Sensory characteristics and functionality of sonicated whey

Abstract

This research employed power ultrasound (US) on a whey suspension containing 28.2% solids (10% total protein) and characterized the US treated whey with respect to descriptive sensory evaluation, thermal stability, particle size, emulsification activity, and viscosity. The sensory attributes of sonicated and control whey were determined at three pH levels (3.5, 4.5 and 7.5) with and without nose clips using a trained panel. Nose clips were used to avoid the detection of aromatics and to evaluate whey quality in terms of taste only. There were pH dependent differences in 7 of 21 attributes tested with nose clips and there were no significant differences between the control and US samples when comparing the same pH levels, with the exception of cardboard which was found at a higher level in the pH 7.5 control sample than in the US pH 7.5 sample. There were 9 pH dependent differences in attributes when tested without nose clips and there were no significant differences between the control and US samples of the same pH, with the exception of cardboard being higher in the control pH 4.5 sample, and malty being higher in the control pH 7.5 sample compared to their respective US samples. Thermal stability was monitored via transmission of samples at 600nm and transmissions of US and control whey were significantly different based on temperature (72 or 85°C), concentration (5 or 10% solids) and pH (3.5, 4.5 and 7.5). Transmissions were higher in all US samples compared to the controls indicating less turbidity in US samples. Transmissions were higher in samples with the lower heating treatment of 72°C, at pH 7.5, and at 5% solids. US whey resulted in a more stable emulsion, lower particle size, and a higher viscosity compared to control whey.