Quality Changes of Monopterus albus Slices during Refrigerated Preservation

In order to explore the quality changes of rice-field eel(Monopterus albus)slices during cold storage,the fresh eel slices were used as materials and stored at 3℃ for fresh-keeping test. The total numbers of colony,volatile basic nitrogen(TVB-N),histamine,pH,texture characteristics,water holding capacity and sensory evaluation were investigated. The quality changes of the eel slices were observed and evaluated every two days. The results showed that sensory quality of the sliced eels was still in a fresh state within 0~2 d,then declined to spoilage up to 12 d. The total number of bacteria increased from 7.38×10³ CFU/g to 4.34×10⁶ CFU/g within 1~10 d,and then exceeded the second-grade freshness index(≤ 10⁶ CFU/g)after 8 d later. During the period of cold storage,the volatile basic nitrogen increased gradually,which was not beyond the first-grade freshness index(≤ 13 mg/100 mg)when the spoilage of the eel slices occurred. The content of histamine increased to 3.69 mg/100 g in 12 days,which did not surpass the national standards for food safety(≤ 20 mg/100 g). The pH showed a slow growth trend(pH changes from 6.69 to 7.18),in accordance with the law of pH change after the death of fish,and water holding capacity appeared a downward trend. The texture characteristics of the eel slices decreased rapidly from 1 d to 6 d,and the changes in hardness,cohesion,elasticity and chewiness decreased by 39.49%,36.31%,33.09% and 68.83% respectively after 6 d. Regression analysis showed that the total number of bacteria could be used as the index of freshness of eel slices under the condition of cold storage,TVB-N could not be used as fresh index,the best edible period was 2 d and the shelf life was 8 d.