Review of history and mechanisms of action of lactulose (4-O-β-D-Galactopyranosyl-β-D-fructofuranose): present and future applications in food

Lactulose is a synthetic disaccharide composed of galactose and fructose. Literature review of history, legal status and possible food applications of lactulose in functional foods, such as confectionery and beverages. In the colon, lactulose is fermented by the microbiota and acts as a selective modulator of bacterial growth, promoting the growth of Lactobacilli and Bifidobacteria. It generates organic acids, such as short-chain fatty acids and lactic acid, which lower the pH of the colon and act as an osmotic laxative. Lactulose was first used in 1957 as an ingredient in an infant formula. Later it was registered as a prescription drug and banned for food use in many countries. In 2012, lactulose received an EU (European union) health claim “contributes to acceleration of intestinal transit”. It can be used in food and food supplements across all age groups, from infants to the elderly. Lactulose has favourable technological properties, such as sweetness of 48–62% sucrose without an aftertaste, high solubility, low cariogenic potential and stability. Lactulose gummy candy, without added sweeteners, has an overall likability comparable to classic sucrose/glucose-based candy. With more than 60 years of safe use in infant, child, adult and elderly population, lactulose is an ideal ingredient for prebiotic functional food. Its technological properties allow for development of functional candy and beverages almost indistinguishable from those made from sucrose.