わが国における異性化糖製造工業について

抄録

Commercial production of high fructose corn syrup (abbreviated as H. F. C. S.) has become on a full scale since the year of 1976 when immobilized glucose isomerase appeared on market. Sales volume of H. F. C. S. from April, 1978 to March, 1979 was 238, 625 tons in solid equivalent. In this report, the technical progress in H. F. C. S, production industry was reviewed. The enzyme, glucose isomerase, is derived from Streptomyces species. This enzyme is stable intracellarly and up to 1976 frozen living cells (mycelia) had been used as the enzyme preparation. A number of immobilization methods for the enzyme have been developed. Most of the commercial preparations available at present are in granular and dried immobilized-form which is produced and supplied by some enzyme manufacturers. There are two reaction systems-descending and ascending. In the descending system, two to four reactors are used in the way like merry-go-round. In the ascending system, only one reactor is used. This system is often called pulse bed system. The most important technic for this system is how to prevent air from entering into the reactor when the enzyme is placed or replenished. The most suitable reaction conditions are 45 to 50 % substrate concentration, pH 7.8 and 55 to 57°C. Purity of substrate influences remarkably productivity of immobilized enzyme. Especially high absorption at 275 nm directly relates with reaction inhibition. Development in technic which reduces amount of remaining sugars other than glucose and fructose is requested. Such remaining sugars will be classified into the following five groups: (1) Condensation products by reverse reaction of glucoamylase. (2) Products formed by transglycosylation of a-glucosidase-Removal of this enzyme is possible. (3) Maltulose formed by isomerization of reducing ends of maltose and other oligosaccharides-This formation is due to high temperature and pH during liquefaction of starch. (4) Molecular substances unsusceptible to glucoamylase such as multiple branched dextrines and phosphodextrines. (5) Psycose formed by epimerization of fructose.