Alex. J. Fd. Sci. & Technol. Vol. 15, No. 1, pp. 35-48, 2018

Quality Assessment of Nile Tilapia and Grey Mullet Fish Collected from Different Local Markets in City,

Saadia, M. H. Mohamed, Abdel-Nabey, A. A., Khalil, M. K. M. & Abo Samaha, O. R. Food Science and Technology Dept., Fac. of Agric., Alexandria University, El-, 21454, Alexandria, Egypt Received: 14 March, 2018 Revised: 7 May, 2018 Accepted: 13 May, 2018

ABSTRACT This study was conducted to determine quality parameters of Nile tilapia (Oreochromis niloticus) and grey mullet (Mugil cephalus) which were collected from different local markets in Alexandria city, Egypt during 2015. Accord- ing to the overall sensory scores, the Nile tilapia and mullet samples collected from the different local markets could be classified into three categories of quality grade as follows: High quality grade (score between 8 to 10), acceptable grade (score between 5 to 7.9) and unacceptable grade (less than 5). The TVB-N values in the different samples were below the maximum value of 30 mg N/100g flesh (upper limit according to E. O. S. Q. C., 2005, ES: 3494). The TMA-N value of Nile tilapia and grey mullet collected from the different markets were within the recommended standard limits for acceptability. The pH values of Nile tilapia varied from 7.01 to 7.38. The data obtained showed significant differences (P< 0.05) among the samples. Further, Hanuvil market samples had the highest value of pH, while samples collected from El Wardian market had the lowest value of pH, with no significant differences between El Wardian, Alqsy and Bab Omar Pasha market samples. It was found that the pH values of grey mullet samples ranged from 6.74 to 7.18. Hanuvil samples followed by El samples were recorded to have the highest value of pH with no significant difference between them. On the other hand, Bakkous samples followed by Zananiri samples showed the lowest value of pH with no significant difference between them. The results indicated that the psychrophilic bacterial count of Nile tilapia and grey mullet collected from differ- ent markets were higher than mesophilic bacterial count. All Nile tilapia and grey mullet samples had high quality considering that the microbiological upper limit for fresh fish proposed by E. O. S. Q. C. (2005, ES: 3494) not exceed 106 CFU/flesh. Key words: Nile tilapia, grey mullet, quality, sensory evaluation, bacteriological evaluation, TNB-N, TMA, pH.

INTRODUCTION A recent value chain analysis of the industry re- Nowadays, there is an increasing demand vealed that the farmed fish value chain in Egypt is on fish which act as an important source of food mainly based on the production of Tilapia with Mul- around the world (Silva et al., 2011). The share let; the first and second most important species on of fisheries production used for direct human con- private fish farms. Other species of fish such as carp sumption increased from about 70 % in the 1980s and catfish are farmed in small quantities (Eltholth to more than 85 % in 2012 (FAO, 2014). et al., 2015). Tilapia and Mullets are the most important fish Egypt has one of the world’s largest aquacul- species for mono and polyculture in Egypt. Nile tila- ture sectors which makes a significant contribution pia (Oreochromis niloticus) constitutes about 70% of to income, employment creation and food security. the Nile and lakes catch. They are important for their Animal source foods provide important sources of palatability, high nutritive value, reasonable price, energy, micro and macro nutrients, but are com- high growth rate, reproduction and tolerance to ad- monly associated with food borne diseases. Live- verse water quality (Balarian, 1979 & Ishak, 1980). stock and fish value chains support the livelihoods of millions of rural and urban poor, for whom they Fish is one of the most highly perishable food can act as pathways out of poverty (ILRI, 2011). products. During handling and storage quality dete- rioration of fresh fish rapidly occurs and limits the

35 Vol. 15, No. 1, pp. 35-48, 2018 Alex. J. Fd. Sci. & Technol. shelf life of the product. Most of the methods that the staff members of the Department of Food Sci- have been used to estimate the quality of fresh fish ence and Technology, Faculty of Agriculture, Al- measure or evaluate parameters that change, disap- exandria University. The organoleptic assessment pear or formed during deterioration of fish. These of raw tilapia and mullet were made according to methods may be divided into several groups such as the scale described by Barile et al. (1985). This bacteriological and chemical methods (Huss, 1995). scale ranged from zero (extremely unacceptable) to Methods for evaluating freshness and quality 10 (highly acceptable) for the following character- of different marine species are based on measure- istics: acceptability, eye, pupil gills, body surface ments of post mortem changes associated with sen- (appearance), odour, texture, flesh condition, vis- sory, chemical, physical changes and bacteriologi- cera and belly wall. cal growth (Ocaño-Higuera et al., 2011). Sensory evaluation of steamed cooked tilapia There is little information regarding the qual- and mullet samples was applied after steaming in ity assessment of Nile tilapia and grey mullet from lidded aluminum pan for 10 min. The panelists different local markets in Egypt. Therefore, the were asked to score the organoleptic properties of present study was undertaken to evaluate quality the sample by giving scores ranged between 0 to 10 and freshness of Nile tilapia and grey mullet using as described by Barile et al. (1985). sensorial, chemical and bacteriological attributes. Total volatile basic-nitrogen (TVB -N) MATERIALS AND METHODS Fish extracts for determination of TVB-N were prepared by homogenizing 10 g fish sample with 90 Materials ml 7.5% (w/v) aqueous trichloroacetic acid (TCA) A total of 15 different samples of fish Oreo( - solution using a laboratory homogenizer for 1 min chromis niloticus & Mugil cephalus) were collect- at high speed. The homogenate was centrifuged at ed from different local markets in Alexandria city, 1409×g for 5 min and the supernatant was filtered Egypt during 2015 (Table 1). through Whatman No. 1 filter paper. The TVB -N were measured by steam- distillation of the TCA The edible portion of the meat from each -fish extract, using the method of Malle &Tao sample was removed, homogenized using blender (1987). Twenty-five ml of the filtrate were added to (Braun type: 4262). a Kjeldahl- type distillation tube, followed by 5 ml Table 1: Local markets in Alexandria city of 10% (w/v) aqueous NaOH solution. Steam distil- lation was performed using a vertical steam distilla- The region (district) Market name tion unit and the distillate was received into a beak- Montazah district El Maamoura market er containing 15 ml of 4% (w/v) aqueous boric acid market and 0.04 ml of methyl red and bromocresol green Derbala market indicator solution up to a final volume of 50 ml. The East Alexandria district Bakkous market titration was allowed to run against aqueous 0.05 M Zananiri market Alqsy market sulphuric acid solution. The results were expressed as mg nitrogen per 100g fish sample. The center of Alexandria Shedia market district Gheat Elsaaeidy market Trimethylamine (TMA) Zine Elabidine market Trimethylamine (TMA) was determined in West Alexandria district El Wardian market one run with the TVB-N according to the method Bab Omar pasha market described by AMC (1979). The nitrogen content El Maydan market of these volatile bases which did not react with for- El Amreya district Hanuvil market maldehyde was calculated, as TMA. After the back market titration of excess acid during the determination of El Amreya market TVB-N, aliquot of 1 ml of 16% (w/v) formalde- Methods hyde solution was added for every 10 ml liquid in the titration flask in order to make amines other than Sensory evaluation TMA react with formaldehyde and the acid released Sensory evaluation of raw tilapia and mullet was titrated with standard alkali. The results were was performed by ten trained panelists chosen from expressed as mg nitrogen per 100g fish sample. 36 Alex. J. Fd. Sci. & Technol. Vol. 15, No. 1, pp. 35-48, 2018

