45C-28 |
Volatile components in plain sufu collected by supercritical fluid extraction |
P. K. J. FUNG, Food and Nutritional Sciences Programme, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China, Hong Kong and H. Y. Chung, Biology Dept., Chinese Univ. of Hong Kong, Food & Nutritional Sciences Programme, Shatin, New Territories, Hong Kong SAR, China. Sufu is a highly flavored traditional fermented soybean food. It has been consumed as an appetizer by the Southern Chinese for many years. It is made by fermenting tofu with mold from the genus Mucor or Actinomucor. Previous investigations on the volatile compounds of sufu made use of techniques such as simultaneous steam distillation and solvent extraction (SDE) or direct headspace injection. However, the former produces artifacts while the latter extract only low quantity of volatile compounds. Supercritical fluid extraction may be an alternative avoiding thermal degradation and facilitating higher amount of compound to be collected. The objective of the current study was to determine the common volatile compounds in three brands of plain sufus collected by the supercritical fluid extraction (SFE). Three brands of plain sufu were obtained from local markets. Each sample was transferred to a sample cartridge containing both inert filler WetSupport and internal standard (2,4,6-trimethylpyridine) for supercritical fluid extraction. Extracts were collected with dichloromethane (solvent) and subsequently injected into a gas chromatography/mass spectrometry for separation and analysis. Brands A, B and C have 56, 55 and 49 components, respectively. All three brands of plain sufus shared similar profiles (44 compounds). A combined total of sixty-seven compounds were identified including acids (16), esters (14), alcohols (13), alkenes (8), ketones (6), aldehydes (5), alkanes (2), furan (1), S-containing compound (1) and pyridine (1). Six volatile compounds previously identified in plain sufu when using SDE and headspace techniques were found in the current samples. These compounds included naphthalene, 1-pentanol, 1-hexanol, n-hexanal, 3-methyl-1-butanol and phenol. Similarly, eight current esters were found in sufus previously extracted using the SDE technique. In short, SFE technique has the advantage of rapid extraction rate, standardized procedures and relatively mild extraction. The volatile profile represents a more realistic condition of the compounds in plain sufu.
Session 45C, Food Chemistry: Flavor and aroma chemistry
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