Influence of ultrasonic application on the enzymatic formation of zinc protoporphyrin

Abstract

Ferrochelatase (FeCH), present in pork liver, catalyses the formation of zinc-protoporphyrin (ZnPP), a stable purple-red pigment found in Parma ham. Kinetics of ZnPP formation is especially slow. Thus, the aim of this study was to improve the ZnPP production using power ultrasound (US) at low (7.05 W/L) and moderate power (36.53 W/L) in homogenised pork liver (HLi) and with added oxyhemoglobin (HLi + OxyHb). ZnPP formation was performed at 37 °C, under anaerobic conditions, for different reaction times (6–48 h). When US was applied at low power, it shortened the time needed to reach maximum ZnPP formation by 50% and increased the yield by 25.77% in the case of HLi and by 4.42% in that of HLi + OxyHb, when compared to the control experiments; however, for the moderate power, ZnPP formation was hindered. Therefore, low power US proved to be an effective method with which to intensify enzymatic ZnPP production.