pH value be attributed to the higher bacterial load of sam- Five g of fish sample were homogenized in 50 ples collected from Hanuvil and Derbala markets ml distilled water at the ratio 1:10 (w/v) using labo- compared to those obtained from the other markets ratory Warring blender and the pH was measured (Table 4). using a digital pH meter (pH 211, Microprocessor The overall sensory scores less than 5 points pH). The pH meter was calibrated using buffers of mean that Nile tilapia samples are organoleptical- pH 4 and 7 (Goulas & Kontominas, 2007). ly rejected (Barile et al., 1985). According to the Bacteriological analysis overall sensory scores (Tables 2 & 3), the samples collected from different local markets could be Ten g of flesh were transferred into 90 ml 0.1% classified into three categories of quality grade as peptone water. From this dilution, other decimal follows: (1) high quality grade (samples collected dilutions were prepared. Total psychrophilic and from Shedia, Zananiri, Zine Elabidine, Alqsy, El mesophilic bacterial count were determined by Wardian and Bab Omar pasha markets) (2) accept- the pour plating technique, using plate count agar able grade (samples collected from Gheat Elsaaei- (PCA) and the plates were inverted and incubated dy, Bakkous, El Maydan, El Maamoura, Asafra , o in an incubator at 35 C for 48 hr for mesophilic Derbala ,Dekhela and El Amreya markets), (3) un- o bacteria and at 7-10 C for 10 days for psychrophilic acceptable grade (Hanuvil market samples). bacteria (Bahmani et al., 2011). The TVB-N of tilapia Finally, the number of colonies were counted and multiplied by dilution factor to calculate the The results in Table (4) show TVB-N of Nile total colonies forming units per g sample (Abelti, tilapia collected from different local markets in 2013). Alexandria city. According to these data, it can be concluded that the TVB-N content of the market Statistical analysis samples ranged from 10.21 to 26.77 mg N/100g Analysis of variance and correlations were flesh. It was found that the TVB-N value varied carried out according to Gomez & Gomez (1984) significantly P ( < 0.05) between different market using SAS (Statistical Analysis System) ver.9.1, samples. Meanwhile, Hanuvil market samples had 2000. the higher amount of TVB-N, while samples col- lected from Bab Omar pasha market had the lower RESULTS AND DISCUSSION level of TVB-N with no significant differences ob- served between El Wardian, Alqsy and Bab Omar Nile tilapia collected from different markets pasha market samples. Sensory evaluation Differences in levels of TVB-N may be due The data for sensory evaluation of raw and the activity of proteolytic enzymes by bacterial steamed Nile tilapia samples collected from differ- action which produced some volatile compounds ent local markets in Alexandria city are presented under low temperature (Nunes et al., 1992, Abou- in Tables (2 & 3). The values were calculated as Taleb & Ibrahim, 2002). Also, Mazorra-Manzano means of ten scoring evaluations. et al. (2000) reported that this increment may be due to ammonia production in the muscle during The results indicated that the sensory evalua- storage from bacterial catabolism of nitrogen, due tion scores of Nile tilapia samples collected from to the fact that TVB-N levels still rise as a result of different local markets in Alexandria city varied the NH formation and other volatile amines. significantly. Also, as shown from Tables (2 & 3), 3 the overall acceptability scores varied from 4.9 to It was clear that all concentrations of TVB-N 9.9 and from 5.3to 9.9 for raw and steamed sam- are lower than the safety limits suggested by CEC ples, respectively. (1995), Connell (1995), Huss (1995), Gökod- lu et al. (1998), Lopez-Caballero et al. (2000), The highest overall acceptability was detected E.O.S.Q.C. (2005), Muhammet & Sevim (2007) in Shedia and Zananiri market samples, while the and Liu et al. (2010), which set TVB-N values of lowest overall acceptability score was recorded in 30-35 mg N/100g flesh regarded as the limit of samples collected from Hanuvil and Derbala mar- acceptability. kets for both raw and steamed samples. This may

