凡纳滨对虾虾仁在冻藏过程中品质变化研究

以凡纳滨对虾（Penaeus vannamei）为研究对象,经过去头和去壳处理后,于-35℃冷冻过夜,然后置于-18℃条件下进行保藏试验。通过测定解冻损失率和肉色变化,明确冻藏期间虾肉的质量变化规律,结合腺苷三磷酸（ATP）及其降解产物、总挥发性盐基氮（TVB-N）和酸碱度（pH）等鲜度指标的测定结果,分析对虾在冻藏条件下鲜度的变化规律,旨在为其生产加工提供理论依据。研究结果表明,冷冻保藏至第18天时解冻损失率达到最大,同时表面色差（L^＊）也达到最大值41.56。而虾肌肉中的ATP质量摩尔浓度冻藏第1天就降低了71.78%,次黄嘌呤（Hx）和次黄嘌呤核苷（HxR）则一直维持在较低水平。第10天鲜度指标（K值）达到最大值7.18%,并能比较稳定地保持这一水平,结合TVB-N测定结果,发现冻藏至第30天时,虾肌肉中的TVB-N仍未超过腐败临界值。因此,冻藏处理可以保持凡纳滨对虾的鲜度,使各项理化指标维持在较低水平,但会加重解冻损失现象。

Study on Penaeus vannamei quality changes during frozen storage

In order to study the quality changes of Penaeus vannamei during frozen storage,the prawn samples were frozen at-35 ℃ for one night after being gutted and washed,and then stored at-18 ℃ for one month.We observed the thawing loss rate and chromatic aberration to study the weight change of prawn muscle,and observed ATP content and ATP-related compounds,total volatile basic nitrogen （TVB-N） content and pH value to evaluate the prawn′s freshness change,which provides theoretical reference for prawn production and processing.The results show that the thawing loss reaches a maximum value and the L^＊ value peaks to 41.56 when the prawns are stored at-18 ℃ for 18 d.However,the ATP content drops by 71.78% at the first day.Hx and HxR are always stable at low levels.At day 10,K value peaks to 7.18% and remains relatively stable till day 30.TVB-N determination shows that TVB-N content does not exceed the critica1 point of deterioration at day 30.Therefore,frozen storage can maintain P.vannamei freshness and keep each physiochemical index at a low level,but will increase the thawing loss.