Iheagwara, J Nutr Food Sci 2013, 3:3 http://dx.doi.org/10.4172/2155-9600.1000199
Effect of Ginger Extract on Stability and Sensorial Quality of Smoked Mackerel (Scomber scombrus) Fish Marcquin Chibuzo Iheagwara*
Department of Food Science and Technology, Federal University of Technology, Owerri, Nigeria
The effect of ginger extract on the stability and sensorial quality of smoked mackerel fish stored at 28 ± 2°C was determined over 20 days. Chemical, microbiological and sensory analyses were performed to investigate quality changes, and to determine the shelf stability of the products. The proximate, thiobarbituric acid (TBA) value, peroxide value (PV), mould count, and trimethylamine (TMA) were found statistically significant (P ≤ 0.05), in the smoked mackerel fish throughout storage. Protein, fat and ash contents of the ginger extract treated samples had marked % increase compared to the control. The lowest TBA (0.08 mg MDA/kg), peroxide (4.50 mEq/kg) and TMA (3.46 mg N/100 g) values were recorded in 5% ginger extract treated samples, while the highest TBA (1.45 mg MDA/ kg), PV(30.07 mEq/kg) and TMA (15.52 mg N/100 g) occurred in the control. The result also revealed that samples treated with ginger extract had lower mould count than the control. The organoleptic results showed that samples treated with 5% ginger extract had the best acceptance, and were significantly different (P ≤ 0.05), when compared to the control after 10 days of storage.
Keywords: Smoked mackerel fish; Ginger; Stability; Quality; Lipid oxidation; Thiobarbituric acid; Peroxide; Storage Introduction Fish constitutes a very important component of diet for many people, and often provides much needed nutrients for a healthy living. Fish serves as a principal source of dietary protein, which is very inexpensive in relation to other protein foods . It is the characteristics of fish as a cheap source of animal protein, which is now evident throughout the world that makes it an excellent component of human diet. Fish protein now takes precedence over other protein of animal origin, and compares favorably with that of milk, egg and meat in its amino acid composition. It is this quality that makes fish protein to be practically indispensable to developing countries, such as Nigeria, for diet supplementation, where the staple diet or food consist primarily of starchy foods . Besides, fish is known to contain a very high quality of fats and oil, and fish fat is very high in polyunsaturated fatty acids, which are very important in lowering blood cholesterol level. The fish oil, on the other hand, contains the fat soluble vitamins. Fish is also a very good source of thiamine and riboflavin, and contains minerals, phosphatids sterols, enzymes, hormones, hydrocarbons and pigments [3,4]. However, fish is an extremely perishable food commodity, and hence, is subject to post harvest losses ranging from bacterial and autolytic spoilage to other factors. These causes cause fish to lose its organoleptic qualities, and generally unacceptable for human consumption. It is this perishability of fish that makes it to be processed into fish based products, such as smoked and canned fish, fish cake, fish meal, fish burger, etc. . Fish smoking is one of the traditional methods of preservation of fish in Africa. Smoke curing, as applied to fish, is a method of preservation effected by combination of drying and the deposition of naturally produced chemicals, resulting from the thermal breakdown of wood . Dried fish spoilage has been characterized by reddening, browning, or other discoloration mould attack, and development of rancidity. The use of synthetic antioxidant has been very effective in controlling rancidity. However, synthetic antioxidants have frequently been associated with certain health problems . This has necessitated the use of natural antioxidants, such as spices, in...