Direct Extraction of Volatiles of Rice During Cooking Using Solid‐Phase Microextraction

Abstract

Cereal Chem. 84(5):423-427An apparatus that allows extraction and enrichment of flavor volatiles of rice during cooking using solid-phase microextraction (SPME) was designed and tested in the Japanese rice cultivar Akitakomachi. Because it is a solvent-free technique, no solvent contaminants were extracted during sampling. This technique enables one to place the fiber of SPME in the effluent of the flavor volatiles of the rice during cooking and it can also be used for simultaneous extraction of those volatiles in the course of the cooking process. Therefore, variations in the composition and amount of volatile compounds of rice during cooking can be determined. The overall flavor volatiles of rice during cooking have been analyzed by using this SPME method. Compounds that have been previously highlighted as flavor volatile markers, such as volatiles from oxidative degradation of lipids, products from thermal decomposition, and fatty acids existing in rice, were extracted directly by SPME in conjunction with this apparatus.

Analysis of volatile compounds from a malting process using headspace solid-phase micro-extraction and GC–MS

“…Routinely, the peak areas from chromatographic maps were indirectly a reflection to the concentration of individual compounds (Pinho et al, 2006;Zeng et al, 2007). In this paper the author reported the dynamics of 6 volatile flavor aldehydes during the whole malting process.…”

“…The flask containing sodium chloride, flour and water was placed on a magnetic stirring plate (model PC-220, Corning, NY) and stirred at 1100 rpm for 20 min. A SPME fiber (DVB/CAR/PDMS) was then exposed to the headspace of the barley slurry for 1 h in a water bath at 18 ± 1°C (Zeng, Zhang, Chen, Zhang, & Matsunaga, 2007).…”

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

“…The whole process was divided into four stages: I, 25 min from the start of heating to the start of steam coming out of the rice cooker; II, 13 min from the start of steam coming out of the rice cooker to the end of steam coming out of the rice cooker; III, 10 min from the end of steam coming out of the rice cooker to automatic stop of heating; and IV, keeping the rice warm for another 30 min from automatic stop of heating. A thermo-recorder (TR-72S, T & D, Japan) was applied for measurement of the variation in temperature at the sampling dots during the rice cooking process, as reported previously (Zeng et al, 2007).…”

“…In our previous studies, a modified headspace SPME method was developed for the analysis of flavor volatiles of rice during cooking (Zeng et al, 2007(Zeng et al, , 2008. The objectives of this research were to identify the flavor volatiles in Tatsukomochi, Kinunohada and Miyakoganemochi during cooking and to compare these three glutinous rice cultivars with the profiles of those flavor volatiles based on the modified headspace SPME method in conjunction with gas chromatography-mass spectrometry (GC-MS).…”

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“…However, they might be important to the overall flavour due to odourant interactions in mixtures 21 . Short-chain aliphatic acids found in khanom jeen have been previously reported in rice flavour volatiles as a result of oxidative degradation of lipids and thermal decomposition, except for 2-methylpropanoic acid and 3-methylbutanoic acid 22 . These two compounds with high OAVs probably contribute to the aroma of khanom jeen.…”