抄録
L-Ascorbic acid (AsA) has diverse physiological activities and is widely used as a nutritional supplement. However, it is disadvantageous that AsA is easily degraded under various oxidative conditions. To solve this problem, we developed a stable derivative of AsA, L-ascorbic acid 2-glucoside (AA-2G), which was synthesized by regioselective transglycosylation with cyclodextrin glucanotransferase from Bacillus stearothermophilus. AA-2G was very stable in neutral solution and resistant to heat, light and oxidation. This vitamin derivative was verified to release AsA by hydrolysis with α-glucosidase and to exhibit its physiological activities in vivo. Moreover, it was confirmed that AA-2G was little affected by coexisting materials such as metallic ions, proteins and vitamins and was highly stable in various food products. We also investigated the metabolic fate of AA-2G following ingestion. As a result, ingested AA-2G was clarified to behave as AsA in the body after the hydrolysis by intestinal brush border α-glucosidase. In addition, various toxicological tests showed that AA-2G was a highly safe material. From these findings, AA-2G is considered to be available effectively as a stable vitamin C supplement in the field of foods.
