Abstract
Introduction
The importance of this study is that cooking methods lead to an increase in organoleptic properties and improve the digestibility and inactivation of pathogenic microorganisms. The method of cooking fish leads to some chemical and physical reactions such as protein denaturation, which increases its digestibility and improves its nutritional value.
Salting is the oldest, practical and most common processing method for fish preservation worldwide due to the simplicity of the process and low production cost. Salt is effective as a preservative because it reduces the water activity of fish fillets and thus prevents the growth of microorganisms and enzymatic spoilage. 1
Today's economic considerations have led to the use of cost-effective and valuable food ingredients to produce canned fish from fish at reasonable prices. On the other hand, the high reduction led to the use of new, low consumption types of fish in canned seafood. 2
HTST (high temperature short time) pasteurization is an effective method of making fish safe for consumption, without unduly changing either its sensory characteristics or its nutritional value. As a continuous process, it makes use of energy regeneration and it is capable of both scales of operation and energy efficiencies that cannot be matched by alternative processes. 3
Fish (Carangoides armatus), locally known as Gish, is most preferred and valuable species of fresh water commercial that was obtained from south of Iran. This fish is a valuable source of protein throughout Iran. The high protein in this fish makes it possible to prevent short stature. Fish species are very important to a healthy diet and their consumption in raw, frozen, canned, thawed, marinated, salted, and dried forms is common throughout world. Processing offers different flavors to consumer and minimizes fish waste. Also, increasing shelf life of such perishable food is very important because it leads to reduction of economic losses. Therefore, there was a great demand for fish processing technology. Fish is an excellent choice as a major source of nutrients and nutritional factors affecting health, quality of life, general wellbeing, and longevity. It is known that 98% of fish muscles consist of water, protein, and fat. However, ratio of these components varies due to fish species and processing technology. Changes in nutrient components in foods that occur due to processing should be recognized because they are important for human health. However, fish is a highly perishable product due to its water activity and high protein content, neutral pH, and presence of autolytic enzymes that cause spoilage. As a nutrient-dense food, implication is that delays in processing fresh fish have a major impact on nutritional quality and organoleptic quality of fish, among other problems such as accelerated spoilage. Different processing methods are used to prepare them for consumption since fish are not usually eaten raw, and some of these processes can have different impact on their nutrient content, texture, and taste, thus requiring. There are studies of the effect of processing on the composition of fish nutrients. 1 Therefore, understanding the chemical composition of fish is essential in the food processing technology of fish products on a commercial and industrial scale. 2 The percentage of these compounds is about 96% to 98% of their total tissue composition in fish. The biochemical composition of the whole body indicates the quality of the fish. Fish are some of the major commodities around the world. 4 Fish consumption is likely to maintain health and prevent various diseases. 5 Therefore, aim of present study was preliminary investigation on effect of some common processing methods on amount of macronutrients in marine fish C armatus, which is usually consumed in Iran as main source of animal protein for individuals and average families.
Materials and Methods
Fish Dead Flesh Collection
Fresh fish dead Gish (C armatus) (average length, 40.25 cm) obtained Behbahan fish market, Iran. The fish were kept in a box filled with ice immediately after the catch and transferred to the laboratory.
Fish Processing
Prior to processing, each dead fish was cleaned, and then wastes removed carefully. The fish flesh was processed with different standard methods. Then the samples were placed in closed packages and kept in the refrigerator until using. Fish meat in each treatment was homogenized by blender and then analyzed to evaluate macronutrients, pH, and energy values. All assessments done in triplicate.
The First Standard Method: The Effect of Slow Freezing on Quality of Thawed Fresh Dead Fish
Frozen dead fish fillet was kept in freezer for 1 week,
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then thawing process done with 2 ways following:
Thawing in hot water
2. The standard method of thawing in oven
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Fifty grams of fillet was placed in hot water at 40°C for 20 min until temperature of distilled water reached to 40°C in heater model 860HS. Then, fillet removed from hot water and weighed, and put under pressure. The difference in weight before and after pressing showed amount of water removed. The percentage of moisture, ash, and water loss measured.
Five grams of frozen fillet weighed and placed in oven at 103°C for 30 min until water comes out and then fillet weighed. The loss of water measured and then moisture, ash, and pH values in each samples measured. The percentage of water removed from fillet in oven was 13.62%.
The Second Standard Method: The Effect of Autoclave Temperatures at Different Times on Quality of Dead Fresh Gish Fish
This method was based on processing of fish canning that fillet is heated during sterilization in autoclave.
