TBA test by an extractive method applied to 'paté'.

The aim of this work was to study the influence of different conditions on the thiobarbituric acid (TBA) test, determined by the extractive method, as a measure of lipid oxidation in 'paté'. Different extracting agents (trichloroacetic acid and trichloroacetic acid in 2 M phosphoric acid), different concentrations of these acids (10, 15 and 20%), different reaction times and temperatures (35 min at 100 °C and 900 min at room temperature) and the effect of sulfanilamide additions were evaluated. All the samples were measured by HP 8451A Diode ARRAY spectrophotometer at 532 nm. Significant differences between 35 and 900 min of MA-TBA reaction time were found. Highest TBA numbers were found in samples with a reaction time of 35 min in a thermostatically controlled waterbath at 100 °C, rather than 900 min at room temperature. Lowest TBA numbers were found in samples with the addition of sulfanilamide rather than without it. The 10% TCA solution gave the best recovery percentages for 'paté', making it the preferred extractant.

Modification of physico-chemical and colour parameters during the marketing of 'paté'.

The evolution of different physico-chemical parameters (iodine number, TBA test, residual nitrite level, pH and moisture) and CIE L (∗)a (∗)b (∗) colour evolution, in pork liver 'pate', with and without sodium ascorbate addition, were studied. The samples were stored in an illuminated display cabinet at different lux intensities and in the dark. The regression equations were obtained for each one of the parameters under study, from the first day of exposure to light. The sodium ascorbate showed a protective effect on the photo-oxidation mechanism (measured by TBA test), but it did not have an influence on the samples in darkness. In both types of paté exposed to light, fading takes place and the most important variations in colour parameters are produced during the first 24 h of exposure to light.