ABSTRACT
Pork adipose tissue was dry-salted for 24 h and then smoked by immersion in two liquid smoke flavourings for 1, 2 or 3 min. Both unsmoked and smoked pork adipose tissue samples were submitted to oxidative conditions at 70 °C in a convection oven with circulating air. Melted lipids of both samples were studied by Fourier transform infrared spectroscopy. Duplicate spectra were collected each day of the experiment by applying a film of melted lipids between two KBr disks. Changes in frequency values of different bands and in ratios between absorbances of some bands allow oxidation degree and oxidative stability of the samples to be determined. The usefulness of this technique for monitoring the oxidation process of pork adipose tissue lipids is shown. The greater oxidative stability of smoked pork adipose tissue samples in comparison with unsmoked samples is proved.
ABSTRACT
The oxidation process of 13 edible oil samples with different proportions of oleic, linoleic, and linolenic acyl groups has been studied using Fourier transform infrared spectroscopy. The oxidation experiments were carried out by heating the samples in a convection oven at 70 degrees C. Duplicate spectra were recorded from a film of pure oil between two disks of KBr for each sample every day during the course of the oxidation, and frequency data of each band of the spectrum were collected automatically. Changes in the values of the frequency of most of the bands of the spectra were observed. The shiftings of the frequency value of specific bands allowed one to distinguish between the different stages of the oxidation process and to establish the oxidation degree of each oil sample. This methodology could be useful to evaluate the oxidative stability of edible oils in a simple, fast, and accurate way.
