1. Bioresources Research and Development Laboratories, Sapporo Breweries, Ltd., 37-1 Nitta-Kizaki, Ota, Gunma 370-0393, Japan.
2. Corresponding author. Phone: +81276561455. Fax: +81276561605. E-mail: naohiko.hirota@sapporobeer.co.jp
3. Frontier Laboratories of Value Creation, Sapporo Breweries, Ltd., 10 Okatome, Yaizu, Shizuoka 425-0013, Japan.
4. Production & Technology Development Center, Sapporo Breweries, Ltd., 10 Okatome, Yaizu, Shizuoka 425-0013, Japan.
5. Research Institute for Bioresources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama 710-0046, Japan.