一种多金属氧酸盐对多酚氧化酶的抑制活性评价及在南美白对虾保鲜上的应用

Evaluation of inhibitory activity of a polyoxometallate on polyphenol oxidase and its application in the preservation of Litopenaeus vannamei

目的:研究新型多酚氧化酶抑制剂对南美白对虾的保鲜效果。方法:通过紫外和红外光谱表征合成的多酚氧化酶抑制剂H_(8)[P_(2)Mo_(17)Ni(OH_(2))O_(61)](P_(2)Mo_(17)Ni),研究其对蘑菇多酚氧化酶(PPO)相对酶活的影响及抑制机制和抑制类型;再测定经P_(2)Mo_(17)Ni处理后的南美白对虾在贮藏过程中的感官评分、色差(L*)值、总色差(ΔE)值、菌落总数、酸碱度(pH)值和总挥发性盐基氮(TVB-N)值的变化情况,评价P_(2)Mo_(17)Ni在南美白对虾保鲜上的作用。结果:P_(2)Mo_(17)Ni对体外蘑菇PPO的活性具有抑制作用,其半抑制浓度(IC_(50))为(0.377±0.004)mmol/L,且对PPO的抑制模式为竞争型可逆抑制,抑制常数K_(I)为0.185 mmol/L。在4℃冷藏条件下,与空白组相比,P_(2)Mo_(17)Ni处理能延缓对虾感官评分的下降和L*值、ΔE值的增加,抑制效果显著;且能显著延缓菌落总数、pH值和TVB-N值的增加,货架期可延长4~5 d。结论:P_(2)Mo_(17)Ni对南美白对虾具有良好的保鲜效果。

Objective:To design new and effective polyphenol oxidase(PPO)inhibitors and expand their application in the field of aquatic product preservation.Methods:The synthesized H 8[P_(2)Mo_(17)Ni(OH_(2))O_(61)](P_(2)Mo_(17)Ni)structure was characterized by ultraviolet and infrared spectrum.The inhibitory effect,type and mechanism of P_(2)Mo_(17)Ni on the relative activity of mushroom PPO in vitro was clarified.Then,the preservation effects of P_(2)Mo_(17)Ni on Litopenaeus vannamei Boone were evaluated through studying the index change of shrimps treated with P_(2)Mo_(17)Ni stored at 4℃,in which included the sensory score,the value of chromatic aberration L*,the value of total chromatic aberration(ΔE),the total number of colonies,the value of pH and the value of total volatile basic nitrogen(TVB-N).Results:The results showed that P_(2)Mo_(17)Ni was synthesized successfully.P_(2)Mo_(17)Ni inhibited the activity of PPO from mushroom in vitro with semi-inhibitory concentration(IC_(50))of(0.377±0.004)mmol/L.P 2 Mo 17 Ni inhibited mushroom PPO in a competitive reversible manner,and the inhibition constant K_(I)was 0.185 mmol/L.Under the cold storage condition of 4℃,compared with the control group,P_(2)Mo_(17)Ni could effectively delay the decline of sensory score and the increase of L*andΔE value in shrimps treated with P_(2)Mo_(17)Ni,and the inhibitory effect was significant.P 2 Mo 17 Ni could significantly inhibit the increase of total number of colonies,pH value and TVB-N value.P_(2)Mo_(17)Ni could extend the shelf life of shrimps for 4~5 days.Conclusion:P_(2)Mo_(17)Ni can slow down the blackening of shrimps and prevent its spoilage.P_(2)Mo_(17)Ni possesses a good preservation effect on L.vannamei and can be used in the preservation industry of aquatic products.