Study On The Culture, Separation And The Thermal Property Of Ice Nucleation-active Protein

The ice nucleation-active protein is a kind of protein that was produced by the ice nucleation-active bacteria. Such protein allows the freezing of water droplets at higher temperatures and lower the super cooled temperature. It is significative that of studying on the culture, seperation and the thermal property of the ice nucleation-active protein, using the ice-nucleating active protein on the food freezing industry. It could reduce the producing-cost , improve the producing-efficiency, ensure the quality of the production, promote the development of the food freezing industry.In this paper, the ice nucleation activity and the biomass of ice nucleation-active bacteria (Xanthomonas campestris and Fusarium graminearum) was studied by the orthogonal experiment. Also, the purification of ice nucleation-active protein from Fusarium graminearum was studied. Then, the influence of ice nucleation-active protein on the freezing point of egg white protein was saw about.The best ferment condition of Xanthomonas campestris was that: 40 ml of the fermented broth, 3% of the seed volume, pH 8.0, the whole ice nucleation activity is 30.73. The best ferment condition of Fusarium graminearum was that: 30 ml of the fermented broth, 3% of the seed volume, pH 6.0, the whole ice nucleation activity is 493.46.The ice nucleation activity of Fusarium graminearum is stronger than that of Xanthomonas campestris.The result of seperation is best using 25% ethanol.The result of DSC shows that both Xanthomonas campestris and Fusarium graminearum can increase the freezing point of egg white protein.