Evaluation of freshness of ground pork tenderloin by visible/near infrared spectroscopy

Visible/near-infrared transmittance spectra (600-1368 nm) of the aqueous extracts of 120 ground pork tenderloin samples from Taiwan black-hair hogs were used to correlate with the freshness-relating data including pH, volatile basic nitrogen and aerobic plate count during 7℃ storage for 5 days. The spectra in 600-840 nm regions varied during storage with the data highly correlated with the freshness parameters. Four characteristic wavelengths (608, 624, 656 and 732 nm) were selected for freshness evaluation based on partial least square regression (PLSR) model using different freshness criteria for dummy regression. The accuracies of freshness evaluation can reach 90% with the PLSR models excluding the data in Day 3.