الفهرس 
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Abstract
Fish is one of the least expensive sources of animal protein, minerals, and other elements in the global human diet, as is widely known. For the population of underdeveloped nations, it provides a great source of protein, vitamins, minerals, and omega-3 fatty acids. It stands out for being a simple-to-digest food that may be served as a meal in a variety of ways. One of the most significant sources of national income in Egypt is fishing. The fisheries in Egypt include more than 13 million acres, or almost 150% of the country’s arable territory. This area includes the Red and Mediterranean Seas, several lakes, and freshwater sources including the Nile River and its two branches, as well as canals and drains. Along with the fish farms dispersed around Egypt, man has developed artificial sources like Lake Nasser and Lake Rayan. In 2020, the Egyptian Fisheries Authority stated that Egypt produced 1 million 920 thousand tons of fish, of which 80% came from aquaculture and 20% from artisanal fishing. The most widely consumed fish species is the Nile tilapia (Oreochromis niloticus). Egypt was the third-largest producer of Nile tilapia fish in the world, and it exported $8,637,000 worth of the fish in a single year. Large portions of Africa are the Nile tilapia’s original habitat.
The Nile tilapia fish comes from either lakes, the Nile River, or fish farms, with the majority of tilapia fish in the Egyptian market coming from these latter two sources. The Central Agency for Public Mobilization and Statistics, Fish Production Statistics in the Arab Republic of Egypt, stated that, Egypt produced 1 million 114 thousand tons of Nile tilapia fish in the year 2020, with a total value of around 25 million Egyptian pounds. Recently, as social patterns changed, mobility increased, family gatherings decreased, and the number of workers increased, fast food consumption rose quickly. The goal of the current study was to examine
The purpose of this study was to: -
1- Produce fish fillet and fish ball products to increase the commercial and monetary worth of fresh Nile tilapia (Oreochromis niloticus).
2. Examine the impact of two natural antimicrobial agents (thyme extract and green tea extract), on the durability of frozen packed tilapia products kept for 10 months.
1-The data showed that the samples’ moisture contents at the beginning of storage had slightly different values. When compared to the samples of fish fillet, the fish balls samples had higher ash content and overall acidity. While the crude protein content and either extract values for the fillet samples were greater than those for the fish balls samples.
2- The data revealed a very low water vapor transmission rate of 0.0006 g/cm2.day.
3- According to the findings, all of the samples under study had a decrease in moisture content as a result of storage time. For the control sample and the sample treated with thyme and green tea extracts, the initial moisture contents for the various treatments ranged between 76 and 78%. The treatment of fish fillet and fish balls in thyme and green tea aqueous solutions is what caused the difference between the two values.
4- For all samples, the results indicated a decrease in the (WHC) levels. After 10 months of frozen storage, the rate of decline was significantly higher in the fillet samples (from 26% to around 17%) than in the fish balls products (from 28% to about 22%). This might be as a result of the ability or impact of the other fish ball components to capture moisture in the matrix.
5- The data showed that for all treated and untreated samples, the (% EW) values increased as storage duration increased. The rate of increment was higher in the samples of control fillet and fish balls treated with thyme or green tea extract than in the samples of control fillet and fish balls. The (% EW) values for the control and thyme or green tea extract-treated tilapia fish fillet samples were 50%, 50.8%, and 52% at the start of the storage period, and they increased to 53.7%, 54.5%, and 55.4% at the conclusion of the storage period, respectively. In contrast, the results for the fish balls rose from 46.8%, 47.0%, and 48.3% to 48.2%, 49.0%, and 50.2%, respectively.
6- The data showed that the pH values for all samples increased over the course of storage. The tilapia fish balls (control and thyme and green tea extract treated samples) showed the highest rate of increment, increasing from 5.72, 5.67, and 5.67 to 6.05, 6.02, and 6.05, respectively. The pH of the thyme and green tea extracts-treated samples, meanwhile, increased from 6.22, 6.15, and 6.15 for the tilapia fillet samples to 6.28, 6.30, and 6.30 for the control samples at the start of the storage period. The tilapia fish balls’ pH values were lower than those of the fillet product, indicating that the ingredients added to make the fish balls lowered the pH of the finished goods.
7- The data indicated that as storage time progressed, the total acidity levels for all samples decreased. Compared to the fillet samples, the rate of reduction was higher for the tilapia fish balls samples. This might be connected to the additional substances that were utilised to make the fish ball items.
8- The data showed that as the storage period extended, the TBA values for all samples increased. Compared to the samples of fish balls, the rate of increase was higher for the tilapia fillet samples. The control sample had the highest rate of increase in the same trend, followed by the sample that had been treated with green tea and the sample that had been treated with thyme extract.
9- According to the findings, all samples showed an increase in (TVB-N) levels as storage time went on. The (TVB-N) values for the control and thyme extract or green tea extract treated samples ranged between 14.0 and 14.7 mg/100g at the start of storage time. However, by the conclusion of the storage period (10 months in a frozen state), the levels increased for the same samples to between 20.7 and 21.7 mg/100g.
10- According to the study, tilapia fish balls have lower cooking loss percentages than tilapia fish fillets. At the conclusion of the storage period, the percentage cooking loss for the fish balls products was reduced from 12% and 17% for (the control and antimicrobial treated fish products) to 9.5% and 15%, respectively. While after 10 months of frozen storage, the fish fillet’s percentage dropped from 42.5% to 42% (for the control and antimicrobial-treated fish items).
11- The data revealed that the total bacterial count (log CFU/g) was less than 6 in all treated and untreated samples. With each treatment and over the course of storage, there was a decrease in the overall bacterial count. In comparison to the treated samples, the control samples had the greatest overall bacterial count. After a zero-time period, samples treated with thyme extract as an antimicrobial have no bacterial colonies, demonstrating the substance’s efficacy as an antimicrobial.
12- The results showed that the log CFU/g of psychrophilic bacteria reduced after all treatments and storage durations. More colonies were observed in the control samples compared to samples treated with antimicrobial extract (thyme and green tea extract). This indicates that adding thyme or green tea extract as a natural antimicrobial had a detrimental impact on the amount of psychrophilic bacteria present in the samples.
13-According to the results, only three samples—control fillet, control fish balls, and fish balls treated with green tea extract—had a coliform group bacterial count at the start of storage time (zero time), and no colonies were found for the remaining storage time. This demonstrated the detrimental impacts of storage temperature, natural antimicrobial extracts (thyme and green tea extract), and on the ability of the coliform bacteria to survive.
14- The assessments revealed that the samples had received unanimously high marks from the panel. Data showed that all of the investigated samples received slightly lower evaluations from the panelists following a 10-month duration of storage at a frozen condition. The reduction was greater in the control samples than in the samples that had been treated with green tea extract.