pasteurised (90°C for 1 min) beverage. The samples obtained were assessed for their physicochemical and biofunctional properties, residual enzymatic activities, bioactive compounds, microbial safety, and sensory attributes. The pasteurised and thermosonicated samples presented no significant (p > 0.05) difference in the pH, total soluble solids, and titratable acidity. However, TS significantly (p < 0.05) increased colour (a^∗) attribute (0.63–0.75), viscosity (42.60–84.00 cP), cloudiness (0.83–1.69), and browning (1.48–1.67) indices of the beverage. Moreover, progressive TS significantly inactivated residual enzymes of pectin methylesterase (PME), peroxidase (POD), and polyphenol oxidase (PPO). Notably, TS at 40°C and 50°C conditions significantly improved ascorbic acid (17.08%–46.95%), phenolic compound (6.83%–22.53%), flavonoids (64.89%–80.82%), and antioxidant capacity (0.22%–7.4%), while treatment at 60°C reduced the bioactive compounds with increasing holding time. Importantly, both treatments reduced the microbiological population below the USFDA-recommended level, and the sensory values from both treatments were not significantly different from the raw beverage. The results obtained showed that TS has the potential to improve the quality attributes of BVTB.