牡蠣含有ビタミンB12の人工消化試験後測定値に与える水煮調理の影響

Abstract

The release of free vitamin B_<12> from ingested food during gastric digestion is the first step for the absorption of vitamin B_<12>. Free vitamin B_<12> can be bound by salivary haptocorrin under the acidic conditions of the stomach and subsequent processes. Among sea foods, oyster and mackerel are especially rich in vitamin B_<12>. Here, we examined how the culinary treatment of oyster affects their digestion in the gas-tric phase and the subsequent release of vitamin B_<12>. Oyster was cooked in boiling water for 0, 10, 20, 30, or 60 minutes. In vivo digestion in the gastric phase was simulated by incubating the cooked oyster for 30 min in the presence of pepsin (167 μg/ml) in 0.06M HCl at 37℃. The digested oyster was centrifuged at 10,000xg for 15 min to obtain a supernatant which was assayed for vitamin B_<12> content. Vitamin B_<12> contents of the soluble B_<12> fraction was twice as high in the oyster boiled for 20 minutes than in raw oyster. Moreover the 20min-boiled oyster was rated highest on "taste" in the sensory evalua-tion. Thus we concluded that boiling oyster for 20 minutes facilitates the absorption of vitamin B_<12>.