Inorganic Components in Rice Germ Affecting Reduction of Amino Acid Content in Sake Moromi Mash

Study on the Brewing of Sake with Excellent Taste and Flavor (Part II)

Abstract

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 Mg²⁺, K⁺ and PO₄^3-, the most effective combination of which was the addition of 0.3m mole, 0.4 m mole and 0. 4 m mole in 50mlof brewing water, respectively. The sake brewed by this addition had a half amino acid content compared with that by no addition. Of these ions, Mg²⁺ was the most effective and its contribution ratio was calculated as 80.2%.
On the contrary, Ca²⁺ and Mn²⁺ inhibited amino acid uptake by yeast.