Effect of Artificial Formalin Treatment on Fish Muscles Textural Quality and Different Formalin Lessening Techniques from Muscles

doi:10.21203/rs.3.rs-1702878/v1

Many countries have reported formalin contamination for extending the shelf life of fish. As a reason, the current study was performed to understand the influence of three different concentrations of formalin on fish muscles quality and thereafter, some formalin lessening techniques were also assessed. The experimental fish treated with 1%, 5% & 10% formalin solutions for 5 min and as a result, the residual content enhanced to almost 7, 11 and 15 times respectively compared to fresh fish. The solubility and water holding capacity of muscle protein were found to be decreased significantly with increase in formalin concentration. The hardness of fish muscles increased with increase in formalin concentration and the value increased by 80% in the fish treated with 10% formalin. Similarly, the chewiness of muscles increased by 16–121% compared to untreated fish. Moreover, the total bacterial load on fish muscles also reduced markedly. In order to reduce formalin content in fish, formalin-treated fish was washed in running tap water, saline water and tepid water separately up to 30 minutes and thereby the content got reduced to the acceptable label in 20 min, 20 min, and 10 min respectively. Similarly, treated fish was fried for five minutes and content was reduced to acceptable limits. From the results, it was observed that formalin treatment not only reduced bacterial load but also impacted the texture of the fish muscles, creating the impression that the fish is fresh. Tepid water washing and frying process were effective in reducing formalin content in fish muscles.

Fish

Formalin

Contaminants

Quality

Water washing

Food safety

The maintenance of top quality of fresh fish is a challenging task, as it is a highly spoilable food item. Though, there are several methods of fish preservation namely chilling, freezing, canning and smoking are in vogue. Each of these methods has got its own merits and demerits. Hence, traders keep on searching some short cuts to enhance the shelf life of the fish without spending much money and labor, so that, they can get maximum benefits. Driven by this aim, they started using some uncalled chemicals such as formalin, which is regarded as Class I carcinogen by the “International Agency for Research on Cancer”. Hoque et al., (2016) proposed that bio-chemical interactions between added formalin and fish muscles may produce noxious products and exert residual ill effects to the consumer. Yeasmin et al., (2010) studied the effect of formalin treatment to rohu during ice storage, and revealed an enhanced denaturation of fish protein compared to untreated fish. Further, they established a lower solubility and gelling ability of fish treated with formalin during low temperature storage.

It is a well established fact that formalin exerts a carcinogenic effect and it is well highlighted, but its effect on muscles quality has not been studied in detail. Hoque et al. (2018) treated the fish with varied concentration of formalin and revealed that the content gets increased as many as thirty times with increasing concentrations (0.5 to 4% @ 5 min each). In another study, formalin treated ice stored fish found to have reduced protein solubility, gel-forming ability (Yeasmin et al. 2010. The same fish detected low non protein nitrogen content it the muscle compared to untreated fish due to low bacterial load ((Jinadasa et al. 2022; Yeasmin et al. 2010). Further, once the formalin is added to fish artificially, it is very difficult to remove completely. However, Jinadasa et al. (2022) suggested that washing fish with the tap water and cooking to 70 ◦C (core temperature ) are the best method to reduce health risks from the formalin adulteration. Kundu et al. (2020) detected high formalin content in rohu (19.66 mg/kg) and catla fish (23.3 mg/kg) that got reduced gradually due to boiling for five minutes. Further, it is proven that frying also found to be effective in order to reduce formalin in rohu fish. A synonymous study conducted on five fish species in Bangladesh, wherein they studied effects of pre-treatment (such as dipped in 1h water, dipped in 1h 5% brine) and cooking effects (boiling, frying etc.) on formaldehyde content in fresh fishes (9.4–32.6 mg/kg), and reveled a significant diminish in the formaldehyde content due to all the pretreatments and cooking methods (Bhowmik et al. 2020). Similarly, a study conducted in Malaysia also established a marginal reduction in formalin due to boiling and frying in fish (Aminah et al., 2013). However, contrasting to abovementioned studies, a study on the squid reported to have increased the formalin content due to boiling, especially at “80°C and 100°C”. However, they could not explain any reason behind this increase in the content. So, there is no comprehensive study, wherein effects of artificially formalin treatments with varying concentrations on muscle texture, functionality and its reduction techniques have been studied. Though, in our previous study (Mehta et al., 2021), we have studied the effect of 10% formalin on the muscle quality. Therefore, in this study, Effect of varying concentrations of artificial formalin treatment on catla fish muscle textural quality and different formalin mitigation techniques was investigated.

