Effect of local hot smoking on proximate composition, lipid oxidation, fatty acid profile and minerals content of <I>Chrysichthys nigrodigitatus</I> from Lake Maga in Cameroon

Abstract

Fish with higher nutrient qualities can be used to solve malnutrition problems in Africa. So the aim of this study was to evaluate the effect of local smoking on proximate composition and lipid oxidation of Chrysichthys nigrodigitatus collected in Cameroon. The proximate composition was assessed using standard methods while lipid quality assessment was based on the determination of biochemical indexes. A change on fatty acid composition was evaluated by gas chromatography while minerals composition was evaluated by spectrophotometer. On nutritional point of view, raw fish have high protein, lipid and ash contents (51.87, 37.48 and 8.55 g/100 g dry weight respectively). Unsaturated fatty acid may be up to 57% of the total fatty acids. Raw C. nigrodigitatus contain reasonable amount of minerals. Smoking process increased ash and lipid content while proteins and moisture contents are reduced in these fish. The iodine value of C. nigrodigitatus was reduced while acid, peroxide and TOTOX values increased during smoking. The marked decrease of polyunsaturated fatty acids was noted during processing. Mineral contents were affected by smoking process. Calcium, magnesium, potassium, sodium, manganese and iron contents increased significantly. In conclusion, hot smoking enhances nutrients content of C. nigrodigitatus while significant reduction in lipid quality was recorded.Keywords: Chrysichthys nigrodigitatus, smoking process, nutritional value, lipid oxidation, mineral contents.&#x0D; Frence Title; Effet du fumage traditionnel sur la composition chimique, l’état d’oxydation des lipides, la composition en acide gras et la teneur en minéraux de Chrysichthys nigrodigitatus du Lac Maga au Cameroun&#x0D; Le Poisson est l’une des sources d’éléments nutritifs de qualité pouvant contribuer à prévenir la malnutrition en Afrique. Ce travail s’est donné pour objectif d’évaluer l’effet du fumage traditionnel sur la composition chimique et l’état d’oxydation des lipides de Chrysichthys nigrodigitatus provenant du Lac Maga au Cameroun. Les méthodes standards ont été utilisées pour la détermination de la composition chimique, la mesure de l’état d’oxydation des lipides par des indices chimiques, la composition en acides gras par chromatographie en phase gazeuse et les minéraux par spectrophotométrie. Du point de vue nutritionnel, ce poisson frais contient respectivement 51,87 ; 37,48 and 8,55 g/100 g de matière sèches de protéines, lipides et cendres. Il contient également 57% d’acides gras insaturés et une quantité raisonnable de minéraux. Le traitement de fumage provoque une augmentation de la teneur en cendres et en lipides. Par contre la teneur en eau et en protéines diminuent. L’indice d’iode baisse tandis que les indices d’acide, de peroxyde et de TBARs augmentent. Une diminution du taux d’acides gras polyinsaturés est observée. Les minéraux sont également affectés au cours du fumage. Le traitement de fumage améliore la teneur en nutriments de C. nigrodigitatus, par contre réduit la qualité lipidique de celui-ci.&#x0D; Mots clés : Chrysichthys nigrodigitatus, fumage, valeur nutritionnelle, oxydation des lipides, teneur en minéraux.&#x0D;

Assessment of cooking methods and freezing on the nutritional value and health risks of heavy metals in four fish species consumed in Douala, Cameroon

“…Smoking and boiling decreased significantly (P < 0.05) water content of C. carpio, Arius parkii and E. fimbriata compared to fresh fish. Similar results were observed by Tenyang et al [ 39 ] who showed that the water content of Chrysichthys nigrodigitatus decreased during smoking and boiling. According to Nsoga et al [ 40 ] fish lose about 20% of their initial weight during heat treatments such as smoking.…”

“…Smoking increased significantly (P < 0.05) lipid content in all three species. Tenyang et al [ 39 ] showed that lipid content increases during smoking. Indeed, dehydration due to heat treatments such as smoking would increase lipid content .…”

“…Djopnang et al [ 23 ] showed that smoking increased the carbohydrate content of Chrysichthys nigrodigitatus . This result could be explained by the concentration of carbohydrates during water loss during heat treatments [ 39 ] . Boiling decreased significantly (P < 0.05) carbohydrate content in C. carpio and E. fimbriata .…”

“…Kiczorowska et al [ 45 ] showed that smoking decreased phosphorus content of Abramis brama and Carassius carassius compared to raw samples. During smoking, Tenyang et al [ 39 ] reported a decrease of phosphorus content in Chrysichthys nigrodigitatus from Lake Maga in Cameroon. Water losses during freezing and smoking allow nutrient concentration [ 41 ] .…”

“…Smoking increased significantly (P < 0.05) magnesium content compared to fresh, frozen and boiled in P. quadrifilis. Tenyang et al [ 39 ] showed that magnesium content increased significantly (P < 0.05) during smoking of Chrysichthys nigrodigitatus. Djopnang et al [ 23 ] showed that magnesium content increased significantly (P < 0.05) during smoking and boiling of Chrysichthys nigrodigitatus.…”