The optimum cryoprotectants formula for S. thermophilus was determined by the orthogonal trial as:nonfat milk powder 12%, trehalose 1%, glycerol 3%, sodium glutamine 1%. The stability equation during storage was established by the accelerated storage test.
This paper studied on the freeze-dried starter of Lactobacillus sp.. Based on the results of single and response surface methodology,the optimum combination cryoprotectant was developed containing: skimed milk 9.7%,L-cystein 0.03 mol/L,and sodium glutamine 3.2%. The survival rate of lactobacillus sp was maintained at 89.5% using this combined protector.
initial pH, 7.0-7.5. Adding 10mg/IZnCl2 to fermentation culture, apparent viscosity of the broth was enhanced by 16%, the same phenomena was not observed adding ammonium molydine or sodium glutamine instead of ZnCI2. Growth kinetics was tested using 721-spectrophotometer at 440nm using the media without inoculation as the standard.
The results showed that sodium glutamine of low concentration could improve the S. platensis growth and the pigment contents of chlorophyll a, carotenoid and phycocyanin, but it would inhibit the growth and pigment contents, and would also destroy the phycocyanin when sodium glutamine concentration > 1g/L.
The effects of sodium glutamine with different concentrations on the growth and pigment contents of Spirulina platensis in Zarrouk culture were studied.
The effects of sodium glutamine with different concentrations on the growth and pigment contents of Spirulina platensis in Zarrouk culture were studied. The results showed that sodium glutamine of low concentration could improve the S. platensis growth and the pigment contents of chlorophyll a, carotenoid and phycocyanin, but it would inhibit the growth and pigment contents, and would also destroy the phycocyanin when sodium glutamine concentration > 1g/L.
This paper studied on the freeze-dried starter of Lactobacillus sp..Based on the results of single and response surface methodology,the optimum combination cryoprotectant was developed containing: skimed milk 9.7%,L-cystein 0.03 mol/L,and sodium glutamine 3.2%.The survival rate of lactobacillus sp was maintained at 89.5% using this combined protector.The survival rate of the starter could stay at 66.4% when storing it at 4 ℃ for six months.
The optimum cryoprotectants formula for S. thermophilus was determined by the orthogonal trial as:nonfat milk powder 12%, trehalose 1%, glycerol 3%, sodium glutamine 1%. The stability equation during storage was established by the accelerated storage test. Samples were incubated at 30,42 and 60 ℃. Viability assays were performed on each sample removed at constant intervals of time. The specific rate of degradation at 4 ℃ was estimated as 1.656×10-4 by the equation.