18C-5 |
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J. KEATKRAI1, W. Jirapakkul2, and S. Trevanich1. (1) Dept. of Food Science and Technology, Kasetsart Univ., Faculty of Agro-Industry, Phahonyothin Road, Jatujak, Bangkok, 10900, Thailand, (2) Dept. of Food Science and Technology, Kasetsart Univ., Faculty of Agro-Industry, Phahonyothin Road, Jatujak, Bangkok, 10900, Thailand Kanomjeen, a traditional rice noodle, is widely consumed in Thailand. There are two types of Kanomjeen: non-fermented and fermented types. A variety of volatile compounds are developed during fermentation period. These volatile compounds play an important role on flavor characteristic of Kanomjeen. However, studies on the flavor volatile compounds of Kanomjeen are limited. Therefore, this study was conducted to identify the flavor volatile components in two types of Kanomjeen and to study the major volatile compounds during fermentation process. The samples were taken during the process (4-hour soaked rice for non-fermented type, 24- and 48-hour fermented rice for fermented type) as well as the finished products (Kanomjeen). Volatile compounds were collected by using dynamic headspace (purge and trap) and analyzed by gas chromatography-mass spectrometry (GC-MS). The volatile compounds found in Kanomjeen could be classified into five major groups such as alcohol, acid, ketone, ester and aldehyde compounds. Non-fermented Kanomjeen contained mainly aldehydes, e.g. hexanal (tallowy, leaf-like), octanal (fatty) and nonanal (tallowy), which were found in the soaked rice sample and the concentration was vary among each compound. The results showed that volatile compounds were dramatically increased during 24 hours of fermentation. The fermentation period from 24 to 48 hours didn't affect overall compounds except for diacetyl and acetoin. Fermented Kanomjeen contained more compounds especially alcohol, acid and ester compounds. 1-Propanol was the most abundant compound. The concentrations of acetic acid, ethanol and ethyl acetate in fermented type were higher than non-fermented type. Isobutyric acid (sour cheesy), Isovaleric acid (sweaty), diacetyl (buttery), 3-methylbutanal (malty) and ethyl hexanoate (fruity) were found only in the fermented type. This study provides information on volatile compounds that might be responsible for unique aroma of non-fermented and fermented Kanomjeen.
Session 18C, Food Chemistry: Food composition, analysis and volatiles
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |