Development of low cost nutrient dense fish products based on low value fish and fish byproducts using small and medium scale processing and preservation methods that stabilize the nutritional value and ensure the safety of the product

Abstract

Fish powders were produced from edible by products such as tuna frames (bones), trimmings and gills from a fish processing factory, Cosmo Seafood Company Ltd in Tema and underutilized fish, burrito (Brachydeuterus auritus) also from Tema canoe landing beach. These raw materials were cleaned thoroughly and dried with a CSIR-FRI gas-fuelled oven at 55°C for 6 h or until dried with a moisture content of between 3.5-8.4% and Water Activity (aw) between 0.6 and 0.65. The dried products were milled with hardened steel hammer mill (Jacobson Machinery Works, Minneapolis, USA. Model 160B) and sieve size of 0.5 mm and stored sealed in polyethylene bags with a gauge of 49.25 mil at ambient temperature (27 ± 2 ºC) until needed. The physical, micro-mineral and macro-mineral content of the dried fish powder showed that tuna trimmings contained 80.71 g/100 g protein while burrito contained 70.40 g/100 g protein. Lead (Pb) was not detected in Tuna trimmings whilst insignificant (P >0.05) levels of 0.44, 0.33 and 0.21 mg/100 g were detected in Tuna frames, gills and Burrito respectively. All fish powders contained high levels of iron, for example, Burrito contained 16.58 mg/100 g while Tuna frames and gills also contained 16.82 and 19.54 mg/100 g respectively. Zinc levels also ranged from 0.41 mg/100 g in Tuna trimmings to 1.88 mg/100 g in Tuna gills. The fish powders were used to produce fortified products from locally known snacks as aboloo, agbelikaklo, yakeyake and mpotompoto. Physicochemical properties of the food products fortified with the fish powder showed that their protein contents were increased significant (P <0.05) between 3.75 to 8.5 % depending on the powder used. The energy contents of the fortified products ranged from 104.09 to 149.04 %. Most of the fortified products also showed high values of other nutrients. All the products were acceptable as they were rated above 6 (like slightly) and they were not significantly (P<0.05) different from the reference samples except food products with trimmings which were not acceptable because of the bitterness. School feeding trials of abolo fortified with the powder of the fish frames was rated highly compared to those abolo fortified with other fishes. However, trimmings in yakeyake was rated high (4) in terms of overall acceptability. Mpotompoto fortified with the various fishes was rated highest in all attributes. In general fortified products were acceptable for the school feeding programme were developed. Fish powder could be stored for over long period of time when packaged under vacuum in polyethylene pouches with a gauge of 49.25 ml at refrigeration temperature of 5 ±2 ºC or freezer temperatures (-18 ±2 ºC)