2.4 Analysis and quantification of volatile compounds by GC-MS system
The analysis of emitted, free endogenous and bound endogenous volatile compounds was conducted using ThermoScientific GC-MS system (GC-Trace 1300 equipped with ISQ QD, Single Quadrupole Mass Spectrometer); the GC was equipped with a split mode injector and a TG-5MS capillary column (length 30 m, 0.32 mm i.d., 0.25 µm film thickness). Analysis of compounds was done as described earlier by Barman and Mitra (2019). The identity of compounds was confirmed by calculating the retention indices relative to C8-C20 n-alkanes. Quantification of compounds was done by external standardization method as described by Majetic and Sinka (2013), using ethyl hexanoate as a known standard. Emitted and endogenous contents of individual scent compound were calculated in nanomole per gram fresh weight of sample using this method: (Peak area of compound× moles of ethyl hexanoate)/peak area of ethyl hexanoate.