Dairy Chemistry & Milk Constituents

Lactulose (4-O-beta-D-galactopyranosyl-D-fructofuranose) is a synthetic prebiotic disaccharide produced by alkaline or thermal isomerization of lactose. It resists digestion and absorption in the upper gastrointestinal tract and reaches the colon intact. In the colon, it acts as a selective bifidogenic substrate ('bifidus factor'), vigorously stimulating the growth and proliferation of beneficial Bifidobacteria and Lactobacilli in bottle-fed infants, mimicking the gut microbiome of breast-fed infants.

Option analysis:

• Lactitol: Sugar alcohol with laxative effect, not the classic infant bifidus factor.
• Lactulose: Correct. Well-known prebiotic bifidus factor produced from lactose.
• Lactate: Metabolic end product.
• Saccharic acid: Oxidation product of glucose.