Fast and sensitive collagen quantification by alkaline hydrolysis/hydroxyproline assay

A preparative protein alkaline hydrolysis procedure, as part of a spectrophotometric collagen quantification method, is presented. The procedure is suitable for small amounts of fresh solid or liquid samples. Various aspects of the procedure, such as the NaOH concentration, time needed to hydrolyse different collagen contents, buffer strength of the reagent solution, pH control of the hydrolysate and spectrophotometric conditions, were evaluated. Compared to other procedures that use alkaline hydrolysis, the sensitivity of this procedure was increased by a factor of 5. Compared to the conventionally used Association of Official Analytical Chemists (AOAC) acid hydrolysis method, the reaction time was reduced from 16 h to 40 min and the amount of sample from 4 g to 3–20 mg, producing equivalent results when applied to porcine liver and sausage samples.