Studies On Mutation Screening And Production Technique Of Tranditional Highland Barley Wine In Tibet

With a long history of more than 1300 years, Highland barley wine has served as an indispensable drink for Tibetans.In this thesis, selecting superior stains from the superior tranditional Tibet starters, making pure culture starters with the selected-superior stains and fermenting Highland barley wine with the pure culture starters are studied , in order to improve the quality of tranditional Tibet wine.(1) To breed strains .Comparing 18 superior diastatic strains which were isolated from Tibet starters, mould ZM6 have been selected for further studies.Then,ZM6 was mutagenized by UV,UV-LiCl and DES, combined natural selection and transparent-loop in plate, and we obtained one mutant ZM6.1.1 which had strong diastatic power (higher 185% than ZM6); We gained one yeast mutant YS2.1.3.2 which came from YS2 that was controlled by ethanol and heat impacting, UV radiating on its cell and protoplast, combine high temperature domesticating and TTC coloration in plate .Mutant YS2.1.3.2 had advantages of stable transmissibility ,fast-synchronous growth velocity, better physiological tolerance, strong fermenting power (alcoholicity was 7.3%).(2) To make culture stater. Via single-analysis test, we obtained the optimal processes of making the Tibei starter :①Preparation of inoculun suspensions :Inoculum suspensions were made by adding 5 mL of sterile physiological salt solution (0.85% w/v NaCl) onto each pure culture slant. The biomass was gently scraped off the agar by means of an inoculation loop;②The ratio of mixed flours is 80g( highland barley flours):20g (wheat bran flours),drying at 100 for overnight (about 17h );③Mixed flours,16% mould suspension,4% yeast suspension ,30% water ,cultulating at 30℃for 24h,then drying at 45℃for 3-5h.(3)To control sound fermenting process. Cooking highland barley ,the dosage of starter and intitial temperature were studied ,and we arrived at the optimal fermenting process of highland barley wine in Tibet :starters were mixed with cooked highland barley whose water-absorbed ratio is 150%~155%.The ratio of starters to mass is 0.4g(dry production starter ):100g(dry highland barley).A fungal solid-state fermentation was undertaking in a dish which have been wrapped with quilt to keep the initial temperature . After 72h, the fermented mass was mixed with added water at the ratio of 100g to 150 mL for 4h, and then filtrated with cloth.