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The purpose of this step was to remove fat and water from fish fillet due to heat under pressure of water vapor, and then fish tissue became soft.
High temperature in short time HTST and Low temperature in long time LTLT (low temperature long time).
Aim of doing these methods to know effect of these 2 of thermal methods on physicochemical properties and nutritional compounds and energy value in Gish fish fillet.
Description of Experiment
The 15 g fish fillet placed into containers and then each samples placed in an autoclave at 90°C, 115°C, and 121°C for 5, 10, and 15 min.
In treatments of HTST were used 121°C and 5 min, 115°C and 10 min and for LTLT was used 15 min and 90°C.
All samples placed separately into autoclave model MG-23 and then weighted each fillet after sterilization while their weight was decreased because loses water in fish fillet due to sterilization thermal process in autoclave.
The lower quality of fillet, more water lost. The percentage of water lost was measured, so that water loss in fillets affected in water holding capacity (WHC). The higher percentage water loss, lower WHC percentage. The pH measured in each samples. Fat energy value = 9.4× fat percentage (Figure 6) Protein energy value = 2.4× protein percentage (Figure 6)
The percentage of water lost in HTST treatment was 17.53%. The percentage of water lost in LTLT treatment was 20.07%.
3. Third standard method: The effect of different methods of brining and salting in different concentrations on quality properties of dead fresh Gish fish.
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The concentrations of 6% to 10% salt in fish tissue prevents action of most spoilage bacteria. The aim of this stage research was to investigate effect of fermentation and salting on chemical composition and moisture content of the fish fillet.
Before weighing each fish, they washed with distilled water for removing microorganisms. This processing divided into 2 stages. Brining and salting.
Length of fish no. 1 = 33.1 5 cm, width of fish no. 1 = 11.5 cm, fish weight = 434.1 73 g. Length of fish no. 2 = 33.25 cm, width = 12.52 cm, fish weight = 449.209 g. The net weight of fillet no. 1 was 172.77 g. The net weight of fillet no. 2 was 203.47 g. Fillet weight for treatment of salt water 40.34 g. Fillet weight for treatment of salting water = 40.67 g. The weight of fillet for treatment 3 was 40.94 g.
Twenty grams of salt dissolved in 200 mL distilled water. At salting stage, fish fillet placed separately between layers of dry salt in a plastic container. In 10% brining process, salt water solution was changed 3 times. The salting stage also was divided into 3 groups in different concentrations of 10%, 20%, and 25% dry salt, then samples placed in a plastic container at room temperature for 10 days and then samples analyzed.
The fillet weight in brining stage for treatment 1 was 22.31 g. The total weight of fillet was 22.33 g. Total weight of treatment 2 fillet no. 2 was 27.18 g. The total weight of treatment 3 fillets was 44.23 g.
4. The fourth standard method: Preparation of marinade from Gish fish fresh dead fillet
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In order to prepare marinade solution, salt concentration of 5%, 10%, and 15% prepared and then vinegar concentration of 12%, 15%, and 20% prepared based on weight of fillet. And 12 g of vinegar in 100 g of fish fillet with 5% salt water for 20 min, mixed and then heated for 20 min. In same way, for treatment 2, 10% and 15% apple vinegar added and solution pasteurized with heating for 20 min, and then same way done for treatment 3. After samples kept at room temperature for 1 week, in a closed container, then quality of marinated fish fillet evaluated. The difference in weight of fish fillets marinated and premarinated measured. As a percentage of weight loss, weight of fillet decreased due to penetration of salt and acetic acid of vinegar. The percentage of weight loss was equal to percentage of water lost.
The higher percentage of water loss, lower quality of fillet, because quality of fish protein decreased.
pH: If pH goes from 7 to below 6, fillet quality will be better.
Ash percentage: The lower the ash percentage of marinated fillets was compared to ash content of dead fresh fillet. The nutritional value of the fish after marinating was decreased.
If fat is reduced, nutritional value of marinated fillet has decreased. The fat in fillet prevents penetration of salt into fillet.
The percentage of protein after 1 week of marinating was lower or higher than the dead fresh fish fillet.
To investigate the effect of different concentrations of acetic acid and salt on fillets in marinade, 4 quality factors should be measured:
1. Percentage of weight loss (percentage of water loss)
Initial fillet weight/marinated fillet weight after 1 week—initial fillet weight = (water loss).