37 Vol. 15, No. 1, pp. 35-48, 2018 Alex. J. Fd. Sci. & Technol. Table 2: Sensory evaluation*of raw Nile tilapia samples The values were calculated as means of 10 scoring evaluations. Means in the same column sharing letters are not significantly different at P< 0.05 level. **Data as mean ± SD. Unacceptable grade: Overall sensory scores 5 or less. Acceptable grade: Overall sensory scores less than 8 and more 5. *High grade: Overall sensory scores between 10 and 8. Shedia Gheat Elsaaeidy Zine Elabidine Bakkous Zananiri Alqsy El Wardian Bab Omar pasha El Maydan El Maamoura Asafra Derbala Hanuvil Dekhela El Amreya L. S. D. Market name 9.7 7.4 8.8 6.9 9.6 8.8 9.3 8.4 6.0 5.9 7.4 4.7 4.6 7.1 5.8 0.67 a d bc d a bc ab c e e d f f d e Eye ±0.95 ±0.84 ±0.48** ±0.69 ±0.52 ±0.82 ±0.74 ±1.03 ±0.70 ±0.57 ±0.52 ±0.73 ±0.79 ±0.79 ±0.67 9.4 7.5 8.8 7.1 9.5 8.8 9.3 8.3 6.1 6.0 7.6 4.9 4.8 7.2 6.1 0.64 Gills ab d bc d a bc ab c e e d f f d e ±0.52 ±0.89 ±0.71 ±0.48 ±0.48 ±0.74 ±0.74 ±0.71 ±0.89 ±0.82 ±0.92 ±0.69 ±0.63 ±0.63 ±0.48 Body surface 9.5 7.5 8.5 7.0 9.6 8.6 9.2 8.3 5.8 5.7 7.6 5.0 4.8 7.4 6.0 0.6 a d c d a bc ab c e e d d f d e ±0.79 ±0.53 ±0.70 ±0.51 ±0.67 ±0.92 ±0.67 ±0.67 ±0.71 ±0.67 ±0.52 ±0.47 ±0.84 ±0.84 ±0.63 9.9 7.4 8.8 7.0 9.8 8.8 9.4 8.4 6.0 5.8 7.6 4.4 4.5 7.3 6.2 0.66 Odour a d bc d a bc ab c e e d f f d e ±1.07 ±0.97 ±0.32 ±0.67 ±0.70 ±0.67 ±0.79 ±0.79 ±0.70 ±0.91 ±0.52 ±0.82 ±0.92 ±0.42 ±0.92 Sensory quality parameters 9.9 7.5 8.7 7.0 9.6 9.0 9.4 8.6 6.1 6.1 7.6 4.9 4.7 7.3 5.9 0.6 Texture a de c e a bc ab c f f d g g de f ±0.88 ±0.74 ±0.74 ±0.32 ±0.67 ±0.82 ±0.70 ±0.52 ±0.52 ±0.57 ±0.67 ±0.71 ±0.82 ±9.52 ±0.67 Flesh condition 9.7 7.5 8.7 7.1 9.7 8.8 9.3 8.5 5.9 5.8 7.6 4.6 4.5 7.2 5.8 0.59 a d c d a bc ab c e e d f f d e ±0.69 ±0.85 ±0.67 ±0.82 ±0.48 ±0.53 ±0.57 ±0.63 ±0.63 ±0.71 ±0.74 ±0.52 ±0.92 ±0.92 ±0.67 9.8 7.3 8.7 7.1 9.6 8.9 9.4 8.5 6.1 5.9 7.5 4.5 4.6 7.1 5.8 0.64 Viscera a d c d a bc ab c e e d f f d e ±0/85 ±0.51 ±0.63 ±0.67 ±0.52 ±0.53 ±0.74 ±0.74 ±0.91 ±0.82 ±0.74 ±0.53 ±0.88 ±0.88 ±0.52 9.9 8.7 7.1 7.1 9.7 8.7 9.3 8.3 5.9 5.6 7.6 4.3 4.6 7.2 5.9 0.59 Belly wall a c d d ab c b c e e d f f d e ±0.95 ±0.52 ±0.32 ±0.70 ±0.67 ±0.48 ±0.73 ±0.84 ±0.57 ±0.67 ±0.74 ±0.67 ±0.52 ±0.92 ±0.48 acceptability 9.90 7.4 9.1 7.1 9.8 8.9 9.5 8.5 6.2 5.8 7.6 5.1 4.9 7.5 6.1 0.53 Overall e bc e a cd ab d f f e g g e f ±0.63 ±0.63 ±0.74 ±0.52 ±0.74 ±0.42 ±0.52 ±0.53 ±0.71 ±0.73 ±0.57 a ±0.88 ±0.74 ±0.53 ±0.32

38 Alex. J. Fd. Sci. & Technol. Vol. 15, No. 1, pp. 35-48, 2018

Table 3: Sensory evaluation*of steamed Nile tilapia samples

Market name Sensory quality parameters Odour Taste Texture Overall acceptability Shedia 9.8a±0.42** 9.6a±0.70 9.8a±0.43 9.9a±0.32 Gheat Elsaaeidy 7.8e±0.63 7.6e±0.52 8.0de±0.47 8.2de±0.42 Zine Elabidine 8.9bc±0.74 8.6b±0.69 8.8b±0.79 9.1bc±0.74 Bakkous 7.7e±0.95 7.7e±0.67 7.8e±0.79 7.9e±0.74 Zananiri 9.7a±0.48 9.3a±0.82 9.7a±0.48 9.8a±0.42 Alqsy 8.6cd±0.70 8.4bc±0.69 8.6bc±0.69 8.7cd±0.82 El Wardian 9.5ab±0.53 9.2a±0.79 9.4a±0.51 9.6ab±0.52 Bab Omar pasha 8.6cd±0.52 8.3bcd±0.48 8.5bcd±0.52 8.9c±0.93 El Maydan 6.3f±0.67 6.0f±0.47 6.1f±0.74 6.1f±0.74 El Maamoura 6.4f±0.84 6.0f±0.67 6.0f±0.66 6.1f±0.73 Asafra 8.1de±0.57 7.8de±0.78 8.3bcde±0.67 8.0e±0.47 Derbala 5.0g±0.94 5.2g±0.63 5.2g±0.78 5.3g±0.48 Hanuvil 4.9g±0.87 4.8g±0.79 5.0g±0.82 5.4g±0.52 Dekhela 8.0de±0.47 8.0cde±0.67 8.1bcde±0.32 8.2de±0.42 El Amreya 6.2f±0.63 6.0f±0.47 6.2f±0.42 6.4f±0.52 L. S. D. 0.6 0.58 0.55 0.53 *High grade: Overall sensory scores between 10 and 8. Acceptable grade: Overall sensory scores less than 8 and more than 5. Unacceptable grade: Overall sensory scores 5 or less. **Data as mean ± SD. Means in the same column sharing the same letters are not significantly different atP <0.05 level.

