Screening for 2-acetyl-1-pyrroline in the headspace of rice using SPME/GC-MS

Solid phase microextraction (SPME) is used to collect and concentrate the c ompounds in the headspace of rice. This research describes optimization par ameters of temperature, moisture, and sampling time. Optimization was based upon the recovered-levels of 2-acetyl-1-pyrrooinn (2-AP), the popcorn arom a in aromatic rice. The method uses a sampling temperature of 80 degreesC a nd adds 100 muL of water to a 0.75 g sample of rice. The rice was preheated for 25 min, a carboxen/DVB/PDMS SPME fiber was exposed to the headspace fo r 15 min, and a subsequent GC-MS analysis took 35 min. Samples of rice can be analyzed as the flour, milled kernels, or brown rice.; Twenty-one experi mental rice varieties were analyzed by the SPME method and compared to a we t technique. Recoveries of several nanograms of 2-AP from 0.75 g samples of aromatic rice were observed, whereas only trace amounts of 2-AP were recov ered from nonaromatic rice. Recovery from a single SPME headspace analysis is calculated to be 0.3% of the total 2-AP in the sample.