Study On The Potential In Vitro Uric Acid Reducing Activity Of Green Tea And Berry Tea Fermented By Eurotium Cristatum

Because of the change of diet structure,the high protein and high purine diet make gout incidence rate increase year by year and tend to be younger.Hyperuricemia is directly related to gout.The change of xanthine oxidase activity will increase the production of uric acid in the body and lead to hyperuricemia.Eurotium cristatum is the dominant strain in the process of "blooming" of Fu brick tea.Some studies have shown that Eurotium cristatum can produce some functional components with stronger biological activity through biotransformation of some nutrients,or secrete some extracellular enzymes during its growth and metabolism,which can change some active components under enzymatic reaction.In this project,several materials with the effect of reducing uric acid were used to develop a solid drink with less side effects and effective relief of gout.It is proposed to use several raw materials for the fermentation of Eurotium cristatum.Based on the inhibition effect of xanthine oxidase,the raw materials with better inhibition effect are selected to be compounded.The inhibition effect of xanthine oxidase before and after fermentation,the change of active components,the antioxidation and the quality stability of solid beverage products with better effect of reducing uric acid during storage are studied The results are as follows:1.Selection of ingredients for reducing uric acid in vitroGreen tea,berry tea,black Mao tea,Smilax glabra and other ingredients were selected for the fermentation of Eurotium cristatum.The raw materials for fermentation and no fermentation were tested for the inhibition of xanthine oxidase in vitro to determine the selection of ingredients by the inhibition rate of the effect of reducing uric acid.After fermentation,the maximum inhibition rate of Strawberry Tea was 93.9%,the IC50 of which was 0.145 mg / ml,the IC50 of green tea was 93.3%,and the IC50 of which was 0.149 mg /ml.after compounding several raw materials according to the ratio of 1:1,the best combination was fermented berry tea and fermented green tea,the maximum inhibition rate was 95.9%,and the IC50 of which was 0.114 Mg / ml,the best inhibition effect.Compared with the inhibitory effect of fermented tea powder and its concentrated powder,the tea powder of fermented berry tea and green tea is 3.5% lower than that of fermented tea concentrated powder.Considering the inhibition effect and cost saving,the final product was determined to be 1:1 mixture of fermented berry tea and fermented green tea.2.Study on the change of active substances in the fermentation by Eurotium cristatum of berry tea and green teaThe content of flavonoids,tea polyphenols,catechins,caffeine,theanine and theanine in Strawberry Tea and green tea during fermentation were determined.After fermentation,the flavone content of green tea increased from 9.68% to 14.20%,and that of berry tea increased from 30.65% to 64.02%.After fermentation,the content of tea polyphenols in green tea decreased from 20.02% to 11.95%,and that in berry tea decreased from 32.3% to27.9%;the content of catechins in green tea decreased from 13.85% to 3.16%.There was no catechins in berry tea,and a small amount of catechins was detected after fermentation.After fermentation,the content of caffeine in green tea slightly increased,from 3.88% to4.05%.There was no caffeine in berry tea,and a small amount of caffeine was detected after fermentation.After fermentation,the content of Theanine in berry tea and green tea increased,from 1.28% to 2.05%,from 0.17% to 0.53% after fermentation,and from 0.17%to 0.53% after fermentation From 1.84% to 7.76%.After fermentation,the content of theanine increased from 1.36% to 7.82%.At the 8th day of fermentation,the content of flavonoids in the mixture increased from 22.1% to 54.11%,the content of polyphenols decreased from 27.19% to 20.12%,the content of catechins decreased from 6.91% to 1.65%,the content of caffeine increased from 1.84% to 2.25%,the content of theanine increased from 0.6% to 1.39%,the content of theanine increased from 1.56% to 7.5%.The inhibition rate of green tea,berry tea and their mixture tea powder on xanthine oxidase first decreased and then increased with the fermentation time.At the 8th day of fermentation,the inhibition rate of green tea increased from 62.03% to 73.47%,that of berry tea increased from 72.3%to 82.67%,and that of green tea berry tea increased from 72.17% to 88.3%.There was a positive correlation between the content of flavone and the inhibitory activity of xanthine oxidase.3.Study on the antioxidation and quality stability of green tea and berry tea fermented by Eurotium cristatum during storageThe results showed that the total antioxidant capacity of fermented green tea decreased from 4.24 mmol / g to 3.46 mmol / g,the total antioxidant capacity of fermented green tea increased from 5.51 mmol / g to 8.21 mmol / g,and the total antioxidant capacity of mixed fermented tea powder was 6.53 mmol/g。 The iron reduction capacity of fermented green tea decreased from 46.79 U / g to 36.85 U / g before fermentation,the iron ion of fermented berry tea increased from 49.21 U / g to 56.98 U / g before fermentation,and the iron reduction capacity of mixed fermented tea powder was 49.99 U / g.After fermentation,the anti superoxide anion capacity of green tea increased from 520.615 U / L to 644.2 U / L,the anti superoxide anion capacity of berry tea increased from 717.37 U / L to 861.8 U / L,and the anti superoxide anion capacity of mixed fermented tea powder was 731.79 U / L.After fermentation,the scavenging rate of hydroxyl radicals of green tea decreased from 57.35%to 52.74%,that of berry tea increased from 63.95% to 76.45%,and that of mixed fermented tea powder was 67.1%.After fermentation,DPPH radical scavenging ability of green tea decreased from 81.45% to 69.8%,that of berry tea increased from 79.45% to 90.45%,and that of mixed fermented tea powder was 79.65%.The antioxidant capacity of mixed fermented tea powder was higher than that of green tea and fermented green tea.In the study of storage stability,the mixed fermented tea powder was packed in sterile PE plastic food bag and stored in constant temperature incubator at 37 ℃.During the storage period of 2 months,samples were taken every 10 days to measure the contents of flavonoids,tea polyphenols,catechins,EGCG,caffeine,theanine,theanine,water content and xanthine oxidase inhibition.The results showed that there was no significant change in the water content of mixed fermented tea powder during storage(p> 0.05);there was no significant change in flavonoids,tea polyphenols,catechins,EGCG,caffeine,theanine,theanine and other components(p> 0.05);the inhibition rate of xanthine oxidase in vitro decreased slowly with the increase of storage time,but the degree of decrease was small The inhibition rate of xanthine oxidase was 90.8% at the beginning and 87.6% at the 60 th day.The results show that the mixed fermented tea powder has good antioxidant property and stable quality under long-term storage,which is suitable for developing into a health food with the effect of reducing uric acid.