| Selenium is an essential trace element with antioxidant properties,which has numerous advantages to the human body.Selenium has inequality distribution in majority areas;its shortage situation has received widespread attention.In order to improve the exploitation rate of selenium,expand the application of selenium and selenium products,and provide basic theory for the antioxidant resistance research of selenium.This report mainly explores the research on the oxidation resistance of selenium and the application of selenium-enriched food,mainly describes the oxidative stress of cadmium abduction Saccharomyces cerevisiae affected by selenium,and flavor content of selenium-enriched yoghurt affected by different selenium sources.The main experimental methods and results are as follows:1 The activity of Saccharomyces cerevisiae was as follows,the fragmentation method of Saccharomyces cerevisiae cell wall was optimized by the application of star point design-effect surface method,the best ultrasound breaking conditions for the Saccharomyces cerevisiae cell wall are ultrasonic power 461.45 W,total working time 15.32 min,working time/intermittent time 17.96 s/17.96 s;The results indicate there are a good linear relationship between concentration of Saccharomyces cerevisiae and its absorbance at 600 nm in logarithmic phase,R2=0.9890,P<0.001,so concentration of Saccharomyces cerevisiae can be indirectly indicated by measuring the absorbance of the culture medium at a wavelength of 600 nm,which provided a method for the determination of enzyme levels in yeast cells in subsequent experiments.2 The effects of different concentrations of cadmium on the growth of Saccharomyces cerevisiae were studied,the inhibition rate of 200 ?mol/L cadmium on Saccharomyces cerevisiae was close to 50%(P<0.05),and 50 ?mol/L selenium could significantly antagonize the inhibitory effect of 200 ?mol/L cadmium on the growth of Saccharomyces cerevisiae,the growth of yeast colonies were compared on different media(blank control,cadmium alone,selenium alone,selenium and cadmium),200 ?mol/L of cadmium can significantly inhibit on the growth of Saccharomyces cerevisiae,50 ?mol/L selenium has a significant antagonistic ability to this inhibition.However,this inhibition can not be completely eliminated.3 The content of Reactive oxygen(ROS)and malondialdehyde(MDA)in yeast cells were significantly increased(P<0.01)by 200 ?mol/L Cd,compared with the control group,these data can reached 5 times and 3 times more;50 ?mol/L selenium could significantly(P<0.05)decrease the contents of ROS and MDA in Saccharomyces cerevisiae,could significantly reduce the intracellular increasing rate of ROS and MDA content by 200 ?mol/L cadmium.The results showed that 50 ?mol/L selenium could alleviate the oxidative stress impact by 200 ?mol/L cadmium through reducing the contents of ROS and MDA in Saccharomyces cerevisiae.4 The activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and glutathione(GSH)in the Saccharomyces cerevisiae supplemented with 200 ?mol/L cadmium(P<0.05).Comparing with the control group,the content of GSH was significantly decreased(P<0.05).The addition of 50 ?mol/L selenium was also significant(P<0.05),and the activity of GSH-Px(P<0.05).The activities of SOD,CAT,POD and GSH-Px in yeast cells were significantly increased(P<0.05),and the activities of antioxidant enzymes were significantly increased(P<0.05),but still significantly(P<0.05)was lower than that of the blank control group and the selenium group alone(P<0.05),but the level of GSH was significantly higher than that of the control group The results showed that the activity of major antioxidant enzymes in Saccharomyces cerevisiae was increased by 200 ?mol / L cadmium stress.Selenium could strengthen the process of yeast cells,but still could not completely abolish the ROS and MDA Content of the content Increased,the reason may be related to the level of GSH failed to return to the blank control group level.5 The optimal ratio of decocted yoghurt was optimized by orthogonal design,and the highest acidity was obtained when the amount of milk powder was 12%,the addition amount of sucrose was 4%,the inoculation amount of activated bacteria was 6%.The amount of whey is also very small,the smell of aromatic,moderate viscosity;then use the proportion of recovery of milk were added three different selenium source for selenium-rich yogurt fermentation,acidity as the main monitoring indicators,select 400 ?g/L sodium selenite,100 ?g/L selenomethionine and 500 ?g/L yeast selenium were used as the optimum selenium concentration.The contents of flavonoids in selenium-enriched yogurt with different selenium contents were determined.Two kinds of organic selenium(selenomethionine and yeast selenium)(P<0.05)were detected to improve the content of diacetyl and acetaldehyde in selenium-enriched yoghurt.Among them,yeast selenium was used as selenium source of selenium-enriched yoghurt with the advantages of high tolerance and high selenium conversion rate. |
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