Detection of Total Volatile Basic Nitrogen (TVB-N) in Pork Using Fourier Transform Near-Infrared (FT-NIR) Spectroscopy and Cluster Analysis for Quality Assurance

Abstract

Fourier transform near-infrared (FT-NIR) spectroscopy was applied to rapidly detect the TVB-N content in raw pork that was stored at room temperature (20C) and refrigeration temperature (4C). The NIR spectra of pork samples were collected before chemical analysis of TVB-N content was conducted. Cluster analysis of average spectra was used to judge and classify the freshness of the pork samples. According to pork freshness, the threshold value of the TVB-N content was confirmed. For pork stored at room temperature, it is fresh when the TVB-N content is 4.0 to 5.0 mg per 100g, it is less fresh but can still be eaten when the TVB-N content is 5.0 to 15.0 mg per 100 g, and it is putrid and not edible when the TVB-N content is 15.0 to 29.0 mg per 100 g. For pork stored at refrigeration temperature, it is fresh when the TVB-N content is 2.0 to 6.0 mg per 100 g, it is less fresh but can still be eaten when the TVB-N content is 6.0 to 10.0mg per 100 g, and it is putrid and not edible when the TVB-N content is 10.0 to 17.0 mg per 100 g. FT-NIR spectroscopy could be applied to effectively determine the freshness of pork. A partial least squares model coupled with optimal spectral processing gave good predictions of the measured TVB-N content, with R2 of 0.91. The cluster analysis of principal components for the NIR spectra can classify pork into different freshness categories and define the threshold value of the TVB-N content for each freshness category.