EFFECT OF CHUNK SIZE AND DIFFERENT AGRO WASTE ON THE STORAGE QUALITIES OF SMOKED CATFISH (Clarias gariepinus) COATED WITH CITRUS PEEL OIL

Abstract

This study assessed effects of chunk sizes and different agro wastes(Charcoal ,maizecob and Saw dust); as energy sources on storage characteristics of Citrus peel Oil coated and uncoated smoked cat fish (clarias gariepinus). Sixty four matured cat fish (Clarias gariepinus) of average size of 1.2kg were purchased from Dagama Fisheries in Akure. The fish samples were eviscerated immediately after capture carefully degutted and washed with clean water to remove blood and slime, while the body was cut into three different sizes 3 cm, 5 cm, 8 cm respectively. The fish samples were smoked in a smoking kiln at a temperature of 70 ±50C€ until equilibrium moisture contents were attained using different agro waste e.g sawdust and; charcoal from LophiraAlata (eki) and maize cob. Essential oil was extracted from orange peel using hydro distillation method and stored in a glass container and refrigerated in the dark at 4 0C.The extracted oil from was used to coat a portion of the smoke cat fish chunks while uncoated samples were used as control . Each sample was sealed in a polythene bag and all the samples were stored at ambient temperature (280C ± 20C). Storage qualities were monitored for six weeks. The crude protein content of the smoked cat fish sample from week 0-6 ranged between 58.39% of 3 cm catfish smoked with sawdust uncoated at (week six(6) to 68.28% of 8cm catfish smoked with maize cob coated with citrus peel oil at (week zero (0). The protein content was significantly decreasing as the storage time was increasing; Fat content ranged from 10.58% in 3 cm cat fish smoked with sawdust uncoated (week 6) to 13.65% 8cm cat fish smoked with charcoal coated with citrus peel oil (week 0). The fat content was decreasing as the storage time increased; Ash content ranged from 6.05% 3 cm cat fish smoked with sawdust uncoated (week 0) to 8.61% 8 cm cat fish smoked with maize cob coated with citrus peel oil (week 6) the ash content increased significantly during the weeks of storage;. The peroxide value (PV), Free Fatty Acid (FFA), Total Volatile Nitrogen (TVN), Thiobarbituric acid (TBA) and pH content of coated and uncoated smoked cat fish were 3.20 meq O2/kg – 6.75 meq O2/kg, 0.23% - 0.69%, 4.12 mgN/100g – 7.0 mgN/100g, 0.17 mgA/kg – 0.59 mg A/kg and 5.86 – 6.57 respectively, there were significant differences (P ≤ 0.05). Coated and Uncoated charcoal smoked Catfish has better keeping quality when compared with other agro wastes Coated and Uncoated sawdust smoked Cat fish has the least keeping quality among the agro waste used. . The vitamin content during the week of storage ranged from vitamin A 0.069 mg/100g 8cm cat fish smoked with maize cob uncoated (week 6) to 0.09/mg/100 8 cm cat fish smoked with charcoal coated with citrus peel oil (week 0) vitamin A content of the sample decreased with the length of storage period while vitamin D ranged from 0.005 mg/100g 8 cm cat fish smoked with sawdust coated (week 6) to 0.013 mg/100g 8cm cat fish smoked with charcoal coated with citrus peel oil (week 0); mineral contents: sodium content (24.90 to 33/3 mg/100g); calcium (7.97 – 12.27 mg/100g); Magnesium (18.31 – 26.94 mg/kg); Manganese (0.02 mg/100g – 0.03 mg/100g); Iron (Fe) (0.09 mg/kg – 1.28 mg/100g); zinc (zn) (0.39-0.55 mg/100g) and phosphorus (154.28 – 184.6 mg/100g) respectively during the weeks of storage there were significant difference (P ≤ 0.05) between the samples and their control. The fatty acid profile result indicated that palmitic acid (C16:0), palmitoleic acid (C16:1 (C15-9), Stearic acid (C18:0), Petroselinic acid (C18:1 (C15-6), Oleic acid (C18:1 (C15-9)), Arachidonic acid C20:4 (C15 5,8,11), Eicosapentaenoic acid (EPA) C20:5 (C15 5, 8,11,14,17) and Docosahexaenoic acid (DHA) were the most dominant fatty acids.The results of this study established that 3cm coated charcoal smoked cat fish was able to retain suitable keeping qualities in terms of nutrients and spoilage parameters.