This qualitative factor of percentage of water loss, was based on difference in weight of primary fillet with secondary fillet, which shows effect of different concentrations of salt and acetic acid on fillet and removal of water from fillet.
2. Measuring the percentage of moisture in fillets of treatments 1, 2, and 3 3. Fat measurement in treatment 1, 2, and 3 4. Ash measurement in treatments 1, 2, and 3
Five grams of fillets in an oven at 103°C for 1.5 h weighed until no water comes out of fillets. The moisture percentage in treatments was compared with moisture percentage in raw fillet.
Five grams of each sample placed in a dish, and after 3 h, ash content measured. In treatment 3, which percentage of salt was higher, percentage of ash was higher.
7- pH of fillet in treatments 1, 2, and 3:
Five grams of fillet weighed and mixed with 45 mL distilled water. The pH measured using a digital PH meter using a homogenizer. The pH of treatment 3, which had a higher percentage of acetic acid, will be lower, goes to acidic value, from 6 to 5.
5. Fifth standard method: Quality control of canned tuna fish
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The purpose of this stage was to determine percentage of nutritional compounds in canned tuna fillet and compare it with nutritional composition of dead fresh tuna, in order to know nutritional value of canned tuna during processing and after that until time expiration. According to reviews from articles, Hoover canned fish had 24% protein, 14% fat, and pH 5, and for fresh yellow fish, protein 22%, fat 16%, and pH was 5.
2- The heating the fish meat in cooking stage and sterilization in an autoclave led to denaturation of tuna meat protein, reason for this was reduction of protein content, and in addition, decreased percentage of fat, ash, and pH. If nutrients in canned tuna have decreased after 2 years, it can be concluded that canned fish has not been processed correctly.
First, the production date, expiration date, factory brand, manufacturer, factory name, and factory code checked. Then, the whole tuna fillet replaced into the dish. Then weight of the empty can measured. The net weight of the fish meat measured, and then the weight of the oil calculated. The protein, fat ash, pH, and moisture measured.
The weight of the fillet without the oil was 210.56 g. Brand name: Nature. The weight of the sample with container was 221.72 g. The weight of added oil was 11.16 g. Product code 4044. 112. Production date 2022. Expiration date 2024. The weight of a can of fillet without oil was 183.88 g. The weight of oil added to the can during processing (vegetable oil) was 20.83 g.
Quality Control of Canned Tuna With Passed Expired Date
Three reasons for canned food swelling: (1) physical swelling, (2) microbial swelling, and (3) chemical swelling.
It is due to difference between internal and external pressure of a can in autoclave. Microorganisms, to grow and to produce gas during 2 years of storage, and this gas causes swelling. It is due to effect of acids on the body of a can. Some of these gases dissolve in canned water and do not show swelling.
Determination of Macronutrients Content
Protein, moisture, fat, and ash content in processed dead fish samples were determined. Moisture content was determined by drying fish fillet samples at 105°C until constant weight. The protein content was measured by determining nitrogen (N) by the Kjeldahl method using a factor of 6.25. Soxhlet method was used to determine fat. The amount of ash was measured by the method of heating the samples in the furnace at 550°C for 4 h.
Determination of Crude Protein
A 10 g of sample was weighed and digested in the macro-Kjeldahl apparatus with concentrated sulfuric acid. The ammonia liberated from the resulting ammonium sulfate after adding sodium hydroxide was distilled into 1 M boric acid and then titrated with 0.1 M HCl. The nitrogen value was multiplied by 6.25 (protein factor) to obtain the value of the crude protein (AOAC, 2005).
Determination of Fat
The crude fat was extracted from 10 g of each sample using a solvent extraction apparatus (Soxhlet apparatus) with low boiling point petroleum ether. The importance of the lipid obtained after evaporating off the solvent from the extract gave the weight of the lipid present in the sample. 10
pH Measurement
Five grams of sample in 45 mL distilled water dissolved and then homogenized by homogenizer and then pH measured by a digital pH meter.
First, standard length and width of the fish was measured, after separation of its waste, fish fillet was measured, and then the fish fillet was divided into several groups.
The length of fish no. 1 was 39.5 cm. The width of the fish was 16.5 cm. The weight of fish no. 1 was 508.4 g. The weight of fish wastes no. 1 was 285.16 g. The weight of no. 1 fish fillet was 223.34 g. Percentage of fish fillet no. 1 was 42.38. Weight of fish fillet no. 1 was 303.96 g. Percentage of fish fillet no. 2 was 38.42. The length of fish no. 2 was 241 cm. The width of fish no. 2 was 217 cm. The weight of fish fillet no. 2 was 527.54 g. The weight of fish waste no. 2 was 303.96 g.
