Effect of modified atmosphere packaging on microbiological and chemical quality of mirrored carp (Cyprinus carpio L., 1758) fishballs

In this study, effect of modified atmosphere packaging (MAP) on the microbiological (Total mesophilic aerobic bacteria (TMAB), psychrophilic bacteria, Enterobacteriacea, coliform group bacteria, yeast and mold count) and chemical (pH, dry matter, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) number) quality of mirror carp (Cyprinus carpio L. 1758) meatballs was investigated. In the study, one control (K) and three experimental groups (D1, D2 and D3) of meatball samples were prepared by using fillets of fresh caught mirror carp in Elazığ Keban Dam Lake as material. K group with normal atmosphere composition and D1 from experimental groups; 55% CO2 + 15% O2 + 30% N2, D2; 65% CO2 + 10% O2 + 25% N2 and D3; Samples were stored at +4°C by using modified atmospheric packaging with 75% CO2 + 10% O2 + 15% N2 composition. Samples were analyzed on days 0, 3, 6, 9, 12, 15 and 18 of storage. K samples were spoiled on the 9th day, while D1 samples on the 15th day, and D2 and D3 samples on the 18th day since they were not accepted as sensory (odor, appearance, taste). Microbiological analysis results were given as log10 cfu/g. While the number of TMAB at the beginning of the cold storage was 4.17±0.13, it reached to 7.44±0.35 in the K group, 7.93±0.35 in the D1 group, 7.86±0.17 in the D2 group and 7.52±0.12 in the D3 group during storage. The numbers of psychrophilic bacteria were 3.79±0.04 at the beginning at the end of the storage they reached to 6.75±0.08 in the K group and 7.11±0.09, 6.83±0.06 and 6.92±0.14 in groups D1, D2 and D3 respectively. The number of Enterobacteriacea was determined as 4.48±0.45, 4.91±0.57, 4.86±0.10 and 4.75±0.09 in K, D1, D2 and D3 samples, respectively. The number of coliform bacteria was determined as 6.17±0.11, 6.30±0.13, 5.66±0.18 and 5.80±0.11 in K, D1, D2 and D3 samples, respectively. The yeast-mold count was 3.12±0.45 at the beginning, while it was 5.08±0.06 at the end of the storage in samples K, D1, D2 and D3, respectively. It was determined as 5.33±0.08, 5.22±0.06 and 5.00±0.24. It was determined that microbial growth was slower in the other groups compared to the K group. In microbiological analysis, it was determined that the D2 and D3 groups preserved their quality for a longer period of time, and the differences between the groups were statistically significant (p<0.05). While the pH value of the samples was 6.44±0.08 at the beginning of the storage, this value was determined as 6.10±0.06, 5.77±0.08, 5.79±0.02 and 5.82±0.11 in the K, D1, D2 and D3 samples at the end of the storage, respectively. While the dry matter ratio (%, w/w) was 36.37±0.16 at the beginning, it was found as 36.45±0.35, 36.86±0.21, 37.02±0.15 and 36.88±0.05 at the end of storage in K, D1, D2 and D3 samples, respectively. While the TVB-N value of the samples was 17.80±0.24 mg N/100g at the beginning of the storage, this value was found to be 30.56±0.76, 36.31±0.47, 36.52±0.88, 35.55±0.71 in the F, D1, D2 and D3 samples at the end of the storage, respectively. While TBA count (mg malonaldehyde/kg) was 0.39±0.02 at the beginning, this value was found as 1.39±0.04, 2.09±0.05, 2.25±0.08, 2.20±0.03 at the end of storage in K, D1, D2 and D3 samples, respectively. It was determined that there was no statistically significant difference between all groups in terms of pH and dry matter (p>0.05). In terms of TVB-N value, it was between the K group and other groups on the 9th day, between the D1 group and D2 and D3 groups on the 12th and 15th days, and between the K and D1 groups and D2 and D3 groups on the 6th and 9th days in terms of the number of TBA. On the 12th and 15th days, there was a significant statistical difference between the D2 group and the D2 and D3 groups (p<0.05). It was determined that the TVB-N value and TBA number increased more slowly in the D2 and D3 groups compared to the other groups during storage. As a result, the first signs of deterioration were observed on the 9th day in the Control samples, on the 15th day in the D1 samples, and on the 18th day in the D2 and D3 samples.