Volatile components of unprocessed rice (Oryza sativa L.)

Abstract

Laboratory tests showed that the volatile flavor components of unprocessed rice are attractive to Philippine ricefield rats (Rattus rattus mindanensis). These results suggested that a Synthetic bait attractant could be made if the important volatiles in rice were identified. To identify the compounds, ground rice was tumbled at 50 °C in a modified rotary evaporator while helium swept the volatiles into a liquid nitrogen trap coated with dibutyl phthalate. The dibutyl phthalate solution containing the volatiles was analyzed by combination capillary-column gas chromatography and mass spectrometry. Altogether, 73 compounds were identified, including alcohols, aldehydes, alkyl aromatics, furans, ketones, terpenes, and naphthalenes. The structural types of another 31 compounds were indicated. Of the 73 compounds identified, only 9 have been previously reported in unprocessed rice and 54 have never been reported in any unprocessed cereal grain.

Analysis of flavor volatiles of glutinous rice during cooking by combined gas chromatography–mass spectrometry with modified headspace solid-phase microextraction method

“…Previous studies (Zeng et al, 2007(Zeng et al, , 2008 have revealed that the volatile components at cooking stage I were representative of the flavor volatiles of uncooked rice, which a few researchers have studied (Bullard and Holguin, 1977;Legendre et al, 1978), and the volatile constituents at cooking stage IV were representative of the flavor volatiles of cooked rice, while the volatile compounds at cooking stages II and III were representative of the flavor volatiles of rice during the cooking process.…”

Multiple roles of plant volatiles in jasmonate-induced defense response in rice

“…11,27,28 (E,E)-2,4-Heptadienal is a C 7 volatile compound produced from linolenic acid via lipoxygenase (LOX) pathway in leek. 29 Our previous study revealed the upregulation of 2 LOX genes in response to JA, 7 suggesting that these genes may be involved in biosynthesis of the JA-responsive (E,E)-2,4-heptadienal.…”

Fractionation and Identification of Volatile Acids and Phenols in the Steam Distillate of Rice Bran

“…The absence of these two phenols in the headspace of unprocessed rice 18 ) supports this assumption. Since 4-vinylphenol, which has a characteristic unpleasant odor, is the main volatile component in both steamdistilled rice bran and cooked rice, 19) this phenol is assumed to be partly involved in the formation of the cooked rice flavor.…”