Optimization of DNA Extraction from Fish Oil Residuals Based on Magnetic Bead Method

As a high-value functional food, fish oil has a substantial market demand, yet adulteration issues are frequent. PCR-based detection of species-specific genes is currently the most direct and reliable molecular approach for identifying the source species and their relative abundance in fish oil adulteration analysis. The concentration and purity of DNA are critical for ensuring efficient amplification and accurate detection. Therefore, this study optimized the DNA extraction protocol from fish oil using magnetic bead-based methods by refining key parameters, including magnetic bead type, binding buffer composition, bead particle size, bead volume, binding buffer concentration, washing conditions, and elution conditions. The optimal extraction conditions were determined as follows: silica-coated OH-500 magnetic beads, a binding buffer containing 3 mol/L guanidine isothiocyanate, 50 µL of magnetic beads, 70% ethanol for washing, and elution in water at 56°C for 15 minutes. Compared to commercial kits, the optimized method improved DNA extraction efficiency by nearly 10% while demonstrating high reproducibility (CV < 5%). This refined protocol provides an efficient and reliable technical solution for DNA extraction from fish oil.