The Functional Trisaccharide Lactosucrose: Research Advances in Physiological Effects and Biological Production

Lactosucrose is a unique trisaccharide that shows promising prebiotic properties and improves the proliferation of beneficial bacteria including bifidobacterium and lactobacillus. It promotes the generation of short chain fatty acids with reduced pH values during fermentation and displays many potential beneficial effects. It can be biologically produced by several enzymes from lactose and sucrose through specific transglycosylation reactions. Three types of lactosucrose-producing enzymes, including levansucrase, β-fructofuranosidase, and β-galactosidase are described. Levansucrase and β-fructofuranosidase catalyze transfructosylation to produce lactosucrose using sucrose as a donor and lactose as an acceptor, while β-galactosidase produces lactosucrose by transgalactosylation using lactose as a donor and sucrose as an acceptor. Plenty of studies focus on the optimization of enzymatic production of lactosucrose; however, the studies on molecular modification and efficient heterologous expression are far from sufficient. Therefore, at the end of the review, we put forward prospects for future research for enhancing lactosucrose production.