Proteolytic activity assessment: Use of the chromogenic substrate hide powder azure

The assessment of the total proteolytic activity in enzymatic preparations through the use of soluble substrates, such as casein (Fuld-Gross and Lohle in-Volhard methods), as well as the correlation of such activity with the b ehavior of such preparations on the skin substrate, are topics that have be en discussed and debated repeatedly. The disadvantage in these test substra tes is that the correlation between the testing data and the effect upon th e hide components is often inadequate. Since chromogenic substrates such as ate-albumin, hide powder azure and ker atin azure are representative of the various hide components, they allow fb r the performance of assessments that are closer to the conditions involved in leather manufacturing. Using these substrates, the curve of enzymatic a ctivity in terms of pH can be obtained in a relatively easy way, providing guidance, in the appropriate use of the enzymatic products. This report provides the results obtained in the assessment of proteolytic activity through the use of hide powder azure (partially denaturalized coll agen) for different commercial enzymatic products. The products were select ed considering the need to evaluate preparations for the soaking, unhairing and bating processes. A comparison between the analytical results and the behavior of the enzymatic products in tanneries was also carried out. The use of hide powder azure allows us to gain better knowledge on enzymati c preparations than that obtained from an isolated value of proteolytic act ivity assessed by the Fuld-Gross and Lohlein-Volhard methods, especially wh en the goal is an analytical tool for predicting the behavior of enzymes up on the skin during the various manufacturing processes and thus making an a ppropriate product selection.