| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2003: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
Since the retention of fish freshness is necessary for the production of good-quality products, the establishment of a simple, rapid, accurate and economical method for the determination of fish freshness is required in marine food industry. Various methods have been proposed to chemically determine the freshness of fish using volatile basic nitrogen, ammonia, polyamine and K value (the percentage of HxR and Hx in the total ATP-related compounds) as parameters. However postmortem changes of fish muscle are complicated. Therefore, it is difficult to determine fish freshness accurately by a single indicator as proposed.
We have developed the 5-channel biosensor system based on screen-printing electrode and SMO sensor system to evaluate fish freshness. The 5-channel biosensor system was assembled with five enzyme electrodes for the determination of K value, IMP, glutamate, lactic acid and glucose. Good comparative results were observed between there components in fish muscle determined by the 5-channel biosensor system and the conventional methods. The SMO sensor system consists of three semiconducting metal-oxide(SMO) sensors with various sensitivities. The sensors showed characteristic responses for dimethylamine, trimethylamine, volatile acidic compounds and aldehydes that are assumed to be fish degradation products. Viable counts of total bacteria and K value provided results that correlated well with SMO sensor results. These sensor systems were applied to the estimation of fish freshness of flatfish, skipjack, horse mackerel, yellow fin tuna and striped pigfish. The deterioration offish quality with storage time could be identified by a method of principal component analysis using the SMO sensor responses, the components in fish muscle determined by the 5-channel biosensor system and viable counts of total bacteria. The contribution rates to the first principal component and the second principal component were 50.61% and 29.91%, respectively.
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