Volatile components of raw and smoked black bream (Brama raii) and rainbow trout (Oncorhynchus mykiss) studied by means of solid phase microextraction and gas chromatography/mass spectrometry

Solid phase microextraction followed by gas chromatography/mass spectrometry of raw and smoked black bream and rainbow trout was carried out. The volatile components of the raw fish belong to a limited number of groups of compounds. Raw black bream has a higher presence of acids than raw trout, while the latter contains more alcohols, hydrocarbons, esters and phenol derivatives; both contain similar concentrations of saturated aldehydes. The volatiles of the smoked fish basically comprise the compounds also detected in the raw fish together with others produced during the processing. Smoke components detected in both smoked fish species were mainly phenol, guaiacol and syringol derivatives, ketones, acetic acid and some polycyclic aromatic hydrocarbons. Smoked black bream contained a higher number and higher concentrations of smoke components than smoked rainbow trout. Large variations in concentrations of smoke components in the smoked fish samples indicated that the smoking process had not been totally homogeneous. The presence of autoxidatively derived compounds, such as unsaturated aldehydes, was mainly detected in some smoked bream samples, showing that this degradation process is not occurring homogeneously. The usefulness of the applied techniques for the study of volatile components of raw and smoked fish is shown. (C) 2002 Society of Chemical Industry.