Research On Optimization And Rich In GABA Functional Red Yeast Rice Of Monascus Strains And Germinated Brown Rice Genotypes

Gamma-amino butyric acid(GABA)is an important factor function,having a variety of physiological functions such as reducing blood pressure and providing nutrition for nerve.Internationally,quantities of studies about GABA were carried out.In fact,germinated brown rice and Monacus strain can accumulate wealth of GABA.This thesis focuses on the ability of GABA accumulation by different varieties of brown rice and Monacus strains,in addition,solid fermentation conditions of red yeast rice were also studied at the same time.The main results are as follows:(1)Comparing eight different extraction methods,the optimal GABA extraction method was determined:5g germinated brown power is placed in a erlenmeyer flask,adding 60 percent ethanol 30 ml,then bathing in 55? water for 6h,shaking the flask for 30s between every 30 minutes,next,centrifuging for 15min in 3000rpm,then the supernatant was concentrated to 5ml,finally the concentrate was filtered with 0.45 microporous membrane.By this method,GABA content can be up to 22.31mg/100g,which is 3.8 times of the minimum amount of GABA extraction.(2)Premium Black rice varietie N84 was selected from 60 different rice types(including rice,red rice and black rice),by catalyticing N84 to germinate,the GABA content can reach to 24.82mg/100g,which is 4.0 times the minimum varieties.(3)By using single factor experiment and orthogonal design experiment to study the soaking temperature,soaking time,the pH of soaking,germination temperature and germination time,the best germination condition was founded for GABA production,it is as follows:soaking temperature is 20?,soaking time is 9h,the pH of soaking is 5.0,germination time is 32h,germination temperature is 35?.GABA content of germinated brown rice for N84 can be reached to 28.94mg/100g,which is 1.17 times than before.(4)92 Monascus strains were isolated and purified from the commercially available red yeast rice,together with 13 Monascus strains,to select the ability of producing GABA.the strain 5008,which has the strongest producing capacity of GABA,was selected from them.Red yeast rice which was inoculated with this strain,its GABA content was 22.43mg/100g,which is 2.0 times the minimum strain.(5)Three main influencing factors were determined by single factor optimization experiment,together with Plackett-Burman experimental design.On this basis,In order to optimize the solid fermentation process,We use Box-Behnken response surface design experiment to carry out the fermentation process optimization.The best fermentation process point is as follows:Set the number of holes 5,keeping cultivate in 25? for 11 days.In this point,the GABA content in red yeast rice can be accumulated to 26.54mg/100g,with an increase of 11.8%compared to unoptimized.