Fish collection and formalin treatment

The live Catla fish (Catla catla) with an average length and weight of 30.56 ± 3.2 cm and 1.2 ± 0.2 kg respectively were purchased from the market and were transported to the laboratory of the Department of Fish Processing Technology and Engineering. After sacrificing the fishes were thoroughly cleaned and are subjected to different formalin treatments by dipping in 1%, 5 % & 10 % formalin solution for 5 min. The different concentration formalin solutions were prepared using commercial 37-40 % formaldehyde. The treated fish were stored at refrigerated temperature for 24 h by wrapping them in polythene packaging material and the analysis was performed.

Analysis of formalin content

The spectrophotometric method with some modification (Benjakul et al., 2003) using Nash’s reagent was applied to determine the formalin content (mg/kg) in fish. Nash’s reagent (Nash, 1953) was prepared by mixing ammonium acetate (15 g), acetyl acetone (0.3 mL), acetic acid (0.2 mL) and the volume were brought to 100 mL by adding water. Nash’s reagent is a light sensitive and was kept in a dark-glass bottle covered with aluminum foil. A 0.1 N NaOH and 0.1 N HCl were used to adjust the pH of the distillate to be nearly 7.0.

The fish samples were cut into small pieces. A finely chopped fish (30 g) was added to 60 mL of 6% TCA solution and homogenized uniformly using a mortar and pestle. The mixture was filtered through a Whatman No. 1 filter paper, the filtrate (5 mL) was collected and pH of the filtrate was adjusted to around 7.0 with NaOH or HCl. The extract was then stored in a deep freezer for 30 min. The Nash’s reagent (2 mL) was added to the extract and heated in a water bath at 60°C for 30 min. The absorbance of the extract was measured at 415 nm immediately using a UV-Vis spectrophotometer. The standard curve was prepared using a 10-ppm standard formalin stock solution.

pH

A 5 g quantity of fish meat was thoroughly mixed in 45 mL of distilled water, and the pH of the resulting slurry was determined with a pH meter (Labman LMMP-30). The pH meter was calibrated with a standard buffer solution of pH 4.2 and 9.2 preceding measuring the pH of the sample.

Protein solubility

The solubility of protein extracted from fresh and formalin treated fish was estimated using phosphate buffer (“15.6 mM Na₂HPO₄, 3.5 mM KH₂PO₄, containing 1.1 M Potassium chloride”e, pH 7.5). The fish muscles were homogenized in phosphate buffer at 9000 rpm for 2 min using laboratory homogenizer and then centrifugation was performed (9000 × g) at 4 ºC @ 15 min. The pellet homogenate before centrifugation and the supernatant obtained after the centrifugation were analysed for the amount of soluble protein (Robinson and Hodse, 1940). The calculation was performed using following formulae,

Protein solubility = (amount of soluble protein before centrifugation/ amount of soluble protein after centrifugation) × 100

Water holding capacity (WHC)

The WHC for fish samples were measured according to the method of Jauregui et al. (1981) with slight modification. Meat sample of 5 g was weighed and put between two layers of filter paper (Whatman No. 1). Sample was placed at the bottom of 50 mL centrifuge tubes and centrifuged at 5000 × g for 10 min at 4 °C. Immediately after centrifugation, the sample was removed and reweighed. WHC was calculated as follows.

