Cooperative De Safran Lab Report

The plant material (10 g) used, was a representative sample of C. sativus stigmas obtained from the Cooperative De Safran (Krokos Kozani, Greece) in 2012. The ISO 3632-1 (ISO 2011) quality parameters E1%1cm calculated at 440 nm, 257 nm, and 330 nm for an aqueous extract were 253, 86 and 34 respectively, indicating that the plant material was of the highest quality (Category I).

2.2. Standards, reagents and solvents

Safranal (>88%), isophorone (>97%), keto-isophorone (>98%) and 2-phenylethanol (>99%) were purchased from Sigma-Aldrich (Amsterdam, The Netherlands). To maintain a fixed relative humidity during saffron storage NaNO2 (>97%) obtained from Sigma-Aldrich (Amsterdam, The Netherlands) was used. For standards preparation, ethanol of
Storage was carried out in identical ovens (Heraeus, Hanau, Germany). Prior to storage, the NaNO2 solution (81.8 g/100 g H2O, 500 ml per desiccator) was placed in the desiccators and left at the selected temperatures for 48 h so that moisture in the interior of the desiccators reached equilibrium. The measurement of saffron volatiles was performed by periodic sampling (in triplicate) over a period of 5 weeks. Portions (~75 mg) were obtained periodically for the PTR-MS analysis. The left over quantities were kept in sealed vials with minimum headspace at -24 oC till further
All of the measurements were carried out under drift tube conditions of 120 - 140 Td (Td = Townsend; 1 Td = 10-17 V cm2 mol-1) over a mass range of m/z 22 to m/z 200 and a dwell time of 0.2 s mass-1, giving a cycle time of 36 s. After preliminary studies, 35 mg of ground saffron (fresh or stored samples) was separately weighed into 250 mL glass bottles (Schott Duran bottles, Germany) and allowed to equilibrate in a water bath at 25 ºC for 30 min. The water in the bath was agitated (60 rpm). Bottles were connected to the PTR-MS inlet flow that was heated to 60 °C via Teflon (0.25 mm) tubing and headspace air was sampled at a flow rate of 48 mL/min. Masses were analyzed in a quadrupole mass spectrometer and detected as ion counts per second (cps) by a secondary electron multiplier (SEM). Mass ion intensities were converted to volume mixing ratio (ppbv) values according to Lindinger, Hansel, and Jordan, (1998). Sample measurements were performed in five cycles (1-5) resulting in an analysis time of 3.0 min. The mean of cycles 2-4 were used in the further analysis. In this way the measurement of a consistent concentration of the VOCs could be achieved, avoiding any effect upon the connection/disconnection process with the transfer line. Background air scans of five cycles were conducted from an empty bottle before each sample