Q21: Liebermann-Burchard (LB) reagent prepared by mixing 1.0 ml of concentrated... - Fluid Milk Processing, Dairy Products Manufacture, Sensory Evaluation & Packaging - ICAR AIEEA PG Dairy Technology 14 July 2023 Shift-1 Paper | Agrigyan

The Liebermann-Burchard (LB) reaction is a classic spectrophotometric assay used for the quantitative estimation of sterols, specifically Total Cholesterol in milk fat, butter, and ghee. When cholesterol reacts with acetic anhydride in the presence of concentrated sulfuric acid under cold conditions, an intensely colored emerald green to blue-green cholesta-polyene sulfonic acid chromophore is produced (absorbing strongly at $620\text{ to }625\text{ nm}$).

Option analysis:

• Peroxide value: Incorrect. Measured iodometrically via reaction with potassium iodide.
• Reichert-Meissl value: Incorrect. Measured by saponification, acidification, steam distillation, and titration with $0.1\text{ N NaOH}$.
• Total Cholesterol content: Correct. LB reagent reacts with cholesterol to yield a green color used for its quantitative measurement.
• Antioxidant value: Incorrect.