Study of the possibility of application of acoustic spectroscopy in dairy products

Abstract

In this paper, we have studied the possibility of using acoustic and electroacoustic spectroscopy in the dairy industry to study processes occurring at the nanoscale. Studies of the dispersed phase of milk and the process of milk fermentation were carried out. The studies were carried out by the method of acoustic and electroacoustic spectroscopy on the DT-1202 spectrometer. Measurements of attenuation spectra, particle size of the dispersed phase, pH, ξ-potential, electrical conductivity were carried out. It is shown that the samples of pasteurized milk have a bimodal particle size distribution. The sample contains 2 fractions of particles. The first with an average diameter of about 65 nm, which corresponds to casein. And the second – 300 nm, corresponding to the fat fraction of milk. It was found that in the study of samples with a low content of the fat fraction (1.5%), a statistical error occurs, which is associated with a significant predominance of the number of casein micelles in comparison with fat globules. As a result of a comprehensive study of the milk fermentation process, it was found that 8 h after the addition of the starter culture, a transformation from free (sol) to structure-bound (gel) is observed due to loss of surface charge and coagulation, followed by coalescence of casein micelles with the formation of a gel structure protein clot. The data obtained indicate the possibility of using the method of acoustic and electroacoustic spectroscopy for the study and control of various processes occurring in milk and dairy products at the nanoscale.