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The aim of the present study was to determine the effect of concentrating skim milk (10–50 g 100 g−1) on changes in contents of minerals as well as values of physicochemical and structural parameters (pH, total protein, micro- and macro-mineral content, viscosity, particle diameter, micrographs by fractal dimension), electrical parameters: conductivity (Z, G), and dielectric parameters (C p , C s). Statistical analysis was conducted to determine the applicability and limitations of electrical parameters as tools for controlling the quality of concentrated skim milk. The obtained results show that as the dry matter content increases, the particle diameter and viscosity increase linearly, while the pH value decreases. The trends for electrical parameters and microstructure, as described by the fractal dimension, were less clear-cut. The electrical parameters suited to control the quality (Cluster 1 and 2 parameters) of concentrated skim milk turned out to be the dielectric parameter (C s 100 Hz, p < 0.001, r ≈ (−0.8) to 0.9), followed by the conductivity parameter (Z – Cluster 1: p < 0.05, r ≈ 0.38; Cluster 2: p < 0.01, r ≈ −0.52) measured at f = 100 Hz, 1 kHz, and 100 kHz. Parameters C s and Z at f = 100 Hz can be harnessed in practice to develop a simple and cost effective measurement device, which could replace time-consuming and costly assays done using reference methods. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents the results of the studies aimed at the identification of changes in the intensity of electric current passing through beef carcasses during high voltage electrical stimulation and correlating those changes with the changes of pH occurring in meat after slaughter. The analysis of correlation of pH value in the Longissimus dorsi muscle of young bulls as the function of intensity of electric current passing through beef carcasses and its change during electrical stimulation showed that at the significance levels of P <0.05 and P <0.01 there is a dependence between the pH values obtained 2, 6 and 24h after stunning (pHh(2,6,24)) and the values of pH before electrical stimulation (pH0), the initial and final value of electric current intensity (I i and I f) and the difference between those values (ΔI). The above identified dependence will allow selection of meat on the rate of changes and the final pH value to be obtained 24h after stunning and identification of DFD meat still before commencement of meat cooling process and an increased mechanization of cattle slaughter plants mainly in the aspect of meat selection. [Copyright &y& Elsevier]