Degradation of Collagen Increases Nitrogen Solubilisation During Enzymatic Hydrolysis of Fleshing Meat

Abstract: The meat portion directly attached to bovine hides (fleshing meat) is a by-product of leather industry that is a potential new source of proteins. In literature different enzymatic and chemical methods have been proposed to hydrolyze and solubilize fleshing meat. Enzyme hydrolysis is preferable for the mildness and the lower environmental impact. Enzymatic hydrolysates have never been deeply characterized, nor the specific enzyme efficiency, deeply investigated. In this study, the activity of six proteolytic enzymes was tested in order to determine their efficiency in solubilizing fleshing meat and to characterize at the molecular level the composition of the nitrogen fraction of the obtained hydrolysates. Total nitrogen content and the degree of hydrolysis were determined by Kjeldhal and o-phthaldialdehyde (OPA) methods. Amino acids and peptides were analysed by high performance liquid chromatography (HPLC) and mass spectrometry techniques. The results showed that papain and Alcalase appear to be the most efficient enzymes, and the corresponding hydrolyzates were rich in peptides and amino acids characteristic of collagen, notably absent in the hydrolyzates obtained with other enzymes. Thus, the ability to efficiently hydrolyze collagen seems to be related to the efficiency in fleshing meat hydrolysis. Graphical Abstract: [Figure not available: see fulltext.]