Freshness Assessments of Moroccan Sardine (Sardina pilchardus):  Comparison of Overall Sensory Changes to Instrumentally Determined Volatiles

Abstract

Freshness of ice-stored sardine was assessed by two sensory methods, the quality index method (QIM) and the European Union freshness grading system, and by instrumental means using the method of aroma extract dilution analysis. Screening of sardine potent volatiles was carried out at three freshness stages. In the very fresh state, the plant-like fresh volatiles dominated the odor pattern, with the exception of methional. Overall odor changes in sardine throughout storage correlated with changes in the concentration of some potent volatiles: after 2 days of ice storage, (Z)-4-heptenal, (Z)-1,5-octadien-3-one, and methional imparted an overall "fishy" odor character to sardine, whereas at a lower sensory grade (B), the compounds (E)-2-nonenal and (E,Z)-2,6-nonadienal could be, in part, associated with the slightly rancid aroma top notes. Trimethylamine was detected as a highly volatile odorant using solid-phase microextraction (SPME) headspace analysis of refrigerator-stored sardine. Intensity and sensory characteristics of some SPME determined volatiles, for example, 3-methylnonane-2,4-dione, were closely related to overall odor changes. SPME headspace analysis may be useful in the characterization of off-flavors in fish.

Volatile compounds of some popular Mediterranean seafood species

“…These alcohols have been confirmed previously in sardines of various origins (Prost et al, 2004;Ganeko et al, 2008). With respect to the other pilchard volatiles, the profound presence of various carbonyls (2,3-pentanedione, pentanal, 2-butanone, cis-2-pentenal, hexanal, trans,trans-2,4-heptadienal and http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 11/05/2018 10:34:51 | trans-4-heptenal) and 2-ethylfuran in sardines have been reported previously and have been considered to contribute to a characteristic sardine-fishy odour (Triqui & Bouchriti, 2003;Prost et al, 2004;Ganeko et al, 2008).…”

“…Sporadic data occur in the literature regarding the volatiles of Mediterranean fish species, referring mainly to sardine (Triqui & Bouchriti, 2003;Prost et al, 2004), gilthead sea bream (Grigorakis et al, 2003;Alasalvar et al, 2005) and European sea bass (Leduc et al, 2012). With respect to Mediterranean shellfish, some literature is available for mussel volatiles (Rasmussen et al, 1993;Le Guen et al, 2000a, b;Fuentes et al, 2009).…”

Characterization of Farmed Ovate Pompano (Trachinotus ovatus Linnaeus) Freshness during Ice Storage by Monitoring the Changes of Volatile Profile

“…The smell of fish changes rapidly while fish freshness level is decreasing. Consequently, the changing profile of volatile organic compounds in fish could be used to monitor the fish freshness (Triqui and Bouchriti, 2003;Duflos et al, 2005). It is thus interesting to explore the characteristic volatile compounds that could be served as fish freshness markers (Mansur et al, 2003;Duflos et al, 2006;Wierda et al, 2006;Edirisinghe et al, 2007).…”

Radical scavenging activity of ‘Nikogori’ gelatin gel food made from head, bone, skin, tail and scales of fishes measured using the chemiluminescence method

“…Triqui and Bouchriti reported the method of the sensory assessments of the freshness of sardine fish (16). In this experiment, soy sauce was added to 'Nikogori' made from scales of bream to improve the odor.…”