New analysis technique reveals nature of milk

The application, called High-Resolution Ultrasonic Spectroscopy (HR-US), promises higher precision and continuous monitoring.

Heat stability is usually defined as the time needed to cause visible coagulation of milk at a given temperature. Analysis of this complex process could be very useful for the dairy industry as a key quality indicator during processing.

Through the use of HR-US, coagulation can be detected during the real time monitoring of milk subjected to high temperatures. High precision measurements can be carried-out and the monitoring of structural transitions in the sample is possible.

Spectroscopy is the study of molecular structure and dynamics through the absorption, emission and scattering of light. It is a discipline that has been used in a number of fields, but has increasingly been applied in the analysis of food.

The practice has enabled food scientists to better understand the behaviour of food. For example, the elasticity of dough and the specific characteristics of colloids in milk and gels can be understood and exploited through the application of this science.

In addition, legislation now largely controls the ways in which foods are produced and the ways in which food products must be described and labelled. The result of all this is that the industry is becoming more and more reliant on scientists, food scientists, to maintain and improve food quality and ensure legislative compliance. Ultrasonic Scientific​ therefore believes that the application of spectroscopy will help food manufacturers better understand the nature of milk.

The HR-US technique enables the continuous monitoring of changes in the composition and structure of the sample while it is submitted to a high temperature. This is extremely difficult with other analytical techniques due to both the opacity of milk, the high temperature and the excessive pressure at which the experiment is carried out.

HR-US uses the two parameters of velocity and attenuation of the ultrasonic waves to access new information about both the chemical dynamics and structure of the sample. The technique provides high-resolution measurements and is a non-destructive and versatile technique that does not require any optical activity or transparency of the samples.

In addition, HR-US requires a small sample volume (typically 1ml) and allows the analysis of a broad variety of sample types, chemical reactions and processes. This includes the measurement of concentrations of components, transition temperatures, temperature intervals and kinetics of sedimentation and creaming as well as the analysis of particle size in suspensions and emulsions.