Quality assessment of sardines during storage by measurement of fluorescent compounds

Sardine alterations during chilled storage (0 degrees C) were investigated by measuring the fluorescence ratio between two excitation/emission maxima (393/463 nm, 327/415 nm) and compared with common quality indices. Sardines were also maintained at 15 degrees C to accelerate all reactions occurring at 0 degrees C. Other quality indices (total volatile base-nitrogen, free fatty acids, formation of conjugated dienes, and thiobarbituric acid values) were determined and the use of the fluorescence ratio (fluorescence shift, delta F) was analyzed. A high correlation was found between the delta F and the total volatile base-nitrogen (r = 0.93, at 0 degrees C; r = 0.92, at 15 degrees C).