WHC (%) = (W₁-W₂)/W₁× 100

Where, “W₁^” = weight before centrifugation (g) and

“W₂^“= the weight after centrifugation. The reported WHC value was arrived after average of three replicates.

“Texture Profile Analysis” (TPA)

The TPA was performed for fresh and formalin-treated fish fillets using Texture Analyser (TA. XT2i Stable Micro System, Surrey, England) with a 75 mm compression plate as a probe with 50 kg load cell. The dimensions of fish fillets used for test was 2×2×2 cm. The hardness, cohesiveness, springiness, gumminess and chewiness were recorded.

‘Total plate count’ (TPC)

TPC was determined for fresh and formalin treated samples by pour plate technique. Exactly 10 g of fish meat was taken and macerated in 90 mL 0.9% saline and the serial dilutions were prepared. 1mL of sample from each dilution was mixed carefully to molten media (TPC agar) and poured onto sterilized Petri dishes. After solidification, the plates were incubated at 37± 1ºC for 24 h. Colonies obtained were enumerated manually.

Different water washing schemes and frying of fish

The fish treated with 10 % formalin solution was used for this experiment. The fish was washed in the running tap water with the flow rate of 2 L/min. The sample was drawn after 5, 10, 15, 20, 25, 30 and 35 minutes of washing in running tap water and formalin content was determined. Similar scheme of washing was followed using stagnant lukewarm water (Temperature 50-55 °C) and 5 % saline water. For frying, 10 % formalin treated fish samples was cut into fillets of standard dimensions (3.5 cm length × 2.5 cm width) and the same were fried at 180 ^°C for 5 minutes in soybean refined oil in a automatic fryer. Thereafter formalin content was determined in the fried fish fillets.

‘Statistical analysis’

The data obtained were analyzed by one way analysis of variance (ANOVA) using SPSS 16.0 software.

Effect of formalin treatments on residual formalin content of fish

In the preset experiment, the initial formalin content in the untreated (fresh) Catla fish was 1.66 mg/kg (Fig 1). More or less similar amount of formalin contents (1.9-2.11 mg/kg) were reported in two freshwater cat fishes (Kundu et al., 2020). In general, the quantity of naturally formed formalin during post mortem is much lower in freshwater fish compared to marine fish (Jaman, 2013) due to higher amount of TMAO in marine fish. In present study, after treatment of the experimental fish with 1%, 5% & 10 % formalin solutions for 5 min, the residual content enhanced to 12.75, 19.49 and 26.24 mg/kg fish (Fig. 1). Significant (p<0.05) difference in formalin contents were observed among different treatments. Similar increment in the residual formalin was documented when the fish was treated with 5% formalin (Sanyal et al., 2016). Further, Hoque et al. (2018), reported that regardless of the fish species or analytical methodologies utilized when fish is treated with increasing concentration of formalin and exposure time indicated higher absorption of formaldehydein fish muscles. This increment in the residual formalin in the fish muscles due to formaldehyde combines with unsaturated lipids along with double bonds and forms a complex compound containing free carbonyl group which probably originates from formaldehyde (Castell and Smit, 1972). In addition to this, aldehyde compound may be easily bonded to the amino acids in a small amount (Rahmadhani et al., 2017).

Effect of formalin treatment on pH of fish muscle

The pH of the fresh fish was observed to be 6.48, indicating the quality as good. On treating withincreasing concentration of formalin,the value decreased accordingly (Table 1).A non-significant (p>0.05) reduction was observed in the samples treated with 1 & 5 % formalin concentrations. However, in the case of fish treated with 10 % formalin, the pH value (6.17) reduced significantly (p<0.05) (Table 1). This decrement in the pH of the fish muscle might be due to the acidic pH of the formaldehyde (Burke, 1933) and the formation of post mortem lactic acid. The findings of the experiment corroborated with Sanyal et al.,(2016) who reported that the pH of fresh fish (control) was 6.72and that reduced to 6.59 when treated with 5% formalin. Similarly, Yeasmin et al. (2016) observed a lower pH value in 5 % treated rohu fish in comparison with the control, where the high pH is due to the production of alkaline bacterial metabolites coinciding with high aerobic plate counts (APC).

