Whey acerola-flavoured drink submitted ohmic heating processing: Is there an optimal combination of the operational parameters?

Whey acerola-flavoured drink was treated using ohmic heating (OH) at 65 °C for 30 min to evaluate different frequencies (10, 100 and 1000 Hz with 25 V) and voltages (45, 60 and 80 V at 60 Hz) and by conventional heating (CH) with the same temperature profile (65 °C/30 min). Rheology parameters, color changes (h°, C∗, ΔE) microstructure (optical microscopy), and ascorbic acid (AA) degradation kinetics were performed. AA degradation rates ranged from 1.7 to 29.3% and from 2.8 to 24.8% for OH and CH, respectively. The beverages treated with both processes exhibited a pseudo-plastic behavior (n < 1), higher saturation (C∗), lesser reddish color (h°), and higher color variations (ΔE∗). In microstructure analysis, OH (1000 Hz-25 V and 80 V-60 Hz) was able to rupture the cell structure. The best results were observed at low frequencies and voltage OH processes on whey acerola-flavoured drinks should be performed at low frequencies and voltages (≤100 Hz and 45 V), an alternating current (A/C). However, despite the use of inert electrodes, the existence of corrosion was not evaluated, being an important information to be investigated.