Study On Preparing High Monacolin K Red Yeast Rice From Different Genotypes Of Rice And Monascus Strains

High Cholesterol content in human blood for a long-term easily lead to atherosclerosis(AS)and other cardiovascular and cerebrovascular diseases.In 1979,Professor Endo Aki,the Japanese found Monascus secondary metabolites of Monacolin K has a cholesterol lowering effect significantly.Monacolin K can be used to improve cardiovascular and cerebrovascular diseases of human.How to improve Monacolin K content in Monascus fermentation products has become the research focus of many experts at home and abroad.In this study,three steps were used to increase the Monacolin K content in red yeast rice:screening of high-yield strains,screening of high-quality rice and optimizing of fermenting process.Besides,it will help to study the effect of red yeast rice(prepared by this study)on reducing the cholesterol by animal experiments on mice.The results are as below:1.Screening of Monascus strains that can produce high yield Monacolin K.One Monascus strain,FG-2,that can produce high yield Monacolin K was screened from 40 Monascus strains according to the content of Monacolin K in the fermented products by solid-state fermentation.The highest Monacolin K content in FG-2 is 2.46mg/g,2.29 times the typed strain APS 002.Comparing the ITS sequence of FG-2 with GenBank by blastn,FG-2 is one kind of Monascus purpureus.2.Screening of high-quality rice.Screening by using Monascus purpureus FG-2 and 26pcs of rice samples.Milled rice,1a825,as fermentation substrate can yield Monacolin K for the most of 3.61mg/g,about 2.70 times the rice from market.Comparing the ability of Monacolin K production by FG-2 and different types of rice,the average of Monacolin K from the milled rice as fermentation substrates is 1.OOmg/g,better than that from brown rice(0.42mg/g).Monacolin K from non-glutinous rice(0.98mg/g)is better than that from glutinous rice(0.39mg/g)respectively.3.Optimizing of fermenting process.Monascus purpureus(FG-2)as yielding strain to optimize through single-factor and orthogonal tests.The results showed that the optimum fermentative condition through orthogonal tests while temperature is 30?,pH is 5.0,the bottle load of rice is 40g,the fermentation time is 17d.In this condition,Monacolin K content was the highest,4.64mg/g,28.5%more than that before optimization,8.36 times that from the red yeast rice in the market.4.Study on effect of Monacolin K on the lowering cholesterol.The hyperlipidemic mice fed on the same amount of different kinds of red yeast rice for 3 weeks.The content of total cholesterol(TC)and triglycerides(TG)in blood of mice was detected.The result shows that comparing with Group B(hyperlipidemic model)as control,the TC levels of experiment Group C(Gutian red yeast powder),Group D(red yeast rice prepared by this study),group E(Xuezhikang)decreased 29.5%,34.1%and 37.0%respectively.There is a significant difference(p<0.01)between the TC level of Group B and other Groups.Comparing with Group B(hyperlipidemic model)as control,the TG levels of experiment Group C(Gutian red yeast powder),Group D(red yeast rice prepared by this study),Group E(Xuezhikang)decreased 3.7%,4.9%and 7.9%respectively.The TG level of Group B is higher than other Groups though not significant difference(p>0.05).The effects on lowering cholesterol of a medicine,Xuezhikang,is slightly better than that of red yeast rice prepared by this study and Gutian red yeast powder.