Statistical Analysis
The difference between the obtained values (mean ± standard deviation) was analyzed using one-way analysis of variance and using SPSS V. 18.
Results and Discussion
Macronutrients Content
The macronutrient contents in fish flesh samples treated with different processing ways were exposed in Figures 1 to 5. The moisture content in marinade T1 was significantly higher than those of marinade T2, T3, HTST, LTLT, salting, canning, and thawed samples (P ≤ .05). The protein content in samples processed with HTST way was significantly higher than that in others fish (P ≤ .05). Fat concentration was also significantly increased in all different salting processing methods (P ≤ .05), being uppermost in salted samples, followed by marinate T2 fish, and lower in marinate T1 fish. Finally, ash content was developed significantly in marinate T2 than in all other treatment groups and next in fish processed in salted 25% than in fresh and other samples (P ≤ .05).
Moisture percentage in dead fresh fish Carangoides armatus and different processes.
Ash percentage in dead fresh fish Carangoides armatus and different processes.
Fat percentage in dead fresh fish Carangoides armatus and different processes.
pH value in dead fresh fish Carangoides armatus and different processes.
Protein percentage in dead fresh fish Carangoides armatus and different processes.
Energy percentage in dead fresh fish Carangoides armatus and different processes.
The fat percentage in fish fillet processed by HTST, LTLT, and marinating methods found the lowest with a significant difference (P ≤ .05) compared to other processing methods. Therefore, these HTST, LTLT, and marinating processing methods seem more appropriate duo to the lower the processed fish fat, because of the less oxidation and destruction and therefore shelf life will be longer.
The protein percentage in fish fillet processed by HTST and LTLT methods found the highest with a significant difference (P ≤ .05) compared to salting and marinating methods, which indicates the superiority of these processing methods.
However, the percentage of energy value of fish fillets processed by LTLT and salting methods showed the highest with a significant difference (P ≤ .05) compared to other processed methods, which showed that the LTLT method with the lowest amount of fat and the highest amount of protein and energy found the best processing method.
Results showed that pH in marinade samples (6.93 and 7.4) was highest, while in other treatments, it decreased to 5.50, 6.48, 6.6, 5.57, 6.29, 6.4, and 6.80 (P < .05). There was significant difference between other treatments (P < .05). The decrease in pH value was due to the effect of acidic compounds in the marinade solution (Figure 4).
Proximate were major constituents, which had been proved for evaluating nutritional value of fish processed. With moisture highest values and lipid lowest, nutritional factors showed variable values in fishes analyzed. The fish examined belonged to high protein (3.12%-17.51%). The low ash, fat, high protein, and moisture content values obtained from proximate analysis agreed with other analysis carried out by earlier researchers such as Effiong and Mohammed, 6 Mumba and Jose, 3 and Abdullahi. 11
In general, there are significant impacts of processing methods on proximate composition of fish. Although it had no significant effect on protein, lipids, ash, and fish content. These results showed that different nutritional components of fish undergo different changes at high temperatures. 4
All processing methods are equally good because they can help increase shelf life of fish products, with exception of thawing methods, T1 marinade. These methods can keep fish products away from attack of spoilage microorganisms for some time.
