Volatile aroma components of Thai fish sauce in relation to product categorization

Abstract

Numerous investigations on aroma characteristics of fish sauce in particular samples have been conducted extensively; however, the relation of those volatile aroma profiles and aroma characteristics to quality and categorization of the product have never been reported. This study explored the contribution of volatile aroma components on product quality categorization of 52 Thai fish sauce samples. First, odour-active compounds were investigated by dynamic headspace gas chromatography-olfactometry (GC-O) from eight selected samples with four different qualities, including mature-unblended samples, premium-grade samples, first-grade samples and second-grade samples. Eleven odour-active compounds, i.e. acetic acid, propanoic acid, 2-methylpropanoic acid, butanoic acid, 3-methylbutanoic acid, dimethyl trisulfide, 3-(methylthio)propanal, 1-octen-3-ol, 2-butanol, trimethylamine and n-propanol, contributed to the aroma characteristics of Thai fish sauce. A combination score was assigned to express the integration of flavour dilution on dynamic headspace dilution analysis and intensity of odour perceived on GC-O. The combination scores were analysed with principal component analysis to categorize these eight selected samples. Furthermore, these odour-active compounds detected as released volatile compounds from 52 fish sauce samples were applied for categorization of 52 samples. As a result, both combination scores and relative concentrations of these odour-active compounds could discriminate the fish sauce products according to their conventional grading which is based on total nitrogen of the sample. © 2011 John Wiley & Sons, Ltd.