Pasteurization of spp. in black fungus () powder by radio frequency heating.

Radio frequency (RF) heating has been studied to inactivate bacteria in some powder foods. In this study, a 6 kW, 27.12 MHz RF system was used to pasteurize in black fungus powder. The effects of different conditions (initial a, electrodes gaps, particle sizes) on RF heating rate and uniformity were investigated. The results showed that RF heating rate was significantly ( < 0.05) improved with decreasing electrodes gap and increasing initial a, and the heating rate was the slowest when the particle size was 120-160 mesh. However, these factors had no significant ( > 0.05) influence on heating uniformity. RF pasteurization of in black fungus powder was also studied. The results showed that, to inactivate for 5 log reductions in the cold spot (the center of surface layer), the time needed and bacteria heat resistance at designated temperature (65, 75, 85 °C) decreased with increasing a, and the first order kinetics and Weibull model could be used to fit inactivation curves of with well goodness. Quality analysis results showed that although RF pasteurization had no significant ( > 0.05) effect on polysaccharide (AAP) and total polyphenols, obvious changes were found on color. Results suggested that RF pasteurization can be considered as an effective pasteurization method for black fungus powder.