凡纳滨对虾高鲜度期评定方法的建立

Establishment of evaluation methods of high freshness of Litopenaeus vannamei period

中文关键词:  凡纳滨对虾  腺苷三磷酸及其关联化合物  非蛋白氮  硬度值  高鲜度期

英文关键词:Litopenaeus vannamei  adenosine triphosphate-related compounds  non-protein nitrogen  hardness  high freshness period

中文摘要:

      目的 建立科学有效的虾类高鲜度期评定方法。方法 以凡纳滨对虾为研究对象, 检测其在4℃冷藏条件下感官指标、生化指标、核苷酸关联化合物、肌肉硬度值和菌落总数的变化, 筛选适宜评定高鲜度期的指标。结果 在4℃条件下, 感官评分确立的高鲜度期为36 h, 货架期为96 h; 经典的K值计算方法不适合指示虾的鲜度变化, 而修正K’更适合评定虾的虾的鲜度变化; 虾死后肌肉硬度值呈先上升后下降的趋势, 可根据肌肉硬度值是否显著低于死后初始水平大致判断原料是否处于高鲜度期, 但不宜根据硬度值判断货架期终点; 与挥发性盐基氮(total volatile basic nitrogen, TVB-N)相比, 非蛋白氮(non-protein nitrogen, NPN)更适宜用来评定虾类鲜度变化, 高鲜度期和货架期终点对应的NPN分别为0.94 g/100 g和1.21 g/100 g; 菌落总数的变化相对滞后, 不宜用来指示高鲜度期。结论 适宜用修正的K’值、肌肉硬度值、NPN值评定凡纳滨对虾高鲜度期。

英文摘要:

      Objective To establish a scientific and effective evaluation method of high freshness period of shrimp. Methods Taking Litopenaeus vannamei as the research object, the changes of sensory index, biochemical index, nucleotide related compounds, muscle hardness value and total bacterial count, were detected under 4℃ cold storage conditions, and the indicators suitable for evaluating the high freshness period were selected. Results The high freshness period established by the sensory score was 36 h and the shelf life was 96 h under the 4℃ cold storage. The classical K value calculation method was not suitable for indicating the freshness change of shrimp, and the modified K’ was more suitable for evaluating the freshness change of shrimp. The muscle hardness value of Litopenaeus vannamei showed a trend of rising followed by decreasing. The end of high freshness period could be judged when muscle hardness value was significantly lower than the initial level after death, but it was not suitable to judge the end of the shelf life. Compared with total volatile basic nitrogen (TVB-N), non-protein nitrogen (NPN) was more suitable for evaluating the freshness change. The corresponding NPNs at the end of the high freshness period and shelf life were 0.94 g/100 g and 1.21 g/100 g, respectively. The change of the total number of colonies was relatively lagging, which was not suitable for indicating the high freshness period. Conclusion Modified K’ value, muscle hardness values and NPN are suitable to assess the high freshness period of Litopenaeus vannamei.