Effect of formalin treatment on water holding capacity (WHC)

In the present study, WHC of the untreated fresh fish muscle was 69.67 % that reduced significantly (p<0.05) by 3.78 %, 5.02% and 15.26% for fish treated with 1%, 5% & 10 % formalin respectively (Table 1) compared to fresh samples. This reduction in water holding capacity may be due to the strong reactivity of the formaldehyde with myofibrillar protein resulted in the formation of crosslinks and displacing the water causing the toughening of the flesh and thereby, a reduction in water holding capacity (Haard and Simpson, 2000) gave rise to lower acceptability and functionality (Li et al., 2007). This may be confirmed with the increment in the concentration of the formalin might be resulting in strong water displacement causing subsequent decrement in the WHC.

Effect of formalin treatment on protein solubility of fish muscle

The protein solubility of untreated fish in the present study was found to be 87.34 % that reduced significantly (<0.05) in fish samples treated with different formalin concentrated solution (Table 2). A significantly reduced to 82.54%, 75.93 % 69.33% with increasing formalin concentration. The reduction in the protein solubility can be due to the protein denaturation causing the aggregation as effected by the formalin treatment (Morisasa et al., 2020). The marked reduction in the pH value also found to be concurrent with the protein solubility and this might be due to shifting of isoelectric pH of the muscle protein. A similar reduction in protein solubility was reported for the protein extracted from rohu fish treated with 5 % formalin solution as compared to fresh rohu (Yeasmin et al., 2010). Initial myofibrillar protein solubility of formalin treated fish was 58% which was significantly lower in compared to fresh fish (86.70%) (Yeasmin et al., 2010). Yeasmin et al., 2010 suggested that the formalin contamination results a marked denaturation of the muscle protein causes lower protein solubility.

Effect of formalin treatment on muscle texture profile

In the rigor or pre-rigor stage,fish remains stiffened leading to flesh hardness, which is one of the criteria to assess the freshness of the fish.Furthermore, the flesh gets softer shortly after the rigor mortis is resolved. Therefore, to understand the influence of formalin treatment on fish flesh hardness compression test was performed using a texture analyzer. In the present study, the fresh fillets had a hardness of 193.63 N. Hardness values of the fillets increased by 6.07 %, 46.86 %, and 65.11 % in fish treated with 1%, 5%, and 10% formalin, respectively.(Table 1). The results indicated that an increase in formalin concentration resulted in a considerable (P<0.05) increase in hardness value, residual formalin content and decrease in the WHC (Fig. 1, Table 1). The findings of the investigation were corroborated with Yeasmin et al. (2010), who reported that after dipping Rohu Fish (Labeo rohita) in 5% formalin for 5 minutes, the muscle texture became slightly firmer as compared to untreated fish. Similar results were observed by Morisasa et al.(2020) when the fish sample was soaked in 1000 ppm formaldehyde (FA).The reason for the increase in the hardness could be due to reduced water holding capacity and dehydration of muscles.In addition, the protein aggregation stimulatedby formalin treatment is also one of the important factors for muscle stiffening (Morisasaet al., 2020).According to Sotelo et al. (1995), formaldehyde accumulates during poor storage conditions of fish and reacts with protein, causing protein denaturing and muscle toughness. In the current investigation, the value of WHC and solubility was found to have reduced significantly as a result, the hardness value might have increased. Consumers are deluded by the increased hardness of formalin-treated fish muscles since fresh fish or fish in rigor have a firm texture, which is an indication of prime quality. As a result consumers are unable to make the difference between the contaminated and fresh fish.

