Determination Of The B Group Vitamins (Thiamine, Riboflavin And Pyridoxol) In The Yeast

This paper was researched the preliminary extraction and determination methods of the intracellular B group vitamins including thiamine, riboflavin and pyridoxol in the yeast cell.The optimum extraction method of the thiamine in the yeast was obtained as follows: In the opaque background hydrochloric acid was 0.1mol/L and the extraction condition was at the temperature of 121 ℃ for 30min.The chromatography conditions of HPLC were found: the mobile phase was methanol mingled with water (V_methanol:V_water=30 : 70) ; the flow rate was 1.2mL/min; 238nm was the thiamine detection wavelength and the column temperature was 35 ℃.The method recovery rate was 88%⁹2%. The retention time of the thiamine was 35min.The range of the standard curve of thiamine was 1.0μg/mL -5.0μg/mL (R²=0.9979) .The optimum extraction method of the riboflavin in the yeast was introduced as follows: In the opaque background, hydrochloric acid was 0.1mol/L and the extraction condition was at the temperature of 121℃ for 30min.Then the solution pH was quickly adjusted to 4.5 after extraction. It also showed in the results that fluorometry was the suitable method to determine the content of intracellular riboflavin of yeast. Fluorescence was excited at the wavelength of 458nm and the emission wavelength was 525nm. To eliminate the effect of other fluorescent substance on determination of riboflavin. Na₂S₂O₄ was employed as quencher of riboflavin.The optimal extraction method of the pyridoxol in the yeast was reported below: In the opaque background the intracellular pyridoxol of the yeast was studied by using antolysis of nonmechanical processes. Autolysis conditions of yeast include autolysis time, autolysis promoter, pH value, using level of water for autolysis, autolysis temperature and so on. Test results indicated the following optimal conditions for autolysis: autolysis time 48h; promoter:3% salt; pH value:7; using level of water 250%; temperature:50℃. The range of the standard curve of pyridoxol was 0.1ng/mL -0.5ng/mL (R²=0.9898) .