The TMA-N of tilapia Capillas & Moral (2001) which is within the range The results in Table (4) reveal that the TMA-N of recommended limit of rejection of 10 to 18 mg of Nile tilapia collected from different local mar- N/100g. Also, TMA-N value was blew rejection kets in Alexandria city varied between 5.13 to 8.21 limit of many fish species which is usually from mg N/100g flesh. TVB-N value varied significantly 5-10 mg TMA-N /100g muscles as reported by (P< 0.05) between different market samples. Fathia et al. (2013). Hanuvil sample had the highest value of TMA- The pH values of tilapia N. On the other hand, Bab Omar pasha samples fol- The pH values of Nile tilapia collected from lowed by El Wardian samples showed the lowest different local markets in Alexandria city are sum- value of TMA-N, with no significant difference marized in Table (4). The data obtained show sig- between them. nificant differences P( < 0.05) among the samples From the results obtained in the present study, collected from the different markets. it can be concluded that a correlation was observed The pH values of Nile tilapia varied from 7.01 between the results of TMA-N and bacterial load. to 7.38. Further, Hanuvil market samples had the In accordance with the results obtained here, El highest value of pH. On the other hand, El Ward- Marrakchi et al. (1990) mentioned that The TMA ian, Alqsy and Bab Omar Pasha market samples production in fish tissue could be used as an indica- exhibited the lowest value of pH with no significant tor of bacterial activity and it is an accepted dete- difference between them. This result is consistent rioration measure. with the results of TVB-N, TMA-N and microbial The TMA-N value of Nile tilapia collected load. from the different local markets in Alexandria city The results in the present study showed that pH was below rejection limit of TMA-N proposed by value was above value of 7. The increment in pH Huss (1978), AOAC (1984), FAO (1986), & Ruiz- may also be due to an increase in total volatile bases

39 Vol. 15, No. 1, pp. 35-48, 2018 Alex. J. Fd. Sci. & Technol. from the decomposition of nitrogenous compounds The overall sensory scores less than 5 points by endogenous or microbial enzymes and this cor- mean that grey mullet samples are organoleptical- roborates with the increase in TVB- N. These re- ly rejected (Barile et al., 1985). According to the sults agreed with those previously reported (Khal- overall sensory scores (Tables 5 and 6), the sam- laf, 1986, Galli et al., 1993, Kyrana et al., 1997, ples collected from Shedia, Zine Elabidine, Alqsy, Pacheco-Aguilar et al.,2003, Daramola et al., 2007, Gheat Elsaaeidy and Bakkous, markets had a high- Erkan & Ozden, 2008, Okeyo et al., 2009, Salau- er quality grade, as well as acceptable grade was deen et al., 2010, Goliat et al., 2016 Moawad et al., observed in samples collected from El Maydan, El 2017). Such an increment in the pH indicates the Maamoura, Asafra, Zananiri, Derbala , Dekhela, bacterial growth, loss of quality and possible spoil- El Wardian, Bab Omar pasha and El Amreya mar- age (Sallam et al., 2007, Moawad et al., 2017). kets). On the other hand, unacceptable grade was Bacterial count of tilapia noted in Hanuvil market samples. Bacterial count of Nile tilapia collected from TVB-N of grey mullet different local markets in Alexandria city are given Table (7) shows the values of TVB-N of grey in Table (4). The data obtained showed significant mullet collected from different local markets in Al- differences (P< 0.05) among the samples collected exandria city. The results indicated that the TVB-N from the different markets for both mesophilic and content of the market samples ranged from 7.79 to psychrophilic bacterial count. 24.52 mg N/100g flesh. It was found that the TVB- The mesophilic bacterial count ranged from N value varied significantly P ( <0.05) between the 8.47x102 CFU/g flesh to 9.83x104 CFU/g flesh for different market samples. A significantly P( <0.05) Zine Elabidine and Hanuvil market samples, re- higher value of 24.52 mg N/100g flesh was detected spectively. On the other hand, the psychrophilic in TVB-N for Hanuvil market samples comparing bacterial count ranged from 9.73x102 CFU/g flesh with the other different samples. These increment to 5.17x105 CFU/g flesh for El Wardian and Hanu- may be attributed to the breakdown of nitrogenous vil market samples, respectively. substances as a result of microbial activity and any autolytic enzymes found naturally in fish tissues The present study indicate that the psychro- (El-Shamery, 2010). On the other hand, Zananiri philic bacterial counts of Nile tilapia collected from market samples showed the lowest TVB-N level. No the different markets were higher than mesophilic significant difference was noted between Zananiri, bacterial count. Bakkous and Zine Elabidine samples with respect to All Nile tilapia samples had high quality con- their content of TVB-N. sidering that the microbiological upper limit for From the results obtained in the present study, fresh fish proposed by ICMSF (1986), IFST (1999) it can be shown a correlation between the results 6 & E. O. S. Q. C. (2005) not exceed 10 CFU/g flesh. of TVB-N, TMA-N, pH and bacterial load. These Grey mullet collected from different markets results agreed with those reported by Fernandez et al. (2009) & Jinadasa (2014). They found that the Sensory evaluation increment in the amount of TVB-N is parallel with Sensory evaluation of raw and steamed grey the increase in TMA during spoilage. Further, these mullet collected from different local markets in Al- results are in agreement with the results recorded exandria city are shown in Tables (5 and 6). The by Yasmin et al. (2001), Özyurt et al. (2009), Liu results show significant differences among the et al. (2010). They reported that significant corre- samples collected from the different markets. The lation coefficient was observed between TVB-N overall acceptability ranged from 4.6 to 9.3 and changes and changes in mesophilic aerobic bacte- from 4.8 to 9.1 for raw and steamed grey mullet rial count. collected from the different markets, respectively. All TVB-N values in the different samples, Samples taken from Gheat Elsaaeidy and are below the maximum value of 30 mg N/100g Bakkous markets possessed higher overall accept- flesh specified by CEC (1995), Connell (1995), ability scores for both raw and steamed samples. Huss (1995), Gökodlu et al. (1998), Lopez-Cabal- However, the lower overall acceptability was re- lero et al. (2000), E. O. S. Q. C (2005), Muham- corded in Hanuvil samples. met & Sevim (2007) & Liu et al. (2010), which set

