Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: 6/1/2011
Publication Date: 6/15/2011
Citation: McClung, A.M., Bryant, R.J. 2011. Volatile profiles of aromatic and non-aromatic rice. Texas Rice Special Section, Highlighting Research in 2011. p. XIII.
Technical Abstract: Rice is enjoyed by many people as a staple food because of its flavor and texture. Some scented varieties command a premium in the marketplace because of their distinctive aroma and flavor. The compound most commonly associated with the popcorn or nutty scent of aromatic rice is 2-acetyl-1-pyrroline (2-AP). This compound can be detected in the leaves and grain of the aromatic rice plant. Although there has been considerable research on 2-AP in rice, it is not known if different aromatic rice varieties produce other flavor volatiles that may influence preference by consumers. In this study, seven aromatic and two non-aromatic varieties were examined for their volatile profiles both before and after storage using solid phase microextraction (SPME) fibers in conjunction with gas chromatography/mass spectrometer (GC-MS). The aromatic varieties were derived from different sources of 2-AP, originating from India, Thailand, China, and the USA. Ninety-three volatile compounds were identified, 64 of which had not been previously reported in rice. Differences were found in volatile compounds of aromatic and non-aromatic rice other than 2-AP. Most of the volatile compounds were present in freshly harvested rice and rice following storage, with very few new compounds being identified only after storage. This indicated that rice does not need to be "aged" to determine its volatile profile. Dellrose, an aromatic variety, and Cocodrie, a non-aromatic variety, had the most complex volatile profiles (over 64 volatiles). Sixteen compounds were found only in aromatic varieties and some volatiles were found to be unique to specific aromatic varieties. However, no distinctive pattern was observed that would identify a variety as being derived from Basmati, Khao Dawk Mali 105 (i.e., jasmine), or other sources of aroma. This study showed that there is a great diversity of volatiles in both aromatic and non-aromatic rice varieties and, with further research, this may lead to a better understanding of the combination of compounds that gives a variety a unique flavor.