In general, fish processing methods with high- and low-temperature treatments including freezing, canning, salting, and fermentation and various combinations of these give an attractive, fresh, and attractive shape to consumers and prolong shelf life of fish product. These processing methods have significant applications, techniques, and impact on chemical, physical, and nutritional composition of processed fish. Because heating, freezing, and exposure to high concentration of salt leads to chemical and physical changes. Finally, different quality can be obtained through these methods, hence subsequent impact on shelf life of processed fish are also different.12,13 Dried fish with 10% to 15% salt can effectively prevent fish spoilage, but may be a limiting factor for consumer acceptance. 14
Effect of Thawing
Proper time and temperature during thawing helps to achieve fresh products similar to unfrozen products. Through the thawing process, water may be reabsorbed by tissues and cells, which depends on the size of the ice crystal and its location in the tissue microstructure, the rate of thawing, the biochemical, and physiological state of the fish before freezing, and the water retention capacity of the muscles before freezing. If the freezing and thawing method is inappropriate, the final frozen product will lose its nutritional components and the possibility of losing its taste is high to the point where it is not accepted by consumers. 15
If fish is not stored properly, freezing causes protein accumulation and water loss after thawing, resulting in a tougher product. The water holding capacity of frozen fish can also be affected during protein denaturation. The water in protein can exist in bound form, which is highly dependent on physicochemical properties of protein, and in nonbound form trapped inside protein matrix. High water holding capacity leads to low protein accumulation and reduction drip loss during thawing. This indicates that texture of frozen muscle product does not cause cracking, which cannot lose more water from muscle, and finally, a similar texture to fresh product can be obtained, which meets consumer's preferences. 14
Slow freezing method for 1 week, it has adverse impact on myofibril proteins. In normal myofibrillar state, fish fillets fold over each other, so that water molecules are locked inside and connected to them. In this case, fish protein quality is normal, but slow freezing separates these strands and water comes out of them. The first cause of denaturation is hydrophobic freezing, second reason was ability to exist water from fillet after leaving freezing state, third reason for changing viscosity of extracted water is ability to extract water. Myofibrillar and sarcoplasmic proteins are more sensitive to solubility due to their strong solubility in 0.5 to 1 M salt solution at neutral pH 7. Because their viscosity decreases in frozen fish proteins, enzymes is used to determine quality of fresh and frozen fish. 4
Salting is a traditional way of processing fish in many countries. Salt is often used to dry fish to remove water from fish body and reduce water activity (aw) in fish meat to prevent the growth of spoilage bacteria. If fish is placed in a brine solution stronger than fish tissue, it will continue to draw water from brine solution into fish flesh. As water enters the fillet from the brine, water also enters the brine from the fillet. 15
Macronutrients Content
All these processing methods use different techniques and have different applications, due to freezing, heating, oxidation, and exposure to high concentrations of salt that cause physical and chemical changes, significantly affecting organoleptic, physical, chemical, and nutritional characteristics of fish. 5 The results of present study showed that long-term high- and low-temperature cooking processing methods increased amount of fat, protein, and ash and decreased moisture in fresh dead C armatus meat. Similar results reported for proximate composition of Litopenaeus vannamei from Indramayu. 16
The results of research work 15 showed that the best quality of frozen fish found between 7 and 14 days of freezing and the quality of fish was best in fresh item. Freezing from the 14 days period did not have any effect on the amount of protein because its amount was constant. The amount of energy decreased from the 14 days freezing period to that of the previous period and fresh fish. Recommendation was eating fresh fish which is most benefit for human health.
Research work 6 showed that moisture content in fresh sample was affected brining process was decreased respectively (84.72% to 33.99%) with significant difference (P < .05), while protein, fat, ash, and energy values were affected, brining process were increased.
The limitations of this research included the short fishing season and the rapid spoilage of fish and the problems of different fish processing methods. In future research prospects, fish processing industries and fishermen must know the beneficial and optimal processing conditions that could result in the production of nutritionally superior products, beyond satisfying the consumer's organoleptic appetite. In order to prevent the effects of processing on nutritional and physicochemical composition in fish, it is necessary to use and adopt appropriate as well as affordable processing techniques for processing fish and fish products.
Conclusion
The results of this experiment showed that C armatus fresh dead fish contains a high concentration of macronutrients, protein and a low concentration of fat, although it can be with high concentrations of ω3 and ω6 fatty acids. The different processing methods investigated had a significant effect on the nutrient content and composition of fish meat. Therefore, canning and marinating is considered the best way to treat fish, as fish has a high nutritional value that is beneficial when consumed as part of a regular diet to improve health and nutrition. Gish fish may be an alternative source of protein and fat for the local community. The high nutrient content of dead fresh C armatus and the methods of thawing in the oven and HTST in the autoclave make this fish as a nutrient-rich food for preventing stunting.
Footnotes
Acknowledgment
The authors would like to thank the Behbahan Khatam Alanbia University of Technology.
Data Availability
All data included in this study are available upon request by contacting the corresponding author.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethic Approval
Understanding the ethical approval is essential, I would like to mention that we as researchers at our institution do not work on alive animals, for example, alive fish. We always buy captured fish (Dead fish) from Behbahan fish market to analyze and process for our research. Therefore, the approval evidence from the ethics committee for our research is not applicable.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Behbahan Khatam Alanbia University of Technology.
Statement of Human and Animal Rights
There is no human subjects in this article, so this statement is not applicable.
Statement of Informed Consent
Written informed consent obtained from all participants.