40 Alex. J. Fd. Sci. & Technol. Vol. 15, No. 1, pp. 35-48, 2018 Table 4: Mean values of TVB-N, TMA-N, pH and bacterial count Nile tilapia samples Means in the same column sharing letters are not significantly different at P< 0.05 level. **CFU Colony forming unit. *Data as mean ± SD. L. S. D. El Amreya Dekhela Hanuvil Derbala Asafra El Maamoura El Maydan Bab omar pasha El Wardian Alqsy Zananiri Bakkous Zine Elabidine Gheat Elsaaeidy Market name Shedia 0.75 (mg N /100g flesh) 17.28 12.63 26.77 18.36 13.07 15.31 11.46 10.21 10.30 10.39 17.55 11.99 10.57 13.22 11.73 TVB-N c ef a b e d g h h h c fg h e g ±0.31 ±0.15 ±0.41 ±0.16 ±0.72 ±0.31 ±0.45 ±0.56 ±0.26 ±0.36 ±0.41 ±0.56 ±0.41* ±0.54 ±0.62 0.5 (mg N /100g flesh) 6.92 6.55 8.21 7.38 6.50 6.69 6.21 5.13 5.44 5.67 7.16 6.33 5.69 6.57 6.26 TMA-N bcd de a b de cde e g fg f bc e f de e ±0.30 ±0.30 ±0.32 ±0.42 ±0.21 ±0.18 ±0.19 ±0.21 ±0.27 ±0.39 ±0.29 ±0.36 ±0.20 ±0.41 ±0.21 0.03 7.28 7.07 7.38 7.34 7.09 7.28 7.05 7.02 7.01 7.02 7.30 7.07 7.03 7.12 7.05 c efg a b de c ghi hij j hij c efg ef d ghi pH ±0.02 ±0.05 ±0.02 ±0.05 ±0.01 ±0.01 ±0.04 ±0.02 ±0.02 ±0.01 ±0.01 ±0.03 ±0.01 ±0.03 ±0.03 quality parameters Mesophilic aerobic bacterial 7.78 ×103 2.53 ×104 3.50 ×103 9.83 ×104 7.27 ×104 8.33 ×103 1.56×104 3.37 ×103 1.58 ×103 1.86 ×103 1.16 ×103 2.97 ×104 4.10 ×103 8.47 ×102 6.73 ×103 2.47 ×103 count (CFU /g flesh) d c e a b de e e e e c e e e e ±3.400 ×103 ±7.61 ×103 ±1.04 ×103 ±1.07 ×104 ±9.29 ×102 ±5.68 ×102 ±4.74 ×102 ±4.68 ×102 ±9.07 ×103 ±1.00 ×103 ±1.45 ×102 ±8.73 ×102 ±5.50 ×102 ±1.14 ×104 ±1.35 ×103 Psychrophilic aerobic bacterial 4.98×104 7.20 ×104 7.30 ×103 5.17 ×105 1.11 ×105 2.03 ×104 5.88 ×104 9.33 ×103 3.03 ×103 9.73 ×102 1.64 ×103 5.23 ×104 7.27 ×103 1.29 ×103 1.08 ×104 4.23 ×103 count (CFU** /g flesh) bc ef a b def cd def ef f f cde ef f def ef ±2.05 ×102 ±6.37 ×102 ±3.73 ×102 ±1.11 ×105 ±2.70 ×104 ± 1.21×103 ±9.07 ×102 ±8.08 ×102 ±7.50 ×102 ± 1.20×104 ± 1.64×104 ± 4.18×103 ±9.86 ×102 ± 2.79×103 ±8.62 ×103

41 Vol. 15, No. 1, pp. 35-48, 2018 Alex. J. Fd. Sci. & Technol. Table 5: Sensory evaluation Means in the same column sharing letters are not significantly different at P< 0.05 level. **Data as mean ± SD. Unacceptable grade: Overall sensory scores 5 or less. Acceptable grade: Overall sensory scores less than 8 and more 5. *High grade: Overall sensory scores between 10 and 8. L. S. D. El Amreya Dekhela Hanuvil Derbala Asafra El Maamoura El Maydan Bab omar pasha El Wardian Alqsy Zananiri Bakkous Zine Elabidine Gheat Elsaaeidy Shedia Market name 0.67 5.3 5.3 4.5 5.4 6.5 5.7 6.5 5.6 5.6 8.3 6.0 9.0 7.7 9.2 8.2 e e f de c de c de de b cd a b a b ±0.53 Eye ±0.67 ±0.82 ±0.85 ±0.85 ±0.81 ±0.63 ±0.70 ±0.82 ±0.42** ±0.69 ±0.67 ±0.85 ±0.84 ±0.95 *

