Development of a biosensor for assaying postmortem nucleotide degradation in fish tissues

Area of Science:

• Biotechnology
• Food Science
• Analytical Chemistry

Background:

• Assessing fish freshness is crucial for food safety and quality control.
• The K value, a biochemical indicator, is widely used to quantify fish spoilage.
• Existing methods for K value determination can be time-consuming and complex.

Purpose of the Study:

• To develop a novel enzyme sensor system for rapid and accurate fish freshness assessment.
• To measure the K value, defined as the ratio of [hypoxanthine + inosine] to [hypoxanthine + inosine + inosine-5'-monophosphate].
• To validate the performance of the developed sensor against conventional methods.

Main Methods:

• Immobilization of enzymes (nucleoside phosphorylase, xanthine oxidase, nucleotidase) onto a nylon membrane and polystyrene tube.
• Development of a polarographic electrode for amperometric detection of degradation products (hydrogen peroxide, uric acid).
• Measurement of [hypoxanthine + inosine] and subsequent conversion of inosine-5'-monophosphate to inosine for total K value calculation.

Main Results:

• The enzyme sensor system demonstrated excellent reproducibility for at least 40 assays.
• Immobilized enzymes showed high stability over multiple uses.
• The K value determination using the sensor took approximately 10 minutes per sample.
• Results from the sensor system closely correlated with those from the conventional enzymatic method.

Conclusions:

• The developed enzyme sensor system offers a rapid, reliable, and reproducible method for assessing fish freshness.
• This technology has the potential to improve quality control in the fish industry.
• The sensor provides a viable alternative to traditional, more laborious K value determination techniques.