Thickness (4 cm diameter × 1.5 cm) samples were analysed.
Samples were scanned for 40 s using a 400–760 nm wavelength.
Lipid oxidation was expressed as thiobarbituric acid reactive substances (TBARS) (mg malonaldehyde/kg sample), as determined by Botsoglou et al. (1994), using a UV2 spectrophotometer
The pH was measured using a micropH 2001 pHmeter , and a combined electrode Cat. No. 52-22, to remove the possible contribution to microbiological or colour changes caused by to variations in the pH of the patties.
. The relative metmyoglobin percentage (MM) was determined according to Krzywicki (1978), using a U3200 spectrophotometer (Hitachi, Tokyo, Japan). Thickness (4 cm diameter × 1.5 cm) samples were analysed.