The comparative studies of the nutritional composition of fresh and smoked Scombia scombrus and TrachurusTrachurus was carried out using standard analytical method to establish their normal values. The two species of fish contained all the analyzed parameters in appreciable quantities. The fresh and smoked mackerel fish for: moisture (53.38±0.0017 and 26.25±0.0023); Ash content (9.77±0.0012 and 7.58±0.0037); Crude fibre (8.40±0.0033 and 6.23±0.0012); Crude protein (34.26±0.058 and 49.88±0.14); Crude fat (14.78±0.0035 and 25.44±0.0028); Carbohydrate (32.76±0.020 and 10.87±0.015); Caloric value (401.22±0.031 and 471.76±0.033). The horse mackerel fish respectively recorded the fresh and smoked forms for moisture content (32.13±0.003 and 59.36±0.002); Ash content (8.70±0.001 and 9.46±0.001); Crude fibre (6.71±0.01 and 8.35±0.005); Crude protein (51.53±0.028 and 45.16±0.028); Crude fat (27.11±0.002 and 18.53±0.0035); Carbohydrate (5.95±0.014 and 18.50±0.15); Caloric values (503.66±0.056 and 421.41±0.072). Ash content, crude fibre and carbohydrate generally occurred in appreciable amount in two fish species both with fresh and smoked forms. The horse mackerel fish was highly rich in crude protein and atlantic mackerel in carbohydrate. These attribute make the two species of fish fit for human consumption and commercial purposes.F.Cal is > Fa tab. at 0.05%, therefore there is significant difference at P<0.05% in both samples.
CHAPTER ONE: INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Fish is greatly perishable mostly in fresh forms but forms a very important food stuff, especially in third world countries, due to its high protein content and nutritional value of unsaturated fatty matter and affordability by the masses when compared with beef. One of such species is the horse mackerel (TrachurusTrachurus); a medium-fat species abundant in the northeast Atlantic (FAO, 2006; Olatunde, 1998; FAO, 2008; Zimmermann and Hammer, 1999) and the Atlantic mackerel, Scombia scombus.
The rate of fish spoilage depends on handling during processing, acidity level, species of fish, weather, mode of storage and temperature during transportation (Oladosun et al., 1996). The Chemical breakdown of protein, fat and water contents contribute to quick spoilage of fish. Quality losses might occur very rapidly after catch, especially in hot climates and tropical areas where cold preservation techniques are often missing. Saliu (2008) reported that fish spoilage in Nigeria is influenced to a large extent by high ambient temperatures, considerable distances of landing ports to points of utilization and poor as well as inadequate infrastructure for post-harvestprocessing and landing (Saliu, 2008). Thus, traditional fish processing, such as salting/brining, drying and smoking, allow better preservation and storage and increase fish availability to the consumers (Egbal et al., 2010). The processes of smoking and drying are the affordable and most widely used method for fish preservation in Nigeria (Food Inc, 2009) that dates back to civilization (Oladosun et al., 1996), it also aimed at preventing or reducing post-harvest losses (Shepherd, 2000).