Screening And Application Research Of Yeast Producing Polyols In The Brewing Process Of Maotai-flavor Liquor

Maotai-flavor liquor gets the majority of consumers because of its outstanding sauce,elegant and delicate,mellow wine,delicious taste and its characteristics of empty cup lasting fragrance,as well as its raw pulp is divided into three typical bodies including maotai-flavor,alcohol sweet,pit bottom incense.Among them,alcohol-sweet liquor is particularly scarce.Polyol is one of the important sources of liquor sweet alcohol,therefore it is necessary to analyze the polyols in the brewing process of maotai-flavor liquor.In this paper,yeast strains with strong polyol were screened by daisy and fermented grains in the brewing process of Maotai-flavor liquor,and the yeast strains were prepared through the tolerance of high glucose experiment,shake flask fermentation screening and re-screening,combining with Thin-layer chromatography.Polyol were analyzed by establishing a high performance liquid chromatography-evaporative light scattering method of qualitative and quantitative.And then the yeast strains which can produce the polyols were screened into the fermented grains to simulate the solid state fermentation in the pits,in order to explore the changes of the content of polyol after fermentation.The main results are as follows:1)The results showed that most of the yeasts isolated fromDaisy and fermented grains in the brewing process of Maotai-flavor liquor were analyzed by the method of high glucose resistance,shake flask fermentation screening and re-screening experiments and thin layer chromatography.They had the ability to produce polyhydric alcohols,including D-ribitol,glycerol,erythritol,D-arabinitol,xylitol and sorbitol,these polyhydric alcohols such as D-arabinose Alcohols,D-ribitol and glycerol are more common and some yeasts can produce three or four kinds of polyols at the same time.Finally,five strains with strong polyol production were screened from these yeasts: Debaryomyces coudertii FBKL2.0130?Trichosporon coremiiforme FBKL2.0310?Trichosporon coremiiforme FBKL2.0307 ? Trichosporonoides sp.FBKL2.0315 ?Saccharomycopsis crataegensis FBKL2.0118?2)The chromatographic conditions of the polyol species in yeast fermentation broth were established by high performance liquid chromatography-evaporative light scattering method through optimizing the injection volume and the flow rate of the mobile phase.The method has good linearity,high precision,good stability and reproducibility.The rate of recovery is between 96.73% and 100.46%,both the separating effect and detecting speed are good.The qualitative analysis of polyols in yeast fermentation broth was carried out by HPLC-ELSD method.The types of polyols produced by yeasts were determined.Quantitative analysis of polyol from yeast fermentation broth showed that the actual contents of polyols were not high,among them,the highest yield is FBKL2.0130,13.028 g / L.3)The functional yeast strains FBKL2.0130 and FBKL2.0310 which can produce high content of polyol were added to the fermented grains according to different inoculation amount to simulate the pits.The results showed that the addition of functional strain could increase the content of polyol,but the increase was not significant.When the inoculation amount of FBKL2.0130 was 10%,the total amount of polyol was the highest,which was 1.418 mg/g.When the inoculation amount of FBKL2.0310 was 12%,the total amount of polyol was the highest,which was 1.461 mg / g.The results showed that addition of functional strains could increase the yield of polyols under the condition of solid fermentation.At the same time,it was found that the production of polyols in solid fermentation conditions was different from that of liquid fermentation.FBKL2.0310 produces xylitol in liquid fermentation,but it is not detected in solid state fermentation.