In order to prepare the mashing materials for $quot;Takju$quot;, Korean wine, with potatoes, theywere steamed, dryed, and pulverized, and their chemical components were analyzed. As a brewing method of Takju with potatoes, general 2nd stage process with Ipkuk and Bunkuk enzyme sources), commonly used now, was carried out and the effects of preparing conditions of Ipkuk(koji) with potato flour, mashing materials and brewing conditions on the contents of Takju mash, and of storing time on the contents of Takju, were investigated and the results obtained were summarized as follows,
1. Chemical components of steamed potatoes and potato flour were Moisture; 76.2, 10.8%, Total sugar; 16.1, 69.8%, Reducing sugar; 3.45, 13.4%, Crude protein; 2.1, 11.3%, Total acid; 0.012, 0.023% and Volatile acid; 0.0012, 0.0025% respectively.
2. The most effective preparing conditions of Ipkuk with potato hour were to incubate the potato flour added 40-50% of water for 48 hours by general preparing process of Koji, and liquefying and saccharogenic amylase activities of Ipkuk incubated at above conditions were D40° 30´ 128 W.V. and 13.2 A.U.
3. The effects of various brewing conditions on the contents of Takju mashes were as follows;
1) Optimum ratio of mashing water and materials for Takju brewing with potato flour was 140㎖ of water to 60g of flour in 1st stage and 260㎖ to 140g in 2nd stage.
2) Optimum fermentating times and temperatures for Takju brewing were at 25℃ for 48 hours in 1st stage and at 30℃ for 48 hours in 2nd stage.
3) Optimum amounts of enzyme sources for Takju brewing were 20-30% of Ipkuk and 0.5% of Bunkuk in 1st stage and 1.0% of Bunkuk in 2nd stage.
4) Methanol content of the Takju mash brewed with raw potato flour was much more than that with steamed potato flour.
5) Alcohol, fusel oil and Formol nitrogen contents of the Takju mash brewed with potato flour were less than that with wheat flour, on the contrary, methanol contents and total acidifies of them were showed conversely above.
4. The changes of chemical components and microflora in the mashes during the brewing potato flour Takju were as follows;
1) The accumulation of ethanol followed rapidly in early stage, being the highest at 72 hours (11.9%).
2) Total sugar content of the mash was decreased considerably within 48-72 hours, being 2.62 at 72 hours, and thereafter slowly.
3) Reducing sugar of the mash had a tendency of decreasing, being 0.29% at 48 hours. 4) Total acidity, volatile acidity and Formol nitrogen content of the mash were increased slowly, being 7.30, 0.20, 2.55 at 48 hours´
5) Total cells of yeast appeared the highest in 72 hours (2.1×10^8) and thereafter decreased slowly.
6) Total cells of bacteria appeared the highest in 48 hoots (2.4×10^8) and thereafter decreased or increased slightly.
5. Takju was made from the fermented mash mixed with water to be 6% of alcohol content, and the change of alcohol content, total acidity, total cells of yeast and bacteria during the storing at 30℃ were as follows;
1) Alcohol content of Takju was increased slightly at 24 hours (6.2%), and thereafter decreased slowly.
2) Total acidity of Takju was increased gradually, being 6.1 at 72 hours
3) Total cells of yeast and bacteria appeared the highest at 48 hours (2.3×10g, 1.5×10g), and thereafter decreased slowly.
6. Alcohol content, total acidity and Formol nitrogen content of the Takju brewed with potato flour Ipkuk or wheat flour Ipkuk and steamed potatoes(1:5) were 9.8-11.3% 5.8-7.4, 2.5-3.3 respectively, and the color of the Takju. was similar to commercial Takju.
7. The results of sensory test for various experimental Takju, showed that the Takjues brewed with the materials combined with wheat flour and steamed potatoes(4:5 or 3.5:7.5) were not significantly different in color, taste and flavor from commercial Takju, However, those with potato flour and wheat flour (1:1 or 7:3) were significantly different from commercial Takju.
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