EVALUATION OF POSTMORTEM INTERVAL USING ENZYME ACTIVITY IN PIG ABDOMINAL SKIN UNDER A CLOSED-SYSTEM SIMULATION WITH FLUORESCENCE SPECTROSCOPY

Abstract

Estimation of the postmortem interval (PMI) is a critical process in forensic science. This study aimed to investigate enzymatic changes in porcine abdominal skin under a closed-system simulation using fluorescence spectroscopy. Enzyme activities of protease, lipase, and esterase were analyzed at 10, 29, 53, 58, 76, 82, 103, 168, 178 and 226 hours postmortem. Data were statistically evaluated using Spearman’s rank correlation and the Kruskal-Wallis test to compare activity levels across early, middle, and late PMI. The results demonstrated that protease activity became distinctly detectable after 30 hours and exhibited a moderate positive correlation with PMI (ρ = 0.45). Esterase activity progressively decreased over time, showing a moderate negative correlation with PMI (ρ = -0.42). Lipase activity remained consistently elevated up to 226 hours postmortem, with a weak correlation to PMI (ρ = 0.22). The Kruskal-Wallis test revealed no significant differences among the PMI groups (p > 0.05). These findings suggest that protease and esterase may serve as potential biochemical indicators for PMI estimation in forensic investigations, whereas lipase shows limited applicability due to its sustained activity regardless of time.