冰鲜和解冻团头鲂在贮藏过程中导电特性变化规律研究

Electrical properties of fresh and frozen-thawed bluntsnout bream during storage

运用物理方法——伏安法测定不同频率下冰鲜和解冻团头鲂的阻抗,分析在不同贮藏条件下团头鲂阻抗的相对变化Q值的变化特点。结果表明:从1 kHz增大到20 kHz,冰鲜和解冻团头鲂的阻抗均随着频率的增大而减小,冰鲜团头鲂的阻抗相对变化Q值明显大于解冻团头鲂。冰鲜团头鲂的阻抗相对变化Q值在第1、3、6、8、10天分别为81.09%、46.35%、29.29%、34.59%、20.43%,而冷冻30 d后解冻团头鲂的Q值分别为16.19%、14.59%、10.30%、16.27%、10.10%。前6天冰鲜团头鲂的Q值下降幅度较大,之后Q值变化不明显,冷冻30 d后解冻团头鲂的Q值随解冻后贮藏时间的延长,无明显变化。以Q值20%为界限,快速鉴定冰鲜团头鲂和解冻团头鲂是可行的。

The study adopted voltmeter-ammeter method to measure the impedance of fresh and frozen-thawed bluntsnout bream under different frequencies during storage. Although impedances of both fresh and frozen-thawed bluntsnout bream decreased as frequencies increasing from 1 kHz to 20 kHz, change ratio of impedance （ Q value） of fresh samples was evidently higher than that of frozen-thawed ones. The Q value of fresh and frozen-thawed bluntsnout bream in the day of 1,3,6, 8, 10 were 81.09% , 46.35%, 29.29%, 34.59%, 20.43% and 16.19%, 14.59%, 10.30%, 16.27%, 10.10%, respectively. The Qvalue of flesh blnntsnout bream decreased greatly in the fist 6 days and became gentleness during the rest storage days. The Q value of thawing bluntsnout bream was not significant changes with the storage time increasing. It is feasible to identify unfrozen and frozen-thawed bluntsnout bream according to the change ratio of their impedance compared with 20%.