Thermal stability of natural pigments produced by in submerged fermentation.

The major aim of the current study was to assess thermal stability of red pigments produced by ATCC 16362/PTCC 5303 in submerged fermentation. Natural pigments were produced by using stirred tank bioreactor. Stability of pigments was assessed under various temperature (50.2-97.8°C), salt (0%-2.5%), and pH (4.3-7.7) values. Thermal degradation constant and half-life value of the red pigments were analyzed using response surface methodology followed by a first-order kinetic reaction. Results of this study showed that pH, temperature, and salt content could affect red color stability of . The pigment showed various stabilities in various thermal conditions (temperature, salt, and pH). At high temperatures, degradation constant of the red pigments increased with decreasing pH, revealing that the red pigment was destroyed at lower pH values and salt could affect stability of the red pigments at lower temperatures.