Sake brewed by rice germ addition has less amino acid content. It suggests that rice germ contains factors promoting amino acid uptake by yeast.
The factors were isolated from rice germ, and were decided to be Mg
2+, K
+ and PO
43-, the most effective combination of which was the addition of 0.3m mole, 0.4 m mole and 0. 4 m mole in 50m
lof brewing water, respectively. The sake brewed by this addition had a half amino acid content compared with that by no addition. Of these ions, Mg
2+ was the most effective and its contribution ratio was calculated as 80.2%.
On the contrary, Ca
2+ and Mn
2+ inhibited amino acid uptake by yeast.
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