The influence of pulsed electric fields on the dynamics of milk fermentation

Abstract

Developing and producing competitive milk and milk-containing products with high nutritional, biological value, and long shelf life are promising directions for the innovative development of the dairy industry. Pasteurized products of the whole milk group are of the most significant interest. One of the strategic areas of milk processors' work is to improve the quality of raw materials and their processing technology. In this regard, the development and improvement of physical and biotechnological methods, which improve the microbiological safety of raw materials and, ultimately, increase the shelf life and quality of the finished product, is of undoubted interest. One of the promising innovative methods is the use of pulsed electric fields (PEF). The main advantages of this technology are the preservation of sensory properties of products, versatility, which allows them to be used in various technological processes, and economy due to the use of a whole complex of high-intensity physical factors. In the Problem Research Laboratory of the National University of Food Technologies, experimental studies were conducted to study the effect of pulsed electric fields on the dynamics of milk fermentation using an experimental setup developed by specialists at Kharkiv Polytechnic Institute. A comparative analysis of the physicochemical indicators of PEF with an electric field intensity of 30 kV/cm during 30 s with pasteurization at a temperature of 85 °С was carried out. Significant changes in the composition and basic Physico-chemical parameters of milk did not occur under all processing modes, and the difference in the obtained values of the experimental parameters was within the margin of error. It was also established that when conducting a test on the effectiveness of heat treatment due to the effect of pulsed electric fields in samples of whole milk at a voltage of 30 kV/cm for 30 seconds, the absence of phosphatase and peroxidase was found. This fact means that the proposed processing method achieves the effect of pasteurization. The influence of PEF on the dynamics of fermentation of processed milk was studied, and it was established that PEF processing does not have a negative effect on the dynamics of milk fermentation since the results show that the processed samples do not slow down the process of lactic acid fermentation, which does not affect the reproduction of lactic acid bacteria to obtain the finished product.