Influence of high pressure homogenization on commercial protease from Rhizomucor miehei: Effects on proteolytic and milk-clotting activities

This work studied the influence of high pressure homogenization (HPH) on a commercial fungal protease. The enzyme solutions (2 and 20 g/100 mL) were processed up to 190 MPa and the proteolytic activity (PA), milk-clotting activity (MCA) and the rheological behavior of the milk coagulation phase were evaluated. The effects of multi-pass (three cycles) HPH at 25 and 190 MPa was evaluated for enzyme processed at concentration of 2 g/100 mL. No differences in PA and MCA were observed for the samples of 2 g/100 mL of enzyme concentration processed by HPH. On the other hand, increase in PA (similar to 3%) and MCA (similar to 10%) were observed for the enzymes processed at 190 MPa at high concentration, which consequent faster clotting and higher consistency of the milk gel. The multi-pass increased PA (<= 6%) but did not alter MCA nor improved the milk coagulation phase. The results highlight that the energy supplied from HPH to enzyme at low concentration is not enough to promote positive changes in the enzyme coagulant profile; however, the HPH of solution with high enzyme concentration showed a positive effect, indicating that the collisions between enzymes during the process was important to reach the observed changes. (C) 2015 Elsevier Ltd. All rights reserved.