Likewise, the chewiness value of untreated fish was 20.65 N, but after treatment with 1%, 5%, and 10% formalin, it increased by 16, 74, and 121 %, respectively, as compared to the chewiness value of fresh fish. Since chewiness is the consequence of gumminess and springiness, the values of these parameters were found to increase as the formalin concentration increased. The increase in the chewiness indicated that fish muscle would be firm as good as or better than fresh fish. With an increase in formalin concentration, the values of springiness, cohesiveness, and gumminess increased as well, however, adhesiveness declined. Fish containing formaldehyde between 10 - 20 mg/kg may not be considered palatable as a human food (Yasuhara and Shibamoto, 1995).

In rigor or pre-rigor stage, fish remains stiffened and flesh hardness is one of the criteria to assess the freshness of the fish. Further, soon after the resolution of the rigor mortis, the fish flesh becomes softer. Therefore, to understand the effect of formalin treatment on fish flesh hardness, a compression test was performed using a texture analyser. In the present study, the hardness of the fresh fish fillets was 193.63 N. Similarly, the hardness values for fish treated with 1%, 5% & 10 % formalin increased by 6.07, 46.86 and 65.11 % respectively. Similarly, the hardness values for fish treated with 1%, 5% & 10 % formalin increased by 6.07, 46.86 and 65.11 % respectively. WHC decreased with increase in formalin concentration (Fig. 1, Table 1). The result obtained in our study were corroborated with Yeasmin et al. (2010) wherein they found that the muscle texture of rohu Fish (Labeo rohita) became slightly harder after dipping in formalin solution (5%) of for 5 minutes as compared to untreated fish. Similarly, Morisasa et al. (2020) measured the hardness of fish sample that was soaked with 1000 ppm formaldehyde (FA) reported to have higher values of hardness compared to untreated fish sample. The reason for the increase in the hardness could be due to reduced water holding capacity and dehydration of muscles. In addition, the protein aggregation stimulated by formalin treatment is also one of the important factors for muscle stiffening (Morisasa et al., 2020). Formaldehyde accumulates during improper storage of fish reacts with protein and this result in protein denaturation and toughness in the muscle (Sotelo et al., 1995). In the present study, the value of WHC and solubility found to have reduced significantly as a result, the hardness value might have increased. This increased hardness of formalin treated fish muscles actually deceives the consumers as the fresh fish or fish during rigor also likely to have firm texture that is basically an indication of prime quality. Hence, consumers believe that the fish is fresh and texture seems to be as good as fresh fish and poor consumers are unable to make the difference between the contaminated and fresh fish.

Further, the value of the chewiness of untreated fish was 20.65 N, after treatment with 1%, 5% & 10 % formalin that increased by 16, 74 and 121 % compared to fresh fish chewiness value. Chewiness is the product of gumminess and springiness, therefore values of these parameters also found to be increased with increase in the formalin concentration. The increase in the chewiness indicated that fish muscle would be firm as good as or better than fresh fish. The values of springiness, cohesiveness & gumminess also increased, whereas adhesiveness recorded a decreasing trend with increase in formalin concentration.

Effect of formalin on the total plate count (TPC)

In the present investigation, the initial microbial load on fish samples was 5.27 log₁₀ CFU/g (Table 1) indicatingthe good quality of the fish. The microbial load for the good quality fish was reported to be in the range of 2 to 6 log₁₀CFU/g (Huss, 1995). This load varies from species to species depending on the place of harvest, condition, and temperature of post-harvest operations (Perigreen et al., 1987).Further, in the present study, when fish samples were treated with 1%, 5% and 10% formalin, the TPC value significantly (<0.05) decreased to 4.98, 4.7 & 4.6 log₁₀ CFU/g, respectively. The result indicated that with increasing formalin concentration, bacterial load decreased significantly (p<0.05) which corroborated with the results of Sanyal et al. (2016) in mrigal and Yeasmin et al. (2013)in rohu fish when treated with 5 % formalin. This decrease in the bacterial load on fish might be related to the bacteriostatic/bactericidal property of formalin itself. Mezbah et al. (2014) established that formaldehyde acts as an antibacterial and antifungal agent; therefore, it may inhibit microbial infestation on the fish skin or in the fish fillet, and delay the spoilage of formalin treated fish samples. Neeley (1963) reported that bacterial cell division was inhibited in the presence of 20 to 50 μg / mL (equal to 2–5 %) of formaldehyde.

