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K. R. CADWALLADER, Department of Food Science and Human Nutrition, University of Illinois at Urbana Champaign, 202 Ag. Bioprocess Lab, 1302 W. Pennsylvania Ave, Urbana, IL 61801 and C. Thongthai, Department of Microbiology, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.

Fish sauce is an important part of the culture and diet of the people of Southeast Asia. Three popular types of fish sauces are nampla, tai-pla, and budu. Each sauce has a unique flavor and aroma. Nampla is a clear brown liquid made by salt-fermentation of small whole fish. Tai-pla is thick red-brown sauce produced by salt-fermentation of only the fish viscera. Budu is a olive-brown sauce produced by salt-fermentation of anchovy.

The aim of the present study was to identify and compare characteristic aroma-active headspace components of nampla, tai-pla and budu fish sauces.

Two representative samples of each sauce type were used in this study. One set was obtained from Thailand, the other set was bought at a local market. Sample (1 g) was placed in a 100-mL round bottom flask and sealed with a septum. The flask was incubated at 40C for 30 min. A headspace volume (0.1, 0.5, 1.0, 5.0 mL) was drawn from the flask using a preheated (60°C) gastight syringe and immediately subjected to analysis by gas chromatography-olfactometry. Dynamic headspace-GC-MS was employed for compound identification in addition to comparison of retention indices and odor properties against reference standards.

Predominant headspace odorants in Nampla were methional, followed by butyric acid, 2/3-methylbutyric acid, 3-methylbutanal, methylpropanal, acetaldehyde and trimethylamine. These same odorants also were predominant in tai-pla and budu, but these two sauces also contained numerous esters (e.g. ethyl 2-methylpropanoate, ethyl butanoate, and ethyl 2-methylbutanoate). In addition, the aroma of budu was influenced to a greater extent by lipid-derived components (e.g. 1-octen-3-one and Z-1,5-octadien-3-one).

This study provides information on the predominant headspace aroma components of three types of common fish sauces of Southeast Asia. The results will aid in establishing baseline data so that processing and storage conditions may be more easily monitored and controlled.