虾夷扇贝易逝期干露处置与活品复水性

为探索捕后初期处置对虾夷扇贝活品品质的延迟效应,将捕后虾夷扇贝分易逝期及后易逝期两个阶段进行研究,分别模拟海上及陆基两个处置环节。易逝期处置条件为冷却干露,分别设置12、24及48 h 3个处理组,即E12、E24及E48;后易逝期处置是将经易逝期的活体扇贝重新置于海水中复水24 h,分别为E12’及E24’。以失重率、存活率、闭壳肌pH、糖原、ATP关联化合物、AEC值及超氧化物歧化酶(SOD)活性等为指标,对活品品质进行跟踪分析。结果显示:①易逝期干露处置的扇贝品质有不同程度下降,E48全部死亡;E12和E24具有100%的存活率,糖原含量在易逝期初期快速下降,由初始点的18.95降至12 h时的14.66 mg/g。②易逝期处置对后易逝期的扇贝活体有延迟效应,复水12 h内,体质量和糖原显著恢复,同时SOD活性显著下降,表明了应激状态的缓解;随着复水时间的延长,各项生化指标反映出活体再次进入应激状态时,E12’的活品货架期明显优于E24’。研究表明,扇贝从采捕至陆基暂养净化存在一个品质易逝期,易逝期处置对后易逝期的活品品质有延迟效应。经易逝期处置的扇贝可恢复,短时间12 h的易逝期处置更有助于扇贝恢复。有效控制易逝期条件参数,复水后活品可表现出很好的恢复性;易逝期胁迫程度越大,即便在易逝期结束时仍具有良好指标,但在后易逝期会呈现持续衰竭趋势,其活力、品质及活品货架期亦将会受影响。

Delayed influence of quality-determination-period emersion on the recovery of live scallop (Patinopecten yessoensis) re-immersed

To explore the delayed influence of post-harvest treatment on the quality change of live scallops, the experiment was performed in two post-harvest stages, including a quality determination period (QDP) corresponding to on-board handling and post quality determination period (P-QDP) corresponding to land-based treatment. There were three chilled-emersing treatments of different duration during the QDP: 12 h(E12), 24 h(E24) and 48 h(E48). In the P-QDP scallops are re-immersed into sea water for 24 h (E12''nd E24''). The quality of live scallops was measured by mass loss rate, survival rate, pH, glycogen content, ATP and ATP-related compounds, AEC value and SOD activity. The results show that the quality of QDP scallops declined in different degrees: E48 presented a 100% mortality and the survival rate in 24 h was 100%. Glycogen content declined sharply from 18.95 (Initial) to 14.66 mg/g (12 h). The QDP had a delayed influence on live scallop in the P-QDP: all indicators show E12'' and E24'' can recover temporarily but the shelf-life of E12'' is superior to E24''. The study shows that there is a quality determination period post-harvest during which the handling has delayed influence on the recovery of live scallop after re-immersing. The post-harvest scallops can be recovered and 12 h treatment in the QDP is helpful for recovery. If treatment conditions are effectively chosen during the QDP, live scallops would have better recovery after re-immersing, otherwise, if overstressed during the early post-harvest stage i.e. QDP, even if indicators are good by the end of the period, depletion would continue in the P-QDP, affecting vitality and shelf-life of live products.