Study On Breeding Of Low Urea-Reducing Strains And Fermentation Technology Of Rice Wine

A high performance liquid chromatography method was established for determination of urea in Rice Wine. Compared HPLC with diacetylmonoxime and PDAB on urea determine.Using strain HJ1615 as the original strain, treated by physical and chemical mutagen, breeded the mutant strains that were able to yield low concentration of urea. Then studies on fermentation conditions.The main results are as follows:The analysis method was established for trace amounts of urea in rice wine. Methods the HPLC separation was performed on PinnacleⅡAmino (250×4.6mm, 5μm) column with a mixture acetonitrile - water (95∶5,v∶v )as the mobile phase, at a flow rate of 1.0mL/min. Detection wavelength was at 203nm by multi wavelength diode array, and column temperature at 40℃.Compared with diacetylmonoxime and PDAB, the results showed that: the lowest detection of HPLC is 2mg/L, detection range was enlarged to100mg/L, The relative standard deviation of urea determination results were 4.05 % and recoveries were 81.31-90.60%. The precision and stability were higher than others.Mutagenized HJ1615 by NTG and He-Ne laser for several times, the method of semi-rational screening was applied. Canavanine,arginine and ornithine were used as screening cribbles, respectively. Finally, the low-producing urea resistant strain HJ1615-4d was obtained, which produced 50% less urea than HJ1615 did. Critical Parameters as alcohol degree Flavor Compounds.Study on the influence of fermentation temperature, inoculation amount and addition of inorganic salt to urea formation. It has been found experimentally that improve fermentation temperature and amount of inoculation could accelerate urea form, but the total amount unchanged. Effect of inorganic salts addition on urea content was obvious. When added concentration was 10mmol/L, the contents of urea was decreased by 45.03%.