ABSTRACT
Carbohydrates such as starch and sucrose are abundantly produced as reserve energy by plants and serve as important nutrient sources for almost all organisms. Enzymes acting on this carbohydrate are therefore widely distributed in nature. Amylase, for instance, is one of the enzymes that have the longest history of research and application. In the 1960s a method for producing isomerized sugar (high fructose corn syrup) from starch using amylases and glucose isomerase (xylose isomerase) on an industrial scale was developed in Japan, and this technology rapidly spread in the world. Decades preceding this innovation, active studies on amylases and related enzymes were carried out, mainly to improve the efficiency of starch saccharification, i.e., to get enzymes with higher optimum temperature, with lower transglucosylation activity, with unique substrate specificities, and with varieties of pH optima. Around 1985, following nutrient and sensory functions, physiological function was discovered in Japan as the third function of food. Meanwhile, functional foods that claim special health benefits appeared and the government started an approval system (Foods for Special Health Use, or FOSHU) for these functional foods in 1991. Oligosaccharides were expected as one of the important candidates of these functional foods, and nowadays about 50% of FOSHU contains oligosaccharides as their beneficial ingredients. A variety of oligosaccharides have been developed over the last 20 years in Japan. This development is based
on very active research on carbohydrate active-enzymes. As a result, discoveries of new enzymes and of new actions of known enzymes were reported, and certainly will be continued.
