Research On Regulated Patinopecten Yessoensis Quality Mechanism Of ROS Induced Endogenous Enzyme During Low-temperature Cooking

Patinopecten yessoensis(P.yessoensis)is advocate scallops in LiaoNing,because of its taste,rich in protein,phosphorus,calcium,iron,iodine and a variety of vitamins and other nutrients and widely popular among consumers.Heat treatment in the process of eating is a common way to processing P.yessoensis but under the high temperature heat treatment,in P.yessoensis there will be a great hardness,the phenomenon of dark yellow color,affect beautiful appetite and eat taste.To improve the quality of P.yessoensis,adductor muscle of P.yessoensis was as the research object,two aspects were studied.On the one hand,study on quality and physicochemical properties of adductor muscle was on heating different time at 55 ?(1/6,1/2,1,2,4,6,12,18,21,24,27,30,32h),through the chemical method for the determination of cooking loss,low field NMR determination of moisture distribution and texture analyzer determination of texture and color,to inspects the quality of adductor muscle changes,the spectrophotometric method for the analysis of caspase-3 and cathepsin L activity,gel electrophoresis explain protein degradation,for explaining why the quality change,ESR determination of reactive oxygen species(ROS)generation at low temperature long time for 55 ?;Determination of carbonyl content of chemical method and determination of thiol content,to illustrate the extent of protein oxidation;Test kit determination of MDA content to illustrate the extent of lipid oxidation;The activity of antioxidant enzymes,including superoxide dismutase,glutathione peroxidase and catalase,was determined by the test kit,to explain the occurrence of oxidative stress.On the other hand,adductor muscle was on heating different time at 45? and 65?(1/6,1/2,1,2,4,6,12,18,21,24,27,30,32h),The changes of all the above indexes were compared.The results showed that adductor muscle of P.yessoensis at 55? low temperature long time treatment,as the treatment time increasing,cooking loss increased,at 32h reached the maximum is 33.29±8.37%;Color and the texture changed.Low temperature long time treatment,the quality of adductor muscle changed.Myosin degradation obviously;The activity of CL showed a rising trend at 24h reached 89.67±8.68U/mg protein;The activity of caspase-3 increased in 30h,reached of 8.33±0.88U/mg protein;Protein oxidation significantly;carbonyl content increased at 27h up to a maximum of 2.15±0.28nmol/mg protein;Thiol content decreased at 12h reached the minimum value of 135.09±11.96nmol/mg protein.The MDA content in 27h reached a maximum of 1.90±0.09nmol/mg protein;The generation of lipid free radicals showed an increasing trend in the 32h reaches the maximum value of(18.98±0.19)×105;The antioxidant enzyme activity decreased with the low temperature treatment.The adductor muscle of P.yessoensis s at 45 ? and 65 ? low temperature long time treatment,as the treatment time increasing,cooking loss were higher at 65 ? than 45?,at 65? in 21h cooking loss rate reaches the maximum value is 33.11 ± 14.43%,14.08±3.26%at45 ?;Water content decrease,water content was lower at 65 ? than at 45?,at 45 ? water content reached the lowest value of 312.14±4.62g-1 in 32h,and 65? water content reached the lowest value of 265.28±3.77g-1 in 21h.The higher low temperature long time treatment of adductor muscle,adductor muscle was more yellow and changed more obvious.At 65 ?electrophoresis of protein degradation is more serious than 45 ?;The activity of CL at 65 ?was higher than at 45 ?.At 65 ?CL activity in 32h reached a maximum value of 79.06±1.53U/mg protein;At 45? the CL activity was 57.09±1.57U/mg protein in 32h;At 45? caspase-3 activity reached a maximum value of 1.01±0.11U/mg protein in 21h;At 65 ?caspase-3 activity had been inactivation.The carbonyl content at 65?was higher than 45?,at 65 ? carbonyl content reached the maximum at 27h 2.45±0.22nmol/mg protein,at 45 ?carbonyl content was at 27h 1.79±0.08nmol/mg protein;Thiol content was lower at 65 ? than at 45?,at 65? thiol content dropped to 72.36±3.90nmol/mg protein in 12h;At 45? thiol content reached the lowest value of 151.68±10.79nmol/mg protein in 12h.It can be seen that at 65 ?,protein oxidation of adductor muscle occurrence more sharply than at 45 ?.At 45 ?the MDA content is lower than at 65 ?;At 65 ? MDA content reached the maximum at 21h 1.66±0.30nmol/mg protein,at 45 ? MDA content was at 27h 1.21 ±0.09nmol/mg protein.It can be seen that at 65?,lipid oxidation of adductor muscle occurrence more sharply than at 45 ?.In 65? as the treatment time increasing,lipid production of lipid free radical in 27h reached a maximum of(27.36±0.08)×105,and 45 ? reached the maximum value of(6.47×0.56)×105 in 24h.With low temperature long time treatment,antioxidant enzyme decreased.The antioxidant enzyme at 65? was lower than at 45?;The basic signal pathway of adductor muscle by low temperature long time heat treatment were as followed:protein oxidation(carbonyl and-SH)and lipid oxidation(MDA),oxidative stress,and a large number of O2·-generated were caused by low temperature long time heat treatment in adductor muscle.A part of O2·-generated by low temperature long time heat treatment in adductor muscle turned into H2O and O2 by superoxide dismutase,catalase and glutathione peroxidase.A part of H2O2 turned into OH·.But the large number of ROS including O2·-,OH· and H2O2 also damaged these antioxidant enzyme and reduced the elimination rate of ROS.Accumulated ROS further activated downstream proteolytic enzymes such as caspase-3 and cathepsin L.Activated cathepsin L accelerated structural protein hydrolysis,protein degradation lead to changes in texture,cooking loss and color.Lastly,they resulted in a quality change of adductor muscle.The higher temperature,each index changed more obvious.Through studying the basic signal pathway of adductor muscle uality changed by low temperature long time heat treatment,determine the relationship of the signal between each other,and lay a theoretical foundation to reveal the mechanism of the quality control in P.yessoensis by low temperature long time curing.At the same time,enrich the mechanism of a quality change of seafood by low temperature long time heat treatment.