Tagatose

Tagatose is a naturally occurring monosaccharide classified as a ketohexose. It is an isomer of fructose and occurs in small amounts in dairy products and some fruits. Industrial production typically proceeds via enzymatic isomerization of D-galactose, which is usually derived from lactose, using the enzyme L-arabinose isomerase.

In terms of properties, tagatose is a white, crystalline solid with a sweetness close to that of sucrose, though somewhat lower. It provides about 1.5 kilocalories per gram, roughly half the energy of glucose. Tagatose is only partially absorbed in the small intestine, which yields a very low glycemic index and a minimal postprandial rise in blood glucose and insulin. Because it is not fully absorbed, some tagatose reaches the colon where it may be fermented by gut bacteria; large intakes can cause gastrointestinal discomfort or a laxative effect.

Tagatose is used as a low-calorie sweetener and bulking agent in a variety of foods and beverages, including dairy products, baked goods, and beverages. It is marketed under multiple brand names and is recognized as a permitted food ingredient in many regions, often classified as generally recognized as safe (GRAS) where applicable.

Safety and tolerance generally indicate good tolerability at typical consumption levels, with gastrointestinal effects possible at high intakes. Regulatory status varies by jurisdiction, but tagatose is widely available commercially as a sugar substitute and is the subject of ongoing research on its metabolic effects and applications in food formulation.