Effect of different smoking processes on the nutritional and polycyclic aromatic hydrocarbons composition of smoked Clarias gariepinus and Cyprinus carpio

The effect of different smoking processes on the nutritional value and polycyclic aromatic hydrocarbon (PAHs) content of Clarias gariepinus and Cyprinus carpio has been assessed in this study. After smoking processes, the finish products were analyzed to determine the nutritional quality and the PAHs content. Different smoking processes significantly decreased (p < 0.05) lipids content of fish. The smoked fish with unfiltered Psidium guajava has revealed higher lipid contents of 14.17 ± 0.15% and 14.96 ± 0.05%, respectively, for SNE GSF and SE GSF. A significant reduction (p < 0.05) in protein content (% DM) has been observed in the two fish's species submitted to smoking processes. We found that evisceration of fish before smoking leads to increase the level of naphthalene, acenaphthene, and benzo (a) pyrene in smoked C. gariepinus and C. carpio. The use of metallic filter in the smoking of noneviscerated fish leads to the significant reduction (p < 0.05) of the PAHs content in smoked fishes. Higher levels of PAH such as naphthalene and acenaphthene with values of 1,451.54 ± 49.58 and 709.91 ± 8.12 ng/kg were found in smoked C. carpio and 1,841.1 ± 11.41 and 809.91 ± 1.10 ng/kg were found in smoked C. gariepinus obtained in the case of traditional smoking. The PAHs content was higher in fish smoked using traditional ovens. Therefore, the quality of smoked fish was improved using a metallic filter during different smoking processes

Influence de la période de capture, du fumage et de la cuisson à ébullition sur le potentiel nutritionnel d’Oreochromis niloticus du fleuve Nkam (Yabassi-Cameroun)

Pour contribuer à la valorisation des bios ressources aquatiques du Cameroun, le potentiel nutritionnel d’Oreochromis niloticus du fleuve Nkam à Yabassi a été déterminé. L’objectif était d’évaluer dans leur partie comestible (chair+peau), la composition bromatologique en fonction des grandes périodes de capture (novembre, mars et juillet), d’analyser l’influence du fumage et de la cuisson à ébullition sur leur composition proximale et le profil des acides gras. Les méthodes conventionnelles ont été utilisées. Les données obtenues ont varié significativement (P<0,05) en fonction du traitement. Dans la période de capture, les protéines (47,85 %MS) et cendres (19,80 %MS) ont été plus élevées en mars et plus faibles en juillet (32,67 et 7,20 %MS respectivement). Le fumage et l’ébullition ont concentré la matière sèche et les cendres, mais ont diminué les protéines (de 47,85 à 35,58 et 40,44 %MS respectivement), les lipides (de 23,34 à 19,91 et 16,90 %MS respectivement) et l’énergie (de 437,50 à 357,91 et 397,30 kcal/100gMS respectivement). Sur les minéraux, le fumage et l’ébullition ont favorisé l’augmentation du potassium (de 4659,29 à 8736,17 et 6988,93 mg/kg respectivement) et magnésium (18,72 à 34,14 et 37,84 mg/kg respectivement). Leurs lipides ont été riches en acide palmitique (26,50-26,79%) et l’acide oléique (14,52-17,72 %). Toutefois, les acides gras essentiels omégas-6 (l’acide linoléique (4,93-9,07 %), arachidonique (3,12-3,73 %)) et omégas-3 (l’acide α-linolénique (4,17-6,27 %), docosahexaénoïque (1,72-2,84 %)) ont été bien représentés. Le rapport omégas-3 sur omégas-6 a augmenté en passant de 0,71 à 0,91 et de 0,71 à 1,20 pour le fumage et l’ébullition respectivement. Par contre, le rapport acides gras polyinsaturés sur acides gras saturés a diminué de 0,60 à 0,42 avec le fumage et augmenté de 0,60 à 0,71 avec l’ébullition. Les différents effets observés ont été plus sévère avec le fumage que l’ébullition. Ces données pourront servir à compléter les tables de composition des aliments locaux, nécessaires pour les formulations alimentaires.Mots clés: Yabassi, Fleuve Nkam, Oreochromis niloticus, valeur nutritionnelle, fumage, ébullitionEnglish AbstractIn order to contribute to the valorization of the bio-aquatic resources of Cameroon, a study on the nutritional value of Oreochromis niloticusfrom river Nkam at Yabassi was carried out. The aim was to evaluate on their edible parts (flesh + skin), the chemical composition with respect to the main periods of captures (November, March and July), evaluate the influence of smoking and boiling on their proximate composition as well as their fatty acids profile, by conventional methods. The data obtained varied significantly (P<0.05) according to the treatments. During the capture period, Proteins (47.85 %dm) and ashes (19.80 %dm) were higher in March and lower in July (32.67 and 7.20 %dm respectively). Smoking and boiling concentrated the dry matter and ashes, but reduced proteins (from 47.85 to 35.58 and 40.44 %dm respectively), lipids (from 23.34 to 19.91 and 16.90 %dm respectively) and energy (from 437.50 to 357.91 and 397.30 kcal/100gdm respectively). Smoking and boiling increased potassium (from 4659.29 to 8736.17 and 6988.93 mg/kg respectively) and magnesium (18.72 to 34.14 and 37.84 mg/kg respectively). Their lipids was rich in palmitic acid (26.50- 26.79 %), followed by oleic acid (14.52-17.72 %). However, the essential fatty acids omega-6 (linolenic acid (4.93-9.07 %), arachidonic acid (3.12-3.73 %)) and omega-3 (α-linolenic acid (4.17-6.27 %), docosahexaenoic (1.72-2.84 %)) were substantially represented. The proportion of omega-3 on omega-6 increased from 0.71 to 0.91 and 0.71 to 1.20 for smoking and boiling respectively. On the contrary, the proportion of polyunsaturated fatty acids on saturated fatty acids decreased  from 0.60 to 0.42 with smoking and increased from 0.60 to 0.71 with boiling. Different effects observed were more severe with smoking than boiling. These data will probably help to complete the tables of local foodstuffs composition, necessary for the formulation of feed.Keywords: Yabassi, River Nkam, Oreochromis niloticus, nutritional value, smoking, boilin