of raw grey mullet samples 0.65 5.0 5.4 4.3 5.1 6.5 5.8 6.3 5.5 5.7 8.3 6.1 9.1 7.7 9.3 8.4 i ghi j hi d efg de fghi efgh bc def a c a b Gills ±0.82 ±0.48 ±0.57 ±0.67 ±0.48 ±0.85 ±0.52 ±0.88 ±0.82 ±0.95 ±0.79 ±0.74 ±0.70 ±0.85 ±0.67 Body surface 0.68 5.1 5.1 4.4 5.1 6.5 5.7 6.7 5.6 5.5 7.6 5.9 9.1 7.6 9.1 8.2 f f g f cd ef c ef ef b de a b a b ±0.56 ±0.57 ±0.74 ±0.82 ±0.87 ±0.88 ±0.69 ±0.57 ±0.70 ±0.63 ±0.82 ±0.70 ±0.71 ±0.85 ±0.74 0.67 5.3 5.2 4.3 5.2 6.4 5.8 6.3 5.5 5.7 8.0 5.9 8.9 7.8 9.3 8.3 Odour fg g h g d defg de fg efg c def ab c a bc ±0.79 ±0.53 ±0.79 ±0.63 ±0.82 ±0.79 ±0.84 ±0.67 ±0.70 ±0.95 ±0.88 ±0.67 ±0.69 ±0.82 ±0.79 Sensory quality parameters 0.68 5.2 5.1 4.2 5.0 6.3 5.6 6.6 5.6 5.6 7.8 6.0 9.1 7.5 9.2 8.4 Texture f f g f d ef d ef ef bc de a c a b ±0.63 ±0.57 ±0.67 ±0.88 ±0.53 ±0.79 ±0.63 ±1.06 ±1.08 ±0.52 ±0.84 ±0.69 ±0.70 ±0.78 ±0.82 Flesh condition 0.67 5.3 5.2 4.5 5.1 6.6 5.5 6.5 5.7 5.7 8.1 5.7 9.1 7.6 9.2 8.2 e d e de c d c d d b d a b a b ±0.67 ±0.53 ±0.70 ±0.85 ±0.87 ±0.79 ±0.92 ±0.85 ±0.82 ±0.67 ±0.74 ±0.67 ±0.70 ±0.42 ±0.88 0.67 5.3 5.2 4.2 5.1 6.5 5.7 6.7 5.7 5.6 8.0 6.0 9.2 7.7 9.3 8.2 Viscera f f g f cd ef c ef ef b de a b a b ±0.82 ±0.79 ±0.88 ±0.82 ±0.63 ±0.67 ±1.03 ±0.67 ±0.48 ±0.63 ±0.80 ±0.82 ±0.52 ±0.71 ±0.86 0.65 5.1 5.3 4.2 5.1 6.5 5.6 6.7 5.6 5.4 8.1 5.9 9.2 7.8 9.4 8.3 Belly wall f ef g f cd ef c ef ef b de a b a b ±0.74 ±0.88 ±0.95 ±0.79 ±0.70 ±0.63 ±0.57 ±0.63 ±0.48 ±0.67 ±0.69 ±0.84 ±0.84 ±0.85 ±0.74 Overall acceptability 0.64 5.4 5.4 4.6 5.5 6.6 5.7 6.8 5.7 5.9 8.0 6.0 8.9 8.0 9.3 8.3 f f g f de f d f f c ef ab c a bc ±0.70 ±0.70 ±0.70 ±0.82 ±0.82 ±0.88 ±0.47 ±0.67 ±0.82 ±0.84 ±0.92 ±0.47 ±0.69 ±0.88 ±0.48

42 Alex. J. Fd. Sci. & Technol. Vol. 15, No. 1, pp. 35-48, 2018

Table 6: Sensory evaluation*of steamed grey mullet samples

Sensory quality parameters Market name Odour Texture Taste Overall acceptability Shedia 8.4b±0.52** 8.1bc±0.74 8.6c±0.52 8.5ab±0.71 Gheat Elsaaeidy 9.2a±0.63 9.0a±0.94 9.3a±0.48 9.1a±0.88 Zine Elabidine 8.3b±0.48 7.9c±0.57 8.2c±0.63 8.2b±0.42 Bakkous 9.2a±0.79 8.7ab±1.06 9.2ab±0.79 9.1a±0.74 Zananiri 6.2cd±0.78 5.9de±0.73 6.1de±0.74 6.4cde±0.70 Alqsy 8.6ab±0.67 8.2bc±0.63 8.7bc±0.67 8.5ab±0.85 El Wardian 5.5e±0.85 5.3ef±0.95 5.6efg±0.70 5.8ef±0.92 Bab omar pasha 5.5e±0.85 5.4ef±0.97 5.4fg±0.69 5.9def±0.73 El Maydan 6.6c±0.84 6.2d±0.63 6.5d±0.63 6.7c±0.82 El Maamoura 5.6de±0.84 5.5ef±0.85 5.6efg±0.85 5.8ef±0.79 Asafra 6.2cd±0.63 5.7de±0.67 5.9ef±0.94 6.5cd±0.53 Derbala 5.1e±0.99 5.0fg±0.94 5.5fg±0.53 5.6f±0.70 Hanuvil 4.3f±0.48 4.5g±0.53 4.4h±0.48 4.8g±0.52 Dekhela 5.4e±0.52 5.3ef±0.48 5.3g±0.67 5.6f±0.67 El Amreya 5.3e±0.67 5.4ef±0.52 5.5fg±0.52 5.7f±0.89 L. S. D. 0.62 0.68 0.59 0.64 *High grade: Overall sensory scores between 10 and 8. Acceptable grade: Overall sensory scores less than 8 and more than 5. Unacceptable grade: Overall sensory scores 5 or less. **Data as mean ± SD. Means in the same column sharing the same letters are not significantly different at P<0.05 level.

