الفهرس 
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Abstract
Fish is a good source of high-quality protein. It also contains water, fats, and many vitamins and minerals necessary to maintain human’s health; however, it is very perishable. As for the carp fish in Egypt, there are four species of carp that are widely and successfully cultured, which are common, silver, grass and bighead carps; this is due to its fast growth rate, ease of cultivation and high feed conversion efficiency.
It is known that fish salting with drying leads to a prolonged storage period and the finished products to acquire the desired flavor. In addition, plant extracts, which act as natural antioxidants, antimicrobials and flavoring agents, are used to obtain high quality and safe fish products with an extended shelf life for dried salted products. Therefore, the aim of this study was to maximize the utilization of some low-priced fish such as grass carp (Cteanopharynogodon idella) to obtain dried salted fish products in the presence of some plant extracts, and to study the effect of these treatments on the quality indices of these products during the storage period at ambient temperature. Samples of grass carp were obtained from the fish market, Al-Obour City, Cairo during June 2019. Some technological processes were carried out to obtain fish fillets, which were salted using different levels; 10% and 15% in the presence of some plant extracts (black cumin, garlic, rosemary and a mixture of them), then dried, packaged in polyethylene bags and stored at room temperature. The chemical composition and some quality indices of the fresh fish and the treatments studied were determined.
The results obtained during the study period showed the following:
Raw grass carp samples
- The yield of raw grass carp flesh was 40.5%.
- Carp flesh contained 77.06±0.86% moisture, 16.44±1.12% crude protein, 4.27±0.34% fat, 1.48±0.10% ash (on wet weight basis).
- Also, carp flesh recorded a value of 6.35±0.01 pH value, 14.20±0.24 mg/100 g total volatile nitrogenous bases, 1.12±0.02mg/100 g TMA, 0.42±0.01 mg MDA/kg TBA value.
Salted grass carp fillets with 10% and 15% levels
- An increase in moisture content occurred in all salted fish fillets; this increase was higher in 10% salted fillets compared to 15% salt fillets. The moisture content was ranged 78.35-82.05% and 76.04-81.32% for salted fish fillets with 10% and 15% concentrations, respectively.
- The salt content was recorded 1.80 - 2.93% of the salted fillets with 10%, while it recorded 2.30 - 2.90% of 15% salted fillets treatments.
- The values of the water phase salt of the salt ranged 2.15 - 3.60% and 2.94 - 3.57% for the salted samples at 10% and 15%, respectively.
- Water activity values were 0.98 for all salted fish fillets (10% and 15%).
- The pH values ranged 6.29-6.74 for 10% salted fillets, while it slightly decreased to 5.95-6.41 for 15% salted fillets.
- The values of TVBN ranged 14.00 - 22.40 mg/100 g of 10% salted treatments, while in the case of 15% all treatments contained 14.00 mg/100 g sample.
- The values of TMAN ranged from 0.65 - 0.89 mg/100 gm trimethylamine in salted treatments with 10%, while it decreased slightly to reach 0.44 - 0.62 mg\100 g in the treatments at 15%.
- The values of TBA ranged from 0.45-0.67 MDA/kg of 10% for salted treatments, while it slightly increased to reach 0.51-0.67 MDA/kg for 15% salted treatments.
Drying of salted grass carp fillets
- The drying process led to a significant decrease in moisture content to reach a range of 8.18-12.33% in 10% dried salted treatments, while it reached 7.75-11.12% in 15% dried salted treatments.
- The salt content was ranged between 3.90 - 5.80% of 10% dried salted treatments, while it recorded 5.60 - 5.80% of 15% treatments.
- The values of the water phase salt of the salt were ranged 24.03 - 41.49% and 34.42 - 41.51% in the 10% and 15% dried salted treatments, respectively.
- The values of water activity were ranged 0.24-0.54 and 0.40-0.54 in the dried salted treatments with 10% and 15%, respectively.
- Stability in pH values was observed; 6.29 - 6.74 in 10% treatments, while it decreased slightly to be 5.95 - 6.41 in 15% treatments.
- Also, there was stability in the values of the TVBN to record 14.00 - 22.40 mg/ 100 g for 10% treatments, while in the case of 15% treatments; it was 14.00 mg /100 g in all treatments.
- TMA values were decreased to 0.50 - 0.65 mg/100 gm in 10% treatments, while it slightly decreased to 0.43- 0.50 mg/100 gm in 15% treatments.
- There was stability in the values of TBA, which was 0.45-0.67 MDA/kg in 10% treatments, while it increased slightly to reach 0.51-0.67 MDA/kg in 15% treatments.
Storage of dried salted fish fillets:
- The loss in moisture content was ranged 10.15-18.17% in 10% treatments, while it ranged 6.84-12.47% in e 15% treatments.
- Values of salt content increased to 6.90-23.26% in 10% treatments and 3.28-61.45% for 15% treatments.
- The values of water activity ranged 0.39-0.70 for 10% treatments, while a decrease found in 15% treatments to record 0.12-0.58.
- The pH values were increased to range of 6.69-7.47 in 10% treatments, while it ranged 6.12 - 6.35 in 15% treatments.
- The values of the TVBN were increased significantly to 55.60-126.27 mg/100g in 10% treatments, while in the case of 15% treatments; it ranged 46.08-55.23 mg/100g.
- The values of TBA were increased to range of 0.45-1.01 MDA/kg in 10% treatments, while it was 0.62-0.75 MDA/kg in 15% treatments.
Conclusion
Based on the results obtained, it could be concluded that carp species are a major source of dried salted fish products; its production contributes 11.42% of Egypt’s total catch during 2019. Salted carp fillets with 15% were more stable and better quality as compared to the products salted with 10%. Salted and dried products were more stable and valid than only salted products. Plant extracts used could be improved the sensory properties of finished products.
Recommendations
Finally, this study recommends the following items:
- Possibility of utilizing carp fish species for production of some dried salted fish products.
- Both salting and drying are cheap techniques and don’t require more experience.
- The wastes of this industry are also a major source for production of fishmeal and oils.
- Salted and/or dried fish have high nutritive value and they used as oppetizers.
- Dried salted fish are considered products have a long shelf life and they can be found in any time through year.