Effect of different washing methods and frying on residual formalin in fish muscle

The fish treated was treated with 10 % formalin (dipping time: 5 min) were employed to develop an appropriate and inexpensive remedial approach for the removal of the added formalin from fish muscle. The residual formalin content of fish samples dipped in 10% formalin was 26.24±0.08 mg/kg. For various lengths of time, the aforementioned treated fish samples were washed in running tap water, tepid water, and saline water (Table 2). From the results represented in Table 2 and Fig.2, it was observed the residual formalin content reduced significantly in running water, tepid water and saline water as the exposure time increased. Frying the treated fish muscle for 5 min lowered the residual content to 4.04 mg/kg. The scientific panel of food regulators i.e. The Food Safety and Standard Authority of India (FSSAI) fixed an Adhoc maximum limit for formalin content with 4 mg/kg for freshwater fish and 100mg/kg for brackish and marine water fish (FSSAI, 2019). Similarly, many countries have set the maximum limit of formaldehyde/formalin for fish and fishery products such as the United States Environmental protection agency (2 mg/kg) (Xuang et al. 2009), Malaysian food regulation act (1885) (5 mg/kg formaldehyde), the Ministry of Agriculture of China and the Italian ministry of health (10 mg/kg) whereas Yasuhara and Shibamoto (1995) has fixed the maximum limit of 10-20 mg/kg.

Considering Indian regulation (4mg/kg), washing fish muscles in running water (20 min), tepid water (15 min) and saline water (20 min) lowered the values to 2.12, 0.78 and 3.51 mg/kg respectively. As a result, it was apparent that tepid water washing, especially compared to saline water or running tap water is more successful in removing residual formalin from fish muscles. It's worth noting that formalin is water-soluble and volatile, which indicates it may be washed away or/evaporated from the fish's body with tap water, warm water, or saline water. The higher reduction in warm water is possibly due to the warm water heat causing enhanced evaporation of formalin from the muscles due to its volatile nature. Hoque et al. (2016) observed a drastic decrease in the formaldehyde in cooked fish sample (0.98 to 5.93 mg/kg) compared to fresh fish (5.80 to 21.80 mg/kg).Contrastingly, Yeasmin et al. (2013) detected formalin in samples dipped into 10–15% formalin solution for 5 minutes after 40 minutes of washing using tap water.

In the present study, formalin-treated fish samples were fried at 180 ^°C for 5 minutes to and formalin content was determined before and after frying. The result showed that frying effectively reduced the formalin content from 26.24±0.08 mg/kg to 4.04±0.05 mg/kg. This reduction might be due to the escape of the analytes (volatile nature) during frying process. Through the ingestion of the formalin contaminated fish causes inflammation of the linings of the mouth, throat, and gastrointestinal tract and eventual ulceration and necrosis of the mucous lining of the gastrointestinal tract in human beings (Owen et al., 1990; Sindhu and Sidhu, 1999; Yanagawa et al., 2007).In the case of chronic exposure, formaldehyde has the potential to cause cancer and a variety of unknown pathology (Wippermann et al., 1999; Vaughan et al., 2000; Hildesheim et al., 2001). Thus, if humans consume high-formaldehyde fish for an extended period of time, they may experience a variety of biochemical and pathological abnormalities, with unknown health consequences.

