Safety evaluation of an enzymatically-synthesized glycogen (ESG).

An enzymatically-synthesized glycogen (ESG), intended for use as a food ingredient, was investigated for potential toxicity. ESG is synthesized in vitro from short-chain amylose by the co-operative action of branching enzyme and amylomaltase. In an acute toxicity study, oral administration of ESG to Sprague-Dawley rats at a dose of 2000 mg/kg body weight did not result in any signs of toxicity. ESG did not exhibit mutagenic activity in an in vitro bacterial reverse mutation assay. In a subchronic toxicity study, increased cecal weights noted in the mid- (10%) and high-dose (30%) animals are common findings in rodents fed excess amounts of carbohydrates that increase osmotic value of the cecal contents, and thus were considered a physiological rather than toxicological response. The hematological and histopathological effects observed in the high-dose groups were of no toxicological concern as they were secondary to the physiological responses resulting from the high carbohydrate levels in the test diets. The no-observed-adverse-effect level for ESG in rats was therefore established to be 30% in the diet (equivalent to approximately 18 and 21 g/kg body weight/day for male and female rats, respectively). These results support the safety of ESG as a food ingredient for human consumption.