Studies On Fermentation 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) Superior Tibet starter selecting and fermentation mechanism study. 10 commercial Tibet starters obtained from the market in Lasa show a considerable variation in shape and quality. There are tow kinds of poperty which could embody the quality of Tibet starters. They are the fragrance and cross section. Starters 5, 8, 9, 10 all have good fragrance, proper water content and uniform distributed white sinensis. However, starters 2,4,6 have sour or mouldy fragrance. It has found that starter 5and 9 interest for further investigation because of their attractive fragrance and sweet alcoholic flavour of their wine through fermentation test. However, starter 2 and 4 which have a strong sour flavour, starter 6 caused a mouldy flavour were noticed. Starter 7 has a unique fragrance like the almond. In both starter 5and 9, the count of yeasts which predominate above 96% was releventily higher than bacteria and moulds which is the lowest one. In Highland barley wine fermentation, yeasts started to convert glucose as soon as it was produced to keep the balance between diastatic and fermentation. It proved to be belifit for the microorganisms grouth and alcohol production. Additionally, just like the China rice wine starter, the Tibet starters gained in Lasa are commonly supplemented with the local plants. But the functionality of the plants in Tibet starters is not clear.(2) Superior stains selecting and puer culture staters making. rComparing 38 stains which were isolated from starter 5and 9, two superior strains have been selected for further studies: yeast ZY2 had a similar fragrance with Highland barley wine and strong fermenting power ( appearent alcoholicity 48.46 % ); mould ZY2 has a strong saccharification (151.32mg/h·g^-1) and attractive flavor. Via single-analysis test, we obtained : â‘ the optimal processes of making the mould starter: highland barley powder, 40% water, 2% (NH₄) 2SO₄, cultulating at 30℃ for 4⁵d, and the spore count is 1.4×10⁹ spores/g dry starter, â‘¡the optimal processes of making the production starter: 40% water, 10% soya flour, 0.5% inoculating mould starter, cultulating at 34℃ for 24²8h, and saccharification is 670.32 mg/h·g^-1 dry starter, â‘¢the optimal processes of making yeast solid starter: highland barley powder, 50% glucose-bean sprout liquid medium(GBM) whose initial pH is 3.5, 15% inoculating ZY2 which breeded in GBM for 24h, cultulating...