The bags were flushed with N2 or a mixture of 2.5 kPa O2+7 kPa CO2 (N2 balanced) in a ratio product/gas mixture of 1/2 and sealed by an EGAR VAC® Basic-9 Digital compensated vacuum machine (Egarvac S.C.P., Terrassa, Barcelona, Spain). The samples were kept at 4 °C in darkness until analysis.