In this paper, a new method for monitoring and controlling fermentation process of branched chain amino acid (BCAA)
was proposed based on color identification. The color image of fermentation broth of BCAA was firstly taken by a CCD
camera. Then, it was changed from RGB color model to HIS color model. Its histograms of hue H and saturation S were
calculated, which were used as the input of a designed BP network. The output of the BP network was the description of
the color of fermentation broth of BCAA. After training, the color of fermentation broth was identified by the BP
network according to the histograms of H and S of a fermentation broth image. Along with other parameters, the
fermentation process of BCAA was monitored and controlled to start the stationary phase of fermentation soon.
Experiments were conducted with satisfied results to show the feasibility and usefulness of color identification of
fermentation broth in fermentation process control of BCAA.