Factors affecting solid phase microextraction (SPME) to concentrate the odorants of Chinese white salted noodles for GC-MS analysis

Over 0.4 billion people consume Chinese white salted noodles (CWSN) as their daily main diet. Rapid flavour and taste control of CWSN has consequently attracted much attention from noodle processors and distributors. In this study, the conventional solid-phase microextraction (SPME) technique plus GC and GC-MS was used to concentrate the odorants in CWSN and examine its potential for improving the related quality control (QC) technology. The results indicated that the optimum adsorption time and temperature are 160 min and 30 `C, respectively. Higher temperatures are not suggested for SPME because of thermal leakage and desorption possibilities. Moreover, dry adsorption is more stable than wet adsorption regarding the amount adsorbed and the operational stability, and CAR/PDMS was found to be superior to PDMS/DVB in this regard. In this investigation, a total of 25 odorant species were identified; corresponding regains of 55.11 and 31.25 p.p.m. were obtained for dry and wet adsorption, respectively, among which hexanal was the most abundant (37.10 p.p.m. dry adsorption vs. 20.79 p.p.m. wet adsorption), while 2-heptenal (4.24 p.p.m.), 2-octenal (2.01 p.p.m.), 2-pentylfuran (1.91 p.p.m.), 2-nonenal (1.41 p.p.m.) and 2-butyl-2-octenal (1.35 p.p.m.) were the next in order of decreasing amount. Interestingly, dry adsorption with CAR/PDMS was specifically more efficient for quantification of total aldehydes (52 p.p.m. vs. 28 p.p.m. for wet adsorption). It is concluded that for flavour quality control of CWSN during both processing and storage, such an analytical technology can be very feasible and satisfactory. Copyright (C) 2007 John Wiley & Sons, Ltd.