内源化学反应及细菌活动对冰温贮藏罗非鱼片腐败变质的贡献研究

目的 评估内源化学反应及细菌活动对冰温贮藏罗非鱼片腐败变质的贡献。方法 研究经抑菌处理及未经抑菌处理的罗非鱼片在冰温贮藏期间的菌落总数、挥发性盐基氮(totalvolatilebasicnitrogen,TVB-N)值、pH、硫代巴比妥酸(thiobarbituric acid, TBA)值及感官鲜度的变化,采用电子鼻监测挥发性成分的变化,并对未经抑菌处理罗非鱼片各指标与菌落总数间进行皮尔逊相关性分析。结果 贮藏期间经抑菌处理的样品的菌落总数始终小于5.05 log CFU/g, TVB-N值小于3.00 mg/100 g, pH及电子鼻测定的各种挥发性成分基本未变,未发生感官腐败,虽然TBA值有所增加(P<0.05),但始终低于0.05 mg MDA/100 g。而未经抑菌处理的罗非鱼片,菌落总数在21 d时达到9.19 log CFU/g, TVB-N值增至40.69 mg/100 g, pH由6.65增至7.63,电子鼻测定的氮氧化合物、硫化物及有机硫化物骤增, TBA值增至0.072 mg MDA/100 g,显著高于抑菌处理的样品,感官腐败明显。结论 冰温贮藏条件下内源...

Study on the contribution of endogenous chemical reaction and bacterial activity to the spoilage of Oreochromis mossambicu fillets under controlled freezing-point storage

Objective To evaluate the contribution of endogenous chemical reactions and bacterial activities to the quality deterioration of Oreochromis mossambicu fillets under controlled freezing-point storage. Methods The changes of total bacterial count, total volatile basic nitrogen (TVB-N) value, pH, thiobarbituric acid (TBA) value and sensory freshness of Oreochromis mossambicu fillets subjected or not subjected to bacteriostatic treatment during freezing-point storage were investigated, and the changes of volatile compounds were monitored by electronic nose. Pearson correlation analysis was carried out between the indexes and the total bacterial count of Oreochromis mossambicu fillets not subjected to antibiotic treatment. Results The results showed that during the storage, the total bacterial count of the samples subjected to bacteriostatic treatment kept less than 5.05 log CFU/g. TVB-N was less than 3.00 mg/100 g. The pH and various volatile compounds determined by electronic nose barely changed. No sensory spoilage occurred. TBA value increased to some extent (P<0.05), but remained below 0.05 mg MDA/100 g. However, in the samples not subjected to bacteriostatic treatment, after 21 days storage, the total bacterial count reached 9.19 log CFU/g, and TVB-N value increased to 40.69 mg/100 g. The pH changed from 6.65 to 7.63 and the volatile ingredients determined by electronic nose such as nitrogen oxides, sulfides and organic sulfides increased sharply. TBA value increased to 0.072 mg MDA/100 g, which was significantly higher than that of sample subjected to bacteriostatic treatment. Meanwhile, obvious sensory spoilage occurred. Conclusions The endogenous chemical reactions in Oreochromis mossambicu fillets only leads to some degree of lipid oxidation under controlled freezing-point storage, and the spoilage of Oreochromis mossambicu fillets are mainly caused by bacterial activities.