English abstract
In Sultanate of Oman, there are plenty of fish species available, but people concentrate mainly in certain species for consumption. As a result, the demand of these species increased and at the same time their prices increased too. On the other hand, there are many underutilized fish species possess high nutritional value and available with rational prices but consumers do not consume them either because of their unpleasant aroma, their undesired taste or their unusual shape. However, if a technology is developed to get rid of the undesired aroma and shape, these species can be utilized and converted to value added products. Catfish, Arius maculatus, is one of underutilized fish species in the Sultanate that is available in abundant quantities with affordable price and most of its produce is exported as raw and cheap materials. So, the aim of this study was to develop a technology capable of utilizing underutilized fish such as catfish and converting it to a value-added product (fish burger) and studying its storage stability during 3 month of storage at - 18°C. Getting rid of the undesired aroma was accomplished by dipping the fillets of the fish in water and then with the use of mixture of spices with the aid of other ingredients like corn flour. Fresh catfish burger contained water, protein, total fat, total ash and carbohydrates as 70.53, 17.82, 1.04, 1.73, 8.89 g/100 g sample respectively. The total bacterial count decreased, from log 4.77 cfu/g in fresh burger to log 4.35 cfu/g after 3 months of storage. The water holding capacity and the peroxide value decreased significantly (p<0.05) from 90.7 % and 15.38 meq/kg fat in fresh fish burger to 83.46 % and 5.19 meq/kg fat, respectively, after 3 months of storage, but the water holding capacity of the cooked burger after 3 months of storage did not change significantly (p>0.05). The color values, L, a and b of the fish burger decreased significantly (p<0.05) after 3 months of storage from 47.69, -0.43 and 13.83 to 45.73, -1.48 and 12.66 respectively, whereas the L and b values decreased significantly (p<0.05) for the cooked burger after 3 months of storage from 43.46 and 14.24 to 39.05 and 13.24 respectively, but the a value increase from 1.12 to 1.45 was not significant (p>0.05). Texture profile analyzer (TPA) parameters of the fish burger namely, cohesiveness, chewiness and gumminess increased significantly (p<0.05) after 3 months of storage from 0.37, 5.19 and 5.19 to 0.47, 6.56 and 6.56, respectively, but adhesiveness decreased significantly (p<0.05) from -0.31 to -0.18. In contrast, hardness and elasticity did not change significantly (p>0.05) and decreased from 14.11 and 0.9999 in fresh burger to 13.94 and 0.9997 after 3 months of storage, respectively. On the other hand, adhesiveness was the only parameter of the cooked burger that changed significantly (p<0.05) and increased from -0.0001 in cooked fresh fish burger to -0.001 after 3 months of storage, but cohesiveness and elasticity did not change significantly (p>0.05) and decreased from 0.779 and 0.9999 in cooked fresh fish burger to 0.776 and 0.9997 after 3 months of storage, respectively. Hardness, chewiness and gumminess of the cooked fish burger did not change significantly (p>0.05) and increased from 43.24, 33.71 and 33.72 in the fresh cooked burger to 46.73, 36.23 and 36.25 after 3 months of storage, respectively. All the attributes of 9 points hedonic scale of sensory evaluation, namely, odor, color, taste, texture and general acceptability, of cooked fish burger did not change significantly (p>0.05) and all decreased from 7.3, 7.5, 7.2, 7.3 and 7.5 in the fresh fish burger to 7.0, 7.2, 6.5, 6.5 and 6.3 after 3 months of storage, respectively. This study developed a technology for underutilized fish species such as catfish in the Sultanate by converting it to a value added fish product, fish burger, which showed a good storage stability for 3 months at - 18°C. This study recommends to implement this technology using other types of underutilized fish in the Sultanate of Oman, like ribbonfish and extend the storage study period to evaluate the stability of its quality during frozen storage.
