Fluorescence detection in aldehyde containing model systems: Relationship with fish deterioration

In previous studies interaction compounds formation was accomplished by flu orescence detection at different excitation/emission wavelength maxima duri ng fish processing. A fluorescence shift towards higher wavelength maxima w as then obtained as a result of damage increase. In the present work, diffe rent aldehydes were tested in order to compare their ability in producing f luorescent compounds with similar properties to the ones obtained during fi sh processing. Aldehydes (formaldehyde, FA; acetaldehyde, AcH; propanal, Pr ; hexanal, Hex; 2-hexenal Hx; benzaldehyde, BzH) were reacted in model syst ems with sardine (Sardina pichardus) muscle and with n-propylamine at 30 de grees C in dark during 25 days. A fluorescence shift was detected for all the aldehydes investigated as lon g as the reaction time increased. Great differences were observed between a ldehydes, according to their chemical structure and reactivity. A sharp shi ft was detected for Hx and AcH, while little changes were observed in the c ases of FA and BzH. As in the case of fish processing, Pr and Hex showed an increasing ratio between fluorescences detected at 393/463 nm and 327/415 nm as long as the reaction time increased.