The gas composition in the package headspace during storage
was determined in a gas chromatograph (GC valve ThermoFinnigan,
Milan, Italy) equipped with a thermal conductivity detector
and fitted with a Poropak QS 80/100 column (1.2 m × 0.32 cm).
The temperatures of the injector, oven, and detector were 125,
35, and 180 ◦C, respectively. Helium was used as a carrier gas at
a flow rate of 22 mL min−1. One mL of the gas sample from the
headspace atmosphere of 5 trays per treatment was measured. Data
are expressed in kPa of CO2 and O2.