糖代谢关键酶活性指示的虾夷扇贝活品品质变化

Activities of key sugar metabolism enzymes refer to change in quality of live storaged yesso scallop Patinopecten yessoensis

为建立虾夷扇贝Patinopecten yessoensis活品的品质评价指标,以探讨捕后干露贮藏过程中闭壳肌能量物质和糖代谢关键酶活性的变化规律,将鲜活的虾夷扇贝在冰箱(4℃)中进行干露贮藏,监测贮藏过程中闭壳肌中的三磷酸腺苷(ATP)、糖原、磷酸精氨酸(ArP)含量,以及糖代谢主要阶段关键酶——磷酸果糖激酶(Phosphofructokinase,PFK)、Opines脱氢酶(Opine dehydrogenases,OpDHs)、柠檬酸合酶(Citrate(Si)synthase,CS)活性、丙酮酸和章鱼碱含量的变化。结果表明:在干露贮藏过程中随着扇贝活力降低,闭壳肌中ATP含量呈现逐渐下降趋势,0 d时的含量为3.88μmol/g,干露贮藏3 d时基本完全消耗(P<0.05);主要储能物质糖原在0 d时的含量为16.38 mg/g,干藏1 d时降为10.11 mg/g,从第2天开始由于代谢减弱,糖原含量变化较小;ArP含量在初始0 d时为3.66μmol/g,干露贮藏3 d后已经基本被完全消耗(P<0.05);在干露贮藏过程中糖原初步酵解产物丙酮酸及无氧糖酵解产物章鱼碱含量均有积累,该过程中PFK酶活力呈先升高后降低趋势;CS酶活力在0 d时较低且随干藏时间的延长逐渐降低;Opines脱氢酶中章鱼碱脱氢酶(Octopine dehydrogenase,ODH)活力最大,其活力在干露贮藏过程中呈上升趋势,在0 d时酶活力为1.74 U/mg,干露贮藏3 d时其上升为2.19 U/mg,说明干露贮藏条件下虾夷扇贝主要以无氧代谢为主。研究表明,章鱼碱脱氢酶具有成为评价活品虾夷扇贝品质指标的潜力。

Changes in contents of adenosine triphosphate(ATP),glycogen,and phosphate arginine in adductors,and contents of pyruvic acid and octopine and activities of the key enzymes in sugar metabolism including phosphofructokinase(PFK),opine dehydrogenases(OpDHs),and citrate synthase(CS)were monitored in fresh yesso scallop Patinopecten yessoensis stored in a refrigerator at 4℃air exposure 0,1,2,and 3 d after storage to establish the quality evaluation index of the live scallop products.It was found that the ATP content in the adductor was decreased gradually with weakening activity of the scallop during storage,with ATP content of 3.88μmol/g at 0 d,and almost complete exhaustion at 3 d(P<0.05).The glycogen(as main energy storage substance)content was shown to be 16.38 mg/g at 0 d,and decreased to 10.11 mg/g at 1 d,with little change due to weakened metabolism from the 2 nd day on.The initial arginine phosphate(ArP)content was 3.66μmol/g,which was almost completely consumed 3 days after storage(P<0.05),and the pyruvate and octopine were accumulated during storage process when the PFK activity was increased first and then decreased;the CS activity was very low at 0 d,and gradually decreased over time.There was the maximal activity of octopine dehydrogenase(ODH)in OpDHs,and increase during storage,i.e.1.74 U/mg at 0 d and 2.19 U/mg at 3 d,showing that the scallop are primarily anaerobic metabolism under dry conditions.The findings indicate that ODH has the potential to be an indicator for evaluation of the quality of live scallops.