Study On Fermentation Of Pear Wine With High ?-Aminobutyric Acid

?-aminobutyric acid is a widely exists in the non-protein amino acids in prokaryotes and eukaryotes,has many physiological functions,such as lowering blood pressure,improving sleep,treating depression,preventing diabetes,activating liver and kidney function,etc.GABA as a biologically active molecule,has been widely used in food,medicine,feed and other industries.GABA is mainly through the glutamic acid decarboxylase(GAD)catalytic transformation of glutamic acid decarboxylase.Lactic acid bacteria,yeast,mold and other microbes were found in this enzyme,as a result,extracting glutamic acid decarboxylase or GABA production by microbial fermentation.Pome meat has thin crisp,high sugar,sweet and refreshing,rich nutrition,is a good raw material for brewing wine.The purpose of this subject is brewing pear wine and rich in GABA,in order to strengthen the health care function of pear wine.Experiment separated from the surface of the fruit and selected a wild yeast KS45,after ARTP mutagenesis obtained high-yield strains of GABA,KS45-60 and KS45-180.KS45-180 has the highest yield and 36.08% over KS45.ARTP optimal mutagenesis condition: power is 120 w,gas flow is 10 L/min,the distance between the plasma source and the sample emission is 2 mm,sample size is 10 ?L,helium as the working gas,the plasma temperature at 25? ~ 35?(room temperature),processing time is 180 s.After six consecutive passages,the GABA production in a stable state,it is applied to high GABA fermentation of pear wine.Production characteristic of ?-Aminobutyric Acid(GABA)during fermentation of Ya pear wine was studied in this work.The results showed that biosynthesis of GABA was initiated immediately when main alcoholic fermentation of pear wine was finished and mass GABA was produced.After main alcoholic fermentation,the viable cell numbers of yeast decreased and the GABA content in the pear wine increased as the fermentation time increased,both of which showed a negative correlation.The possible reason was that intracellular decarboxylase(GAD)was released duo to autolysis of died yeast cells and mass GABA was biosynthesized.Duirng main alcoholic fermentation,GAD activity increased rapidly until the maximum value reached,and then GAD activity declined quickly.Supernatant of the pear wine was feremented at 30? for 14 d and it was found that residual GAD still synthesized GABA,and the GABA content of pear wine increased.Duirng main alcoholic fermentation,the sugar in the medium rapidly declined and GABA also decreased,while ending the main alcohol fermentation,the sugar ended to be stable and the accumulation of GABA increased;Duirng main alcoholic fermentation,pH rapidly declined,After the end of the fermentation,pH was tended to be stable,which was due to the yeast consumed the organic,resulting in a number of acidic,such as pyruvic acid and so on,these substances reduced the pH of the culture medium,After the end of the alcohol fermentation,organic acid consumption was reduced,the acid production capacity had declined and finally was tended to be stable.The strain KS45-180 as production strain.By single factor experiment to optimize the fermentation conditions.The fermentation time,inoculation,initial sugar,temperature,time of supplementation of sodium glutamate,filter,pH and SO2 were influenced the content of GABA in ya pear wine.the conclusion was obtained that the best amounts of fermentation medium was: liquid volume 100%,inoculum 10%,initial sugar 20%,temperature 30?,initial pH 5,added the appropriate glutamate fermentation in the early fermentation and the amount of SO2 60mg/L.Under optimal conditions,thealcohol of ya pear wine was 9.4 V/Vvol,the GABA content was 101.42 mg/L,which was more than Angel yeast production.The taste of GABA pear wine was similar with ordinary pear wine.