The effects of ohmic cooking process on some physical and chemical characteristics of button mushrooms

In this research, the ohmic heating method was used to reduce the moisture content of white button mushroom (Agaricus bisporus). The purpose of this research is to investigate some physical and chemical characteristics of the button mushroom at the end of the ohmic process. In this research, three voltages of 60, 75, and 90 volts were used, and according to the 8 cm distance between the electrodes, 7.5, 9.37, and 11.25 volts/cm were obtained. Also, three types of steel, brass and aluminum electrodes and three concentrations of 5%, 10% and 15% ohmic solution were selected for the experiment. In order to colorimetrically measure button mushrooms, the images were scanned in color using Image J software in the Lab space, and the extracted values were expressed as percentages. Also, in order to measure chemical properties, 0.5 g of dried samples were separated and methanolic extract was prepared and properties including antioxidant activity, total phenol content, flavonoid content, vitamin C, pH and Brix were measured. The results showed that with the increase of the voltage gradient, the value of the browning index and the total color changes increased significantly. The highest and lowest values of the browning index were 244.39 (voltage gradient 11.25 V/cm-aluminum electrode) and 86.39 (voltage gradient 7.5 V/cm-steel electrode). The highest and lowest total color changes were 27.98 (aluminum electrode) and 16.01 (steel electrode) and the increase in browning index and total color changes were observed in steel, brass and aluminum electrodes, respectively. . In the chemical properties section, similar information was obtained in the parameters of antioxidant activity, total phenol content, flavonoid content, vitamin C and soluble solids; So, with the increase of the voltage gradient, the value of these parameters increased significantly. In the voltage gradient of 11.25 V/cm, the highest values have been observed.