Analysis of the Early Stages of Lipid Oxidation in Freeze-Stored Pork Back Fat and Mechanically Recovered Poultry Meat

Abstract

An analytical method that can detect low levels of oxidation in food earlier than a sensory panel would be a valuable tool for food manufacturers as well as research institutes. Two model matrixes, pork back fat and mechanically recovered poultry meat (MRPM), were freeze-stored in air at −20 °C for 26 weeks. Peroxide value, thiobarbituric acid reactive substances, volatiles analyzed with dynamic headspace gas chromatography−mass spectrometry (GC-MS) and a gas-sensor array technique (electronic nose), chemiluminescence, and front-face fluorescence were evaluated against sensory analysis with regard to detection of early oxidation and correlation with sensory data. Fluorescence and GC-MS could detect oxidative changes in pork back fat earlier than the sensory panel and the electronic nose at the same time. The three methods were highly correlated with sensory attributes ( r = 0.8−0.9). GC-MS gave the best results with regard to detection of small oxidative changes in MRPM. Keywords: Pork back fat; mechanically recovered poultry meat; dynamic headspace/GC-MS; fluorescence; chemiluminescence; peroxide value; TBARS; gas-sensor array; electronic nose; sensory analysis; lipid oxidation; rancidity