The effect of ultrasound times and amplitudes on the solubility and turbidity of whey protein concentrate

The current work was conducted to explore the influence of ultrasound times and amplitudes on the solubility and turbidity of whey protein concentrate (WPC). Ultrasound (US) application was employed using VC-750 ultrasonic power equipment with the frequency of 20 kHz at various times (10, 20, and 30 minutes at 50% amplitude) and amplitudes (60%, 80%, and 100% for 5 min). The outcomes exhibited that the US process have a significant impact on both solubility and turbidity (p<0.05). The highest protein recovery was obtained for the samples exposed to 30 min the US at 100% amplitude (65.56%). WPC samples treated at 100% amplitude showed higher solubility compared to the other samples at 60% and 80% amplitudes. While the solubility of WPC samples treated with 10 min showed the lowest solubility (9.13%), samples treated with 30 min showed the highest solubility (38.14%). There is a negative relationship between solubility and turbidity. All US-treated samples showed less turbidity and higher solubility where the control WPC samples showed the most turbid structure (0.88 NTU) with the lowest solubility (4.15%). Overall, US treatment with 30-minutes at 100 % amplitude showed the highest solubility (65.56%) and least turbidity (0.26 NTU) compared to the other sonication times and amplitudes.