🔸 Lactose is a type of carbohydrate (disaccharide) naturally found in milk, such as cow’s and goat’s milk. It is composed of two simple sugars: glucose and galactose. Once consumed, lactose is broken down in the small intestine by the enzyme lactase, allowing the sugars to be absorbed and used for energy.
🔸 Lactose Intolerance is a condition in which the body lacks sufficient lactase enzyme to digest lactose, resulting in symptoms such as bloating, abdominal pain, nausea, and diarrhea. The condition affects approximately 80–100% of individuals in some populations — with up to 98% of Thais affected. A common solution is lactose-free milk, which has had lactose removed, allowing for safe consumption without symptoms.
🔸 Lactose-Free Milk is cow’s milk that has undergone enzymatic treatment with lactase to break down lactose completely. It retains the same taste and nutritional profile as regular milk. Additionally, lactose-free milk may offer prebiotic benefits, supporting digestive health by reducing harmful bacteria and enhancing calcium absorption. These products are often enriched with vitamins B1, B2, B6, and B12.
🔍 Lactose Analysis Methods
Traditionally, lactose in milk is measured using Gravimetric Analysis, Gas Chromatography (GC), and High-Performance Liquid Chromatography (HPLC). While these methods offer high accuracy, they can be time-consuming, require large amounts of reagents, and involve complex procedures.
🔬 Megazyme offers a better way with easy-to-use lactose assay kits based on enzymatic reactions and absorbance (spectrophotometric) detection, validated under AOAC Official Methods.
✅ Megazyme Assay Kits for Lactose Testing
1. K-LACGAR: Lactose/Galactose Assay Kit (Rapid)
🔗 K-LACGAR
• AOAC Official Method 2006.06
• Measures both lactose and galactose in one kit
• Rapid testing – suitable for routine analysis when quick results are needed
• Not recommended for lactose-free products due to its detection limit
2. K-LOLAC: Lactose Assay Kit – Sequential / High Sensitivity
🔗K-LOLAC
• AOAC Official Method 2020.08
• High Sensitivity – accurately detects low levels of lactose, ideal for low-lactose or lactose-free products
• Sequential Assay – reduces analyst workload and saves reagent cost
• High Selectivity – uses β-galactosidase with high substrate specificity
• Accurate Results – includes a 15-minute pre-incubation step to remove background glucose for precise lactose quantification
🧪 Application Examples of K-LOLAC:
• Regular dairy products, low-lactose, or lactose-free milk
• Foods containing dairy (e.g., weight-control products, bread, chocolate, desserts)
• Food additives
• Cosmetics, pharmaceuticals, and bioproducts
• Animal feed
• Infant formula (e.g., SMA-LF and Aptamil Lactose Free) – validated against HPAEC-PAD results