食用昆布5種類の遊離アミノ酸含量について  [in Japanese] Free Amino Acid Content of Five Kombu Species  [in Japanese]

2002年8月〜9月,北海道の各沿岸海域で採取された5種の昆布,ラウスコンブ,リシリコンブ,ミツイシコンブ,マコンブ,ナガコンブを東京中央市場から購入し,その遊離アミノ酸を測定した。グルタミン酸はすべての昆布に1,000mg/100g以上含まれ,特にラウスコンブとマコンブはそれぞれ3,540と3,307mg/100gであった。他の昆布は1,400〜1,700mg/100gの範囲であった。アスパラギン酸はマコンブとラウスコンブにそれぞれ1,560mg/100g,2,270mg/100g含まれ,他の昆布では360〜530mg/100gで含まれていた。昆布の味と密接に関わっているグルタミン酸とアスパラギン酸が全遊離アミノ酸の83〜92%を占めていることがわかった。今後,昆布の利用方法と遊離アミノ酸含量についての関係をさらに検討する必要性があると思われる。

Kombu is one of the major sea weeds used well as food in Japan. It is known that the general quality of kombu is determined by the color, thickness, form, and recognizing of impurity with the specialist's naked eye. The taste of kombu is also an important factor for the quality and is influenced by the free amino acid content, especially glutamic acid content. However, the relation between the free amino acid content and the kind of kombu has not been reported. We investigated five kinds of kombu, Rausu-kombu (Laminaria diabonica), Risiri-kombu (Laminaria ochotensis), Mituishi-kombu (Laminaria angustata), Ma-kombu (Laminaria japonica), and Naga-kombu (Laminaria longissima), produced during August and September in 2002. And the contents of those free amino acid were determined by amino acid analyzer, Hitachi L-8500 A-type. The amount of glutamic acid was more than 1,000mg/100g in all samples. In particular, Rausu-kombu and Ma-kombu had the amount of glutamic acid, 3,540mg/100g and 3,307mg/100g, respectively. The amount of other kinds of kombu were 1,400〜1,700mg/100g. The amount of aspartic acid was 1,560mg/100g and 2,270mg/100g in Ma-kombu and Rausu-kombu, respectively. The amount of other kinds were 360〜530mg/100g. The percentage of glutamic acid and aspartic acid, which are related to the taste of kombu, in the total amount of free amino acid was 83 to 92%.