TVB-N values of 30-35 mg N/100g flesh regarded proposed by Huss (1978), AOAC (1984), FAO as the limit of acceptability. (1986), Ruiz-Capillas & Moral (2001) and Fathia The TMA-N of grey mullet et al. (2013). The data presented in Table (7) show the TMA- The pH values of grey mullet N values of grey mullet collected from different The data in Table (7) show the pH values of local markets in Alexandria city. The results indi- grey mullet collected from different local markets cated that the TMA-N content of market samples in Alexandria city. It was found that the pH value ranged from 4.90 to 7.69 mg N/100g flesh. It was ranged from 6.74 to 7.13. found that the TMA-N value varied significantly Hanuvil samples followed by El Amreya sam- (P<0.05) between the different market samples. ples were recorded to have the highest value of pH Hanuvil market samples followed by El Am- with no significant difference between them. On reya samples showed the highest value of TMA-N, the other hand, Bakkous samples followed by Za- with no significant difference between them, while naniri samples showed the lowest value of pH with samples collected from Zananiri market followed no significant difference between them. by Bakkous had the lowest level of TMA-N with The post mortem acceptable pH is usually 6.8- no significant differences observed between them. 7.0 (Zang & Deng, 2012). After death of the fish, The TMA-N values of grey mullet collected the glycogen present in the tissues gets oxidized to from the different local markets were within the lactic acid and the creatine phosphate in the mus- recommended standard limits for acceptability cle breaks down releasing phosphoric acid (Huss,

43 Vol. 15, No. 1, pp. 35-48, 2018 Alex. J. Fd. Sci. & Technol. Means in the same column sharing letters are not significantly different at P< 0.05 level. **CFU Colony forming unit. *Data as mean ± SD. Table 7: Mean values* of TVB-N, TMA-N, pH and bacterial count grey mullet samples L. S. D. El Amreya Dekhela Hanuvil Derbala Asafra El Maamoura El Maydan Bab omar pasha El Wardian Alqsy Zananiri Bakkous Zine Elabidine Gheat Elsaaeidy Shedia Market name quality parameters (mg N /100g flesh) 0.58 19.79 13.88 24.52 16.03 11.73 13.97 10.39 16.03 16.57 9.49 7.79 8.24 8.86 9.85 9.02 TVB-N gh j j i gf hi ±0.27 ±0.15 ±0.27 ±0.38* ±0.16 b d a c e d f c c ±0.41 ±0.15 ±0.06 ±0.16 ±0.31 ±0.41 ±0.40 ±0.31 ±0.41 ±0.71 (mg N /100g flesh) 0.57 7.30 6.24 7.69 6.92 6.21 6.80 6.09 6.92 7.16 5.97 4.90 5.33 5.56 5.98 5.83 TMA-N ab cd a b d bc de b ab de g fg ef de def ±0.17 ±0.55 ±0.75 ±0.54 ±0.21 ±0.18 ±0.37 ±0.19 ±0.18 ±0.36 ±0.36 ±0.35 ±0.20 ±0.22 ±0.76 0.04 7.13 7.01 7.18 7.06 7.01 7.04 6.97 7.08 7.09 6.92 6.74 6.77 6.83 6.96 6.85 a de a bcd de cd ef bc b g i i h fg h pH ±0.01 ±0.01 ±0.01 ±0.02 ±0.01 ±0.02 ±0.05 ±0.02 ±0.03 ±0.03 ±0.07 ±0.02 ±0.02 ±0.01 ±0.03 Mesophilic aerobic bacterial count (CFU / g flesh)** 4.01×10 7.37 ×10 2.33 ×10 2.70 ×10 3.97 ×10 7.40 ×10 2.20 ×10 6.97 ×10 5.40 ×10 5.13 ×10 5.83 ×10 1.29 ×10 2.16 ×10 5.07 ×10 2.02 ×10 1.79 ×10 4 4b 4cd 5a 4bcd 3d 4cd 3d 4bc 4bc 3d 3d 3d 3d 3d 3d ±8.89 ×10 ±1.10 ×10 ±1.25 ×10 ±1.25 ×10 ±1.61 ×10 ±5.12 ×10 ±4.67 ×10 ±1.16 ×10 ±2.30 ×10 ±5.58 ×10 ±8.44 ×10 ±5.32 ×10 ±1.24 ×10 ±9.61 ×10 ±7.40 ×10 4 4 3 3 3 2 2 3 2 2 3 3 3 4 3 Psychrophilic aerobic bacterial 5.30×10 2.37 ×10 2.27 ×10 5.37 ×10 1.70 ×10 7.63 ×10 1.53 ×10 5.27 ×10 1.37 ×10 1.34 ×10 4.30 ×10 2.61 ×10 8.20 ×103 3.47 ×10 1.72 ×10 5.63 ×10 count (CFU** /g flesh) 4 5b 5b 5a 5c 4d 5c 4de 5c 5c 3e 3e 4de 4e 3e e ±6.03 ×104 ±2.95 ×104 ±3.04 ×104 ±2.40 ×104 ±2.15 ×104 ±9.64 ×102 ±6.28 ×102 ±2.80 ×103 ±1.35 ×103 ±6.99 ×104 ±8.19 ×104 ±1.40 ×104 ±9.16 ×102 ±6.66 ×103 ±6.11 ×103