Formalin treatment not only reduced bacterial load but also alter the texture of fish muscles that deceiving the consumers as if it is fresh. This study concluded, the formalin treatment caused fish muscle hardening that deceives the consumers in identifying fresh fish along with enhanced shelf life due to reduction in bacterial load. Further, warm water washing for 10 min. and frying for 5 min. may reduce the formalin from fish muscles effectively and eliminate the deleterious effect for formalin.

Acknowledgements

The authors are thankful to Dean, College of Fisheries, Central Agricultural University (Imphal), Lembucherra , India, for providing the laboratory facilities to carry out the work.

Authors’ contributions

“All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Naresh K. Mehta, Durba Pal, Ranendra. K. Majumdar and M. Bhargavi Priyadarshini . The first draft of the manuscript was written by Naresh K. Mehta and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.”

Data availability –Data set generated during research are available from the corresponding author on reasonable request.

Funding

Authors are also greatly thankful for funding support received from the Department of Biotechnology, Govt. of India under the project- Centre of Excellence- DBT-NER/LIVS/05/ 2011 Phase II.

Ethics approval - Not applicable.

consent to participate- Not applicable.

Consent for publication- Not applicable.

Competing Interests – “The authors have no relevant financial or non-financial interests to disclose.”

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Table 1. Effect of formalin treatment on fish quality parameters

Parameters	Fresh Fish	Fish treated with 1% formalin	Fish treated with 5% formalin	Fish treated with 10% formalin
Formalin content(mg/kg)	1.66±0.04^a	12.75±0.14^b	19.49±0.29^c	26.24±0.08^d
pH	6.48±0.03^a	6.42±0.02^a	6.33±0.03^a	6.17±0.04^b
WHC (%)	69.67±1.51^a	67.13±0.46^ab	66.17±1.53^b	59.04±1.28^c
Protein solubility(%)	87.34±1.98^a	82.54±0.29^a	75.93±1.25^b	69.33±4.34^c
TPC(log₁₀ cfu/g)	5.27±0.14^a	4.98±0.06^b	4.70±0.03^c	4.6±0.05^c
Hardness (N)	193.63±24.42^a	205.39±5.07^ab	284.38±54.63^bc	319.71±12.52^c
Adhesiveness(N-sec)	-0.25±0.09^a	-0.52±0.46	-0.68±0.31	-0.77±0.30^b
Springiness	0.45 ± 0.09	0.47 ± 0.07	0.455± 0.06	0.51± 0.02
Cohesiveness	0.23 ± 0.00	0.245 ± 0.02	0.267 ± 0.02	0.28 ± 0.01
Gumminess(N)	45.15 ± 4.63^a	50.31 ± 5.50^a	76.69 ± 21.07^bc	89.65± 3.79^c
Chewiness(N)	20.65 ± 9.58^a	23.94 ± 6.56^a	36.08 ± 15.34^a	45.70 ± 2.47^a

Value are means ± SD, n=3, p< 0.05, value in the same row bearing unlike letters differ significantly.

Table 2. Effect of different washing methods and frying on formalin reduction in fish muscles treated with 10 % formalin.

	Formalin content (mg/kg fish)
Time (Minutes)	Running water	Warm water	Saline water washing	Frying
0	26.24±0.08	26.24±0.08	26.24±0.08	26.24±0.08
5	24.07±0.08	20.37±0.08	23.83±0.01	4.04±0.05
10	15.5±0.01	4.34±0.01	18.68±0.01
15	4.35±0.01	0.78±0.01	7.88±0.01
20	2.12±0.01	0.68±0.01	3.51±0.02
25	2.08±0.01	0.64±0.01	3.22±0.01
30	2.02±0.01	Not detected	3±0.03
35	0.88±0.01	-	-

Value are means ± SD, n=3.

Effect of Artificial Formalin Treatment on Fish Muscles Textural Quality and Different Formalin Lessening Techniques from Muscles

Status:

Version 1

Abstract

Figures

Introduction

Material And Methods

Results & Discussion

Conclusion

Declarations

References

Tables

Status:

Version 1