**5.7 Collagen determination**

Hydroxyproline content was evaluated according to the method of Reddy & Enwemeka (Reddy & Enwemeka, 1996). Absorbance of each sample was read at 550 nm using HPLC (Spectrochrom). Serial dilutions of commercial pure hydroxyproline (Sigma-Aldrich) were used as standard. All samples were assayed in duplicates. Results were expressed as mg/g wet tissue.
