Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/18/2011
Publication Date: 6/1/2011
Citation: Grimm, C.C., Champagne, E.T., Lloyd, S.W., Easson, M.W., Condon, B.D., Mcclung, A.M. 2011. Analysis of 2-Acetyl-1-Pyrroline in rice by SBSE/GC/MS. Cereal Chemistry. 88(3):271-277. Interpretive Summary: This research describes a new analytical method for detecting the compound (2-acetyl-1-pyrroline), which produces a pleasant nutty or popcorn like aroma in aromatic rice. Quantification of this compound is needed by rice breeders trying to maximize their concentration in new varieties of rice, as well as, researchers trying to determine its concentration as a function of processing and shelf-life. The method employs a stir bar, coated with a special adsorptive material, placed in a sealed vial containing the rice sample. After a sufficient time period elapses, the stir bar is removed and any compounds collected are separated and detected. The new method was compared against two currently used methods and was found to be the most sensitive. This work will aid researchers in the development of new varieties of rice that can be grown locally, and meet consumer demand for high quality rice and rice products.
Technical Abstract: An alternative method for the analysis of 2-acetyl-1-pyrroline (2AP) in rice employing stir bar sorptive extraction (Twister™), is described. The Twister stir bar is placed in the headspace of a 20 ml vial containing 1 g rice kernels, 5 ml 0.1 M KOH, 2,2 g NaCl, and a second Teflon™ coated stir bar for mixing. Optimization parameters of are given. The SBSE method was compared to SPME and a solvent extraction method. SPME was the simplest method, and gave good sensitivity, but poor precision. The extraction with MeCl2 gave the best precision, but was less sensitive, and required the most preparation time. SBSE was the most sensitive, but gave poor precision, and required specialized equipment. Using SBSE, 2AP was observed in all samples deemed "aromatic", but 2AP was not observed in any non-aromatic samples.