44 Alex. J. Fd. Sci. & Technol. Vol. 15, No. 1, pp. 35-48, 2018

1995). A release of both lactic acid and phosphoric Analytical Methods Committee (AMC). 1979. Rec- acid triggers rapid change in pH of tissue fluids ommended general methods for the examina- (MANAGE, 2008). tion of fish and fish products. Analyst, 104: The pH values of grey mullet collected from 434- 450. the different local markets were correlated well with Association of Official Methods of Analytical the results of TVB-N, TMA-N and bacterial load. Chemists (AOAC). 1984. Official Methods of Analysis. (14th Ed), Arlington. Bacterial count of grey mullet Bahmani, Z. A., Rezai, M. Hosseini, S. V., Re- The data presented in Table (7) show the bac- genstein, J. M., Böhme, K., Alishahi, A. & terial count of grey mullet collected from different Yadollahi, F. 2011. Chilled storage of golden local markets in Alexandria city. The results indi- gray mullet (Liza aurata). Food Science and cated that the significant differences (P<0.05) were Technology, 44: 1894-1900. observed between the samples collected from the different markets for both mesophilic and psychro- Balarian, J. D. 1979. Tilapia: A guide to their Biol- philic bacterial count. ogy and Culture in Africa. University of Ster- ling Press. pp: 1-79. The mesophilic bacterial count ranged from Barile, L. E., Milla, A. D., Reilly, A. & Villadsen, 1.29x103 CFU/g flesh to 2.70 x105 CFU/g flesh for A. . Spoilage patterns of mackerel (Ras- Zananiri and Hanuvil market samples, respective- 1985 trielliger faughnimatsui)- mesophilic and ly. The psychrophilic bacterial count ranged from psychrophilic spoilage. FAO Fisheries Re- 2.61x103CFU/g flesh to 5.37x105 CFU/g flesh for search, : 146-154. Zananiri and Hanuvil market samples, respectively. 317 Variation in the initial bacterial load could be as- Commission of the European Community (CEC). cribed to the microbial load of the waters in which 1995. Decision 95/ 149/EC of fixing the total they live (Huss, 1988). The eventual increase ob- volatile basic nitrogen (TVB-N) limit values served in mean total plate count could be due to for certain categories of fishery products and multiplication of organisms favored at the storage specifying the analysis methods to be used. condition (Ibrahim & El -Sherif, 2008). Brussels: CEC. th The present study indicated that the psychro- Connell, J. J. 1995. Control of Fish Quality .4 ed. philic bacterial count of grey mullet collected from London: Fishing News Books Limited. pp: the different markets were higher than mesophilic 240. bacterial count. Daramola, J. A., Fasakin, E. A. & Adeparusi, E. O. . Changes in physiochemical and sen- The levels of mesophilic and psychrophilic 2007 sory characteristics of smoke-dried fish spe- aerobic bacterial count of grey mullet collected cies stored at ambient temperature. African from the different local markets, agreed greatly Journal of Food Agriculture Nutrition. and with the recommendations set by ICMSF (1986), Development, : 1-16. IFST (1999) and E. O. S. Q. (2005) which claimed 7 that the maximum bacterial limit for fresh fish nev- Egyptian Organization for Standardization and er exceeds the 106 CFU/g flesh. Quality Control (E.O.S.Q.C). 2005. Chilled Fish. ES: 3494: 1-12. REFERENCES El Marrakchi, A., Bennour, M., Bouchriti, N., Hamama, A. & Tagafait, H. 1990. Sensory, Abelti, A. L. 2013. Microbiological and chemical chemical, and microbiological assessments changes of Nile tilapia (Oreochromis niloti- of Moroccan sardines (Sardina pilchardus) cus L.) fillet during ice storage: effect of age stored in ice. Journal of Food Protection, 53: and sex advance. Journal of Food Science 600- 605. and Technology, 5: 1260 - 1265. El-Shamery, G. 2010. Studies on contamination Abou-Taleb, M. & Ibrahim, S. M. 2002. Relation- and quality of fresh fish meats during -stor ship between freshness degree of Nile bolti age. Egyptian Academic Journal of Biologi- fish and quality of its processed products. cal Sciences, 2: 65-74. Annals of Agriculture Science, Moshtohor, 40: 1571-1582. 45 Vol. 15, No. 1, pp. 35-48, 2018 Alex. J. Fd. Sci. & Technol.

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تقييم جودة �أ�سماك البلطى النيلى والبورى التى مت جمعها من �أ�سواق خمتلفة مبدينة الإ�سكندرية - م�صر �سعدية حممد ها�شم حممد ،على �أحمد عبد النبى ،حممد خليل حممد خليل، �أ�سامة را�شد �أبو �سماحة ق�سم علوم وتقنية الأغذية – كلية الزراعة – ال�شاطبى– جامعة الأ�سكندرية – الأ�سكندرية – جمهورية م�صر العربية

الهدف من هذه الدرا�سة هو تقييم جودة �أ�سماك البلطى والبورى التى مت جمعها من �أ�سواق خمتلفة مبدينة الإ�سكندرية -م�صر. ًوفقالدرجات التقييم احل�سى ميكن تق�سيم جودة �أ�سماك البلطى التى مت احل�صول عليها من �أ�سواق خمتلفة �إىل ثالث درجات من اجلودة على النحو التاىل: الأ�سماك ذات اجلودة العالية )درجات مابني 10-8 ( ، والأ�سماك املقبولة )درجات مابني 5- 7.9( ، والأ�سماك البلطى غري املقبولة )درجات �أقل من 5( وهى العينات التى مت احل�صول عليها من �سوق الهانوفيل. �أو�ضحت النتائج ان كل قيم القواعد النيرتوجينية الكلية املتطايرة بالن�سبة لكل من البلطى والبورى �أقل من احلدود امل�سموح بها ًتبعا للموا�صفات القيا�سية امل�صرية. �أو�ضحت النتائج �أن كل قيم مركب ثالثى ميثيل الأمني بالن�سبة لكل من البلطى والبورى كانت �أقل من احلدود امل�سموح بها. وتراوحت قيم pHلعينات البلطى التى مت احل�صول عليها من الأ�سواق املختلفة من 7,01 �إىل 7,38 وبينت النتائج وجود �إختالفات معنوية بني الأ�سواق املختلفة. بالإ�ضافة �إىل ذلك �سجلت العينات التى مت احل�صول عليها من �سوق الهانوفيل �أعلى قيمة pHبينما �سجلت العينات التى مت احل�صول عليها من �سوق الورديان �أقل قيمة pH. تراوحت قيم pH لعينات البورى التى من 6.74 �إىل 7.18 . و�سجلت العينات التى مت احل�صول عليها من �سوق الهانوفيل متبوعا˝بالعينات التى مت احل�صول عليها من �سوق العامرية �أعلى قيمة pH مع عدم وجود فروق معنوية بينهم بينما �سجلت العينات التى مت احل�صول عليها من �سوق باكو�س متبوعا˝بالعينات التى مت احل�صول عليها من �سوق زنانريى �أقل قيمة pH مع عدم وجود فروق معنوية بينهمت. وقد تبني من هذه الدرا�سة �أن عد البكترييا املحبة للحرارة املنخف� ة ضلأ�سماك البلطى والبورى التى مت احل�صول عليها من الأ�سواق املختلفة كانت �أعلى من عد البكترييا املحبة للحرارة املتو�سطة. كما �أن قيمة عد البكترييا املحبة للحرارة املتو�سطة و املنخف�ضة بالن�سبة لكل من البلطى والبورى كانت أقل� من احلدود املو�صى بها.

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