Determination of, physical, chemical and microbiological changes in raw milk applied with solution plasma technique

Milk is highly nutritious due to its chemical composition and has an important place in nutrition. Milk can be contaminated if hygienic conditions are not provided during milking, processing, packaging, distribution and storage. Thermal and non-thermal techniques are used to reduce the microbial load of milk, extend its shelf life and improve its quality. The solution plasma technique, which is one of the non-thermal techniques applied in this research, compared to thermal techniques, the temperature does not rise too much during microbial inactivation, small amount of Maillard reaction, little color change, greater preservation of bioavailability. By ensuring that the unique structure and properties of milk are preserved, conventional heat treatment application, negative effects of many physicochemical properties of milk, especially its nutritional value, and It is aimed to eliminate the problems of the formation of some undesirable metabolites with the reactions occurring during the heat treatment. In this technique, different parameters of interval, voltage, repetition and duration are used from the physicochemical analyzes of raw milk and solution plasma technique applied samples; While analyzing °SH, pH, brix, water activity, % dry matter, density, color values (L*, a* and b*). From microbiological analysis; total yeast-mold, coliform bacteria, mesophilic bacteria and psychrophilic bacteria were analyzed. In the samples examined physicochemically, the ºSH value varied between 7.5 and 9.81, and the average ºSH value of the samples was determined as 8.5. The pH value varied between 6.15 and 6.85, and the average pH value of the samples was determined as 6.5. The brix value varied between 8.5 and 10, and the average brix value of the samples was determined as 9.04. The water activity (aw) value varied between 0.69 and 0.83, and the average water activity (aw) value of the samples was determined as 0.78. The % dry matter value varied between 10 and 14, and the average % dry matter of the samples was determined as 11,7. The density value varied between 1.025 and 1.031, and the average density value of the samples was determined as 1.028. The L* value varied between 96.4 and 88.5, and the average L* value of the samples was determined as 92.1. The a* value varied between 0.13 and 1.81, and the average a* value of the samples was determined as 0.77. The b* value varied between 0.44 and 5.25, and the average b* value of the samples was determined as 2.2. When examined microbiologically, it was determined that there was a decrease in the number of total yeast-mold, coliform bacteria, mesophilic bacteria and psychrophilic bacteria in the samples depending on the time. It has been determined that for raw milk treated with solution plasma technique, it provides an average of 3 log reduction in total flora. Keywords: Raw milk, Solution PlasmaTechnique, Physicochemical, Microbiology