饲料中适宜含量铁对建鲤鱼糜冻藏品质变化及组织蛋白酶B/L的影响

Effect of iron supplement on the changes of Jian carp( cyprlnus carpio var Jian) surimi quality during frozen storage and cathepsin B/L

对经过不同铁含量的饲料(缺乏组53.9 mg/kg,适宜组146.1 mg/kg)饲喂90 d后的建鲤,取鱼肉加工为鱼糜,于-20℃条件下进行冻藏实验,取样点为0、1、2、4、6周,测定鱼糜冻藏品质指标的变化,包括Ca^(2+)-ATPase活性、总巯基、二硫键、表面疏水性、TBA值;鱼糜冻藏期间组织蛋白酶B、组织蛋白酶L活性采用荧光合成肽底物法进行测定。结果表明,适宜含量铁能极显著提高鱼糜肌动球蛋白初始Ca^(2+)-ATPase活性、总巯基含量(p<0.01),降低二硫键含量(0.01<p<0.05)、表面疏水性(p<0.01)及TBA值(p<0.01),且可延缓冻藏期间Ca^(2+)-ATPase活性、总巯基含量的下降,以及表面疏水性、二硫键含量的增大;冻藏6周后,缺乏组和适宜组TBA值分别上升264%、143%;适宜组组织蛋白酶B/L活性均低于缺乏组,且对组织蛋白酶L活性下降有一定促进作用,而对组织蛋白酶B作用不明显。综上所述,饲料中添加适宜含量铁能够减缓冻藏期间建鲤鱼糜蛋白质的变性,降低组织蛋白酶B/L活性残留,对提高鱼糜冻藏品质稳定性具有潜在的促进作用。

Jian carp （cyprlnus carpio var Jian） fed for 90 days were compared with different iron content （146 1 mg/kg and 53.9 mg/kg） in their diet. Fish meats were collected and processed into surimi. After frozen storage at -20℃, the sample was collected at 0, 1st, 2nd, 4th, 6th week respectively. Indexes including Ca2＋ -ATPase activity （CA） ,total sulfhydryl （TSH） content, disulfide bonds （DB） content, protein surface hydrophobicity （ PSH）, and thiobarbituric acid （TBA） value were detected. Meanwhile, the activities of Cathepsin B/L of Jian carp surimi were detected by fluorescent synthesis of peptide substrate method. The results indicated that the initial CA and TSH content in suitable group was improved extremely significantly （p 〈0.01）,while the initial DB content （0.01 〈p 〈0.05）, PSH and TBA value （p 〈 0.01 ） was decreased at different degree. In terms of surimi quality during frozen storage, higher iron diet group delayed the decline of CA and TSH content,and increase PSH and DB content. After storing for 6 weeks,TBA value of Jian carp surimi increased 264% in higher iron diet group and 143% in low iron content group. During the frozen storage, CAT B/L activities in higher iron group were lower, and CAT L activity was decrased. In conclusion,the higher dietary iron supplement could retard the denaturation of Jian carp surimi protein during frozen storage,and reduce the residual of CAT B/L activities, and has the potential in stabilizing the quality of surimi during the frozen storage.